DLG2 Intragenic Exonic Deletions Reinforce the Link to Neurodevelopmental Disorders and Suggest a Potential Association with Congenital Anomalies and Dysmorphism.

Purpose: Multiple studies suggest an association between DLG2 and neurodevelopmental dis-orders and indicate the haploinsufficiency of this gene; however, few cases have been thor-oughly described. We performed additional studies to confirm this clinical association and DLG2 haploinsufficiency.Methods: Chromosomal microarray analysis was performed on 11,107 patients at the Cytogenetics Laboratory at the University of Alabama at Birmingham. The Database of Genomic Variants-Gold Standard Variants and the Genome Aggregation Database were selected for the association analysis. Fifty-nine patients from the literature and DECIPHER, all having DLG2 intragenic deletions, were included for comprehensive analysis of the distribution of these deletions.Results: A total of 13 patients with DLG2 intragenic deletions, from 10 families in our cohort, were identified. Nine of 10 probands presented with clinical features of neurodevelopmental disorders. Congenital anomalies and dysmorphism were common in our cohort of patients. Association analysis showed that the frequency of DLG2 deletions in our cohort is significantly higher than those in the Database of Genomic Variants-Gold Standard Variants and the Genome Aggregation Database. Most of DLG2 intragenic deletions identified in 69 unrelated patients from our cohort, the literature, and DECIPHER map to the 5 ' region of the gene, with a hotspot centered around HPin7, exon 8, and HPin8.Conclusion: Our findings reinforce the link between DLG2 intragenic deletions and neuro-developmental disorders, strongly support the haploinsufficiency of this gene, and indicate that these deletions might also have an association with congenital anomalies and dysmorphism.(c) 2023 American College of Medical Genetics and Genomics. Published by Elsevier Inc. All rights reserved.