Welcome to day one of the 2021 ACMG Annual Clinical Genetics Meeting. I'm Cara Moore and I'll be serving as your MC throughout the week. I'll be highlighting what to expect each day or let you know when something important is coming up. On behalf of the ACMG leadership and staff, I welcome you to this virtual experience. Today we'll begin with two short courses that will be held 12 p.m. to 5 p.m. To view the broadcast of each, simply click on the join session button in the listing of each session you want to attend. Other sessions being held this afternoon will include the first trainee mentor session, the student workshop, careers in medical genetics, the young professionals session, early career job hunt and transition success, and a workshop on genomic informatics. At 7 p.m., all trainees, postdocs, residents, and students are invited to attend the networking reception. Learn more about the important role that ACMG can play in your future and meet many of the ACMG leaders. Hello, welcome to the short course on syndromic and non-syndromic obesity. Dr. Slovotnik and myself are the moderators of this session. I think there's been an increasing amount of information related to the etiologies and treatments for both non-syndromic and syndromic obesity conditions, and personally, it's impacted my clinical practice over the past several years, so I think this is a very timely topic. We'll have presentations from leaders of the field in obesity and plenty of time for discussion and ability to answer questions from the audience, so please put in any questions that you have in the question and answer section, and given the length of the course, we'll also be having a 20-minute break after our third speaker. I'd like to first introduce Dr. Kim Kepler-Norell, and she's the Division Chief for Genetics and Metabolism at the University of Wisconsin School of Medicine, and she'll be giving our first presentation. And just to say thank you and welcome, I have no disclosures. And I do have a disclosure. I am a site PI for a clinical trial with Soleno on DCCR and Prader-Willi syndrome. And as Dave said, we would welcome questions and discussion, so I think we're ready for the first video. Thank you for the opportunity to present on clinical presentation and management of syndromic obesity. I have no financial disclosures. The objectives for my talk today are to define the causes of obesity, to formulate an approach for genetics evaluation, to distinguish between syndromic and nonsyndromic obesity, and to be familiar with the clinical findings and common syndromes that include obesity. Obesity can be defined in children as a BMI for age and sex at or above the 95th centile. In adults, it is defined as weight above the 99th percentile or significant height weight discrepancy with BMI greater than 30. Obesity for this talk includes truncal obesity and is typically characterized by early onset severe obesity. The causes can be categorized into primary, where there is no specific cause identified, idiopathic, and usually is multifactorial, arising from an interaction between genetic factors and a number of non-genetic factors with a heritability estimate of 40 to 70%. It's very common in the general population. For a clinical genetics evaluation, secondary obesity may be categorized as either monogenic, in which obesity is an isolated finding caused by a single gene variant that is involved in pathways that regulate energy intake and expenditure, or syndromic, in which obesity occurs as a manifestation in a broader syndrome. This algorithm provides an overview of the approach to evaluation of obesity, early onset severe, and I will discuss each of the components of the algorithm in the following slides. As you can see, it includes understanding of the definition of obesity, focusing on history and exam with key questions and findings, and testing, which is considered in all forms of obesity or causes as shown here. History includes getting a three-generation pedigree with height and weight of the parents and siblings to determine if this is knowable or heritable, pregnancy and perinatal history with birth weight, length, and head circumference to determine if obesity started at birth or occurred later, detailed feeding history in infancy, for example, poor feeding and hypotonia in the first year would point to Prader-Willi syndrome. When did the abnormal weight begin? In infancy, toddler age, pubertal onset, rate of progression. Each of these different onsets is associated with different syndromes, as we'll discuss. Is appetite affected? Is there impaired satiety or food scaling? This can be seen in Prader-Willi syndrome, as well as other syndromes, including 1P36 deletion, which we'll discuss. Detailed developmental and behavioral profile is important because these are unique to certain syndromes, as well as vision assessment. Is there night blindness or loss of central vision seen in retinal dystrophies associated with some of the syndromes we'll discuss? Hearing assessment, is there hearing loss, sensorineural, or conductive, which is characteristic of other syndromes? In the physical examination, growth parameters, height, weight, and head circumference, of course, are important, as well as the distribution of obesity. Truncal obesity is more common in Prader-Willi, Bardet-Beetle syndrome, Ahlstrom, and Cohen syndromes, as opposed to generalized obesity. Are there dysmorphic features, and do they point to a specific syndrome? Hand findings, like small hands, short fingers, particularly short fourth and fifth fingers or toes, as well as polydactyly and syndiactyly, are seen in different syndromes that we'll discuss. Is there foci of calcification in the skin, more commonly seen in Albright hereditary osteodystrophy? Is there genital abnormalities, like hypogonadism, seen in multiple syndromes? Further, cardiovascular abnormalities, are they present? And it's important to do eye exam with dilated retinal and visual fields. Acanthosis in Igricans is indicative of insulin resistance, seen in Ahlstrom and some of the other syndromes. Testing to consider in obesity with or without developmental delay includes thyroid function studies, calcium, phosphorus, and BTH in Albright hereditary osteodystrophy, as well as these other endocrine tests, including growth hormone testing, glucose insulin, leptin, cortisol lipid profile, and hemoglobin A1c. Tests used to diagnose genetic and hormonal disorders in obese children are reflected in this table and include those that I've just discussed, as well as their associated disorders and the result that's expected when there is exogenous obesity compared to syndromic obesity. And we'll review some of these findings in discussion of these disorders. Obesity with early onset and being severe without developmental delay warrants pediatric endocrine referral. After pediatric endocrinology evaluation with testing that I've just described, we consider monogenic causes for early onset severe, mostly isolated obesity without developmental delay. These result from single gene mutations and will be discussed in detail in other talks in the session. Some are listed here. They arise from defects in proteins that act in the hypothalamus to control food intake and energy expenditure in which children develop severe hyperphagia leading to weight gain in the first year of life. Genetic testing for these disorders includes targeted single testing as well as non-syndromic monogenic obesity panels. Characteristic findings in hormonal disorders associated with increased weight gain include These distinctive findings shown as an example to focus on microphallus, neonatal hypoglycemia, and giant cell hepatitis. These can be seen in growth hormone deficiency and hypopituitarism, whereas additional findings like striae or muscle wasting could be seen in Cushing's syndrome. Defects of monogenic disorders with infantile obesity and hyperphagia can include tall stature as opposed to short stature more common in syndromic forms. This is characteristic of MC4R deficiency, for instance. Adrenal crisis is more common in POMC deficiency. In contrast to monogenic disorders, the development of obesity and syndromic conditions typically occurs after infancy. In addition, individuals usually have developmental delay or cognitive impairments with anomalies. Diagnostic evaluations to consider include ophthalmology evaluation for dilated exam is suspicious for retinitis pigmentosa or ERG, hand x-rays, renal ultrasound, and referral to pediatric neurology and endocrinology. We would consider referral to neurology and brain imaging if there is developmental delays, seizures, or other neurologic problems. Genetic testing depends on the clinical findings in the differential diagnosis and may include one or more of these evaluations in the workup. Or there may be both studies that are done at the initial evaluation, depending on the specific diagnosis under consideration. Therefore, syndromic obesity is distinguished from primary and monogenic obesity by age of onset, distribution of fat, and by presence of additional associated anomalies, as well as the presence of variable cognitive disabilities and neurobehavioral findings. Many syndromes have overlapping phenotypes, which may indicate shared pathogenic mechanisms. The clinical assessment of syndromic obesity includes evaluation for associated anomalies. It's possible to assess for the presence of absence of a given anomaly directly for existence. For example, the presence of polydactyly and Bardet-Beetle syndrome, but may also rely upon findings from other specialists, for example, ophthalmology evaluation for retinal dystrophies in BBS, Ahlstrom, or Cohen syndromes. Syndromes are typically characterized by multi-system involvement, and may involve any organ system. However, anomalies of the CNS, ocular, cardiovascular, renal, skeleton, and endocrine systems occur most commonly of its manifestations. And this table summarizes those and the characteristic associated findings, along with the evaluations recommended. I will review the findings of highlighted syndromes because of the relationship between them and obesity is well established. Some are relatively common, as you can see from their associated estimated prevalences. Although there are more common syndromes in which obesity may occur, for example, Down syndrome, Fragile X syndrome, or achondroplasia, obesity is unlikely to be the presenting sign. So let's discuss Albright Hereditary Osteodystrophy. It's in the disorders of GNAS gene inactivation, and includes phenotypes including Pseudohypoparathyroidism PHP1A, 1B, 1C, and Pseudosudohypoparathyroidism, or PPHP, or progressive osseous heteroplasia in addition to Albright Hereditary Osteodystrophy. And organ resistance to endocrine hormones, including parathyroid hormone, thyroid stimulating hormone, LH, FSH, GH, RH, and CNS neurotransmitters lead to obesity and intellectual disability. In 1B, PHP, there is partial TSH deficiency and a mild Albright Hereditary Osteodystrophy phenotype. Pseudosudohypoparathyroidism is distinguished by the presence of an AHO phenotype without obesity or hormone resistance. Therefore, the cardinal clinical features of Albright Hereditary Osteodystrophy include developmental delay, round face, short stature, brachydactyly type E, which includes short 4th and or 5th metacarpals and metatarsals, and distal phalanx of the thumb, subcutaneous ossifications in some, and obesity. This photo collage shows those findings I've described, including the brachydactyly type E with shortening of the 4th and or 5th fingers, x-rays that show shortening of the 4th and or 5th metacarpals, as well as the dimple sign or archbulk sign when a person forms a fist with the 4th knuckle being depressed, and the presence of subcutaneous calcifications as shown here. Albright Hereditary Osteodystrophy, again, is an autosomal disorder of GNAS, gene lack of expression or function, and it can be caused by several mechanisms, including inactivating GNAS, pathogenic variants, genetic alteration, and imprinting regulatory elements in the complex that's shown to the right, preventing maternal imprint of a complex, uniparental paternal 20q diazome, and isolated epimutations. Prevention of Albright Hereditary Osteodystrophy is dependent upon what features are present. I focused on the obesity and metabolic issues. We suspect PHP1A with early onset obesity, and also PHP1B. Obesity tends to be less impressive in adulthood. Dietary management and exercise is recommended, although decreased resting energy expenditure makes obesity difficult to control. There also are complications of obesity, including metabolic syndrome and obstructive or central sleep apnea, which require evaluation and treatment. Other complications include endocrine abnormalities, short stature, and brachydactyly, as well as neurocognitive problems, as mentioned. Now, moving on to Ahlstrom's Syndrome, clinical findings that suggest diagnosis include cone rod dystrophy with decreased vision and secondary nystagmus and photodysphoria, usually within the first year of life. Full field ERG is required to diagnose cone rod dystrophy. Early childhood onset obesity, primarily truncal, with a body mass index greater than 25 for adults or greater than the 95th percentile, is found. Restrictive bilateral sensorineural hearing loss, usually initially in the high frequency range, is diagnosed between 1 and 10 years of age. Acute infantile onset cardiomyopathy and or adolescent or adult onset restrictive cardiomyopathy is a frequent finding and helpful towards the diagnosis. Normal stature or short stature in adulthood can be present. Hypogonadism is common. Other complications include urologic dysfunction, progressive decrease in renal function, hepatic disease, hypertriglyceridemia, hypertension, and alopecia. This photo shows typical clinical finding with central obesity in small hands and feet. This slide shows diagnosis by age of onset for Ahlstrom's Syndrome, and there are key major and minor findings, but I highlighted the obesity which occurs, as mentioned, between birth and five years of age and is present in all individuals. The genetic cause of Ahlstrom's Syndrome is biallelic ALMS1 pathogenic variants, which on gene sequencing and deletion duplication analysis identify this mutation in 90 to 95% of individuals. It is caused by loss of function of the protein ALMS1, which is implicated in cilia formation and maintenance, but also has non-ciliary functions. There's clinical overlap with other ciliopathies, including Bardet-Beetle Syndrome. Management of Ahlstrom's Syndrome of the most frequently affected systems is shown here, and treatment is similar to those issues in the general population, and we've discussed some of those already. Moving on to Bardet-Beetle Syndrome, the clinical diagnostic criteria include the presence of either four major or three major and two minor features. The most common feature and diagnostic is the retinal conrod dystrophy in 94%, and it's often the presenting sign with symptoms in the first year of life. Internal obesity occurs in 89%, but birth weight is usually normal. Post-axial polydactyly, cognitive impairment, hypogonadism, and GU abnormalities, as well as kidney disease are major findings. Minor findings include variations of these, as well as olfactory dysfunction with anosmia or hyposmia. Molecular abnormalities, GI, and endocrine abnormalities are frequent features. These photos show the typical findings of BBS with obesity. The facial features can be subtle, including deep-set eyes, hypertelorism, downslanting palpabrial fissures, flat nasal bridge, small mouth, retrognathia, high arch palate, and the brachydactyly with evidence in this child of surgical removal of the post-axial polydactyly and fundoscopy exams showing the rod cone dystrophy. The genetic cause of Bardet-Beetle is extremely heterogeneous with 21 known genes identified. Autosomal recessive biallelic variants cause this disorder and account for about 80% of affected individuals. The most common mutations are BBS1 and BBS10 that occur in 15 to 25% of individuals, most commonly in Europeans. BBS2, 6, 9, and 12 are seen in 5 to 10%, and the others are much less frequent and associated with allelic disorders. There are founder effects in different populations, including French-Canadian and Arab groups with higher prevalence in the range of 1 in 13,000 shown above, compared to 160,000 in the general population. These genes play a role in cilia formation, stability, and function as shown in the diagram of a primary cilia. Assessment for those who meet full clinical criteria is shown on the left here with annual assessments of weight, blood pressure, renal, thyroid, liver function tests, ophthalmology, and endocrine evaluation. ERG is recommended after age 5 years. It is important when BBS is suspected, as on the right, to consider the differential diagnosis, which includes Ahlstrom syndrome as well as other ciliopathies. Here I've outlined evaluation and management of the common complications. Obesity is managed with reduced calorie diet and restricted carbohydrates, as well as exercise. Metabolic syndrome and other obesity-related complications are treated like that in the general population. Cohen's syndrome has cardinal features, and if an individual has six or more of the eight features, then this supports a clinical diagnosis. These include truncal obesity with slender extremities, retinal dystrophy and high myopia, microcephaly, developmental delay, joint hypermobility, characteristic facial gestalt as we'll see, overly sociable or friendly behavior, and neutropenia. Additional findings include small or narrow hands and feet, as well as intellectual disability, and global developmental delays, as well as hypotonia. These photos show typical features with thick hair, eyebrows and eyelashes, wave-shaped, downward-slanting palpebral fissures, short upturned philtrum, maxillary hypoplasia, and the appearance of prominent central incisors. In the adult, as shown in this feature, they often have a grimacing appearance with smiling. They have long slender fingers and narrow feet, as shown, as well as joint hypermobility. Cohen syndrome is one of the more commonly underdiagnosed syndromes, occurring in about 0.7% of a thousand individuals with developmental delay or ID. The obesity and endocrine characteristics include failure to thrive in infancy and early childhood. Truncal obesity occurs with onset usually around 11 years, but between 8 to 14 and a half years, where there's a rapid change in weight that occurs over 4 to 6 months. BMI is typically in the range of 20 to 30. They don't have significant hyperphagia and may have short stature and delayed puberty. The genetic etiology is due to VPS13B or COH1 variants on chromosome 8q22 to q3, through common founder mutations in the Finnish, Amish, Irish communities and Greek islands, inherited as an autosomal recessive disorder. Molecular genetic testing and variant detection identifies abnormalities or mutations in about 70% in the general population, with higher detection rates in old order Amish and Finnish populations. This gene has a role in intracellular vesicle mediating sorting and transport of proteins and in the Golgi structure and function. Management is based on the clinical findings and it's important to evaluate for these common features as well as treat those as they develop. I focus on obesity, which as mentioned is mostly truncal and treated with dietary changes and exercise. Ophthalmology is important to do detailed eye exam and ERG to screen for the retinopathy. And importantly, neutropenia distinctive finding rarely needs treatment and is just monitored. Now I'd like to highlight the chromosome disorders 1p36 to q37 and maternal UPD14. I also mentioned a newly identified disorder called 16p11.2 deletion, which will be discussed in more detail in an upcoming talk in this session. 1p36 deletion syndrome has major clinical findings including distinct facial features, large anterior fontanelle, intellectual disability, hypotonia, brachy-campodactyly, brain abnormalities, congenital heart defects and seizures. Obesity occurs in about 25 to 50% of individuals associated with hyperphagia. Individuals can also have other complications including sensory neural hearing loss, hypogonadism and behavior problems. This photo shows typical craniofacial features including straight eyebrows, deep set eyes, mid-face hypoplasia, broad nasal root or bridge, long philtrum, pointed chin and microbrachycephaly. They have low set ears as well. All cases are caused by de novo deletions of the distal tip of chromosome 1p as shown from the karyotype on the right. Management is based on clinical findings as in the other syndromes with obesity and hyperphagia managed by caloric intake and behavioral management techniques. It's important to screen for other common associations as mentioned here. 2q37 deletion is also known as BDMR or brachydactyly mental retardation syndrome and has characteristic clinical features including mild to moderate developmental delay or an intellectual disability, brachydactyly of digits 3 through 5, a type e similar to that seen in albright hereditary osteodystrophy, short stature and obesity in 34% of individuals. They also have hypertonia, around dysmorphic features as shown here and autistic features, joint hypermobility, scoliosis. They have a distinctive feature of normal endocrine function which distinguishes it from other diagnoses that we've discussed and will discuss in the differential diagnosis albright hereditary osteodystrophy and smith-mcginnis syndrome. It is caused by a deletion of chromosome 2q37 as shown on the right or haploinsufficiency of the HDAC4 gene which encodes histone deacetylase 4 protein. This gene has a role possibly in downstream gene expression and regulation of RAI1 which is the gene variant causing smith-mcginnis syndrome. It also has been found in some studies to down be down regulated in obese individuals and may have a role in appetite regulation. Maternal uniparental diazomic chromosome 14 or temple syndrome has clinical features of prematurity and uterine growth restriction, neonatal hypotonia and mild truncal obesity. Also seen are short stature, small hands and feet, developmental delay and similar findings to Prader-Willi syndrome. It has a unique finding of precocious puberty when comparing to the other diagnoses in the differential. MEG3 the gene involved in the 2q in maternal uniparental diazomic chromosome 14 can be tested for methylation to identify this syndrome. This table compares 5 cases reported by Hosaki compared to other studies and different mechanisms and you can see that obesity occurs in almost 50% of those patients. Prader-Willi syndrome will be discussed in more detail including management and treatments by Dr. Miller later in the session. Cardinal clinical features are well known including subtle craniofacial anomalies with round faces, epicanthal folds, hypotonic faces and almond shaped eyes. Individuals have infantile hypotonia and intellectual disabilities of varying degree, hypogonadism and behavior problems including hyperphagia leading to obesity. The mechanism for causing Prader-Willi syndrome is well known as well. It involves loss of function or absence of 15q11.2 to q13 with three main causative mechanisms. The most common is maternal deletion in 70%, maternal uniparental diazomy 15 and or an imprinting defect. It is diagnosed in greater than 99% of individuals by DNA methylation analysis. Management in childhood and later adolescence, adulthood include management of feeding, hyperphagia and obesity, well-balanced low calorie diet, exercise and close supervision to minimize food stealing is important. Calorie needs approach 60 to 80% of the RDA. Growth hormone is used to normalize height and it also increases lean body mass and decreases fat mass. Education and behavioral management are key for this management of the hyperphagia and obesity and management of complications of obesity such as metabolic syndrome, hyperlipidemia, etc. Hypogonadism is common. Behavioral management for skin picking and sleep issues is also important. Finally, Smith-McGinnis syndrome has clinical findings in 50 to 75% of characteristic craniofacial features which I'll describe, obesity which is truncal and occurs usually after age 10 years, broad short hands, hypotonia and distinctive behavioral issues with inverse sleep pattern or disorder, self-injuries behaviors, hyperactivity and stereotypic behaviors. Hearing loss occurs in 79%, short stature and other findings are common as well. These photos show appearance from infancy to adolescence. In infants, brachycephaly, broad forehead, upslanting palpebrial fissures, short upturned nose, downturned tent-shaped for a million border or upper lip are common. School age, they have broad forehead, deep set eyes and mid-face retrusion and then in the adolescence, continued short philtrum and relative prognathism because of the mid-face retrusion and downturned upper lip as seen in the girl on the right. It is caused by either 17p11.2 deletion including RAI1 and commonly is in the range of 3.7 megabases or it's caused by an RAI1 heterozygous pathogenic variant. This has a role in neural crest migration and development and in circadian rhythmicity. The diagnosis is made in the majority of patients as seen by chromosome microarray analysis and the identification of the RAI1 gene by sequence analysis is abnormal in five to ten percent. Management is based on the common complications including neurologic with epilepsy management and followed by neurology, developmental and speech and language delays as well as management with drugs and counseling for behavioral and psychiatric disorders and sleep disorders. Obesity is treated as in the general population with dietary changes and exercise. This table summarizes and compares the findings of the selected obesity just syndromes described in this talk and all have obesity having differing ages of onset as well as distribution that can be seen. Most had hypotonia, short stature and many had failure to thrive in infancy. Microcephaly was unique to colon and 1p36 deletion. Each have unique craniofacial features but some have overlapping facial features that would indicate distinguishing by other associated findings. Retinal dystrophies occur in alstroem, VBS and colon only. Sensory neural hearing loss in alstroem, VBS and 1p36. Cardiomyopathy is unique to alstroem syndrome although it is less frequent finding in 1p36 along with congenital heart defects. And renal cysts or function abnormalities in alstroem and VBS are common. In summary, distinguishing between the different causes of obesity by history and exam is extremely important. Syndromic forms of obesity have many overlapping but some distinctive features. Testing for endocrinologic disorders as well as other monogenic isolated causes is important for individuals especially who have early onset severe obesity. Genetic testing plays an important role in all these causes of obesity. Clinical differential diagnosis guides the specific testing with chromosome microarray and or methylation testing for Prader-Willi or maternal UPD-14. Single gene sequencing can be done if a diagnosis is highly suspected and there are also monogenic obesity panels that are useful if it is diagnosis is overlapping with many diagnoses rather than one specific one. I'd like to acknowledge my colleagues studying these disorders and to the organizers and other presenters of this session. Thank you. So thank you, Kim, for a wonderful presentation on the syndromic causes that can be associated with obesity. It was very comprehensive and very informative. So I'd like to open the session up for questions now and I think you can see that we've got our panel of speakers present. So the first question from the audience is from Dr. Hua Huang and he asks if cardiomyopathy is a common complication in Bardet-Beetle syndrome. Dilated cardiomyopathy has been reported rarely. However, when you have a patient with infantile cardiomyopathy, it's going to think about the diagnosis of Alstrom's syndrome within the differential, the other ciliopathy. There can be congenital heart defects, laterality defects have been reported. In one retrospective study, it was reported that about 1.6% of individuals had laterality disorders, defects with associated congenital heart defects. Thank you. And so the next question is from Dr. Collette DeFilippo and she asks, as you mentioned, growth hormone therapy has been helpful in Prader-Willi syndrome in terms of increasing lean body mass, increasing height, helping with weight to height ratio and decreasing fat mass. Has growth hormone therapy been studied or found to be helpful in any of the other obesity syndromes, especially short stature conditions like Cohen syndrome? I don't have specific information about recently available studies, but I think part of the evaluation for these conditions should include endocrinologic studies, including evaluating for growth hormone deficiency. And based on the age and clinical presentation, if there was growth hormone deficiency, then they probably would benefit from intervention. Question about whether if they are growth hormone deficient, whether growth hormone would be helpful. I don't know any of that information in terms of the specific syndromes, other than Prader-Willi syndrome, which Dr. Miller will discuss later. Great, thank you. And then a question from Dr. Michael Gambello. Has anyone identified any molecular pathways that might link some of these CNV obesity syndromes, so the ones associated with copy number variants? Not sure if anyone from the panel can help out. I think we're going to discuss a few of those during my lecture a little bit later, where we try to put together how individual copy number variations and the associated critical gene within them has been linked to signaling pathways associated with obesity. So stay tuned. Great, thank you. I think that's very helpful. And then some more questions on clinical aspects from Dr. Vicky Stephens. Is there anything helpful for the sleep and circadian rhythm disturbance in Smith-McGinnis? It can be one of the most troublesome symptoms. I alluded to that in the summary. I know there was a lot of information there, but they do utilize melatonin for that, and the dose can be titrated up to three milligrams per day. Also, there are some other medications that can be helpful that I discussed in the talk as well, that are based on the presence of other behavioral issues that might be present. Great, OK. And then there's several questions that are kind of linked towards the approach. So the first of those is from Dr. Robert Best. To what extent does knowing a specific genetic etiology guide therapeutic approach in non-syndromic obesity? And also, a little bit further on, there's also a question about, would you consider whole exome sequencing as a first tier, second tier, or only for other multiple congenital malformations in your typical testing approach? That question is from Dr. Theodore Wilson. So talking about therapeutics and also just testing strategies. I think testing strategy depends on the clinical presentation. If somebody fits, if a patient fits with the clinical findings that are well described within the syndromes that I've described, and perhaps doing single gene testing, or in the case of the micro deletion syndromes, starting with that. However, if someone doesn't fit into those patterns perfectly in terms of the clinical history and physical exam findings, then I would consider moving to whole exome sequencing in these patients. Great. If I might, to answer the question about clinical significance of knowing the diagnosis of this non-syndromic obesity, I think it is very relevant in today's day and age because there are treatments that are being investigated for specific genetic causes of obesity. And I'm going to talk about those in my talk, but I do think it is very relevant in today's day and age to know the diagnosis because these people might be able to be amenable to treatments that are being offered. And Jennifer, to add to that point, I mean, I think it's probably important to know the actual genetic ideology because some patients may respond or not based on where in the pathways those genes are located. So that's also relevant. Great. Thank you. And so back to clinical questions, Dr. Simotas, Christopher, is the hypocalcemia in Albright's hereditary osteodystrophy lifelong or can it resolve with age? I guess it would depend on the underlying cause. When we describe Albright hereditary osteodystrophy, I think I alluded to the different forms of the pseudo-hypoparathyroidism, type 1A, 1B, 1C. And depending on the degree of the resistance to PTH, as would kind of dictate. And it probably has to be monitored throughout life. So, got it. Okay. A question from Dr. Gary Bellis. As we all know, childhood obesity is an increasing problem in the USA. When is it appropriate to refer a child with obesity to genetics? I think when looking at the definition, I think early onset obesity is the most common looking at the definition. I think early onset obesity, as well as severe obesity, and that has been defined in different ways. As I mentioned in my algorithm, when the weight or the BMI is above the 95th percentile or above 30, then it's worthwhile to consider that. As you all know, if there are other associated features, that's when often we get referred patients with obesity in terms of degree, some degree of intellectual disability, plus or minus the absence of the presence of other anomalies that might be present. And it sort of takes looking at, I think it would be important to rule out endocrinologic causes. That's why I kind of put those basic endocrine studies even before referring to endocrinology. And in the history, of course, it depends on looking at parental family history, parents' height and weight, as well as exogenous factors that might play a role. But I agree with you. I think at least in my own practice, we're getting more and more referrals for individuals with obesity and trying to come up with some sort of algorithm for approach about which ones we would see in genetics, as well as what testing we would do is going to be very important. Great. Thank you. And then the last question from Etta Friedrich. As we all know, treatment for obesity in the general population, so diet and exercise, is cumbersome and not terribly successful. Is there any evidence of efficacy of these broad-based measures in syndromic obesity? Yes, I think there is. Again, I've alluded to that in the management recommendations, and it's sort of repetitive, is that the recommendations are to try diet, exercise, and behavioral management directed towards those specific behaviors that are problematic, such as in Smith-McGinnis syndrome, or even in Prader-Willi syndrome, where there's decreased satiety or other behaviors that lead to the overeating. So I think it is beneficial to try those, as well as other measures that will be discussed in the future talks in this session. Great. Thank you so much. And just to wrap up with a comment from Junan Gold, who would like to add that in Prader-Willi syndrome, growth hormone treatment has also shown to result in increased IQ. So with that, I think we'll finish the first question and answer session and move on to the second presentation. It's entitled Clinical Presentation and Pathways Involved in Non-Syndromic Monogenic Obesity, and the presenter will be Dr. Sadaf Farooqui. She is a Professor of Metabolism and Medicine and the Wellcome Trust Principal Research Fellow from Cambridge. Thank you. Great to talk to you today. My name is Sadaf Farooqui. I'm Professor of Metabolism and Medicine at the University of Cambridge in the UK, and we'll talk to you today about non-syndromic forms of monogenic obesity. No financial disclosures to tell you about. Now, really, we're talking about patients who develop severe obesity from a young age, and it's interesting, there've always been some individuals who gain a lot of weight. But of course, what we're seeing now is with the change in our environment predisposing people to obesity, we're seeing a greater proportion of people who present with severe obesity and a subset of those will have genetic disorders. But it's important to realise that actually whilst we focus on monogenic disorders for this talk, genes influence our weight right across the spectrum. And we know that from studies of twins, from studies of adopted children who have weights very similar to their biological parents and rather different from their adoptive parents, and also from studies of overfeeding identical twins where colleagues showed that people gain weight, but the amount of weight they gain is very dissimilar between sets of twins. And overall, these studies have shown that the heritability of body weight is 40 to 70 percent. Now, what we know across the piece is that genes affect our weight and they do so by predominantly affecting several different phenotypes, specifically appetite, but genes can also potentially affect basal metabolic rate. And even the response to some treatments is strongly heritable. But today we're going to focus on monogenic disorders and they predominantly affect one key pathway that's involved in the regulation of weight. Now, of course, it's quite likely that other pathways will be involved. But really, that's something that we need to figure out in the future. The key central regulation of appetite and of weight comes from the hypothalamus, and we've known that for a long time because tumors of the hypothalamus can cause obesity in a very short period of time. They often also disrupt sleep, neuroendocrine function and thirst. The first molecular clue really came from the discovery of these mice shown here, the Obi-Obi mice, and these were an inbred stream of mice that were found to develop severe obesity and shown by Friedman and colleagues in 1994 to be lacking the hormone leptin. That work really led on to the unraveling of a pathway that's key to regulating weight, and that's the leptin melanocortin pathway. Now, a simple overview is shown here, but this was really discovered through studies in mice. So that includes the leptin deficient mice, like I've just mentioned, but also mice lacking the leptin receptor, which are also severely obese. Now, the pathway is shown here and it really focuses on the brain, on the hypothalamus and also the brain stem, which receives signals from the periphery, particularly leptin, which is made by adipose tissue and then circulates in the bloodstream to act in the brain to regulate weight. But we also receive signals from the gut, both neural signals and hormonal signals that input and tell us about satiety in relation to meals. And it's the integration of these signals that leads to the regulation of body weight over time. And for most people, weight remains reasonably steady over time because we have this homeostatic system. But disruption of this system, we now know, can cause severe obesity. And the first monogenic disorder causing obesity to be described is congenital leptin deficiency. We showed over 20 years ago now in children who were severely obese and found to lack the hormone leptin, just like those mice that I showed you, that they developed obesity from a very young age. And this was due to homozygous mutations in the gene that encodes leptin, which led to a protein that is not secreted. Now, this was really the first example of a single gene disorder causing purely obesity, not other syndromic features, as you would have heard about previously. Now, to give you an idea of the extent of the obesity, you can see the weight of these children here. And this was in the context of siblings who are entirely normal weight. The parents were first cousins of a family of Pakistani origin in the UK, and they were slightly overweight. Now, we know that those mice that were lacking leptin develop severe obesity, but we know that treating those mice with leptin can correct their obesity. And that led to the first clinical trial giving children with leptin deficiency injections of recombinant leptin. And here's some of my more recent patients. You can see here with leptin deficiency treated with subcutaneous injections of recombinant leptin with really very dramatic effects. So replacing leptin in congenital leptin deficiency can restore all of these abnormalities. Now, what we learned is that what is the primary problem in leptin deficiency is a disorder of appetite. Without leptin, these children are constantly hungry. They're always seeking food and they'll pretty much do anything to get at food. So parents often have locks on the cupboard doors. They're trying to keep food away from these children. Now, when we treat them with leptin, what happens is a dramatic improvement in their eating behavior. They eat an awful lot less. And that's really telling us about leptin's physiological role. This is just some interesting data I want to show you where we're looking at the fact that these children are incredibly open to eat and they'll eat any kind of food. They won't eat non-food. This is not pica behavior, but it is an intense hyperphagia. So much so that we ask them to rate food. We see high scores for things like cake. We also see high scores for food like cauliflower. Any kind of food is highly appetizing in the context of leptin deficiency. And we see that images of food lead to huge activation in areas of the brain that include reward, such as the striatum. And when we treat these children with just seven days of a common leptin, there's a real improvement in their appetite. The amount of food goes down. They're much less hungry and they also have a change in their behavior. So they now start quite liking cake, but they now don't like cauliflower anymore. So the behavior becomes more normal, if you like. And there's also a change in the activation in the brain. And what this really shows us is that a hormone such as leptin can regulate a pretty complex behavior such as appetite. Now, here's more of the children with congenital leptin deficiency at a very young age. And you can really see, again, the very striking clinical phenotype. They're very heavy at a very early age. This is the autosomal recessive disorder, as I mentioned, homozygous mutations. Most of the mutations that have been described to date in this rare disorder are either frameshift or nonsense mutations that result in the complete lack of circulating leptin. So measuring leptin in the bloodstream is useful. If you have undetectable levels of leptin, you sequence the leptin gene and there's your diagnosis. But in the last few years, a few mutations have been identified that actually result in detectable levels of leptin, but the leptin molecule is actually bioinactive because of the specific missense mutation that's involved. And so what that means is if you have patients who have this kind of clinical appearance, but leptin levels are normal, you should nonetheless sequence the leptin gene. Now, the clinical features, as I've described, are really severe hyperphagia from a young age. These children are constantly demanding food. It's very obvious to everybody there's a complete disorder here. Otherwise, development is normal. Vision, hearing, motor development, all entirely normal. But sadly, there is a very high mortality with this condition due to infections and there is evidence of impaired T cell mediated immunity. And the other thing is adults have been described with congenital leptin deficiency and they do have hypogonadotropic hypogonadism, so they fail to go through puberty. And some of the children, particularly males, you can see signs of hypogonadism in this child with micropenis. Now, what we found is when we treat the children with leptin, they will go into puberty, but at the appropriate developmental stage. So they'll develop the clinical characteristics. You'll see hormone pulsatility develop and they go on to have normal menstrual cycles as females, normal fertility as males and females. So leptin replacement can permit puberty at the appropriate time. Now, leptin does quite a few other things and we see some subtle changes in these patients as we treat them. It is associated with mild hypothyroidism and that normalizes with leptin treatment. And also in the absence of leptin, these children have very low blood pressures. There's a subtle increase when they're treated with leptin. Now, leptin, as I mentioned, is made by adipose tissue. It acts in the circulation and then acts in the brain. And in the brain, it acts on the leptin receptor, which is expressed in the hypothalamus. Now, quite a few mutations have been identified in the leptin receptor, in fact, more so than in leptin itself. There are, again, homozygous mutations. Quite a few compound heterozygous mutations have been reported, often in non-consanguineous families, and the phenotype is very similar. Here's one of our patients with a leptin receptor deficient mutation and different types of mutations have been described. They affect the different domains of the receptor. Some very specific mutations that cause cleavage of the extracellular domain can cause a very high level of leptin. But in most patients with mutations, the leptin level is appropriate. So moving on downstream of leptin, what we see is that when leptin actually docks on its receptor, it activates specific populations of neurons. And this is the kind of primary circuit that we think about. So there are neurons that are there to tell you to eat. And they expressed AGRP. And there are neurons that are there to tell you to stop eating. And they express POMC or proacrymal anacortin. And it's this part of the circuit that if defective in monogenic obesity will cause hyperphagia and weight gain from early childhood. So POMC is then cleaved to yield these melanocortin peptides, which are agonists of the melanocortin 4 receptor. And activation of that receptor results in a decrease in food intake, telling you to stop eating. And we and others have been studying children with severe obesity that starts in very early childhood, invariably before the age of five, often before the age of two, and identified several disorders that affect this POMC or melanocortin pathway. I'm just going to briefly mention some of those disorders now. But the primary one downstream of leptin is the POMC gene itself. So, again, homozygous or compound heterozygous mutations in POMC result in the lack of these peptides, the melanocortin peptides. Now, interestingly, they bind to five different melanocortin receptors. The melanocortin 4 receptor is the one that's really involved in appetite. And I'll tell you more about that in a second. But interestingly, in the adrenal gland, the MC2 receptor is involved in cortisol production. And as a result, if you're totally lacking these ligands, the patients present with a lack of cortisol due to ACTH deficiency. In neonatal life, that present with hypoglycemia. And in the skin, the melanocortin peptides act at the melanocortin 1 receptor to regulate pigmentation. So these patients often have very pale skin and red hair because of the lack of these melanocortin peptides. Now, there's another disorder, again, autosomal recessive due to PCSK1, which is the enzyme that actually cleaves all these different peptides. So you get very similar features in terms of the loss of the peptides. But in addition, PCSK1 can cleave many other peptides. And so you get lots of different neuroendocrine abnormalities, including hypogonadism, hypothyroidism and cranial diabetes insipidus. And due to a failure of processing insulin, the patients present with postprandial hypoglycemia. And they have very high levels of pro-insulin versus mature insulin. Some of the patients also get enteropathy because the processing of peptides in the gut means they fail to absorb nutrients in the gut. Now, the commonest genetic form of obesity involves the melanocortin 4 receptor, that key target downstream of leptin action. Here, mutations are heterozygous, a predominantly inherited disorder, but with variable penetrance. The prevalence is about 1% of severely obese adults, 3 to 5% of severely obese children. And many different mutations have been identified by groups around the world. And they're summarized on this website here where you can look up the mutations, what's known about them, where it's been published. Now, what happens is when we study these mutations in cells, we can classify a loss of function. And this is a G protein coupled receptor. So we measure cyclic AMP production. And if it's reduced, then you get a loss of function. We and others have characterized many of these patients. They look entirely clinically normal. There are no distinguishing features. Development is normal. The predominant phenotype is hyperphagia. Again, these children are very hungry. They want to eat food. This is not as severe as leptin deficiency, but it's still pretty severe. The children gain weight from a young age. They're often quite tall. They have accelerated linear growth and they have an increase in lean mass or muscle mass and disproportionate hyperinsulinemia. So they have high insulins from a very young age and often develop early type two diabetes in their 20s. Interestingly, there's a complete genotype phenotype correlation. So the more severe the receptor abnormality in cells, it correlates with the degree of hyperphagia and the degree of weight gain. And this has led to a lot of interest in targeting MC4 for therapy. Now, very recently, in fact, last week, we published a paper where we showed that some of the mutations found in obese patients that don't seem to affect cyclic AMP have previously been thought to be variants of unknown significance or query pathogenic. And that's because we've considered that's the main readout for MC4R function. But actually, we took a large number, about 50 mutations that were not thought to affect function and characterize them using several different assays and indeed show that they all affect different aspects of the function of MC4R. And so it's really important that we think more broadly about how these mutations disrupt signaling, but they can, for example, affect the receptor homodimerization. They can affect its endocytosis. They can affect its trafficking back to the membrane. So there are many different processes that can be affected, which is interesting because it may yield new targets for therapy. Now, one of the interesting things about patients with MC4R mutations is they don't develop some of the complications you may normally associate with obesity. In fact, for example, here they may have low blood pressures or protected from hypertension. And the reason for that is they have impaired sympathetic tone. Now, this was relevant when people were developing drugs targeting MC4R, which seemed to cause weight loss. But unfortunately, they also caused increased blood pressure, as shown here. And through a series of studies undertaken by colleagues in mice, we now know that the leptin melanocortin pathway is key to the regulation of blood pressure and links changes in weight to changes in blood pressure. So in regular obesity, when people gain weight, leptin goes up. There's a signal through the brain, through the hypothalamus, driving up melanocortin tone, increasing sympathetic tone and increasing blood pressure. And when you disrupt that with these genetic disorders, you don't get that rise in blood pressure with obesity. Now, this has been important because when you're developing drugs, there's no point in developing a drug if you get hypertension, even if you lose weight. But actually, there is now a drug, set melanocortin, which has been given in clinical trials to patients with genetic disorders, and it targets the MC4 receptor. I think you'll hear about that a bit later on in this session. But essentially, several of these disorders, QAMC deficiency and leptin receptor deficiency can now be treated with set melanocortin with good effect. So this has really been the key in the last few years, is that through the discovery of these disorders, we can now find new treatments for patients. We showed many years ago that giving recombinant leptin can restore the normal phenotype in patients with leptin deficiency. Set melanocortin, as I mentioned, is now in clinical trials and has recently been approved in the US for a couple of genetic obesity syndromes. GLP-1 receptor agonists can be effective, as can Roux-en-Y bypass surgery in heterozygous carriers of MC4 mutations, but not really in leptin and leptin receptor deficiency, which are very severe disorders. I just want to briefly mention some of the other disorders that can cause obesity that are also monogenic and show some interesting insights into how they tell us about the brain pathways that regulate our appetite and our weight. Now, you'll be familiar with the fact that sometimes obesity in childhood can present with other features. And I'm not really talking about developmental delay here. I'm talking about other behavioral features. So we found that mutations in a gene called CYM1, which affects the development of part of the hypothalamus, were associated with obesity and hyperphagia, but also with emotional lability and autistic type behaviors. And we see something very similar with another transcription factor called OTP. Now, these transcription factors are important in the development of the hypothalamus. And in mice models, we can show that the mice are also anxious, have some autistic type of features in terms of they have social anxiety and they have very reduced levels of oxytocin in the brain. And this is important because people are looking at therapies targeting these neuropeptides for the treatment of these disorders, but this is really obesity and autistic behavior. Another group of disorders involve BDNF and TRACB, again, dominantly inherited, often de novo mutations because it's quite a severe phenotype affecting this nerve growth factor and its receptor. And here the patients have speech and language delay, hyperactivity and impaired short term memory. And just to give you a sort of an idea of a mechanism that underlies that phenotype is that BDNF and TRACB are involved in development of neural circuits and specifically that dendritic spine density in the hippocampus is involved in memory. And you can see here are many of the mutations seen in our patients that severely affect the ability of these dendrites to grow. And then another group of disorders involve SH2B1, which is also linked to BDNF that I've just shown you, where chromosomal deletions on 16p11.2, a region that you'll know has been associated with autism, with developmental delay and also obesity, links SH2B1 to the weight gain. We found that heterozygous mutations in the gene itself are associated with obesity and early type 2 diabetes. But interestingly, many of these patients often have other behavioral abnormalities, including being relatively socially isolated and sometimes in males, aggression. And just a bit of data I wanted to show you is that when we test this in mice, because it's hard to really nail this down in humans, we find that if you delete SH2B1 in the brain, you get both obesity, but also aggression in mice. Here are mice where the gene is deleted in the black bars. You can see that they really attack an intruder mouse. They keep on attacking and they're very quick to attack. And we find that this phenotype is corrected when we restore the expression of SH2B1 in the brain in these mice. And last couple of slides was really just to focus on the fact that I've told you all about monogenic disorders, but actually there are now emerging quite a few genes in which rare variants that are not inherited in the classical Mendelian fashion are nonetheless strongly associated with severe obesity. And just one example I wanted to mention is a gene called FIP, where other groups had identified mutations in patients with developmental delay who were also some of them were obese. But we found mutations in patients who were not obese, sorry, who were not developmentally delayed, but were obese. And so essentially you get a very broad spectrum of mutations, which in some part may be explained by the particular molecular defect in the patient. So really just to say, keep an open mind. These disorders may not be monogenic, but they may well be a link between the mutation in the patient and their clinical phenotype. So really, to summarise, I've told you about the genetic disorders that cause severe monogenic obesity, which can be viewed as a neurobehavioural disorder because it's predominantly about the dysregulation of appetite. Clinical guidelines for the assessment of childhood obesity now recommend genetic testing, particularly when obesity is severe and before the age of five. Even if you're seeing the patient much later, if it starts before the age of five, that's a clear clue, as is hypophagia. It's important that when we think about genetic testing, there are other things to consider and that often these children, particularly in their families, are blamed for parental neglect, causing obesity and finding a genetic diagnosis can be incredibly helpful to the families and can help to challenge stigma. And more recently now, there are mechanism based therapies for some of these genetic disorders. And you'll hear about some of those also in the other talks. Thank you. Well, that was a great presentation. We now are open to any questions that the audience might want to pose. I do have one specific question. Can you discuss your experience of treating with leptin and leptin deficiency? Yeah. I mean, we've been treating patients with leptin deficiency for many years. It's very safe. It's very effective. And essentially, we can treat patients as young as one year old. And we've been treating patients, as I said, for many years. So it works very well, but really only where leptin is lacking. It's not useful in other syndromic forms of obesity, nor in common obesity. And the reason for that is that in those disorders, people have plenty of leptin. And so giving more leptin doesn't really do anything. Thanks. Another question. Do MC3R variants play a role in monogenic obesity? Yeah. I think the jury is still out on that one. It certainly doesn't appear to be a sort of Mendelian disorder. But the jury is still out on whether rare MC3R variants can contribute in some patients. Great. Can you discuss the phenotypes of the MC4R heterozygous? Yeah. So it's interesting. Development is normal. Clinically, there are very few distinguishing features. It's really about hyperphagia from a young age, but without PICA behavior. And it's really early growth and increase in size. The children are generally, they're big. They look solid. People often say that they'd be good enough to play rugby or, for you guys, American football. So they look really solid. And the adults often grow up to be quite big, quite tall, quite solid. But there are no really other clinically distinguishing features. They tend to develop, people tend to develop type 2 diabetes at a young-ish age. And really, that's about it. There are no distinguishing neuroendocrine abnormalities. A subset do seem to develop sort of autistic type behaviors, but it's not a feature of the disorder itself. So really, there's very little else to distinguish it. And of course, they're heterozygous mutations. So it's mostly, it's dominantly inherited. So you will see a dominant family history. Thanks. Another question from the audience. Can you comment on the failure of one of the MC4R agonist trials? Yes. So I think that was really the first generation MC4R agonists, where the efficacy was quite variable, but the main problem was the blood pressure. So the agonist that is in current use, which is the only second generation agonist that's in clinical use, does seem to be effective, was effective in preclinical studies, and is effective in people. And it appears to be effective on weight without affecting blood pressure for reasons that we don't understand. Many companies are actually looking to target MC4R in different ways, because it is such a critical regulator of appetite and weight. Another question by Melissa Parisi. What percent of those with severe early-onset obesity can be diagnosed using known genes, genetic testing, when a monogenetic cause is suspected? In other words, what is the yield with current diagnostic approaches? Of course, it will depend on who you put in, but if you take some of the patients that I showed you as sort of example, that's kind of our cohort of patients with severe obesity. And the genes that I've told you about there can probably at the moment explain somewhere between 10 and 20% of the patients with that severe degree of obesity. Now I think there's certainly more genes that we and others have identified that are being worked up, and I think that number will go up. But I think there's still quite a lot more that we don't understand. And I think later on in our discussions, we can kind of comment on what is the degree of obesity and onset of obesity that we could use in clinical management to try to decide when to look at these monogenes. I mean, there are some guidelines from the, there are guidelines approved by the American Endocrine Society, and those guidelines really go with onset before the age of five, and the severity of obesity, as Kim talked about. Now, usually in these disorders, the obesity starts well before five, actually, often around before two. So that's really the critical findings. Another question by Catherine Nowak. When family history identifies obesity in a parent, extended family in a child with obesity or plus or minus developmental delay or behavioral issues, it is difficult to know if the obesity is familial or part of a syndrome. Are there recessive obesity disorders in which carriers may present with obesity of a less degree and without the developmental behavioral phenotypes? So there's probably about three questions wrapped into that one question. So let me dissect them if I can. So yes, there are disorders where, recessive disorders, where the heterozygous parents, for example, will have a milder phenotype. So the best example is MC4R again, because heterozygous mutations in MC4R are sufficiently prevalent that you either can get homozygous mutations, or even you can get sort of double heterozygous mutations, two different heterozygous mutations. So that can occur. You can get severe obesity or even moderate obesity with one allele affected. And if you have two alleles affected, you get very severe obesity. So that's a good example of that. With leptin and leptin receptor deficiency, they behave much more like a classical autosomal recessive disorder, where the heterozygotes are not severely obese, but they may be overweight. And what you usually get is a history of struggling with their weight since childhood. And then when it comes to the disorders with developmental delay or behavioral phenotypes, more of those are de novo. Quite a few of those are de novo. Some of them, like SH2B1, missense mutations, can be dominantly inherited. And again, you know, like with all genetic diseases, you get a variation in phenotype there. What I would say is it's really when the phenotype presents at a young age that usually it's more of a clue that this is linked. Did you have a question? I was asking what proportion of the monogenic obesity is de novo versus inherited, and are there differences, I would assume, between the different pathogenic gene variants? Yeah, I mean, obviously, we're talking about quite a broad group of disorders. Most of the disorders that I talked about, for example, they are inherited in a Mendelian fashion. It's the ones that are de novo really are the ones with the more severe de novo really are the ones with the more severe developmental phenotype. So BDNF and TRACB, for CYM1, for example, we and others have identified many missense mutations, but the one patient with a heterozygous frameshift mutation, that was de novo. So that just kind of gives you a flavor for that. For MC4R, pretty much all the mutations we have identified are inherited. So most are inherited, actually, apart from the syndromes with quite marked effects on development. So if they are inherited, any thoughts about penetrance and any thoughts about pre-symptomatic management? Yes, so penetrance, so far what we can see is, you know, penetrance like in other disorders, MC4R is the best example, I think, whereby because we have many patients and many families, we clearly see even within families, variable penetrance of the same mutation. And I think that's much, I've never seen that with leptin deficiency or even with homozygous leptin receptor deficiency. So I think with the very severe extreme end, unlikely, but with MC4R, you clearly can see a variation in penetrance, for which we don't have an explanation, of course, like we don't in many diseases. And then your other question was about screening or? Pre-symptomatic management. Yeah, so I often get asked that by often young mothers who have an MC4R mutation, for example, about their children. I've tended to resist it in the past because I've not really been sure if it would be helpful or counterproductive, but actually families sometimes do find it would be helpful when the child is becoming hyperphagic at a young age. If they know that the child has an MC4R mutation, they tend to exert tighter control at an early age. So I tend to be guided by the families. Thank you. What proportion of severe childhood obesity is explained by known genes? Yeah, again, that kind of depends on the criteria used at the outset. But as I would say, from the sort of cohort that we have, which is really the very severe end of the spectrum, it's definitely 10% is explained and up to 20% is probably explainable by some of the new genes that we and others are finding. I think if you kind of lessen the criteria a little bit, if you aren't so focused on early onset, if you're not so much thinking about the hyperphagia, then the hit rate will be less. I was quite intrigued, actually, about the cauliflower. I was wondering, is that similar to other conditions outside of leptin deficiency in the sense of interest in any foods, including cauliflower, with other obesity conditions? Or is there some sort of grouping that would explain that? Yeah, so I like that because I like it for lots of reasons. So this hyperphagia, and many colleagues will know this from their patients, I think the feature of leptin deficiency particularly is this incredible desire for food, where any food is rewarding. But the fact that we see that when we treat leptin deficiency, that changes within seven days, shows you that's a real biological phenomenon. And so the same happens when people go on a diet, and this is any people, including regular people without genetic disorder. If you go on a diet, your leptin levels fall, and it's that fallen leptin that is making you very hungry, but also making you crave food. So popularly, we call it cravings. And if you fast long enough, or if you don't eat, or if you're on a severe calorie restriction, you will really like food, and even cauliflower will probably be quite rewarding for you. So it tells us about the physiology, if you like. Now, it's interesting is I think many of the disorders, certainly the leptin melanocortin disorders, share that phenotype. So MC4, our patients and others, examples will be when we have the children for clinical studies, they'll follow the nurse around if she's carrying the food. Just so they'd like to have any bit of the food that she may leave behind. But it's intriguing. I think that there probably are disorders where that incredible liking for food is not so apparent. So I have seen and assessed children, and other colleagues are nodding here, where actually that liking, I mean, the leptin kids like it so much, they start singing when you provide them with food. They're so happy. I don't see that with some other disorders, where actually it's just a fundamental drive, and they've got to have it. And then there are other disorders, particularly the ones with the autism combined, where we see quite interesting things like despite the fact there's a drive to eat and they want to have more food, the autistic traits are so powerful and probably higher function cognitively that they'll be more worried about the fact that they have to eat the purple food followed by the so-and-so followed by the so-and-so than they are about the drive to eat. So the fact that you've mixed in two foods together will bother them much more than you would think. So I think there is a variation in these behaviors. I think it's clear that the leptin melanocortin pathway is about the drive to eat. It's about fullness. These kids aren't full. Very soon after eating a meal, they'll want more food again. And it's also about the liking for food and the motivation to get food. The kids will display incredible motivation to get food. But I suspect there are other disorders where those features are a little bit less prominent, but there may be other things. And it's all because you're disrupting the pathways in the hypothalamus. I will say that in our functional MRI studies, we've seen exactly that as well. And it's interesting in Prader-Willi, you see it translates into if you show them a cow, they can perceive that as potentially being food. Or showing them plates and silverware, they'll still have that same bold signal on functional MRI because they know that's associated with eating. So yeah, it's really a fascinating thing. But you're right, some of the PCSK1s, that is not the same response that they have. Another question is whether or not leptin could be used as a treatment for cravings in people who are dieting. Yeah, I've been trying to do this study for about 20 years, actually. Which is that we know that the fall in leptin is the signal to tell you don't want to have more food, drive you for those cravings. And so clearly, a very good question would be to supplement, give people leptin at that stage. A series of small studies have been done by Rudy Leibel and other colleagues and Michael Rosenbaum in an experimental medicine setting where they at least showed that some of the endocrine and other abnormalities with weight loss are attenuated if you give leptin. But the trial has not been done and it needs to be done. And I think it would work. Other groups are interested now in leptin sensitizers. So hopefully, we may get some other drugs that could be used in that setting. Another question was regarding testing. So what is the increased benefit for monogenetic obesity of genome versus exome sequencing? Obviously, testing can be extremely difficult to get covered in many countries, including the US. So at the moment, I see no value in doing genome sequencing. But I guess probably the most effective way is targeted panels which cover the known obesity genes. It depends obviously a little bit on local availability, and then if not exome sequencing of the patient and the parents. I guess if you look at examples from other disorders or penetrant monogenic disorders where people have done whole genome sequencing in clinically quite distinctive phenotypes where exome sequencing was negative, the pickup rate is probably at maximum at the moment 10%. But at the moment, I'm not aware of a single example of something having been identified using whole genome sequencing that was not detected using exome sequencing. So I would not consider that value for money at the moment, unless you had a fabulously interesting case and you'd excluded everything else, in which case, call me. Sadaf, do you think that people are utilizing the prevention genetics testing that Rhythm has offered? Because that's free of charge right now. And I feel like not enough people know about it and are utilizing it with some of these patients. Yeah, I know. So you're referring to the kind of Rhythm Pharmaceuticals, who's a company who have made set melanotide available for use in clinical trials, have as part of that tried to sort of reach out to people to say, we're going to make testing available. And I think that's important for people to know and be aware of, because it is at least a way of getting testing for your patients. And there are many, many panels of many different genetic testing companies that have created obesity panels. And so everyone should really take a look at all of those and make the appropriate decision for their patients. And I hope in the future, we may find the groups of people listening to these talks will advocate for this to be part of something that is, you know, there's no reason why this, like in other genetic testing for other clinical disorders, particularly where there's benefits to patients and treatments for patients. So I think we should be advocating for this on behalf of our patients. We have just a couple of minutes left. I was interested in one of your discussions about SH2B1, but there have been any reports of pathogenic homozygous individuals with SH2B1. No, not to my knowledge, and I think it would be pretty severe, so may not be compatible. In the animal studies of that, has that shown, are they lethal? No, no, they're not lethal. So homozygous knockout mice, well, they're lethal because they kill other mice, but they're not lethal because of their obesity. So homozygous knockout mice are very obese. So yes, you know, homozygous knockout humans could in theory exist. I'm not aware of any, as I said, but the main problem appears to be the kind of behavioral phenotype. And that's prominent in males, actually, particularly. So I think we, I don't have any other questions in the chat. In the chat, so. There's a comment. Yeah. I think the comment says about the gene panels from Rhythm allowing testing for up to 40 genes. And so that is the case. And partly the reason for that is that the genes that I've talked about, obviously, POMC, PCSK1, leptin receptor are all genes in this melanocortin pathway. But there are other genes which we know from studies in mice are in the same pathway, but we don't yet have convincing evidence that they may be relevant for human obesity. It's quite likely some of them will be. We have data on some of them that they, that, you know, we hope to publish soon. And then I think the way that certainly I'm looking at things and I know that others are looking at it is that if there are other disorders with an overlapping phenotype, those disorders may be caused by other mutations in other genes that are closely related. And that's important to know for diagnostic information for patients and families, but also because those disorders may be treatable. And of course, if they're in the melanocortin pathway, they may be treatable with a drug that targets a melanocortin pathway, but they may be treatable by other drugs. There is now, for the first time in many years, a lot more interest in developing drugs for obesity, but also for rare obesity disorders, which I think is very welcome. So I think it's still, the field has changed. And I think the potential to have treatments for our patients has also changed. And indeed, there are even treatments now for, of course, Pariwili syndrome, you'll hear about in a second, but also Brada-Bedel syndrome, based on an understanding of the mechanism involved. So one last question. There was a question about whether or not there is a phenotype in individuals that have heterozygous BBS variants in terms of genetic predisposition to obesity. Not obviously to my knowledge. Other colleagues may have more knowledge than me in that area, but we've identified quite a lot of, actually, BBS genes are highly heterogeneous. And we and others have identified many heterozygous variants in BBS, and they don't appear to be, to my knowledge, associated with obesity. Well, thank you for a wonderful discussion. I think we'll now move on to our next talk by Dr. Julian Martinez, who's an Associate Professor at the David Geppin School of Medicine at UCLA in the Division of Medical Genetics. My name is Julian Martinez, and I'm an Associate Professor in the Departments of Human Genetics, Pediatrics, and Psychiatry at UCLA. And today I'm going to talk to you about genes and pathways related to obesity. I have no financial disclosures. The objectives today are to explore the pathophysiology of severe early onset obesity, to review signaling pathways that contribute to obesity, discuss how Mendelian forms of severe early onset obesity are providing insights into the biology of adipose tissue and its interactions with the nervous system, and to discuss the genetic heterogeneity and the diagnostic yield of genetic testing in early onset obesity. When we talk about obesity, there can be a number of factors that can contribute to it. It could be due to excess adipose cells, due to increased tissue differentiation and ectopic fat development and localization, or it could be due to decreased apoptosis of those very adipose cells. It could be excess accumulation of fat within cells due to increased food intake, sleep and mood disorders, or metabolic or endocrine promotion of fat storage. And of course, there could be reduced usage of fats, either because of environmental conditions due to decreased activity, defects in the use of those fats, either through metabolic or endocrine defects or uncoupled proteins. Now, obesity has a significant genetic contribution. Twin studies have shown that genetic inheritance contributes towards 40 to 75 percent of all obesity cases. And monozygotic twin studies have shown that they're more similar in body fat acquisition in comparison to dizygotic twins, suggesting that an ultra genetic balance is highly influenced by genotype. And adoption studies further confirm this because the BMI of adopted children correlates more to the BMI of their biological parents than their adopted parents. And when we look at this spectrum of genetic contribution, it can range from syndromic and monogenic causes of genetic contributions to obesity to more oligogenic and polygenic ones. And of course, within this background, we have the environment that's further contributing to the development of obesity. You've heard already lectures that have described a number of mechanisms due to genetic contributions to obesity. And we can divide those between syndromic and non-syndromic monogenic causes of obesity. The most common ones are the ones associated with celiopathy genes, because it's a large number of them. And amongst them, Bartow-Beatles syndrome is one of the classic syndromes that are represented. And it's not surprising that celiopathy syndromes lead to obesity, given that the melanocortin-4 receptor is located in cilia, and that abnormalities that lead to cilia maldevelopmental function can therefore then alter the melanocortin-4 receptor syndrome as well. In addition, there are syndromic and monogenic causes of obesity that are due to changes in genes that contribute to the melanocortin leptin receptor pathway. And as you already heard, adipose tissue secretes leptin with receptors in the brain that actually mediates activation of expression of melanocortin-4 receptor through neurons that express POMC and melanocortin hormone. In addition, there are other pathways and syndromes that are associated with obesity, particularly early onset severe obesity. And those are the ones that we're going to focus our discussion next, because they provide a new insight into the pathophysiology of obesity. As we describe how these genetic ideologies lead to obesity, it's important to understand the process of adipocyte development, essentially the development of the cells that will store the fat in the body. And this all starts with the mesenchymal stem cells that then give rise through monoclonal expansion to adipocytes, but then through the activation of transcription factors like PPR gamma, lead to their differentiation into adipocytes. Those adipocytes then mature by expressing enzymes that will sensitize and store lipids into mature adipocytes. Those adipocytes are influenced by innervation of the peripheral nervous system, which regulates the use of fats whenever necessary. And of course, some of these adipocytes will undergo cycles of apoptosis and growth. So when we look at the first stage of adipocyte development, there are genetic ideologies that have led us to understand this process and that contribute to obesity by affecting the mitotic clonal expansion that results from mesenchymal stem cell P adipocyte determination. One of those syndromes is due to mutations in a gene called PRNT7, which is a gene that codes for one of a member of a family of enzymes that transfer methyl groups to arginine in proteins. And this arginine methylation is an important biological process that regulates signal transduction and transcriptional control. There are currently 10 patients that have been described that have compound heterozygous or homozygous variants in the PRNT7 gene. And those mutations are associated with a novel intellectual disability syndrome known as AIDS for its multiple findings. And they're associated also with late-infancy onset obesity in 60% of cases. What we know is that PRNT7 loss leads to promotion of adipogenesis through mitotic clonal expansion of pre-adipocytes. And you can see here that using RNAi to downregulate PRNT7 in those pre-adipocytes you actually get an increase in their expansion. So there can also be effects in adipocyte formation by regulating the process of pre-adipocyte differentiation into an adipocyte. And that's primarily mediated by a transcription factor called PPAR gamma. So changes in genes that alter the function of the transcription factor will therefore have an effect on number of adipocytes by changing differentiation. One of those genes is DERK1B. And there actually have been a description of three Iranian families with juvenile onset central obesity associated with insulin resistance and metabolic syndrome that had a founder mutation R102C in DERK1B. And it turns out that DERK1B inhibits sonic signaling and that that inhibition is required for adipogenesis to occur. This is associated with an increase of DERK1B that also continues to go up in levels as adipogenic differentiation occurs. And this particular variant R102C promotes adipogenic differentiation, suggesting that the function of DERK1B in these individuals might be through a gain-of-function phenotype. This is further supported by a duplication syndrome, where there's trisomy of 19Q13.2, where DERK1B is located, which is also associated with morbid obesity and ID, suggesting that having too much DERK1B is associated with increased obesity. And it turns out that overexpression of mutant DERK1B promotes adipocyte differentiation, particularly of this particular R102C variant. You can see in this picture that there is an increased amount of red staining in these adipocytes, which is a marker of fat storage by view of oil red staining in cells that have been transfected or adipocytes that have been transfected with the R102C DERK1B variant, suggesting that it's a gain-of-function mechanism that allows downregulation of heterosignaling with associated adipocyte differentiation. Another gene is COL4B. Hemizygous variants in the COL4B gene have been associated with X-linked intellectual disability, microcephaly, and seizures. And during adolescence, those individuals, particularly the males, are typically affected with central obesity, delayed puberty, hypogonadism, and relative microcephaly and moderate short stature. COL4B codes for a ring E3 ligase, which is a protein that can promote polyubiquitination of other proteins and lead to their degradation. And in this case, COL4B directly polyubiquitinates PPR gamma, a promoter of adipogenesis. So loss of COL4B, what it does is by not removing PPR gamma, which is what it normally does, it causes accumulation or increases in its levels, and therefore promotes adipogenesis. And you can see here that levels of PPR gamma when you remove COL4B are much higher than in control, and that that is associated with an increase in adipogenesis, as seen by the increase already seen here in red. Another gene is PHFS6, which causes Borgeson-Forsman-Lehman syndrome. It's an X-linked disorder characterized by moderate to severe intellectual disability, epilepsy, hypogonadism, hypometabolism, obesity, swelling of the face, and narrow and particular fissures in large ears. PHFS6 has not been very carefully studied in terms of its roles in adipocyte differentiation, but it does interact with ASXL1, which we know suppresses adipocyte differentiation by core repressing PPR gamma. So by virtue of it being a chromatin-binding protein that functions as a reader of histones and its interaction with ASXL1, we can hypothesize that having loss of function variance in PHFS6 will alter its interaction with ASXL1 and therefore lead to de-repression of PPR gamma and adipocyte differentiation. Another gene is CETD2, where we know that heterozygous loss of function mutations cause Luskan-Lumisch syndrome, which is associated with postnatal overgrowth, autism spectrum disorders, seizures, tiara malformation, microcephaly, intellectual disability, speech delays, low sociability, and behavioral problems. And infected individuals also develop obesity. CETD2 codes for a methyltransferase that's responsible for trimethylating lysine 36 of histone 3. So it is essentially a regulator of expression. And we know that in mice, loss of CETD2 in mesenchymal stem cells promotes adipocyte differentiation. You can see here that specific removal of CETD2 in those mesenchymal stem cells leads to an increase in those red cells that are accumulating lipids and staining red with our red. And then in addition, there's an upregulation of PPR gamma leading to the adipocyte differentiation as well as markers of fat storage. Now, in addition to mechanism by which these rare genetic diseases alter PPR gamma function and therefore lead to an increase in adipocytes, there can be genetic conditions in which there is an accumulation of mature adipocytes due to changes in the enzymatic networks that are responsible for fat storage and fat degradation and use. Mutations in BPS13B are one of those examples. We know that homozygous and compound heterozygous mutations in BPS13B have been identified in patients that have Cohen syndrome. That's an autosomal recessive condition that can present with a variable number of features, including developmental delay, dental retardation, microcephaly, facial dysmorphic features, progressive retinopathy, similar to celiopathies, severe myopia, and utropenia. They present with significant truncal obesity that develops in mid-childhood. And it turns out the lack of BPS13B increases the lipid droplets and triglyceride content in adipocytes. And that is associated with developmental insulin resistance. And you can see here that by down-regulating the expression of BPS13B in adipocytes, you get an increase in accumulation of lipid droplets and triglyceride as assessed by oil red stain for lipids. Another interesting syndrome is caused by mutations in AFF4. These are heterozygous D-level mutations, but that are causing a gain of function in the protein through its missense variants. And they're associated with a syndrome called CHOP syndrome. That's an acronym for cognitive impairment, heart defects, obesity, pulmonary involvement, and short-saturn thrombosplasia. Now, AFF4 is a component of the super elongation complex, which is required for promoting transcription. And while there's not a lot of information about AFF4 and its regulation in obesity, it turns out that in fruit flies, if you down-regulate AFF4, you increase the levels of lipase and fatty acid reductase expression. So, we propose that if loss of AFF4 causes an increase in the enzymes that degrade fatty acids, that having a gain of function in AFF4, the loss of function causes an increase in lipase, that gain of function may decrease the expression of those lipid and fatty acid metabolism enzymes, therefore leading to the obesity phenotype. And as you can see here, the complexes are very conserved from flies to mammals and are responsible for, as I mentioned, transcription of many genes, including those of fatty acid metabolism and fat accumulation. So, in addition to defects in pre-adipocyte mitotic clonal expansion, adipocyte differentiation through PPR gamma, and accumulation of the fatty acid and metabolism enzymes, there is also a role played by the peripheral nervous system, directly communicating through the brain to regulate how much fat is stored in adipocytes. And there are a number of genetic conditions that provided some insight into that. One of them is BDNF and NTRK2. Loss of function mutations in and helpful insufficiency of NTRK2 cause severe early onset obesity with developmental delay, memory and learning defects, and nociceptor defects. Now, NTRK2 codes for the TRKB receptor, and the ligand or the protein that binds to that receptor is BDNF. It's a secreted protein. And it turns out that haploid insufficiency of BDNF, the ligand of TRKB, causes also severe obesity, hyperphagia, and impaired cognitive function. And that was found through a syndrome called WAGRO, which is a variant of Wager syndrome, that you may be familiar with, associated with an ophthalmic and wounds tumor, because a subset of WAGRO patients develop hyperphagia and obesity. And the reason that some of them do is that if the lesion extends to include the BDNF gene, those are the ones that were presented with hyperphagia and obesity. And you can see that their BMI scores are much larger. The hyperphagia scores are higher than controls, and that's associated with a lower level of BDNF than normal controls. So having less BDNF signaling and mutations in its receptor can alter signaling through the RAS pathway, PS3K signaling pathway that are important for synaptic plasticity and function in the brain, and then lead to obesity and hyperphagia. It turns out that injection of BDNF into the ventricular space increases, or into the cerebrum, increases neuroadrenaline turnover in adipose tissue, suggesting that in the brain, centrally, BDNF can have an effect on adipose tissue peripherally. And it's recently been identified that a population of BDNF-expressing neurons in the brain regulates that sympathetic innervation of the adipose tissue downstream of the POMC neurons in the brain, and that BDNF-expressing neurons are necessary for leptin to restore sympathetic innervation of adipose tissue in obese mice, because some of that is lost as part of obesity. So again, the brain, through different pathways that involve sympathetic nervous system innervation of adipose cells, through neuroadrenaline and all the modifiers, can be sustained if BDNF signaling occurs. In its absence, there's actually loss, and leptin cannot maintain that signaling. Now, there are a number of other genes that have emerged recently as potential candidates for regulating obesity as monogenic process. There are recessive NKX22 loss-of-function mutations that cause severe diabetes due to lost pancreatic beta cells, and that's associated with childhood obesity and developmental delay. And that severe obesity phenotype also is associated with Brelling secretion, increased hunger, and fat deposition. There's also one case report of a heterozygous de novo nonsense loss-of-function variant in NLGN2 that presents with severe anxiety, obsessive-compulsive features, autistic features, short attention spans, injurious self-injury behavior with low sensitivity to pain, and physical abnormalities that include microcephaly with multi-features. When we look at this set of very diverse and heterogeneous ideologies, the question is how to pursue a genetic evaluation in these individuals, and some studies, although very few, have shown the diagnostic value of chromosome microarray testing in obesity, particularly in severe early-onset obesity associated with developmental delay. There, there appears to be an enrichment for rare CNBs. The most common one is a recurrent 220kb16p1.2 deletion that's associated with severe early-onset obesity and insulin resistance, but there are additional CNBs that are either associated with developmental delay or not that could be either gains or losses of material that are both inherited or de novo that can be associated with obesity as well. Now, a few additional studies have further expanded that. For example, in syndromic forms of obesity, there has been a yield of 22% of pathogenic CNBs. Some of them are associated with syndromal obesity, and some of them were novel at the time. The recurrent ones are deletions of 1p36, 2p37, and 7tp11.2 in 5% of cases, but there are many others that were identified as including recurrent deletions that have since been confirmed. And then, of course, there are other studies where they have looked, again, at syndromic forms of obesity with intellectual disability and developmental delay, and in those individuals, the yield in that cohort, the yield was much higher, where 33% percent of the CNBs that were either pathogenic, variants of uncertain significance, or the result of monoclonal biasing. But again, the yield of chromosomal microarray testing, fairly significant in obesity and syndromic forms. I'll give you some examples of those. 17p11.2 deletion might be familiar to many of you because it's associated with Smith-Manganese syndrome, and we know that it's haploid insufficiency of RAI1 that is responsible for that phenotype. It's associated with intellectual disability, behavioral abnormalities, and sleep disturbances, and a significant number, about 45%, have early onset truncal obesity, and although 76% are female. Again, a disproportionate effect of gender here. And the loss of function mutations in RAI1 alone also cause a phenotype similar to SMS associated with hypophagia and obesity, therefore confirming that at least most of the phenotype is due to loss of function of one copy of RAI1. Now, RAI1 also regulates circadian rhythm through clock, so we know that sleep disruptions affect or contribute to obesity, so that might be one role, but in mice that have haploid insufficiency for RAI1, they develop obesity, and it's actually the females that are affected, and that is associated with a decrease in BDNF expression within the brain, and you can see here that it's actually the female mice that have one copy loss of RAI1 that have significant weight gain due to excess body fat as opposed to the males, confirming what we see in the human syndrome. Another copy number variation in humans, 16p11.2 microdeletion, and its associated gene SH2B1 is very prominent. That is the recurrent 200kb deletion that was identified over and over again in most cases where microarray testing was performed. It presents with developmental delay and obesity. The way that SH2B1 was confirmed as the gene of interest within that region was because missus mutations in SH2B1 have been described, were associated with hyperphagia, childhood onset obesity, insulin resistance, social isolation, and aggression. As you can see here, the typical 16p11.2 microdeletion that's associated with neurodevelopmental disorders and microcephaly is the 600kb proximal region, and that is different from the 200kb microdeletion that includes SH2B1 that's associated with obesity, although there are large deletions that includes both regions that can present with both overlapping phenotypes. SH2B1 is an adaptor protein that links receptors like the leptin receptor to intracellular signaling pathways, so the PF3K and STAS signaling pathways that mediate signaling within the brain for promoting leptin signaling. And we know that the isoforms of the SH2B1 protein that are primarily expressed in neurons in the brain are the ones that promote leptin signaling and prevent hyperphagia and obesity, confirming their role in human syndrome. Another microdeletion syndrome is 6q16 deletion syndrome that includes the CYM1 gene. This 6q16 deletions present with a part of willy-like phenotype with incomplete penetrance, developmental delay, hyperphagia, and obesity. In addition, loss of function misses mutations in the CYM1 gene located within the region, also present with severe early onset obesity associated with developmental delay and a part of willy-like phenotype, confirming that that is the gene within the region associated with that phenotype. And in mice, CYM1 loss in the hypothalamus causes hyperphagia and obesity, but it's associated with reduced melanocortin-4 receptor expression, which may make it less likely that we'll be responsive to melanocortin-4 receptor agonism. You can see here that the weight in total over time is much higher in the mutant mice than in the controls. Another copy number variation is 2p25.3 deletions that include the MYT1L gene, and this is an autosomal dominant disorder composed of syndromic obesity with polyphagia, intellectual disability, developmental delay, and behavioral problems. The point mutations in this gene also present with intellectual disability, obesity, and behavioral problems. Haploid insufficiency of MYT1L in mice causes social deficits, hyperactivity, hypotension, and obesity. You can see in the graph that the total weight due to fat accumulations much higher than controlled mice, thus confirming that the phenotype is similar to the human syndromic presentation and confirming its role in controlling obesity. Now, in addition to chromosomal microarray testing, gene panel testing has emerged as the next tier of testing for evaluating patients with early onset obesity. And next generation sequencing panels typically include both syndromic and non-syndromic forms of obesity. In this large study of 1,230 affected individuals, 52 obesity genes were included, and that actually gave a 3.9% yield. But if you focus on the pediatric subgroup that had the most severe early onset obesity, the yield was even higher at 7.2%. So again, showing that there's a significant contribution from these celiopathy, melanocorticoid receptor and other pathway genes to obesity, but also reminding us that there's a significant gap in our understanding for additional monogenic process or these definitions. I wanna highlight that a lot of these gene panels are available commercially, and some of them have overlapping genes, but some of them don't. And many of those that don't overlap are because these are genes that are included, but have been previously associated only with polymorphic variants that are fairly common in the population. So when you're looking at variants that have been identified in your patients with those genes, then you have to be careful about how you interpret them. In addition, there are also genetic conditions that have initially been identified that are due to have low sufficiency that perhaps now with the advent of larger databases of normal controls, I question the likelihood of those disease association. Now, in addition to gene panels, of course, whole exome sequencing could be more comprehensive to assess additional etiologies that are missed by panels, because this might represent a typical presentations of well-established syndromes where obesity is a component, but not a prominent feature. And when you couple that with CMV detection, where the exome sequencing is serving almost like a microarray at the same time, you actually get a very significant yield. So this study identified 16% of the time by exome sequencing pathogenic CMVs. And the most common one in that cohort was a 16P11.2 200PV deletion. And in addition, they also found single nucleotide variants in a number of genes in 17% of cases. And there the melanoclonin 4 receptor was the most common one, but also for example, P10 was one of the cases and many others, including RAI1, which are good examples of other genes that were not necessarily anticipated to have a prominent role in monogenic causes of obesity. But this shows you that there are many syndromes in which obesity is prominent. And by using exome sequencing, you may be able to find a more mildly effective presentation that's just primarily obesity related, but is associated with a very well-known established gene ending of that syndrome, and not included in BARN. Now, the other utility of understanding these rare monogenic causes of obesity is that it has led to the hypothesis that perhaps personal life therapeutics could be merged that could help both these conditions and obesity in general. The problem is that current strategies for weight reduction are limited to altering caloric intake by manipulating the central nervous system, like using non-reporting receptor agonists or encrypting genetics, or through blocking the absorption of lipids in the gut and treating insulin resistance, that's sometimes associated with these syndromes. So there are potential additional strategies that I'm just proposing as future avenues for looking at therapeutic interventions, like for example, looking at CDK9 inhibitors, a component of the super elongation complex where AFF4 or the gene that causes CHOP syndrome is involved. They're currently being explored as candidates for treating cancers. And it may be that they may also be used in the context of adipogenic regulation in obesity. Now, BDNF has been tried in the past in a number of neurogenetic conditions as a treatment, both through injections and peripherally and into the brain. And it turns out that they're all been unsuccessful because BDNF as a drug candidate is not very good, it's very sticky, doesn't migrate long distances within spaces in the brain. And in addition, we know that serum BDNF levels do not correlate with obesity, so it's not clear that that can be a biomarker. So perhaps using TRKB agonists that are actually penetrating the problem area may be another way to, or BDNF pneumatics could be another way of enhancing that process. DERK1B inhibitors could be another category because they're being explored as candidates for some forms of cancer. And again, by inhibiting DERK1B, you may actually be able to reduce its role in promoting adipogenesis. And then of course, leptin levels are elevated in obese individuals, and leptin had been tried as a therapy to treat obesity, but it failed because of leptin receptor resistance. So now there have been recent studies that have shown that perhaps by removing leptin using CRISPR gene editing or antibodies, you can actually promote weight loss, and that might be another avenue in the future. So given this knowledge, how do you evaluate a child that has early onset obesity? Well, universal screening of children with severe early onset obesity for a genetic etiology process is a substantial reason for burden because there's a significant number of them. And therefore, selective evaluation of those that will have a highest pre-test probability of genetic obesity is essential. One criteria is that they're presenting at a very young age. And of course, if they present younger than five, that's a very high likelihood that they'll have a genetic etiology. But also looking at the BMI and the starting deviation in tissue that is greater than three, that the adipose tissue is distributed in certain areas like the truncal region. If there's hyperphagia associated with the clinical presentation, any metabolic or endocrine abnormalities that might provide clues to a syndromic cause, complex clinical phenotypes that are associated with non-governmental disorders or growth parameter changes. And then once that workup is triggered, then you can start with whether there are probably like syndrome features that then will trigger you to pursue 11p15 manipulation. But keeping in mind that there are also individuals that can present with hyperphagia and obesity that might be presenting as a manifestation of Fragile X syndrome. And the Fragile X syndrome testing has to be performed in that 10% of cases that present with hyperphagia and obesity. Of course, chromosomal microarray is definitely a tool that will provide a high yield in some cases. A severe early onset of obesity gene panels to ensure that you've evaluated deletions of those genes as well. And then perhaps exome sequencing as a final approach if you have a syndromic etiology that requires a further evaluation. I'm gonna launch the place that I work, the Buketan School of Medicine at UCLA, and I'm here to sort of help. Thank you. Thank you to Dr Martinez Agosto for an excellent presentation and an outstanding number of different conditions which can predispose to obesity. So questions are now open. Anyone want to type a question in? I will start off and ask that I think that testing for many of these conditions is probably performed for another indication like developmental delays or anomalies. What relevance do you put on counselling and do you have any thoughts on how we should counsel for the risk of obesity when we're explaining these results to families? Right, I mean I think as part of any rare genetic epidemiology and diagnosis, typically we go through the list, the laundry list of anticipatory guidance that we all should implement. And I think for these particular conditions you're going to hear very soon in the rest of the sessions how a multidisciplinary clinic that addresses those concerns actually can lead to appropriate care and implementation of both referrals to specialists and interventions for the obesity itself whether it's with medications or otherwise. So I agree that there should be a very carefully thought out process in which you either counsel about the risk but also refer to clinics that have provided the care and the treatments associated with these conditions or useful for these conditions. Great, thank you. So open for questions. I don't think anyone's typed in anything yet. Just give a few minutes while people might think. Any questions from the panel for Dr. Martinez-Agosto? I did have a question about who we're going to test and how medical genetics can tackle the number of individuals that need to be tested. You mentioned individuals that are less than five years of age with onset of obesity but I think in the U.S. that percentage is around 13% from what I've read. So do you have any suggestions on other ways that we can narrow down that scope or how we as a medical genetics community can handle this volume? I think keeping in mind as you've heard earlier from the previous two talks the behavioral phenotypes that are associated with the obesity is really important and that's part of the initial evaluation and assessment that we should all ask when we identify those phenotypes. I think it would also, I think it's easier to refer to a geneticist when you have comorbid situations where there's developmental delay and other well-known phenotypic manifestations that have a significant genetic contribution. But I think it's harder when you have a child that's probably representing a typical presentation of a fairly well-known syndrome. An example is in that study where they identified the PTEN patient, it was actually a patient that had no other stigmata of Cowden syndrome or PTEN hematoma syndrome other than significant obesity and lipomas. And yes you could argue that a lipoma could sort of stand out as a feature for PTEN hematoma syndrome but I mean lipomas is also fairly common. So in the context of an individual that's presented with significant obesity and no other manifestations we may be missing opportunities where we could find a case like that where the surveillance and the care for that patient should be tailored to that ideology because we know that PTEN has very clear diagnostic and clinical criteria both for surveillance and treatments. So I think trying to tackle the utilization question is harder because I think that, I'm hoping that it will be an opportunity for us to discuss later as a panel as we find more and more genetic ideologies and we'll find many more. I'm sure that there are hundreds that are waiting to find it particularly when they're probably multigenic. How are we going to then as a specialty accommodate that testing particularly because many fields are now looking at polygenic risk scores and other ways of diagnosing genetic risk and we will have to be more comfortable counseling situations in which we don't have just a very clear single genetic cause but there may be contribution for more common variants. And that poses both challenges for identifying those genetic changes and also identifying the individuals that would benefit from that testing and the counseling that has to be provided. So I think it's one of the both opportunities where challenges for our profession as this field evolves when we understand more of how genes are contributing to disease. I just wanted to add, you know, choosing the age of onset, you know, the obesity may exclude some of the syndromic forms that I described earlier and some that you described Julian is that if many of those syndromic forms have onset of obesity after age five, it's a range but for instance, in Cohen syndrome, it may be average age of onset is at 11 years. So obviously think about those potential diagnoses because of the other possible associated findings but I think with sort of a surveillance, if you have sort of a pattern of looking for other anomalies as well as, you know, the obesity, it can help direct the testing that you do as well as consideration of diagnoses. I think when we talk about less than five years of age or even onset of obesity in infancy severe, as we've talked about with the BMI being over a certain level that we're thinking about those monogenic forms and less about some of the syndromic forms. I would just add that in. Thank you. Great. Thank you. And then some questions from the audience. If a patient does not have developmental delays, it's best to start with a multi-gene panel and then proceed with a ray. And there's also a question about whether or not one should start with a microarray and then go to a panel. So questions on testing order. Right. That's a very good question. Given the yield, it would seem that the panel would be the first approach, particularly if you're dealing with monogenic, non-syndromic suspicion of a diagnosis, because most of the CMVs by definition present in a more syndromic fashion. Now, there are exceptions to that, but most of the time that will be the case. So I think if you're suspecting that the individual has significant severe early onset obesity in the context of other phenotypes, a complex clinical presentation, then yeah, monogenic testing, panel testing would be the first tier approach. Great, thank you. And then a question about how we should be managing. So to what extent should we, as geneticists, care for these patients as opposed to our endocrine colleagues? And where's the correct clinical home or the ownership? I think that's a broader question for our field, right? I mean, I think we see this in cancer. We see this in other areas where, as geneticists, we have an impact in identifying genetic predispositions. And there's recent inroads being made in identifying treatments. And the question is, who owns the treatment once that diagnosis is made? And you can see where oncologists want to own that space, where endocrinologists want to own that space, where for many years metabolic genetics was owned by other specialties. So I think, again, one other opportunity for our field to start owning these kinds of conditions and their treatments, because I think their rarity and the uniqueness of how personalized that approach has to be and how careful and thoughtful you have to be about when to choose the treatment, because we're going to hear soon about how some of these monoclonal receptor agonists are not going to help some of these conditions just by knowing the basic physiology. So having that genetic insight to these rare conditions can help in sort of facilitating the treatment. So I'm an advocate for empowering medical geneticists to take ownership of these rare conditions and develop the guidelines and participate in identifying the treatments and implementing both the surveillance and the treatment process. Great. Excellent point. So a further question comes back to investigation aspects and wonders about when exome should be used. Again, I mean, exome has its limitations, and the limitations include sort of the fact that the health care system imposes barriers to access to testing, number one, right? Number two, the availability of certain, the extent to which the platform or the exome platform that's used is able to identify as many ideologies as possible. For example, some commercially available exome sequencing testing includes copy number variation reporting. Some don't. And the other limitation is interpretation. And I think many labs will feel more hesitant to share variants that they feel are more common in the population versus not. And that may also limit the ability for you to diagnose someone. Whereas if you go to a panel, there may be sort of more liberty to report any variant that's reported as a VUS. So I think keeping that in mind, to me, exome is essentially a test of last resort when you've exhausted what are clearly very common and high yield testing modalities that are available clinically in the form of panels and microarray testing. Now, exome, again, will play a larger role over time because I think what we're going to find as more studies about yield are pursued, particularly in the university field, and more genes are found, that is not going to be as clear as just including them all in a panel, that we may be able to then be more comprehensive if we don't assume that a clinical presentation is going to be restricted to very well-known genes and not an atypical presentation. So I think if you follow a tiered approach, exome sequencing still has a role, but again, in a minority of cases. Great, thank you. So two more questions. Sorry, if I may, I think I've seen the questions in the chat and you'll hear about our experience with a multidisciplinary clinic later. But one thing that is important, and I think we all face these as all the insurance limitations and all these other things, but reaching that threshold as a medical geneticist is in understanding that obesity is a genetic trait and it needs to be tested. I think it's really where the definition of what you do first or what you do last really is less important because we all know that many times our testing strategies are really driven by our resources and abilities and the patient's individual social backgrounds, et cetera. So obviously, I would say that just practicality issue, but understanding that it's a trait that needs to be pursued and that delineation of the phenotype within the family and see how it is inherited needs to be done. I think it really takes that portion of that population that may be polygenic or maybe multifactorial to enhance our knowledge over time. So I think that we're all in the field. There is not a lot of grass that this is a trait that needs to be pursued more often as we do with other things that are more obvious, like developmental delays. That would be my comment to add to that to that definition of what to do first and what to do last. Thank you. Very valuable contribution. So we're actually at break time. There's one more question I think pertains to this session, and then I'll hold the other one over for a wider discussion. The last question is, is there evidence for polygenic contributions to susceptibility to obesity? Quick thought. So, yes, I mean, there are many examples, both from GWAS studies and other contributions from large population studies that have identified a very common variance and with high penetrance on GWAS studies. But again, Sadaf, you might have sort of. Yeah, I think maybe I can speak to that. So so the GWAS studies did highlight lots of common variants. But most recently in 2019, a large paper is about to be a couple of follow up papers actually, in fact, that I've seen where polygenic risk scores, which now include about two million variants. So the key is how much of the variation are you capturing? Before we were capturing some, but it wasn't predictive. So now that we are able to capture more, about two million variants, the scores that are being generated are actually predictive of the development of obesity, of severe obesity, of need for bariatric surgery, for example. Now, that's, I think, a little different than the patients we're mostly talking about here, who are presenting in early childhood with a severe phenotype. But it's quite likely there will be, of course, that grey zone where there'll be a subgroup of patients who have a high polygenic risk score and then maybe a rare variant that's quite penetrant, but not Mendelian, and then that's resulting in a severe phenotype. So that's the kind of area that you colleagues will all be seeing, I'm sure, and are familiar with. Yes, polygenic risk scores, the very recent ones, are now predictive for obesity, particularly in adolescents and adults. Great, thank you. So, excellent. Thank you to all of the speakers, very much appreciated. We'll now break, so we'll return at 2.35 East Coast time. Thank you. Hello, I'm Claudia Soler-Alfonso, I'm an assistant professor of molecular and human genetics at Baylor College of Medicine, and I'm going to be talking to you about pediatric cases and our experience at the Genetics Obesity Clinic. First I want to thank the organizers and the program committee for opening the opportunity to learn more about genetic obesity and the importance of the clinical genetics evaluation for the diagnosis and outcomes and the development of future treatments for this patient population. I have no specific financial disclosures. We will go through four different things today. First, a very general brief review. We will go through the general aspects of obesity in the pediatric population, the reason why we got motivated to initiate a Genetics Obesity Clinic at Texas Children's Hospital. We will review three cases that we have seen at the clinic, and lastly, I will share with you the lessons on genetic testing and obesity that we have learned at the Center for Genetic Disorders of Obesity since May 2019. Through the course outlined today, you have heard extensively about epidemiology of obesity. We know that this is a common trait with more than 124 million children worldwide affected by obesity. Texas, for sure, is one of the states that presents a higher challenge. We have significant obesity rates here. For instance, in the city of Houston, the obesity rate can be as high as 34%. In more detail, in the pediatric population, genetic obesity tends to be considered as an important phenotype, and oftentimes, genetic testing is pursued. This is particularly true in cases where severe hyperphagia is noted, and in cases where severe early onset obesity is diagnosed, and this is usually before the age of three years old. In these cases, genetic testing is able to identify an etiology in at least 10% of the cases. If a syndromic presentation is suspected, a screening can yield a genetic diagnosis in up to 22% of the children. For the last two decades, efforts to understand and guide clinicians on how to undergo evaluation for genetic obesity has been made. Classically, the literature instructs us to divide the genetics of obesity into syndromic and non-syndromic obesity. This classification is helpful in many scenarios, but in many other times where children don't have a classic presentation for a classic genetic syndrome, such as Prader-Willi syndrome or Bardem-Mittal syndrome, et cetera, this classification may not be too helpful in the clinical setting. So what referral should we make? Is obesity an endocrinology problem or a genetic problem? Most times the answer is both. We know now that adipocytes are understood beyond a simple cell for fat storage, but beyond that as an organ that helps signaling and the maintenance of appropriate adipose tissue. We know that the leptin pathway as well as many adipokines are recognizable causes of obesity and that frequent comorbidities have an endocrine component that needs to be treated. For instance, now clinical geneticists and endocrinologists have seen increased rates of referrals to their specialty clinics for the evaluation of a potential endocrinology or genetic cause of obesity. So in May 2019, I was approached by Dr. Stephanie Sisley from the endocrinology team here at Texas Children's with the concern of putting together a dedicated clinic space for multidisciplinary evaluation of patients with concerns for genetic obesity. After using different tools through the electronic medical records, we set up the Center for Genetic Disorders of Obesity. We agreed to begin patients with specific eligibility criteria. We wanted to capture those patients that were at a higher risk and that they needed a joint evaluation by endocrinology and genetics more urgently. We wanted to start with patients with severe early onset obesity, and instead of just using the three-year-old cut up, we increased our cut up to five years old. We also used the terminology severe obesity or anyone having a BMI higher than 120th or the 95th percentile in patients that also have concern for hyperphagia, patients with dysmorphic features, and plus minus developmental delays. We didn't want developmental delays to be in its stopping criteria or not allowing patients with normal development to be seen in the clinic. So we also wanted to have the ability to follow these patients over time, to document our joint evaluations thoroughly with all the right information, specifically dietary information, concern for hyperphagia. We wanted to go beyond the objective observations and be able to use metrics, and ultimately be able to follow outcomes in terms of genetic testing and in terms of pharmacological therapy. We've been doing the clinic since May 2019. It's been a monthly clinic, and up to February 2021, we continue to receive referrals and getting busier. So we'll show you three cases of genetic obesity. Some we inherit, and now we're following the clinic. Some are new cases that we have seen in the clinic, and the last case is a case of overgrowth versus obesity, which is a common question area of great referrals for us. So the first case is a four-year-old that first came to the clinic with concerns of excessive weight gain. She was born large for gestational age. She had an uneventful transition to solid food during infancy. Her mother got more concerned about her weight when she was approximately three years old. She had clear food-seeking behaviors. She will eat dog food and the parents had to be in constant supervision. They had to secure the refrigerator and hide the food from her. She also had very limited physical activity and it was very challenging for the family to maintain dietary compliance. She had significant behavioral outbursts whenever food was denied and there were several reasons why mom expressed these concerns including transportations and the challenges with behaviors which made compliance difficult to achieve. Her medical history was remarkable for high blood pressure at four years old, elevated liver enzymes, obstructive asypnea. In more detail around her pregnancy, it's important to notice that she had gestational hypertension but no gestational diabetes. She was delivered at term and her birth weight was 10 pounds. She was discharged after the five days of life but the only neonatal complication was neonate neonatal jaundice for which she required phototherapy. She was also noted to have red hair at birth. Her developmental history was not that remarkable. Her fine motor skills and gross motor skills were achieved on time. She was fully tolerant at two to three years old. She was able to make sentences at two years old. At four years old, she had mild speech articulation deficits but she was receiving therapy and making progress. This is her family history. Both families denied consanguinity. The families of mixed Mexican and Caucasian descent. There is significant history of obesity on the maternal side of the family. Remarkably, there are two full siblings to the problem. The first, a 14-month-old also with obesity and the second, a deceased boy that passed away at three weeks from sudden death. He was reportedly also large for gestational age but the autopsy was unable to reveal a specific cause of death. The problem's mother is 28 years old and also with severe obesity. She already had multiple strokes. This is a summary of her vital signs during the initial evaluation. As you can see here, her BMI was already at 33.9. So she was generally non-dysmorphic with acanthosis negligens but she had no other pertinent physical findings. Here you can see at a glance her weight, length for age, and her BMI. So you can see she had exaggerated weight gain throughout the years that is on control. Her stature is also a high get a suspected for her mid-parental height and her BMI has sustained incredibly high through the years. The workup summary in this slide, it's just to give you more of the numbers that we usually see in our clinic with patients that oftentimes come with a family history and personal history of liver osteoarthritis and liver dysfunction. So she had elevations in AST, ALT, hypertriglycidemia, some vitamin D deficiency, but all the endocrinology testing was normal. She had a normal renal ultrasound and also a normal sleep study with the mild central sleep apnea. Her hearing evaluation was normal. Genetic testing for her was remarkable for an exosequencing back in 2016, which found a heterozygous likely pathogenic variant on the Nc4R. The variant was located in exome one and was considered to be damaging and probably damaging by the predictive softwares. Mother was found to be heterozygous and eventually her sister was also found to be heterozygous. So along with this patient, her mother and her sister were now considered to have melanocortis for receptor deficiency. So the Nc4R was found to be melanocortis for receptor deficiency. So the Nc4 receptor is a redoxin-like GPCR or redoxin family couple to heterotrimeric G proteins. The function of the receptor is to transmit signal by activated adenyl cyclase. The receptor is restricted to be expressed in the nervous system and is mostly found in the hypothalamic nuclei, which is very important for the regulation of energy and the balance of energy. The receptor regulates food intake by integrating a society signal provided by the alpha-melanocyte stimulating hormone, here in this picture shown as alpha-MSH, and an antagonist signal provided by the agouti-related protein AGRP. Nc4R is a major role player for society regulation, energy expenditure, and growth. In more detail about this variant, this patient variant has been seen in another six individuals with exaggerated overweight and severe obesity. It's of low frequency on the Latino population, and all in vitro functional studies indicate the pathogenicity, through pathogenicity of this variant. She has been doing remarkably well after the diagnosis. This is a case in which whole exome sequencing really gave a lot of light and took the family out of the simple idea that they were probably eating too much and not exercising. So, after she was diagnosed at around eight years old, a decision was made to start a trial of off-label use of ADHD medication to moderate her appetite. And ever since, she has made significant improvements, including a significant increase in her BMI, as much as 197 percentile. She also has significant improvements in food-seeking behaviors. Oftentimes, she will even come home with some food in her lunch bag. The family has made also significant improvements in not eating out, getting healthy lifestyles in terms of food. But all of this is because her appetite has improved significantly, so she's moderating her appetite much more, so the behavioral difficulties are not as notorious. She's also been able to increase her physical activity, even playing outside for two hours at the time. So, this has been incredibly helpful for her. The second case is a nine-year-old. He was also seen for excessive weight gain at the clinic. He had a history of recurring sinus and ear infections since he was three or four months old. This will happen apparently almost on a monthly basis. He was eventually diagnosed with conductive hearing loss and hypogammaglobulinemia at three years old. He's currently receiving IBIGG infusions, which are helping with the frequency of the infections. He also has excessive day sleepiness without a normal sleep study, showing mild obstructive sleep apnea. He has history of speech delays and fine motor delays and concerns for recent excessive weight gain. Mother was ensured that this was related to the pandemic, but there was definitely not a history of hyperphagia, but definitely a concern for excessive weight gain in the last year. The prenatal and birth history was uncomplicated. He was born at a term and appropriate for gestational age. He went home on day light number two. In more detail about his developmental milestones, as you can see here, he, especially in the social aspect, is able to make eye contact. He responds to a speech, but he's socially immature. At nine-year-old, he's in the third grade, and he's completing course work at a first grade level. He's receiving ancillary therapies, which he responds well to that without history of developmental regression. And there's still concerns about autism spectrum disorder diagnosis, but he hasn't achieved that to the point of this evaluation. He was seen by a developmental psychologist, and this investigation is still ongoing. As you can see here, a three-generation pedigree was obtained also in this family. And the patient also has a brother who is healthy and has met all his developmental milestones on time. His mother is reported to have dyslexia. The paternal family history is significant for an undefined learning disability and potentially autism spectrum disorder in a paternal uncle. But a specific genetic disorder was not reported from the family. The family is of mixed Caucasian descent. This is his physical examination. As you can see, he has some mild dysmorphic features without slanted papilla fissures and perhaps a flat nasal bridge. But as you can see here, since April 2019 to almost two months after, he was gaining weight very rapidly. Here is all his growth at a glance. As you can see, I think the most remarkable aspect is the rapid weight gain, which may be not that notorious without the background or thinking about genetic obesity. But as you can see here, this also affected his growth velocity and more remarkably, his BMI is increasing rapidly. So all the workup with him was unrevealing prior to genetic testing, except for the hypogammaglobulinemia. He had all the endocrinology testing completed, which was also unremarkable, including also brain MRI and an audiology evaluation, which did not give any major clues about potential etiology. So he underwent the usual route of global genetic testing for developmental delays, and the testing revealed a deletion on chromosome 16p112. So here you can see that this patient was considered to have a pathogenic deletion. Parental testing was negative, so this was a de novo pathogenic deletion, and it was between breakpoints four and five. As you can see, the critical area of the 16p112 deletion or duplication region here in this ideogram highlights the region of interest in the short arm of chromosome 16, and all the genes encompass or span in the breakpoint number four and number five. The green bars are all omin genes, and the red bars represent genes that are expressed in the brain. This is important because all these genes are important, and they had to have a significant impact in brain development. But what's important about this well-recognized micro deletion, particularly in chromosome 16, is that this is a very rich area on homologous low copy repeats. So it's an area that's very prone for genetic rearrangements via LCR-mediated non-allelic homologous recombination, and we know that patients with deletions in this area have several distinct recurrent imbalances, and several breakpoints have been described, but more particularly breakpoint four and number five are the importance for this patient. Obesity is a common trend on individuals with 16p112 micro deletion syndrome, and usually it starts in between eight to nine years old, so it is right at the age of this patient presented to our clinic. Most recently, the gene of interest that's including between these breakpoints is the SH2B1 gene, and this gene has been recently reported in association with obesity, and it's probably the culprit gene causing the excessive weight gain in these individuals. The gene is important as it plays a role in leptin and insulin regulation, so the gene encodes for a member of the SH2 domain containing mediators family, and the protein made by the gene activates various kinases, and it may function in the cytokine and growth factor, receptor signaling, and cellular transformation regulating the leptin pathway through JAK2. So, interestingly, we have found other patients in our clinic that have variants in SH2B1, but the further knowledge needs to be developed to understand what a single pathogenic variant in this gene will do, but in terms of the deletion, we think this is the most important gene. So, in many of the cases that we see when we have obesity and overweight, and there's a genetic component, it's important to initiate weight management and nutrition counseling, so we work extensively with the family to maintain active lifestyle, and we began surveillance of all the obesity-related complications, including sleep apnea, and liver steatosis, et cetera. Last case is case number three, a case of overgrowth versus genetic obesity. The first evaluation was a four-year-old. The patient was a Hispanic female with renal degenesis, mixed conductive sensorineural hearing loss. She was born on time, but had no major complications, especially, or the only complication that was reported by ultrasound was a single kidney, and postnatally, the ultrasound showed that she had two kidneys, but one was pelvic. At the time, she was known to have met all the developmental milestones, including speech abilities, and she wasn't wearing a hearing aid anymore. This was the initial pedigree that was completed for her. As you can see, no other family history was reported, but families were of Hispanic descent. They denied consanguinity, so nothing remarkable. Re-evaluated again at seven years old, at the time considered to be an average student, but at the time, for the first time, it was noted that she had significant increase in her head circumference, weight, and height, all at higher than a 95th percentile. She also had some mild facial asymmetry, which you can see here in this picture, but remarkably, no genetic diagnosis was achieved at the time, and you will see in a second the genetic testing strategies, but this is the first time I met this patient at 14 years old. As you can see here, she has elevated or increased high weight and FOC for her age with a BMI of 29. She was considered to have mild dysmorphic features, including dolichocephaly, frontal bulging, and a long philtrum. You can see here her growth and even much wider detail, including her height and weight and her FOC, so you can see that she's overall symmetrically large for her age. She had bone age studies at the time. The bone age was 5.7 standard deviations advanced, and the phalangeal bone age per standards were considered to be 12 years old at the time of this x-ray. She was 7 years old. She also had left upper rib anomalies with concerns for cervical ribs, so some potentially vertebral segmentation anomalies, mostly at the cervical-thoracic junction. So, given this pattern of overgrowth with vertebral malformations, several differential diagnoses were considered, including brachio-to-renal syndrome, and also the question of the pelvic kidney was in consideration. Sotosyndrome was also considered at the time, given her growth problems and renal anomalies, and Weaver syndrome was also considered due to the tall stature, microcephaly, and advanced bone age. Syncyngolabibemal type 1 was also considered due to the microcephaly, broad nose, coarse facial features, the vertebral fusion or vertebral segmentation anomaly, and the renal component. Eventually, she had a CMA that was normal, and gene sequencing for AR1, 6,1, all negative, and also NST1, and eventually, gene sequencing for GPC3, for syncyngolabibemal, and she was found to have a heterozygous variant in this gene. As you can see here, the variant was most likely benign, but it was a low frequency. There was no particular concern that this variant could be real, and at the time, an exon sequencing was ordered, but the exon sequencing was denied. Fast forward, a patient continued to struggle with overweight and overgrowth in general, but now we knew that her brother was also presenting with similar symptoms and also concerns for overgrowth. Here is her brother, and similarities for dysmorphic features, slanted papillary features, frontal bossing, coarse features. He had much more marked developmental delays, but again, the exon sequencing was not obtained at the time. She presented again at 13 years old at the time with focal neurological symptoms. She had vomiting, blurry visions, lower speech, and left-sided weakness. She was also febrile, and there were concerns she may have COVID-19. She tested positive for antibodies, but nonetheless, all the hospital workup was done for hypercoagulability. Eventually, she was diagnosed with a superior sagittal sinus and right transverse sinus cortical venous thrombosis. It was quite extense, and she received appropriate treatment and all the consultations. Throughout the workup, the only etiology that was identified was a high homocysteine level provided the diagnosis of homocysteineuria. This was subsequently repeated, and then finally, an exon sequencing was sent. The patient was finally treated with pyridoxine and was pyridoxine responsive, and the exon sequencing found a homozygous pathogenic variant confirming the diagnosis of classic homocysteineuria. So, homocysteineuria is known as CVS deficiency, or cystatium beta synthase deficiency, which is important for one carbometabolism and transsulfuration pathways. The function is condensation of homocysteine with serine to form cystatine, and we know that pyridoxine is the precursor for pyridoxal phosphate, which is the co-factor for CVS. Some patients with pyridoxine-responding forms have some enzyme activity and therefore may present with a milder phenotype, which was the case. There is not a clear link between overgrowth and homocysteineuria patients, but we know that homocysteine elevations do cause endoplasmic reticulum stress, an abnormal intercellular signaling, and impaired ventilation reactions. So, this is for more forwarded analysis. The most important aspect of this case in relation to this class of this course is the importance of continuing the workup whenever genetic obesity versus overgrowth is suspected, especially in this patient in which an ideology that was treatable was eventually diagnosed. So, here we are fast forward. I have only a few more minutes to tell you more about our clinic demographics. In average, our patients are usually evaluated in between 5 and 10 years old, average age around 7 years old. Most are actually female, and most are Hispanic-white patients of Hispanic-white background, and most have commercial insurance. Actually, around 42% of them, but the remaining are actually covered by state-based insurance. The mean BMI for our patients is around the 95th percentile. So, we do have patients with excessive, exaggerated as the first case that we show you, but we do see that this mean BMI is conserved across the ethnic backgrounds, which is an important part. Genetic testing has been ordered in at least in almost 60% of the patients, and as you can see here, CMA is the most common test, followed by the sponsor by industry obesity panel. Testing approval by insurance continues to be a headache in general, not different from other genetic clinic practices. And as you can see here, all the times we order testing, depending on what we order, we get different levels of approval, but in the majority of the cases, we were able to complete testing. The diagnostic yield is still fluctuating, but it appears that barriers of a non-clinical interest, either by exosequencing or the sponsor obesity panels continue to lead, and we have a small portion of actual diagnostic testing. And here is a list of other genes of interest in which we have found variants of a non-clinical significance, which will continue to feed our interest to continue to delineate this population much further. So, the things that we have learned are that these red flags do help and guide the diagnostic odyssey. Obviously, we see a patient with syndromic obesity, as we just saw case number two, will probably go first with a chromosomal microarray analysis. In the other cases where there is no dysmorphic features or major red flags for developmental delays, we will probably offer genetic testing with a sponsor gene panel for genetic solicity followed by a whole exome sequencing. The key factor is hyperphagia, and though we have some tools in which we can measure hyperphagia, this is difficult to achieve, but this is one of the areas of improvement that we have in our clinic. So the things that we have learned the most is that we need a great deal of compassionate care. Families do struggle significantly. They've been bumping back and forward, seeing many specialists trying to secure a diagnosis and we are performing a quality of life study. The need for non-reimbursed global genetic evaluation, it's still hard to convince insurances that obesity is a genetic trait and needs to be investigated. We also need to fine-tune our dietary assessment and understand how much the diet is contributing to weight gain in order to help families more. And we also need a more systematic evaluation of what we call early onset obesity. So we started a registry with assessments, so we're going to be collecting first sets of data in April. And we also need to follow up more about our patients where we have done off-label treatment with ADHD medication for hyperphagia. We're currently treating 14 patients and obviously this is a clinical trial opportunity that is in the future. And of course, we want to be able to investigate these genetic variants with more translational collaborative efforts. With these, I just want to acknowledge first the patients and families who allow me to share their cases and stories today. And Dr. Stephanie Stensly, who is the sole of our clinic and very passionate about studying these disorders. Dr. Matt Snyder, who evaluated case number three with me and helped preparing the slides. And Dr. Horn, who kindly helped me with a lot of the information prior to us knowing case number one in our clinic. We will have the opportunity to discuss questions in the live session. Thank you for your time. Thanks for coming. My name is Margaret Dow. I am a professor, sorry, assistant professor of OB-GYN and I'm board certified in both OB-GYN and in obesity medicine at Mayo Clinic in Rochester. And I was humbled to be asked to talk about obesity and pregnancy. So we'll go through a couple of cases talking about what we know, what we think we know and where we're headed. I have no financial relationships with industry, no off-label uses of medications. The one thing I'll say as a disclosure is I approached this from an OB-GYN perspective and from an obesity medicine perspective and I'm not a geneticist. So forgive me if I sound like it's just a dalliance in genetics because that's definitely not my area of expertise. We'll talk about two different cases. We'll talk about the genetic implications in those cases and prognosticate as to where this research might lead because there's some very interesting directions that were pointed in. So here we go. Polygenic obesity and pregnancy. A 38-year-old gravity two pair of 1001 at 39 weeks comes in for induction. So she's been pregnant twice. She's had one delivery and she's at full term. Her prenatal care includes all the basics. Her blood type is A positive. She's rubella immune, hepatitis surface antigen negative. She had a normal one hour bucola screening of 129, abnormal is greater than 140 and her group B strep is negative. Those are just obstetric details, may not mean much to you, but it basically means she's just coming in for normal routine induction. She has no medical surgery, no major medical history or surgical history. Pregnancy is uncomplicated except her excessive gestational weight gain. She had a prior vaginal delivery without any complication and her cervix is closed. So you start her induction, give her some cervical ripening. She gets to six centimeters. Then she has no change in her cervix for more than eight hours. She develops maternal tachycardia, fetal tachycardia, and eventually a fever demonstrating choreoamnionitis and ends up with a cesarean birth for a nine pound, nine ounce baby followed by a wound infection requiring opening of her wound and readmission of the hospital for IV antibiotics. The neonate has hypoglycemia and both of them end up with a prolonged hospitalization. So what kinds of things went wrong? When you look back in the history, there are several things associated with obesity and pregnancy. So the part that I didn't tell you is this woman starts her pregnancy with a BMI of 50. Starting a pregnancy with a BMI of 50 increases virtually every complication and the difficulty in obese gravidas particularly is that the weight gain often happens as a result of postpartum weight retention from a first pregnancy. So what happens in a first pregnancy does not predict what happens in a second pregnancy. In women with normal BMIs or women who are overweight, who've had a normal pregnancy and delivery previously, they are overwhelmingly likely to have a normal induction or normal vaginal birth the second time around barring any complications in that pregnancy such as development of gestational diabetes. And in women who have higher postpartum weight retention from a pregnancy and then further weight gain in a pregnancy leading to BMI greater than 30, greater than 35, greater than 40, there are several break points for risks. They have markedly increased risks of abnormalities in their second pregnancy and delivery just like this woman. Women with polygenic obesity, likely polygenic obesity, have several obstetric issues. They often have infertility and require assisted reproductive technology. Assisted reproductive technology in and of itself increases the likelihood of fetal abnormalities and placental abnormalities and pregnancy complications including delivery complications. There's an increased risk of congenital abnormalities and we'll talk about those in a moment. There are issues with excessive weight gain. A woman who starts a pregnancy at a normal BMI is far more likely to return to a normal BMI than a woman who starts with a higher BMI and then continues through the pregnancy. They're far more likely to gain excessive weight. And then there are higher risks of virtually every complication in pregnancy, preterm birth, low birth weight, and macrosomia, so both sides of the coin for the fetal size. So higher risk of gestational diabetes and hypertensive disorders, higher risk of labor dystocia and shoulder dystocia, so labor that tends to be really prolonged and then shoulder dystocia is when shoulders actually get stuck during delivery, which is an obstetric emergency. And a higher risk of both cesarean birth and postpartum complications. Matter of fact, a woman who starts a pregnancy with a BMI of 50 or greater has greater than a 50% likelihood of requiring cesarean birth. So the highest risk patients also have the highest risk of needing a high-risk surgery. So it's a terrible rock and a hard place to be stuck in. So let's talk about recommended weight gain in pregnancy, since I mentioned that's one of the problems. The former Institute of Medicine recommends that women with a BMI of 18.5 to 24.9 gain 15 to 25 pounds in pregnancy, BMI greater than 25, 11 to 20 pounds in pregnancy. The problem is, as you may know, that's two thirds of women right now, even in the reproductive ages that have a BMI greater than 25. Furthermore, less than 17% of these women are going to adhere to the normal guidelines of exercise in pregnancy or exercise outside of pregnancy. And 50% of those who have excessive weight gain in the pregnancy are going to remain obese after their pregnancy. They're not going to lose the weight either in the immediate postpartum period or even in the 12 months following the pregnancy. But as I mentioned before, if they start the pregnancy with a normal BMI, they are nine times more likely to return to baseline after the pregnancy. So as I'll make the point several times through this presentation, one of the most useful things we can do, particularly as we elucidate potential genetic interventions, is target women to help them achieve a normal BMI before the pregnancy to reduce a host of these complications. Pediatric and neonatal outcomes are also greatly affected by maternal obesity. There's an immediate risk of birth injury, like I talked about, the shoulder dystocia or shoulders getting stuck. There's a markedly increased risk of hypoglycemia requiring admission to a special care nursery and an increase in jaundice in the first few days of life. Now we've come a long way with jaundice and can often treat that as an outpatient, but there are situations in which it requires inpatient management, thus prolonging hospitalization and decreasing maternal and fetal bonding or maternal neonatal bonding in the first few days postpartum, which we know is a really important marker for the first year of life and development. Long-term, these kiddos have a markedly increased risk of obesity, about a 4.5% increased risk of childhood obesity per two pounds gained by the mama. So every two pounds over the recommended weight gain increases their risk really dramatically. They have higher adiposity, particularly centripetal adiposity, higher risk of non-alcoholic fatty liver disease, lower HDL levels throughout life, and higher visceral fat concentrations, which we know are risks for all cardiovascular maladventures in obesity. There's also a 30% greater risk of congenital defects overall. The prevailing defects that we see are orophageal clefting, heart outflow tract abnormalities, hypotrophic left heart syndrome, and potentially hydrocephalus, clubfoot, and diaphragmatic hernia, though these are a little bit less clear in the literature. And the longer-term risks include things like astrocytoma, childhood leukemias, all kinds of atopic spectrum disorders, including asthma, again, non-alcoholic fatty liver disease, all cardiometabolic abnormalities, so hypertension, hyperlipidemia, the full spectrum of metabolic syndrome, early adrenarche for both genders, and possibly some associations with lower IQ, attention deficit disorder, and depression. So a lot of things that we can change by potentially moving the needle on maternal obesity and weight gain in pregnancy. Certainly polygenic, and as we identify more and more gene targets, we may have some great opportunities to affect greater long-term health for mamas and for babies. So things that we can do for women with polygenic obesity, again, in early pregnancy, the best thing we can do is outline our expectations. So talk about weight gain in pregnancy, talk about exercise guidelines in pregnancy. The vast majority of United States pregnant women are unaware of the exercise guidelines in pregnancy. They all think they don't need to exercise in pregnancy. It's probably really dangerous, but it's not only not dangerous, it is highly beneficial to them and to their offspring. We do early glucose testing for all women with obesity, including first trimester screening to make sure there's not an underlying disorder of glucose metabolism. Nutritionist and dietician intervention can be critical in guiding dietary choices. We'll talk about that a little bit more as we talk about some of the identified genetic underlying causes. The availability of exercise, and what I mean by this is make sure that they have a pair of running shoes. You know, encourage them to get a membership in a gym or get an online app that helps stimulate them to exercise. We know that just having easy access to exercise increases the likelihood of meeting the exercise guidelines. It's also important to review weight gain every single visit. We found through a small study at Mayo that just mentioning weight gain and how the patient's doing on the long-term spectrum does seem to mitigate overall weight gain in the pregnancy. And finally, encouraging postpartum weight loss. This is a really difficult rabbit hole because typically in OBGYN, we see women for about six weeks after the pregnancy. More than half of women have not lost their pregnancy weight in that first six weeks. This is a big change over the last couple of generations when most women had lost a lot of their pregnancy weight by that six-week visit. So they haven't lost the weight already. They're leaving their obstetric care, and it might be another three years before they see a physician. As you know, PAP guidelines have changed, and breast screening guidelines have changed, and women are far less likely to go see the doctor every year just because. So it may be quite some time before anybody sees them or has any opportunity to intervene. Of course, as I mentioned, probably the greatest thing that we can do to mitigate these risks is start with a lower BMI. So if they get pregnant with a lower BMI, all of these risks go down concomitantly. So let's talk a little bit about monogenic obesity and how it presents in pregnancy. So we have a 32-year-old gravity one who comes in for a new OB visit. She has a medical history significant for a binge eating disorder and had early onset obesity as well as increased linear height early in pregnancy. That is just the quintessential presentation of a patient with MC4R receptor deficiency. Now there are a whole bunch of different types of MC4R deficiency, and that falls far more in the genetic realm than in the OBGYN realm. But I'll review for you the basic pathophysiology. MC4R receptors are concentrated in the paraventricular area of the hypothalamus, and they mediate all of the orexogenic, that's the agouti receptor proteins, and the anorexogenic or alpha melanocyte-stimulating hormone signals. So they balance hunger and satiety. And when you knock out these receptors, you see these things like binge eating disorders, and like I said, increased linear height with obesity, which is a sort of odd combination that may lead someone to go, hmm, and think about one of these monogenic kinds of causes. MC4R deficiency is associated with two of the syndromes in childhood that are associated with obesity, including Vardet, Beutel, and Ahlstrom. It's a little bit outside of where we're going to go right now. But on its own, there are at least 72 variants of MC4R receptor abnormalities, and all of those 72 are associated with different patterns of obesity and different associated risks and targets for intervention. So this particular patient has used CBT, and she's gotten her BMI down to 31 before she starts the pregnancy, which is totally awesome. We're going to start in a much better place than if she had started with class 3 obesity. So during her pregnancy, what are we going to do to try to help her? Well, first of all, the effects of MC4R receptor deficiency seem to attenuate over time. So for women with MC4R deficiency in childhood, I told you they have a tendency to binge eat and have rapid weight gain in childhood, but they tend to have a decrease in those behaviors over time, probably due to some difference in methylation and epigenetic changes. But that's not really clear yet. It just seems to get better as they get a little bit older. So it is not outside of norm for this woman to be able to get down to an almost normal BMI before her pregnancy. Part of the issue is that MC4R receptor deficiencies have variable penetrance. So they're definitely heritable, but they express themselves very, very differently. What's interesting is when we look at the different areas of hyper and hypomethylation on the receptor genes, it's very similar to the difference in receptors for preterm infants, who we know are also more likely to become obese in childhood. So this may be part of the explanation for those infants that have rapid weight gain in childhood who are born prematurely. So again, lots of room for moving the needle on a lot of poor health outcomes as we work with these receptors. What's interesting is these women do tend to have higher fat diets and they tend to respond worse to high fat diets. It's a terrible catch-22. Seems to be that the craving is for higher fat diet and higher processed foods. In fact, in a couple of studies that demonstrated very clearly that pregnant women with MC4R deficiency dropped their protein intake by about 10% in pregnancy and drastically increased their intake of highly processed high sugar foods. Now the study was done with no guidance as to dietary changes. They tested for several different genetic variants associated with obesity and followed a self-recorded diet notebook, both before the pregnancy and during the pregnancy. So no shaping whatsoever. They knew that they were being tested for some genes, but they didn't even know the genes were associated with obesity. And MC4R is independently associated with those kinds of dietary pattern changes in pregnancy. So very, very interesting stuff. There is interestingly as well, a medication that's associated with MC4R called setmelanotide. It's MC4R agonist. And in the early trials results in weight loss of about 10% at one year. The problem is of course, none of these medications are going to be approved in pregnancy for quite some time. So we don't have a great intervention once the woman has become pregnant. Now we talked about with the polygenic obesity exercise and exercise availability. One of the big issues in pregnancy in women with MC4R deficiency is it appears that if we make exercise readily available, they intrinsically have an increased motivation to exercise, to balance out the extra calorie intakes. So very interesting. A lot of these studies are of course in murine models. So not a clear transition to human models, but it appears that they'll try to balance out their energy expenditure and energy intake if you make it available. So risk mitigation is really also an interesting topic in pregnancies complicated by obesity and particularly those with MC4R deficiency. There are some fantastic long-term benefits actually to MC4R deficiency. First off, in gestational diabetes in these patients, which is far more likely, the postpartum changes are far easier to affect with lifestyle interventions. So women with MC4R, CC or TC subtypes respond really well to lifestyle interventions with lower fasting insulin and lower beta cell activity, just from intervening in lifestyle, just from changing their diet and getting them to exercise further. You see true biometric changes that contribute to greater overall health. There's also a very interesting effect on placental ischemia. All of these studies are done in mice and in rats so far. But very interestingly, when we look at MC4R blockade or MC4R knockout mice, they have a much lower risk of developing hypertension overall. And then when they're pregnant, while their blood pressure does increase in the pregnancy, they don't have the same kind of placental flow abnormalities that other women have. This is fascinating because we know in obstetrics that obesity is highly associated with risk of hypertensive disorders in pregnancy. But for this particular subset, those increases in blood pressure are not met with the same kinds of vasospasm and other vascular remodeling that we see in the placenta that affects the fetus. And then they do not develop the same downstream effects of impaired placental blood flow. So in human models, we think that that impaired placental blood flow is a big contributor to the systemic changes that we see and the long-term health risks in mama of developing any kind of gestational hypertensive disorder. So we have the opportunity to benefit fetus and mom just through MC4R deficiency, probably very particular subtypes, and probably not something we would want to induce in a pregnant woman given the other risks. But it's interesting that there may be some kind of protective effect. So as we look at potential targets, there may be some light at the end of the tunnel from the ways that we can't necessarily intervene. So take-home messages, the pregnancy risks from obesity are huge, the genetic implications of obesity and pregnancy are tremendous, and MC4R is just one of very many targets that are currently being investigated. The potential to affect long-term health benefit for mom and for baby are clear and extend to virtually every system of development. So it'll be very interesting to see where this goes over the next 10 to 20 years. Obviously looking at the genetic schema involved in obesity has been a 25-year process already, and the strides have been massive, but there's a lot more to go. These are some of my references. I know we'll have many minutes for discussion so that I can address any questions that you have. But thank you for being here and thanks for listening. We want to thank those presenters, and we now are going to have a panel discussion, and we have a number of questions that have come up. I think one of the big questions that I thought was quite interesting related to hyperphagia, and the question was, I'm interested to hear what the criteria you mentioned for hyperphagia are. I feel like some families say their children are hungry, but the family does not have to lock up their refrigerators, but often find their children sneaking snacks in the night and ask whether that qualifies as hyperphagia. So I think that's an interesting point of what is hyperphagia and how do we measure hyperphagia, and I'm wondering if any of our speakers would be able to comment on that. Yes, I think particularly in our clinic experience is a topic in which we spend a bulk of our evaluation with our patients, specifically in those that don't have a classic presentation that will be more concerning for a syndrome. And as we're all familiar, there are different tools out there that you can utilize to quantify this symptom a little better and make it more objective. So for instance, some of the tools that people use for Prader-Willi syndrome is something that we try to use at least to have some sort of quantification. And as you all may be familiar with this, this is a set of 13 questions that include all these questions, including food in the trash, hiding food, how smart the patient is about getting food, what are the behaviors about asking for second portions. So that gives us a sort of quantification to understand it. There may be some concern for hyperphagia in those patients in which that can be a little much of a gray area. I also use other things that I just use for my metabolic training. So some of the things that I do, it takes me five to six minutes in average is to do a 24 hour dietary recall. So I just go through all the different things they eat in the last 24 hours the parents were with the patient. So that gives me a window opportunity to understand what are their dietary habits until we refine our dietary assessment much further as we continue to move forward with the clinic. That also opens opportunity to know, for instance, if their dietary habits are not that healthy. In many cases in which we don't offer testing, we provide more recommendations about avoidance of high calorie meals or items, in particular juice, sodas, all those usual things. And I had seen families again for follow-up in six months and they had lost weight and improved their BMI. So that is a way that we have found to be helpful to try to tease out if the hyperphagia may be driven by a high calorie meal that may expect that insulin and two or three hours later may be hungry again. So it takes that time that we spend and that the multidisciplinary studies allow us to spend more time getting a little bit more of that data that could help understanding better who will be a good candidate for testing. If at the end of the six months they continue to struggle with similar issues. Does anyone here utilize any clinical measures of hyperphagia in clinic rather than just in clinical trials? We do utilize the hyperphagia questionnaire that was developed by Elizabeth Dykins that Claudia was talking about. It of course has its limitations and we've also developed a series of questions that I ask the families about. For example, like that question alluded to, kids get up in the middle of the night to get snacks. That's one question I ask, does your kid sleep through the night or do they get up to try to eat when everyone else is asleep, things like that. So yeah, we do use the Dykins hyperphagia questionnaire regularly with all of our obesity patients just to try to get an assessment of hyperphagia as good as we can, knowing the tool has its limitations. Great, Sadaf, could you comment on the common SNPs near the MC4R region and kind of how that's not necessarily MC4R deficiency? Yeah, I just wanted to clarify, there are a couple of things that were coming up in, I think Margaret's presentation just there where she was referring to the obese lady who was pregnant and referring to that as MC4 deficiency. And then a little later we saw on the slide, CC and TT. So obviously I'm thinking some genetics colleagues will be already familiar, but just to be sure, that refers to genotypes that are reported on some commercial chips or platforms when people ask for a risk score. So that refers to as common SNPs that are around MC4, effectively three primed from MC4 and that are in the population that do confer an increase in MC4 deficiency. So they do confer an increased susceptibility to obesity, but that's not the same as MC4 deficiency. So what we've all been talking about earlier, obviously in my talk, and then also Claudia in her young child patient, that is loss of function mutations in the gene itself, causing a dominantly inherited form of obesity. Now that is not the same as the patient that Margaret was referring to. And I think it's important to correct that, that's not MC4 deficiency, basically polygenic obesity with a particular SNP being found there. And I think the other point is really important. Her patient may well have had binge eating, but binge eating is, one needs to be a little careful about the terminology of binge eating, I think. It's been used a lot in the psychiatry field for a long time with very specific connotations. It's different from hyperphagia. And hyperphagia is an increased drive to eat and constant hunger. And binge eating is of course is very different and with a kind of psychiatric connotations of a disordered pattern of eating and vomiting and purging and those kinds of things. So it's important not to mix up the two terms. Another question was, is red hair at birth a significant finding for MC4R mutations? No. So red hair is a feature of POMC deficiency because it's the lack of the ligand POMC and POMC acts on MC1 receptor. So red hair is a feature of POMC deficiency, not of MC4R deficiency. If a person has MC4R deficiency and red hair, they happen to have the two things. It's interesting about the red hair since we're talking about it. People of different ethnicities may not have red hair. So people of Turkish, Middle Eastern, Southeast Asian ancestries may present with darkish hair, but they may have red roots or just a slightly lighter tone to their hair than other family members. People of Caucasian or European ancestry will have pretty fair hair, sorry, will fair skin and often have red hair. And people of scientific and genetic interest, people of Celtic, Scottish, Irish origin who have freckles and red hair have activating mutations in the melanocortin-1 receptor. So there's a kind of longstanding genetic basis for understanding this pathway. And I was curious about that when I was preparing this case because when I first talked to Mom, she kept asking me about this. I was hoping that this will be picked up and thankfully it was, because it's one of those things that help us thinking about the likelihood of being genetic a little higher, but it is certainly confused by the background which is exactly what happened with these families. Yes. Another question was, what disorders present with early onset obesity less than one year without hyperphagia? And Kim, I think you presented some of the syndromic forms that may not have dramatic hyperphagia and mentioned that Alstrom frequently doesn't have significant hyperphagia. But what about the non-syndromic obesity conditions? Do any of them not have hyperphagia? Kim, I'm not sure if we can hear you. I was hoping that non-syndromic obesity presenters would chime in there. I think Alstrom is one of the few that has onset of obesity at an early age, like one to two and no hyperphagia. There are other conditions like Albright hereditary osteodystrophy that can have later onset obesity and they do not have hyperphagia. So those are the syndromic forms that I reviewed that do not have hyperphagia and early onset obesity. I don't know if- Yeah, very few actually. To be honest, if the weight gain is at that young age, you invariably have hyperphagia. And I think if you don't have hyperphagia, it's usually because parents, it's because the history of hyperphagia is not coming through or people are feeling embarrassed about the hyperphagia and not telling you. I find it hard to imagine a scenario with severe obesity at one year of age without hyperphagia because that mechanism can't exist really. And I think that's one of the differences between many of the syndromic forms and the non-syndromic forms that tend to have a later onset of obesity compared to the non-syndromic forms. For the boy with the 16P11 microdeletion who was receiving IgG infusions, had there been prior to his treatment any clinical evidence of immunodeficiency? No, everything else was okay from the immunological standpoint, except for the low levels of immunoglobulins that he responded well with the infusions and the infections improved. Okay. Another question from the audience was, at what point in the workup do you test for maternal UPD-14 as the usual tests wouldn't typically identify it? Now with the SNP microarray, you might pick up a portion of those, but any idea of when you would go further to look for maternal UPD-14? Yeah. In the review that I did of that condition, it was recommended to consider doing methylation studies for 14 when you're considering doing it for 15 for Prader-Willi syndrome. Another question, what percentage of your patients have intellectual disability or learning disabilities and are the patients with intellectual disability more likely to get insurance approval than those without intellectual disability? And specifically, I think talking about the clinic that you are running, Claudia. I'd say generally speaking, I don't, I haven't run those numbers, but it's a very interesting perspective, but I would say it's my perception that yes. I mean, if you have other phenotypes like developmental delays or congenital malformations, oftentimes we get a better chance to get a testing approved, but I feel that it's pretty much insurance dependent in what the policies dictate we can do or we can't. So I don't have that number. I haven't run my data against that. That would be a good point to look for a later review. I think that would be a good thing to look into as we look at syndromic versus non-syndromic obesity and whether or not insurance companies will be covering just obesity as an indication. Generally speaking, you can find an appeal when we have more data on syndromic obesity, geo, it is a higher geo, right? So generally speaking, it's probably higher in general, but yeah, we'll be good to have a more tangible number. And my thought with the advent of new medications that are being approved for specific monogenic obesity conditions that we'll have more ability to appeal these decisions with insurance companies. Another question regarding the 16P deletion case, was the SH2B1 gene encompassed in the patient's deletion? No, it wasn't, no. So, and that's very important because that was one of the first questions that came around, you know, knowing the importance of the gene and what we know about SH2B1. But we also know, and maybe Dr. Farooqui for sure may add more to this discussion since I'm sure she'd seen many more deletion patients that I had. And I understand that once the duplication came around and more duplication patients were characterized, it is known that patients with the distal duplication are also at increased risk of having a higher BMI. So it's my understanding that there might be other candidate genes in that area that have not been well characterized. Yeah, absolutely. That's right, Claudia. So there is reasonable amount of data now with the deletions that, well, the CNVs that don't encompass SH2B1 also seem to be associated with obesity. They're quite often associated with intellectual disability or other neurobehavioral phenotypes. They could be affecting, of course, the expression of SH2B1 and indeed other genes. And actually we do have some evidence that there are other genes in that region that regulate weight. Another question, is the increase in congenital fetal malformations attributed to the group of women with obesity and diabetes, or can that be seen in obese women without diabetes? So basically, is this all related to diabetic, diabetic embryopathy, or just do obese women in general, is there another reason for the risk of congenital fetal malformations? I think to my knowledge, most of it's diabetes related. I don't think there's any good evidence of there being an obesity associated risk of fetal malformations. And we hope that Dr. Dow will be present for the final panel discussion. So maybe she could contribute to that question. I didn't prepare for this, but years ago at the David Smith workshop, Max Munker and Sonia Rasmussen presented data from the National Birth Defects Prevention Study that looked at maternal obesity and tried to look at cholesterol levels and risk for fetal anomalies and saw increased or significant association. I don't remember if they controlled for diabetes or not, but there is some suggestion that perhaps there is a relationship with, possible relationship between those. Yeah. Question for Dr. Sola-Alfonso. I just wondered, in setting up an obesity clinic, it's quite a brave move. How do you go about that? And how do you decide any tips, any guidelines for which kind of specialties to invite, or how many referrals do you make? We welcome any kind of practical considerations. Yes. So I came around this because of my metabolic training and interest on other disorders like glycogen-stressed diseases, and generally anything related to endocrinology and normalities. And I made this acquaintance with Dr. Sisley, who's very passionate about the subject. So when she first approached me, the first thing that came to my mind was 16P112 deletion. And it's been a learning process and a learning curve, of course, to dig into the literature and getting to know more of what's been done through the years. And it's certainly a pleasure to be surrounded by all of you today. It's really nice. It's sad that we can see each other in person, but it's one of the things in which there was an area of interest. And one of the discussions that I have with her is, what is the actual need? And when we started looking at the rates of obesity in Houston, and we use things like the Slicing Epic that allows us to see what is the population that we could impact with the clinic. I thought that doing this multidisciplinary approach would be impactful for our population here locally. So we didn't really know what we were doing at the beginning. We will meet and we will do separate evaluations. But now, if I go first and she goes first, we meet for at least five to 10 minutes to interchange information. So we get to hear each other's input from our individual standpoints from the specialty. And with that in mind, I think it's, I'm sure that it may be in other academic centers that have more abilities to provide the space. I think a lot of people want to do these clinics, but the space is something that is difficult to obtain. But you can at least get those numbers of what you can eat. But I think it was really helpful to make the argument at the hospital that we needed to have a setting like this. So that is one of the reasons why I came out and I found my metabolic training to be helpful in an area that I never thought I will utilize those skills. But I think anyone with a good interest in medical genetics and a board certified geneticist could certainly dig into it and attend it because it's a significant need. And we know now referrals from out of state as well. So we know that the need is out there for sure. Good for you, Claudia. Another question was about comfort food. And is it assumed that many people overeat to cope with anxiety? And is this the correct way to think about it? How does anxiety correlate with hyperphagia? Okay, shall I take that? So it's really interesting because we recognize this, right? And particularly, I mean, I look after a lot of people with adult onset obesity and many of us ourselves do it, right? You have a busy day, you don't want a piece of broccoli. And if you do, you need to come into one of my research studies. But, and actually there is a physiological basis for that. And actually there is a physiological basis for that, right? So we know that from the cauliflower pictures and the other pictures, and also from what Jennifer was saying about the patients too, is that food is rewarding, okay? And food eating and images and thinking about food activates the reward centers of the brain. Now what happens is in the patients with genetic obesity syndromes, we've seen it for leptin, but it's also been shown for other syndromes. That pathway is on all the time because it's dysfunctional. The normal function is that we activate that pathway if we're fasting or we're not eating, but it's likely we also activate it when we're stressed. We don't know that and it, cause it's hard to study that. We do know that for example, dopamine is highly linked to these circuits and there are leptin receptors on dopamine neurons. So if you like, we know in animals that those circuits exist. We know in animals that those circuits link stress responses and eating. So it's very likely that the same happens in people and it would entirely explain why if you're stressed, you would seek rewarding stimuli and one easily accessible rewarding stimulus is food. I would agree with that, but then I would also flip it. So one of the things that we've seen in some of the Prader-Willi studies with drugs that are efficacious at treating hyperphagia is that prior to the hyperphagia decreasing, you actually see a decline in anxiety and then you see a decline in hyperphagia, which is quite interesting to me. Didn't expect that at all. I sort of, I've always thought about it the way that you explained it, you know, and so I really just, and I thought honestly in the syndrome, the things were true, true and unrelated, right? They have anxiety as part of the syndrome and they have hyperphagia, but in reality, when you find drugs that do work for one or the other, they actually are very closely tied together. It's a very interesting phenomenon. And of course, in Prader-Willi syndrome, we know that BDNF is involved and we know that oxytocin is involved and both of those neuropeptides affect feeding and they affect aspects of behavior. So BDNF affects anxiety, oxytocin affects, you know, emotional responses, bonding. So it's very easy to imagine a neuronal basis for linking the two, as well as dopamine reward and other circuits. Absolutely, in the talk that I gave, that I'm gonna give, I talk about some new technology in triple reuptake inhibitors that are looking at this pathway as well. Great. And I found also, doing that 24 hour diet recall, surprisingly rewarding with food in children with significant neurodevelopmental problems is often something that parents find to be the only useful activity to get some peace at home. So, you know, that matters. And the importance of getting that 24 hour recall is it gives you that window of standing with them at home and see what they're doing on a daily basis a little bit. It's very sad. That is entirely true. Yes. So we only have time for one more question and we'll save some of these questions for the end that relate to pregnancy. But the last question is, how do we know how cannabinoids influence appetite? So we do know something about how cannabinoids, they clearly do as we know from what I hear from people who take cannabis, but essentially the cannabinoid one receptor is intricately involved in the hypothalamic response to feeding. And actually it's also involved in the response to leptin. And so of course, drugs that targeted the cannabinoid one receptor, as you will all know, were very effective for controlling appetite and weight. Of course, they had the adverse effect of suicidal ideation. So we do know quite a bit about the cannabinoid one receptor. All right. Well, thank you all for your questions from the audience and helping to answer those questions. Our next speaker is Dr. Jennifer Miller, who is a pediatric endocrinologist at the University of Florida. She's had a lot of experience with individuals with obesity, including Prader-Willi syndrome, and we'll proceed with her presentation. Hi, I'm Jennifer Miller. I'm a professor of pediatric endocrinology at the University of Florida, and today I'm going to talk about treatment trials and therapies for genetic obesity conditions. I do have some financial disclosures. I have received research funding from a variety of pharmaceutical companies, including Rhythm Pharmaceuticals, Soleno, Lebo, and Harmony, and I am a consultant for a company called Conscience Therapeutics. The agenda for my talk today is going to be to review FDA-approved medical treatments for genetic obesity conditions, and then to discuss some ongoing and upcoming clinical trials for these conditions, and then to answer any questions you might have. As you've heard from the previous speakers, genetic obesity conditions ultimately result in abnormalities in the hypothalamic nuclei that control the hunger and satiety pathway. This disruption in the nuclei of the hypothalamus actually has a lot of far-reaching effects, including disruptions in the gut-brain axis, as well as disruptions in the sympathetic and parasympathetic axis, which result in abnormal metabolic rate. The drugs that we're going to talk about today, in terms of therapeutics, are designed to address all of these different issues that are associated with hypothalamic obesity. To start with, we're going to talk about some FDA-approved medications. These conditions, as you've heard and seen, are extremely difficult and complex, and very difficult to treat as well, but fortunately, there have been a few drugs that have been FDA-approved that do seem to help these conditions. The first is setmelanotide, called Insembri, is the brand name of it, and it is a drug that was developed by Rhythm Pharmaceuticals and FDA-approved in November of 2020. It is FDA-approved for treatment of homozygous, POMC mutations, leptin receptor mutations, and PCSK1 mutations. What you can see here on this slide is the melanocortin pathway, with these conditions delineated along the beginning of this pathway. Here you can see that what setmelanotide, the drug does, is it hits downstream from these mutations, the leptin receptor mutation, the PCSK1 mutations, or the POMC mutations, and actually activates the melanocortin-4 receptor, turning it on, which then decreases appetite and decreases weight. This drug was approved, like I said, in November of 2020, and was approved based on success with weight loss and appetite reduction in a couple of open-label trials. The effectiveness was assessed in a total of 21 patients, 10 in the first study and 11 in the second. In the first study, more than 80% of patients with POMC or PCSK1 homozygous mutations lost 10% or more of their body weight on the drug trial, and in the second study, which was a study of individuals with leptin receptor mutations, 46% lost 10% or more of their body weight. The interesting thing about this drug is that the weight loss was achieved in these individuals despite no changes at all to diet or exercise, so purely just effects on appetite and metabolism. Again, as I mentioned, this works as the melanocortin-4 receptor to initiate the cascade of satiety hormones and neurotransmitters. The melanocortin-4 receptor and the pathway have been researched for many years as a target to try to treat obesity, but the problem is that most drugs prior to this one had a lot of unacceptable side effects, including profound high blood pressure, but this one actually doesn't, and it has a very acceptable side effect profile, including darkening of skin pigmentation, nausea and vomiting, which typically go away after a couple of doses, and then some sexual activation in both males and females, but again, the safety profile was found to be very acceptable to the patients who were on the drug. This is given one time a day as a subcutaneous injection, and the major side effect actually was some redness and irritation at the injection sites for patients. This is from the paper that was published in the New England Journal of Medicine detailing the effect of this medication on two patients with POMC mutations, and as you can see in this first panel, this is their weight prior to treatment with the drug, and you can see that it started at around two to three years of age and just went up relentlessly and severely from that point in time. Here on this side of the panel, you can see these two patients during treatment with setmelanotide. This is the first one. You can see this weight loss that this individual was experiencing. The drug was then temporarily stopped to see if the weight regain would happen, and indeed, not only did weight regain happen, but you can see on this y-axis is the hunger score, so weight on one y-axis, hunger on the other, and you can see that both weight and hunger increased when setmelanotide was discontinued temporarily, and when it was restarted, the weight gain restarted again, and you can see the same effect here in patient two, who also has a proopiomelanocortin deficiency, and you can see the degree of significant weight loss and decline in hunger score that this individual had on this treatment. So it is thought by the company that there's somewhere between 10 and 20% of individuals with childhood onset obesity that actually have a genetic etiology of this obesity and weight gain, and that this genetic etiology can be affected by interfering with the melanocortin-4 pathway using a drug like setmelanotide. So these studies are currently being done with this drug in heterozygous mutations of POMC, leptin receptor, PCSK1, melanocortin-4 receptor, and 30 other gene mutations that possibly could be pathogenic for obesity. Additionally, there's ongoing studies for some syndromic causes of genetic obesity like Bartlett-Betel and Ahlstrom syndrome. This drug was tried in Prader-Willi syndrome and unfortunately did not work to decrease appetite or weight significantly in Prader-Willi syndrome, but the data analysis is being done for these other syndromes and looks promising. The other medication class which is approved by the FDA for treatment of genetic obesity conditions is actually the GLP-1 agonists. GLP-1 is glucagon-like peptide 1, and these agonists are medications that stimulate the effect of this hormone that allows the body to produce extra insulin in response to eating. So insulin is a satiety hormone, so it makes you feel full, and so the idea is that by producing extra insulin in response to food intake, you will terminate meals earlier and feel more full. Additionally, these drugs work in multiple different areas as well. They do hit a receptor in the hypothalamus that signals satiety and early meal termination, so again, stopping eating sooner. In addition, they also delay gastric emptying, and so by delaying gastric emptying, you are doing two things. One, you're keeping the food in the stomach longer, which triggers the vagal nerve feedback to the brain saying, the stomach is full, don't put any more food in it, and two, giving the stretch response of the stomach saying, I'm full, don't put any more food in it. And so they are pleiotropic medications, which have been really a big source of research in both genetic obesity and pleiotropic obesity for several years and have a lot of beneficial effects. They also, interestingly, are thought to have some neuroprotective and cardioprotective effects as well, which makes them very interesting targets for general obesity in addition to genetic causes of obesity. Medications that are currently FDA approved, including fentermine, methylphenidate, naltrexone, rupropion, and topiramate, have been trialed for these genetic causes of obesity in case reports. The general consensus is while these medications, either alone or together, work initially to decrease appetite and induce satiety, they don't exercise longstanding weight loss effects in these genetic obesity conditions. So they may work for a few months to decrease appetite and body weight, but then ultimately they stop being as effective and the individual basically then goes back to where they were at the beginning. So in the long term, these medications that are FDA approved tend to not be super successful in treating genetic obesity conditions. Bariatric surgery is something that is of interest to a lot of people who deal with genetic obesity conditions, and bariatric surgeons are really excited to deal with genetic obesity conditions using either the gastric sleeve or the bypass procedure. They very strongly feel that these procedures should work to decrease body weight and improve health in individuals with genetic obesity conditions, but there is very limited high quality evidence and very limited long-term evidence that this is actually a reasonable treatment option for these conditions. In monogenic non-syndromic obesity, however, there is no contraindication to having a genetic abnormality that may or may not be pathogenic for obesity in terms of getting bariatric surgery, but some of these mutations, like for example, the leptin receptor mutation, do seem to have some sex-specific outcomes, whereas males show better bariatric surgery outcomes than females. The problem is that most people who have bariatric surgery have not been screened for genetic mutations that may affect their weight, and so therefore the total numbers of patients who succeed or fail from bariatric surgery with genetic obesity conditions is really unknown. This particular leptin receptor mutation data was based on six patients in total. So the studies that do exist for known genetic mutations that may be associated with obesity show that in general, people with genetic causes of their obesity are more likely to have weight re-gain after a bariatric procedure, or at the very least, have lesser weight loss than those who have pleiotropic obesity. Additionally, a lot of the bariatric surgery literature, when discussing these genetic causes of obesity, talks about weight loss in terms of total kilograms or total weight, and indeed, because people with genetic causes of obesity start out at a much higher weight and BMI typically than those who have pleiotropic obesity, it really is essential if they're going to look at these conditions to compare the percentage of total weight or BMI loss instead of absolute weight loss in these patients, because they do start out heavier, and so losing weight in kilograms may not be equal in terms of overall percentage of weight loss to those with pleiotropic obesity. Additionally, it's unknown because the defects often are in the area of the hypothalamus, whether or not individuals with these conditions would actually long-term be okay after bariatric surgery. We know, for example, in Prader-Willi syndrome, that those individuals will often out-eat bariatric surgery down the line as soon as they are allowed to have unrestricted access to food and can burst the stitches and cause death. So we do want to be very cautious in individuals with genetic obesity syndrome when considering bariatric surgery. We're now going to talk about upcoming and ongoing treatment trials that exist, because while it's great to have a couple of drug options, there are a lot of these obesity conditions, and we want to make sure that there are drug treatment trials that are available for people who need them, no matter what the genetic cause of their weight gain and appetite is. So the first thing that I'm going to talk about is the fact that combination therapy is something that is being considered for a lot of these genetic obesity syndromes. The idea behind this is that using multiple drugs that have FDA approval for weight loss and appetite control will have better success or synergistic effects compared to just a single drug alone. So, for example, people have used these drugs called SGLT2 inhibitors, which cause glycosuria, so they in effect cause you to pee out extra calories, combined with the GLP-1 receptor agonist that we talked about earlier, and phentermine, which is a known appetite suppressant. And the combination of those three drugs together results in significantly greater weight loss than any of the agents as a single agent alone. And this is being tried with a variety of different appetite regulating medications, specifically and primarily those that work in the gut to induce satiety. But the idea, again, is that the combination of these medications should work better than any medication alone. The next area that is being researched is the endocannabinoid pathway. And so there is substantial evidence that this pathway is involved in the control of appetite and body weight. And the effects of the endocannabinoid pathway on appetite and body weight are mediated by the CB1 receptor in the hypothalamus. The central actions of the endocannabinoids on food intake are actually mediated directly by binding to the CB1 receptor within the hypothalamus. And this is under negative control by leptin. So leptin actually tells you to stop eating. And so the negative control by leptin actually means that with excessive leptin, then there is increased orexogenic signaling or increased activity of the endocannabinoid system, which makes people want to eat even more. Therefore, turning down this system in somebody with obesity could help to induce satiety. So one of the drugs that's being researched in the endocannabinoid pathway is something called delta-9-tetrahydrocannabivarin, or THCV. And THCV is a derivative of THC or marijuana, but it is a derivative that actually in rodent studies has decreased appetite, increased satiety, and improved metabolic rate. It actually is thought to improve cognitive control in the brain and normalizes reward and aversion regulation for food. So in other words, where it's making you less prone to impulsively take food and to get less reward value from food, and to find things that are not edible to be more averse and so that you don't want to eat them. Because in a lot of these genetic obesity conditions, individuals will eat anything and everything that they possibly can because they are so hungry. So THCV is an inverse agonist or reverse antagonist of the CB1 receptor, similar to a drug called romanibam, which was trialed in the early 2000s. These trials were stopped in 2008 because there were some severe psychiatric events on romanibam, but it did result in significant weight loss and decreased appetite in several genetic obesity conditions. THCV is thought to have less of these psychiatric problems than the romanibam did. And indeed, it has been shown to not cause depression the same way that romanibam did. And so it's thought to be a safer drug to trial in this population. The trials are just starting, and so it will remain to be seen whether or not that bears out in human trials. The next thing that is being tried is fecal transplants. So fecal transplants is, again, using the gut axis to manipulate the gut-brain axis, and it will manipulate the human gastrointestinal tract microbiome by transferring a healthy donor microbiome into a disturbed microbiome. And so in other words, you take poop from a lean individual and you transplant it into an obese individual, and the idea is that then that bacteria from the lean individual will take over in the gut and cause the gut microbiome of that previously obese individual to become more of a lean person's microbiome, and therefore decrease their appetite and weight. There's been one study in patients who had prolonged obesity and thought to have genetic etiology of their obesity, and it did actually sustain effects on the gut microbiome. So in other words, the gut microbiome of the obese people transferred more to be looking like the lean donor's microbiome, but unfortunately didn't have any longstanding changes in BMI or weight gain. The next class of drugs that we're going to talk about is the melanin-concentrating hormone drugs. Melanin-concentrating hormone, or MCH, is an orexigenic, or a hunger-stimulating hormone, and it is a potent stimulator of appetite. And so by antagonizing the system, you should therefore decrease appetite. Melanocortin-concentrating hormone receptors are widely expressed throughout the body and the nervous system, adipose tissue, islet cell, enterocytes, monocytes, and the antagonists of this system are shown to decrease food intake, improve metabolism, and have anxiolytic and antidepressant effects. However, it needs to be very strongly considered that small molecule MCH1 receptor antagonists also may influence multiple hypothalamic pituitary axes, including the hypothalamic pituitary gonadal, thyroid, and adrenal axis, and this could have untoward consequences in terms of hormonal abnormalities from these drugs. And so this needs to be much more significantly researched before it is considered anything that may come to a phase three trial. Other concerns with these hormones are that the MCH receptor antagonists do have roles in learning and memory and in maintenance of bone mineral density, and those roles are that by antagonizing the receptor, you actually may decrease learning and memory and decrease bone mineral density. So again, much further study is needed on these molecules. BDNF, or brain-derived neurotrophic factor, is another hormone that plays a critical role in energy homeostasis, and this one is in the brain. And a mutation of these hormones actually causes hyperphagia and obesity, and so the idea is that these hormones definitely play a role in weight and in appetite, and so the idea is that potentially you could target the BDNF hormone as a treatment for obesity, and so clinical trials with this hormone and the TRKB protein are widely anticipated but not yet started. And then there is a class of drugs called triple reuptake inhibitors. There's actually two of these drugs that are currently about to enter into trials. Triple reuptake inhibitors refers to the fact that these are norepinephrine, serotonin, and dopamine reuptake inhibitors. The two drugs are CSTI-500 and testophenzine, and these drugs are thought to impact satiety, energy expenditure, compulsive eating, appetite, cravings, reward value of food, and so the idea is that this triple reuptake inhibitor, like set melanotype, targeted downstream from the problems of genetic obesity that we showed before. These will target downstream from the hypothalamus to the reward and executive and autonomic systems in the brain to help restore the dysregulated signaling that is affected by hypothalamic and genetic obesity. And so the idea behind these is not only will these effects of the triple reuptake inhibiting improve the things I just talked about, but that there will be possibly an increase in mood, increased interest in thinking about other things besides food, decreased rate of eating, more enjoyment of eating, more concentration and focus and attention and decision making, improved school and exercise performance, and better drive and follow through and execution of tasks. Again, this seems like the golden ticket, if you will, because of all these possible effects, but again, these drugs may have potential unknown side effects, and so the trials definitively need to be done in genetic obesity conditions before one could say that they are definitively effective and safe. And because they do have effects on multiple different hormonal systems, there could be unknown effects as well, and so definitely these trials are going to be interesting to follow, and like I said, they are just about starting in genetic and hypothalamic obesity conditions. This is just a slide showing, as I just mentioned, about setmelanotide and where it acts versus the CSTI-500, which is one of the triple reuptake inhibitors, and you can see here on the left that setmelanotide acts here at the melanocortin-4 receptor in the hypothalamus, and these triple reuptake inhibitors are going to act downstream of that in the higher cortical regions to regulate food behavior, eating behavior, that kind of thing. And so there's thought to be more of an effect of these particular drugs on energy homeostasis in the brain. So another drug that's being studied for these genetic obesity conditions is called DCCR, or diazoxide choline-controlled release formulation. This is, the parent molecule is diazoxide, a medication that's been available in endocrinology for many, many, many years for treatment of hyperinsulinism and has just completed a phase three trial in Prader-Willi syndrome, and you can see here one of the individuals who participated in that trial before and after the drug treatment trial. This is about a two-year time span difference in these pictures. And the way that DCCR works is multiple, as many of these drugs do, because again, these are very complex conditions and you have to hit them in multiple different areas. So it is thought that DCCR works in the hypothalamus to reduce the levels of neuropeptide Y, which is a potent hunger hormone, and it drives hunger and food seeking, so that by working in the hypothalamus, it turns down neuropeptide Y, decreases hunger and food seeking behaviors. It is also thought to work in the vagal nerve to lower insulin level and improve insulin sensitivity, which then results in increased satiety and reduced appetite. It is also thought to work in the fat tissue to reduce the deposition of new fat and increase the use of fat for energy, thus reducing fat mass overall. And in the pancreas, it is known that DCCR actually decreases post-meal insulin levels, which actually results in decreased deposition of fat, and improved leptin and insulin resistance. And so this is just a graph from the DCCR trial in Prader-Willi syndrome showing the changes in the hyperphagia questionnaire scores in individuals on trial, and what you can see here is the more hyperphagic the individuals were, here on the right, the more significant the effects from the medication were in terms of their effects on hyperphagia. The drug also did, on dexascan, decrease fat mass as expected, and increased lean muscle mass as well, which was interesting. Oxytocin is another drug that's been highly researched in a lot of these genetic obesity conditions because it is a satiety hormone, it's a hypothalamic hormone that's secreted directly into the brain, and affects a variety of biologic processes, including behaviors, bonding, metabolism. And in rodents and non-human primates, chronic oxytocin administration leads to sustained weight reduction by reducing food intake and increasing energy expenditure. Therefore the thought is that oxytocin might not only, in humans, lead to decreased food intake, but independently might improve glucose homeostasis or decrease the risk for type 2 diabetes. And so in a few studies that have been done investigating oxytocin's effects in humans on weight, a single dose of oxytocin intranasally does reduce caloric intake and increase fat oxidation and insulin sensitivity in men. And a pilot study of eight weeks of oxytocin treatment intranasally in adults with obesity led to substantial weight loss in these individuals compared to those treated with placebo. So together the data support the investigation of interventions in this pathway, investigating oxytocin as a potential therapeutic for these genetic obesity conditions. And the version of oxytocin called carbitocin, which is a very selective agonist of the oxytocin receptor, has been trialed and just resulted from phase 3 trials in Prader-Willi syndrome and indeed did show some efficacy in reducing hyperphagia in that syndrome. Genetic manipulations are the last thing I'm going to talk about in terms of upcoming treatment trials and that is because I think these are sort of the furthest out, but very important nonetheless. And so there are a variety of things being tried in terms of genetic manipulations in order to decrease hyperphagia and obesity in these conditions. The first involves long non-coding RNAs, which actually work in multiple cellular functions and regulate chromatin remodeling and transcription and transcriptional events and thus affect gene expression. And these long non-coding RNAs do play a pivotal role in modulating the relationship between white fat or metabolically inactive fat and brown or beige fat, which is metabolically active fat. And so you want to have more brown or beige fat because it's metabolically active and burns more calories. And so the idea is that by manipulating these long non-coding RNAs, you can potentially change the ratio of white to brown fat in individuals with obesity conditions. And then by doing, to do this, you actually would activate or silence the therapeutically relevant genes involved in weight gain and metabolism. And so the idea would be that you would increase metabolism by this genetic manipulation. Additionally, some gene therapy is being tried. So for example, there is a gene hormone called, or I'm sorry, a protein called folistatin, which is a muscle protein that works to keep muscle growth in check. And so mice were given gene therapy using a viral vector injecting, carrying folistatin. And what this did was allow the mice to gain significantly more muscle mass without exercising more than usual. And they also had less cartilage damage, inflammation, fewer metabolic problems, healthier hearts and blood vessels than their littermates who didn't receive the gene therapy and were less sensitive to pain. So this is a great idea, you know, to increase muscle and metabolism given a protein like folistatin, but the long-term effects are actually, you know, unknown. And, you know, so there is concerns about what the long-term effects of something like this could potentially be, but exciting stuff for people who don't want to do diet or exercise or diet and exercise doesn't work very well. The consideration that gene therapy may ultimately improve metabolism in the future. And lastly is CRISPR. CRISPR is a technology that I know you all are familiar with, and it can be used to insert a molecular switch into the DNA of white fat cells. So I mentioned before you want brown fat, not white fat, because white fat is metabolically inactive. And so with CRISPR technology, you can turn on a switch in the white fat for something called uncoupling protein one. And what that uncoupling protein does is make brown fat and cause mitochondria to turn out heat, so therefore increasing metabolism. And so by doing this, it boosted almost 20-fold how much protein the uncoupling protein made. And that extra protein turned the white fat cells into brown-like fat cells that they call humble or human brown-like fat cells. And there's also a form of CRISPR called CRISPR activation, which can find a working satiety gene and turn up its volume. So this would be used potentially in people who have heterozygous causes of their genetic obesity conditions by turning up, or I'm sorry, not turning up, regulating the active effective satiety gene and thus sort of overriding the defective gene that potentially is contributing to the obesity. And so when they did this technology in the brains of mice with only one working copy of satiety genes like melanocortin-4 receptor or leptin receptor, what happened was that it actually prevented them from becoming obese because it turned up their working satiety gene that was there, thus overriding the effects of the missing gene or the inactive gene that was causing the problem. Unfortunately, despite all this really exciting data, there are some barriers to treatment of genetic obesity conditions. Number one being insurance coverage. Insurance coverage, as you all know, is very poor for many obesity treatments. It's very poor even for reimbursement when we see these patients with obesity. So obesity being the diagnosis code actually results in lower payments for physicians. And there also needs to be a workforce of physicians who understand that there are biopsychosocial causes of early-onset obesity, and it's not just lifestyle alone. And I do feel that that is the biggest barrier, is that most doctors believe, or many doctors, I won't say most, many doctors believe that obesity results from poor lifestyle choices and lack of willpower. And as such, doesn't really warrant this type of intensive treatment investigation that's being done because they think that it should be able to be changed with diet and exercise. However, it should be understood that this is a combination of both genetics and environment, and aberrant biology is at the core of these genetic obesity conditions. And while they do often manifest in the context of poor lifestyle, the genetic basis is there, and therefore there needs to be some treatment options available for these genetic conditions. And in conclusion, as you've heard, obesity beginning in young childhood and associated with increased hunger or hyperphagia is much more likely to be genetic in origin than obesity that starts later in life. It's a huge problem in this population and needs to be viewed as a real disease with a need for a real treatment. And a few treatments have been approved and more are coming, but we're very excited that this seminar is being held at the American College of Medical Genetics meeting to address these conditions and to recognize that they are conditions that do need treatment urgently and that these individuals need help with managing weight and their overall health. And so lastly, in acknowledgement, I'd like to thank the organizers of the American College of Medical Genetics for the invitation to speak at this conference. And thank you to all the patients and families with these conditions who have participated in a myriad of clinical research trials, trying to find answers for genetic obesity conditions. Thank you. Great, very nice presentation. Thank you, Dr. Miller. Impressive array of possibilities there. So I'd like to introduce Dr. Dow, who was a presenter of the previous cases, who's able to join us for this final Q&A. We have about 35 minutes. And so I'm going to start from some questions from the audience related to the last talk on treatment. So were there double-blind placebo trials with crossovers for emsyvery? There were not. These were open-label trials for individuals with these specific genetic conditions. There will be upcoming placebo-controlled trials for some of the heterozygous conditions. But currently, the trials have been open-label trials. Great, thank you. And then the next question to follow on is that, is there any reason to think that new medications such as setmelanotide will also not have long-term sustained effects? What do you predict? Do you know? So, yeah, I mean, my prediction would have been, yes, I would suspect that it would ultimately lose efficacy. But actually, some of the first patients treated are close to five years out now and still on treatment. And they are maintaining their weight loss and their decreased appetite, which is really reassuring to know that the drug is still working. You know, again, when you stop the drug, unfortunately, the appetite and the weight come back. But on drug, they're doing very, very well long-term. Good to know. All right. And then just a question for General. A major advance in preventing tobacco-related diseases was the regulation of tobacco marketing and legal penalties against tobacco companies. Should we be taking the same approach towards food companies? So something a little bit different. I'm not touching that one with a 10-foot pole. Okay. All right. So, actually… Shall I say something about that? Sure. Yes. I mean, this comes up often at meetings I speak at, including obesity meetings, okay? I think there's two ways of looking at this, you know, clearly to deal with the population problems associated with obesity, the public health problem on a massive scale, one needs interventions for society, right? And that includes the availability of food, the cost of food, the choices of food, the availability of exercise, the cost of exercise, all those things. There are many, many people who study research, work in those areas. There is some evidence that taxation can have benefits, but there's also evidence that taxation has no benefits. So it's a complicated issue. I think the really key thing to think about is that, like with any trait or disorder, here in genetics, we're talking about the severe end of the spectrum, strongly biologically driven, genetically driven. And I think, you know, that's quite different from the population problems associated with obesity. Now, it would be oversimplistic to think about the population problem as being something that can be solved by addressing access to food, exercise, et cetera, because the population problems are, of course, in significant part down to environment, but also down to genetic susceptibility. So it's the people who have the highest genetic susceptibility who respond in the worst possible way in an obesogenic environment. So I think we have to think about both population derived measures for the population public health problem and clinical care for people with severe obesity, a proportion of whom will have a strong genetic driver. And I'll also add, based on Claudia's patient, that we should be mindful of the inequities that any of these interventions would have based on certain ethnic backgrounds, right? Because she just showed us a clear example where there might be an overrepresentation or burden of a specific variant in a specific ethnic group, and we may be disproportionately affecting populations based on those criteria. Yes. Great. Thank you. So some more questions just relating to treatment. This is one that was from a prior session. How many of the total conditions have treatments or medications in terms of monogenic obesity syndromes? Three. Right? So is that a fair statement? I mean, it's the monogen... I mean, POMC, LEPR, and PCSK1 are the only ones I know. And leptin deficiency, of course. Yeah, and leptin deficiency. I forgot that one. So very few. And then... Very few. Right. Okay. As so far. And then if we see patients in clinic, how do you determine, you know, which patients are suitable for your clinical trials? How do you approach them? So personally, you know, I try... Well, it depends. I mean, it depends on what the trial is. If it's looking at specific genetic causes of obesity and hyperphagia, then, of course, you know, we do genetic testing. And if they qualify based on their genetic testing, then they can be recruited into trials. But the, you know, the thing I always sort of personally look for is, I hate to say this, but it's the worst of the worst, right? It's the people who are truly suffering, the people whose families are suffering, their siblings are suffering, they're, you know, they can't hold a job, they can't go to college, you know, because of the degree of their hyperphagia. And so that's personally how I recruit patients for studies, is really, you know, looking to try to help those that are the most severely affected. Great. Okay, good. And then one final treatment-related question. What would be the best current approved treatment and best option for clinical trial for MC4R-affected individuals? So right now, it would be the GLP-1 agonists are what's being trialed, or, you know, what's considered to be the most effective for the MC4R mutation patients. But I know bariatric surgery has also been looked at and still worries me, quite honestly, but it is being investigated. And then I really do think that DCCR has a great potential for the homozygous MC4R mutations, in that it's going to work differently than the other drugs that are currently available and might have some true potential in those patients, but it's not been trialed yet. Okay, great. So, Daphna, anything that I got wrong there that you would add? No, I think that's absolutely fine, yeah. Okay, good. And I would agree about caution for bariatric surgery, with the exception of heterozygous MC4R patients. And being specific there, we're talking about Roux-en-Y bypass surgery, or sleeve gastrectomy, and definitely not a band. Right. Right. Okay. Great. Thank you. So I think there were a few questions regarding the prenatal cases, which we didn't get an opportunity to ask Dr. Dow previously. So we're going to move to that now. For the low HDL association in neonates with mothers who were obese during the pregnancy, I wonder if the mothers were also known to have low HDL? Trying to discern, so that, sorry, the person asking question goes on to say, trying to discern if the low HDL is associated with intrauterine environment or is an independent way or predisposition requirement? Probably a little bit of both. Again, hello, everyone. I apologize deeply for not being present earlier, and I appreciate the chance to answer some of the questions. Probably a little bit of both. There was actually one study that looked at newborn HDL and compared it to maternal HDL by obesity class, and it appears that the two are interrelated pretty highly. So the lower the maternal HDL and the higher the maternal fat mass, the lower the neonatal HDL. So probably a combination of all of the above. Okay. Sounds very reasonable. And then continuing the underlying theme from the prior discussion, this question answer writes, is there evidence enough to consider referring or testing, for example, our subgroup of super obese graviders, BMI greater than 50, particularly if they do not have glucose intolerance or excessive weight gain for underlying monogenic disorders? I think that's a million-dollar question. Unfortunately, super obese graviders are no longer the rarity. Most days have at least one patient with a BMI greater than 50 on our labor and delivery board. So we're talking about a huge expense to the healthcare system, particularly when we don't know everything about all the different MC4R mutations amongst other mutations. So it would probably be beneficial if we could look specifically at the MC4R mutations that are associated with lower risk of GDM, lower risk of hypertensive disorders, and better outcomes for babies, higher weight loss after pregnancy with GDM. We might save some healthcare dollars there, but in order to test that growing population, probably not worth it yet. So Sadaf has a contribution. I'll follow up with Margaret about MC4 and genotypes later, because we've made that point, Margaret, in your absence. Just again, with respect to testing, I think there's no reason to differentiate the pregnant woman with a BMI of 50 from the earlier conversations that we've had, which I know Margaret won't have been privy to. But I think the same criteria apply. I think it's the early onset of obesity and weight gain. So you can be BMI of 50 and have been obese since before the age of five is quite different from being BMI of 50 and gained weight after your first pregnancy. They're entirely different phenotypes, and the likelihood of finding a pathogenic variant is substantially different. So the same features that we've been, several of us have spoken about in our different talks hold true. It's the early onset and the severity early on. Great. So it's irrespective of when you can select. Right, it's a take home message, clearly, from this session. Yeah. OK, good. All right. And then another question for Margaret, Dr Dow. So some questions regarding prenatal and postnatal cases. Is the genotype of the fetus ever and mother ever helpful in terms of when you combine them both? So the example that this question writer wrote was, as we know, with HELP syndrome and fetal fatty acid oxidation disorders, it's interesting to look at the phenotype of the baby and predict something about the mother. So do you have any thoughts regarding that? I wish I did. I rarely get to be involved with the neonate, and I'm not sure if our pediatricians are following up with any kind of testing. But especially as the testing becomes more widely available and less expensive, I think that's a critical area of identifying folks early, especially as we develop targets for intervention, so that we can find these kiddos when they're really young and intervene before they have a BMI of 50 by the age of five, as you just said. Not just for monogenic, but for polygenic causes. And then another final question. Do you know why individuals who have bariatric surgery, future children do not have as much obesity? So there are not a lot of great studies of this, actually. So we know that the offspring of mothers who have restrictive surgeries tend to be of lower initial body weight. But the obesity rates in the children, there have been a couple of studies suggesting that those rates are just as high, that the curve of weight gain is actually more accelerated in these offspring. So I don't know that we can really call them at lower risk for obesity, even though they are smaller in gestational age, or less likely to be large for gestational age at the time of birth. OK, great. Thank you. Another question for Dr Miller regarding treatment. So there was an antihistamine some years ago called Hismenal that caused increased hunger and weight gain. Is that molecule in any way related to the drugs that are now being used to regulate hunger? Not that I am aware of. OK, so something. No, that molecule is not related, but the pathway is related. So histamine, histaminergic pathways are very, we actually understand very little about histaminergic pathways in appetite, but we do know that they are almost like parallel to noradrenergic neural pathways in the brain. And histamine 3 receptor knockout mice, for example, are obese. So there is a tight link between histaminergic neuronal pathways and appetite and weight. And so there is a study ongoing of a drug called patolisant, which is a histamine 3 receptor antagonist, yeah, agonist, yeah, and one of the outcome measures, it's actually being used for narcolepsy and cataplexy, but one of the outcome measures is actually looking at weight as well. Great, OK, thank you. OK, thank you. And then a remark from Dr. Wilson, though in theory MC4R leptin receptor and POMC variants could be added to universal carrier screening at a relatively low additional cost. So what do people think about doing screening for these genes and their variants? Well, like with anything, if you're going to do screening, what's the point? What are you going to do if you find something, right? Right. So what you do is you screen the high risk population where you might want to intervene. I would say five years ago, we didn't have the interventions. And so like, you know, testing was only being done as part of research. Now we have some interventions and we can prove that a finding has an impact on the lives of patients and on potential treatments. It's worth testing, but you still test where you're likely to find something and where you're likely to be able to do something if you find it. So I think it's not justified at the current time. But I think it's quite clear where the guidelines currently stand. and I think that's where the best evidence is. I think as more testing is done, things clearly may change, and we may get a better handle on whether, you know, of the women presenting for neonatal or for antenatal testing, do you do a subgroup? What about people applying for, you know, coming for bariatric surgery? Those things are being discussed and there are sort of potential panels and consensus meetings happening, because I think that is the next frontier, and I think it's quite likely that that will evolve, because we will learn more. But at the moment, based on current knowledge, I think the current guidelines are reasonable for where the most likelihood is of finding something clinically important. I think it's also important to consider the pregnant mom's state of mind of if we are getting these data and can't give them any intervention to deal with it, we're giving them one more thing to worry about in a pregnancy, and while it may not be the medical focus of our discussion, it's an important clinical consideration. Thank you. Dr. Miller, did you have something you wanted to add? No. Okay. So not yet is the answer, but maybe. I do have a question. Is it today a requirement that anyone that wants to have a gastric bypass surgery should have genetic testing before doing it? That's so interesting, because of those concerns. So I wonder how many people are undergoing these procedures without knowing exactly what the theology is. It's very dangerous. It is dangerous, yeah. Yeah. We went to bariatric surgery clinic and we're doing genetic screening on people who were a year out, trying to figure out, like, okay, if you were a year out and didn't have success with your bariatric surgery, were you more likely to have had a genetic problem in the first place? And the problem is, if you don't have success with your bariatric surgery at a year out, guess what? You don't come back to clinic. And so we weren't able to figure out the answer because people just were no-showing. And so, you know, did they no-show because they no-showed or did they no-show because they really had no success with the surgery? We don't know. So it's a very hard question to answer, but it is a really reasonable question. I think that people who are going to undergo bariatric surgery should be screened for these conditions because it is, as Sadaf said, it is dangerous for some people, you know. So I think it would be a really good thing to do. Right. Yes. I can only hope that that becomes more routine. I think it's likely to come in some sort of consensus form and because I think it's to advise it is a different matter and has substantial implications not only for cost, but of course for patients. But I think, you know, the studies need to be done to advise that kind of decision making because it's a question we're now being asked. So I do have a follow-up question on bariatric surgery. As you mentioned, so what conditions would be contraindicated? So that's, I don't think we have that data necessarily, but we would think that those that have monogenic obesity that have hyperphagia, will the signal still be affected by doing bariatric surgery and then you get a ruptured stomach. Exactly. So, but can we make those, do we have enough data to suggest that if you have a specific genetic etiology that bariatric surgery is contraindicated? I think it's contraindicated in almost all of them. And I would say almost flip it around, like to use Jennifer's language, to say probably the only evidence for where you could safely undertake Roux-en-Y bypass surgery is heterozygous MC4R mutations. And everything else, I would say contraindicated or extreme caution. It's very helpful clinically to know it. So question once again about treatment. Are people who are being treated successfully with newer agents either eating less or making better food choices or both? So is it satiety? I mean, do you know how it works? It's a good question. And the answer is with the GLP-1 agonists, it's actually that they are eating less. They're consuming less. With semelanotide, the trials were done without allowing the PIs to make recommendations about diet and exercise. So it's very interesting. They are eating less, but they are definitely not making better food choices. And so, which is fascinating to me to watch because you can tell them that the drug also must have pleiotropic effects on metabolism as well, because although they are definitely consuming less. They're definitely eating less. They definitely are. They are definitely eating less. But, you know, we have one person that comes in with his Mountain Dew and his doughnuts every time that he comes in for the trial. And I'm just like, you know, it kills me that here you have a second chance, you know, of a drug that works for something that you've lived with your entire life. And yet you're still you're going to die skinny because you're still making bad food choices. You know, it's really it's frustrating for me as a clinician to see that happen. But I agree. He originally came in with a box of doughnuts and ate all 12 and now he's eating one or two. Yeah. So definitely they are consuming less. Yeah. So there's less hunger and there's more satiety. So for sure. Yeah. Great. And then a question relating back to Dr. Sola-Alfonso's talk. For the boy with a 16p11.2 microdeletion who is receiving IgG infusions, had there been, prior to his treatment, any clinical evidence of immunodeficiency? I couldn't make that connection when I was looking forward. So I hate to defer the question, but I was not able to make that particular connection. And that is also a common paediatric problem, nonetheless. So I thought that it was just likely a red herring and not an association with the deletion. So I'm not aware that those two are connected. Yeah, I've never seen it in patients with those deletions. OK, great. And then finally, we talked a little bit previously about any relationship between obesity, per se, and birth defects compared to obesity that's associated with diabetes or impaired glucose tolerance. And just wanted to ask Dr. Dow if she has any thoughts about whether or not malformations are linked to obesity, per se, after her presentation. So malformations related to diabetes specifically? No, actually just obesity without any impaired glucose. Absolutely. Yeah, absolutely. There are a multitude of fetal effects of obesity on the neonate that are independent of glucose metabolism. So it's really interesting. It seems to be related to obesity alone. All of the psychological and behavioral aspects, the ADHD risk, some mild developmental delay, autism spectrum disorders are all more common in women with obesity independent of glucose metabolism disorders. Margaret, just be a little careful there. Those are just to be a little careful between cause and association. Absolutely. Absolutely. Thank you. The question was more causal related, a bit like diabetes and the mother causing fetal malformations. That's entirely different from associations. That is a very, very fair and valued qualifier. Yes. These offspring are at higher risk of having a multitude of congenital challenges related to maternal that may be related to maternal obesity, associated with maternal obesity, regardless of their glucose metabolism. But it's not like, you know, in diabetes, it's very clear cut. The mother who has diabetes, substantial risk of that mother's child having malformations. And we've known that, of course, for many, many years. It's not like that for obesity. Absolutely. There may be associations with features, but, you know, that's very complex. It may well be that the genetic factors that increase the mother's risk of obesity also increase the risk of some of those other disorders. So I would be very careful about association versus causality. And it's also I don't think there's any evidence for causality to my knowledge. And it's important that even those associations only increase the risk. Absolutely. Very mildly. So we're not talking about a significant effect. OK. All of those are true. Claudia, you were mentioning your obesity clinic. And if we were to start to develop obesity clinics, if somebody wanted to put together a multidisciplinary clinic, is your clinic a virtual clinic or a non-virtual clinic? When the pandemic hit, I think we went through the same challenges that everybody else experienced. So we ended up using a virtual setting for most of the first six months of the pandemic. And then we've been doing a combined setting. So if I have a follow up patient, I've been doing telemedicine. But I strongly prefer in person due to the dysmorphology exam being so important. So I'm trying to do new patients. We're trying to do new patients in person and follow ups through telemedicine. So David, if I can just make another point, I'm sure Claudia does it automatically and probably without thinking. But another very I mean, COVID aside, another very important reason for I mean, to be honest, it's about being a physician. These are highly vulnerable groups of patients and families. And trust between the physician, the patient and the family is important, of course, for all of our patients. It's particularly important for patients where other health care professionals and teachers and society makes them feel pretty guilty and pretty bad about it. So having the trust of the physician is absolutely essential. Yes, to be honest, yes, you can deliver some of that virtually, but, you know, it's a lot easier when you're meeting the patients. I agree with you. I feel that. Thank you for making that point, because that's one of the this clinic is very rewarding in that sense. You really need to establish good rapport for people to be able to open that universe to you. So I found that to be an essential part of what we do in clinic. And the other part of this also is to get accurate weights. So, you know, you really want to know what's happening. And sometimes it's challenging if they're waiting at home and you don't know if the scale has been calibrated. And that, I think, is obviously a remarkable piece of data that is a little bit more relevant than, you know, the clinical setting. So right now we're in that combined environment. But for me, I just want to see everybody in person. I think it's the best we can for this particular population. And if you said that 15 percent of the childhood population in Texas would qualify for your obesity clinic, how are you advertising or how are you managing, you know, getting referrals? So what's your process of trying to identify all these individuals and how you then scale up? Yes. So that was a big part of the beginning. We weren't getting that many. As you can imagine, people really understood what was it that we were offering different than the evaluation by one of the specialties of the other. So we had to go and do a stronger work on the marketing department at the hospital and create specific pamphlets in which we will explain much better what our goal was and what was the population we wanted to serve. And one advantage, obviously, at this hospital is that it's a large facility. It's spread out the city of Houston, which is the fourth largest city in the country. So we definitely had no problem reaching out to most of the pediatricians in the area. But we also set up other strategies. We have a dedicated website for the clinic. We had done a couple of webinars for pediatricians in the region, including an activity called Evenings with Genetics, in which it's a way-based community activity in which we review genetics obesity. And that was tailored towards pediatricians as well as families. So those are some of the strategies we utilized to get the word out there. We started with three patients, and we are now booking eight to 10 patients per clinic. Great. Yeah. It's impressive. I should give a little credit to Stephanie Sisley, the endocrinologist that works with me. She's really the soul and the engine of the clinic. So it's a lot of useful endocrinologists, yeah. We can be useful every once in a while. No, no. I mean, I think we understand that. Thank you. Yeah. So just any tips from the clinicians on how to broach a very sensitive subject? You know, by the time they get to the specialist, it's already been broached. I mean, they don't come to us not knowing that they're obese, right? You know, I mean, it's already been addressed. And nine times out of 10, I would say that the parents are, I mean, especially with these genetic causes of weight gain, you know, the parents are upset because of the way people have treated them along the way. And so it's a very open conversation and discussion. It's not like having to be the primary care physician who has to say, oh, by the way, your kid's obese. We've already gotten there. We're just now talking about what to do about it and how to approach it. No, I think we do a really crummy job in the grown-up population. In adults presenting for bariatric surgery, about a third of them have no understanding of their diagnosis of obesity as an illness. So I think it's very difficult to or very important to separate the adults from the kiddos. If we're catching them early, we're talking about it as a medical disorder because it's affecting their pediatric health and their ongoing health. And I think it's somehow easier to wrap your head around than if you're an adult and you've had this disease for a gazillion years and nobody's ever told you that you had it or tried to treat you for it. And suddenly you're trying to wrap your head around how and why you're being treated for something that's been going on for a long time that has so much shame associated. But I think it also extends to the whole family. I mean, I think it's a unique diagnostic odyssey because their mother's guilt is also part of this, where there's always a concern that there's overfeeding or there's sort of different ways of treating the child. There's sort of familial stigma associated with obesity in and of itself. And then in addition, there are opportunities where multidisciplinary clinics, which I think should be the standard for any of these rare conditions, can play a role in sort of managing all those expectations from the social to the medical to the psychological, all the impacts that the condition can have on the patient and the family and provide adequate counseling and stewardship. So I think hopefully we've all got it in a sense from Sadaf and Claudia, how a compassionate multidisciplinary team that's kind, that understands those conditions and those journeys can go a long way to have a significant impact. And you can only find the rare places like Claudia's clinic. And I think kudos to her and everybody else who's really taken on this lead to emphasize how important that sort of holistic approach to patients should be. Something that I learned often, too, especially in the younger kids of certain ethnic backgrounds, is that, as you all know, being overweight is considered to be a sign of health in general, right? And I guess that also has helped a little bit for those that are coming from Hispanic backgrounds and with different languages to overcome that. This is not healthy. We should address this. This is different. But many families actually, beyond that, come into the clinic and they don't understand what they've been referred. So I've been studying with that. Do you know why your pediatrician sent you? Did you hear why you're here? And then I start asking all the food questions with the introduction. I know you've been asked several times, what are you eating? But it's important that we review this together from this perspective and try to understand if this could be genetic. And it took me a little bit of time to get to that because it's a subject that is relatively newer in the last decade. I don't think I got a lot of exposure during my training to get, you know, we sort of all develop a little bit of a script that we have for certain things, right? So I also learned to use words like, is your parent also heavyset? Or, you know, just use words, identify what is the code word that you've seen for obesity as well. This is no different to what you will do, but these are some of the experiences I had that I have grown to to become more efficient when I'm getting the history that has been helpful over time. I also think that there's certain populations that don't like their child to be upset. Right. They don't want their kid to cry and they definitely don't want their kid to be hungry. You know, and so you definitely can see overfeeding there as well. You know, and I think that that's something that I see all the time when, you know, I say, well, just don't give it to them. You know, what are you talking about? How could you not? You know, I mean, so it's it's harder. I have a hard time wrapping my brain around that one because I'm a mean mom. But, you know, I mean, I do think that is definitely there is some cultural influence there as well about families that don't like their kids to be upset and cry and be hungry. Claudia, besides the physicians that are involved in the clinic, I didn't catch that. I'm sure it is. I find that for the patients that are referred to us, that it would be wonderful to have sort of a supportive team of, you know, the dieticians that you could because I'm always telling the parents, you know, we need to refer you to the dietician to figure out what the calories and, you know, what the substance of your diet is. And so I agree. I think a multidisciplinary team would be wonderful because I'm getting referrals from endocrinology and they're sending to us to try and figure out what's going on. And then on the periphery is this, you know, trying to get them into sort of practical management in terms of fitness and diet. I agree. That's a big need that we are actively working on getting resources for. Some patients, they're already followed by GI because of the fatty liver component. They sort of have that need covered with the dietician. Usually, you know, they usually have a fair GI evaluation with nutrition. I think that the 24-hour diet, I recall, helps, but it's definitely insufficient and it's not a standardized tool to understand caloric intake. I also think it's really hard. You know, this is Margaret and I actually have talked about this before because I, you know, know that like with Prader-Willi syndrome, we know how to control the weight, right? We know it's a carbohydrate intake thing and we can affect the diet by changing, you know, what type of carbohydrates, how much carbohydrates, that kind of stuff, how to balance them out. But with a lot of these other conditions, I just feel like it's not known what is the best type of diet for them to be on. And I feel like there probably is a best type of diet for some of these conditions and we just don't know enough yet about diet to know how to, you know, counsel them appropriately. I mean, we can all counsel about reduced calories, right? But I mean, I do feel like, I mean, it's something that through my 21 years of working with Prader-Willi that we've seen change, right? Because the reduced calorie diet worked, but it sure didn't work great in terms of, you know, because they were hungry. You know, whereas now we know by controlling the type of carbs and how they're fed that we can control weight a lot more effectively in that population. And I suspect the same is true for a lot of these conditions that we just don't know enough yet. So I think dietary research is still tremendously lacking and needed. Yeah, it's still a long way to go, right? Many, many, many, many things to do. OK, one last question. Do we know how many multidisciplinary clinics there are in the USA? So I'm not sure that any of the speakers could particularly answer this one, but obviously probably too few. So something to think about. It's inspiring to hear from Claudia and how she set up her clinic with Dr. Sisley and think about, you know, bringing back a similar model or trying to establish a model similar in our own centres. So with that, we should probably wrap up to be done by five or Eastern time, I guess. Oh, Sadaf has one comment. No, sorry. I was just wondering anything about the speakers? Very quick in the chat. Someone's asking if the homocysteineuria, the third case I presented, would have been picked up by the screening, newborn screening. The answer is yes, with the current newborn screening in Texas, it would have, but it was expanded in 2007, I believe. And this patient was born way before. So it was a patient that did not benefit from the newborn screening program. So just to clarify that. Thank you. I think that's really great that they get their question answered. So thank you for doing that. So any last comments from the speakers? No? Okay, great. Well, I just wanted to thank them all for their time and for their attention and their hard work. And thank you also to the organisers of ACMG and the staff that helped put this session together. Great. I think we're done. Thank you, Anne and Raven. Thank you. Good job.

non-syndromic forms of monogenic obesity

genetic disorders

leptin deficiency

leptin receptor deficiency

POMC mutations

PCSK1 mutations

MC4R mutations

mechanism-based therapies

behavioral features

genetic testing

16p11.2 deletion syndrome

MC4R-related obesity

multidisciplinary evaluation

FDA-approved medications

ongoing clinical trials