Dissecting Lateralized Overgrowth – Clinical and Molecular Diagnosis and Tumor Risk
September 12, 2024 | 1:00 – 2:00 pm ET
Description:
Lateralized overgrowth (LO) is characterized by asymmetric, increased growth or size of any part of the body and can be observed in defined overgrowth syndromes but can also occur as isolated lateralized overgrowth (ILO). For some of the well-described overgrowth syndromes including CDKN1C-related Beckwith-Wiedemann syndrome (BWS), PIK3CA-related overgrowth spectrum (PROS), AKT1-related Proteus syndrome (PS), and PTEN related hamartoma tumor syndrome (PHTS), an increased but heterogeneous tumor risk is known and, in some cases, periodic screening for neoplasms is recommended.
Historically, in children with ILO, there is a malignancy risk of approximately 5% for Wilms tumor and hepatoblastoma, however these cohorts did not molecularly distinguish mosaic syndromic cases from isolated cases.
Knowledge of underlying molecular causes of the various overgrowth syndromes has improved and genomic testing has become more readily available. Mosaicism and somatic variants play a significant role in the pathogenesis of certain overgrowth syndromes. Examples include mosaicism causing BWS and somatic variants or mosaicism in the genes of the PI3K/PTEN/AKT/TSC/mTORC1 signaling pathway, which can lead to distinct overgrowth conditions and may only be detected by deep sequencing of affected tissue. Recognizing individuals with specific overgrowth conditions caused by mosaicism can be challenging since the phenotypes can be more variable and significantly milder when compared to the classic forms of the disorders. We provide a clear approach for the evaluation of mosaicism or somatic variants in affected tissue in lateralized overgrowth with the goal to increase diagnostic accuracy. This in turn will improve the ability to develop more tailored tumor surveillance and help prevent unnecessary cancer screening, which can have adverse ramifications for the patients and their families.
Target Audience
All healthcare professionals interested in the diagnosis, management, treatment, and prevention of genetic conditions and increasing their understanding of the genetic basis of common, chronic health problems affecting both children and adults will find the programming applicable to their practice. The ACMG Annual Meeting is targeted for the following professionals:
- Medical and clinical geneticists; genetic counselors; pediatric, obstetric, and maternal-fetal specialists; and all medical practitioners who are providing comprehensive diagnostic, management, and counseling services for patients with, or at risk for, genetically influenced health problems.
- Laboratory directors and technicians who conduct genetic testing.
- Researchers involved in the discovery of genetic disorders and treatments.
- Clinical, laboratory and research trainees of genetics and all biomedical sciences.
- Any healthcare and public health professionals who have an interest in medical and clinical genetics and genomics.
- Advocates for patients with genetic conditions and their families.
Agenda
Presentation followed by live Q&A.
Presentation
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Presenter
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Affiliation
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Welcome and Introduction
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Julian A. Martinez-Agosto, MD, PhD, FACMG and Alexandra Keefe, MD, PhD
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UCLA
University of Washington
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Isolated Lateralized Overgrowth - Diagnostic Criteria and Distinction from Other Overgrowth Conditions
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Angelika L. Erwin, MD, PhD, FACMG
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Cleveland Clinic Cleveland
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Beckwith-Wiedemann Syndrome: Clinical and Molecular Diagnosis
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Jennifer M. Kalish, MD, PhD, FACMG
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The Children's Hospital of Philadelphia
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Cancer Risk in Lateralized Overgrowth: Characterization and Screening
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Julian A. Martinez-Agosto, MD, PhD, FACMG
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UCLA
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Molecular Testing for Syndromic Forms of Lateralized Overgrowth: Lessons from PIK3CA-Related Syndromes
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James T. Bennett, MD, PhD
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University of Washington
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Proteus Syndrome and its Mimics: Optimizing Diagnosis and Treatment
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Matthew A. Deardorff, MD, PhD, FACMG
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USC
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Learning Objectives
At the conclusion of this session, participants should be able to:
- Define diagnostic criteria of isolated lateralized overgrowth and distinguish from other overgrowth conditions.
- Apply appropriate genetic testing strategy in patients with lateralized overgrowth.
- Recognize phenotypic variability of lateralized overgrowth and integrate into the testing strategy.
- Differentiate Proteus syndrome from other overgrowth syndromes.
- Apply appropriate tumor risk and screening recommendations to individual patients with overgrowth conditions.
Meet the Faculty:
Angelika Erwin, MD, PhD, FACMG, Cleveland Clinic Cleveland
James Bennett, MD, PhD, FACMG, University of Washington
Jennifer Kalish, MD, PhD, FACMG, The Children's Hospital of Philadelphia
Julian Martinez-Agosto, MD, PhD, FACMG, University of California, Los Angeles
Matthew A. Deardorff, MD, PhD, FACMG, University of Southern California, Los Angeles