2023 ACMG Annual Clinical Genetics Meeting Digital Edition: Poster Gallery-Two New Cases of 9q21.13 Microdeletion Syndrome and Review of the Literature

Pdf Summary

Two cases of 9q21.13 microdeletion syndrome are reported in this study, expanding on the existing phenotype and providing further evidence of the role of the RORB gene in the neurological features of the syndrome. Patient 1 had a de novo 10.43 Mb deletion in bands 9q21.11-q21.31 and presented with global developmental delay, hypotonia, short stature, dysmorphic features, chronic lung disease, sleep apnea syndrome, dysphagia, constipation, and autism. Patient 2 had a de novo 10.049 Mb deletion in bands 9q21.11-q21.2, with the entire coding sequence of RORB being deleted. This patient exhibited developmental delays, abnormal eye movements, epilepsy, lethargy, vomiting, macrocephaly, dry skin and hair, and mild hypotonia. The RORB gene, found within the 9q21.13 deletion region, is believed to contribute to seizure susceptibility.<br /><br />The study calls for further investigation into the natural history of this microdeletion syndrome, particularly in relation to epilepsy treatment response, to guide management and surveillance of the condition. The RORB gene, which codes for a DNA-binding protein that enhances gene expression, has been associated with epilepsy. Previous literature has reported 14 cases of 9q21.13 microdeletion syndrome, characterized by epilepsy, developmental delay, neurobehavioral disorders, and dysmorphic features. In one case, a patient with a 9q21.13 deletion had a normal phenotype, suggesting that disruption of the RORB gene may be necessary for the syndrome's manifestation. Other patients with disruptions in the RORB gene have exhibited similar phenotypes to 9q21.13 microdeletion syndrome.<br /><br />In conclusion, this study presents two cases of 9q21.13 microdeletion syndrome, expanding the understanding of its phenotype and providing further evidence of the involvement of the RORB gene. Further research is needed to explore the natural history of the syndrome and its association with epilepsy treatment response.

Asset Subtitle

Presenting Author - Emma C. Pastoor, Undergrad; Co-Author - Elizabeth VanSickle, MS; Co-Author - Caleb Bupp, MD, FACMG;

Meta Tag

array CGH

Brain/Nervous System

Chromosomal Abnormalities

Clinical Cytogenetics

Cognitive Disorders

Exome sequencing

Genetic Testing

Identification of Disease Genes

Microarray

Phenotype

Variant Detection

Co-Author Elizabeth VanSickle, MS

Co-Author Caleb Bupp, MD, FACMG

Presenting Author Emma C. Pastoor, Undergrad

Keywords

9q21.13 microdeletion syndrome

RORB gene

neurological features

de novo deletion

global developmental delay

epilepsy

dysmorphic features

seizure susceptibility

phenotype

gene expression