A De Novo 13q21.33-q31.1 Interstitial Deletion in a Child With Megalocornea and Neurodevelopmental Delay: A Clinico-Genomic Correlation.

Interstitial deletions of the long arm of chromosome 13 (13q) represent a rare and clinically diverse group of chromosomal abnormalities. We report the case of an eight-year-old Moroccan male with a de novo 9.8 Mb deletion at 13q21.33-q31.1, diagnosed via whole-exome sequencing (WES). The patient exhibited global developmental delay, absent structured language, macrocephaly, distinctive facial dysmorphism, ocular anomalies including bilateral megalocornea and nystagmus, musculoskeletal features such as scoliosis and hyperlaxity, and bilateral cryptorchidism. This case is the first to document megalocornea in association with a 13q deletion and supports the involvement of POU4F1 in human corneal development.