BRWD3 (bromodomain and WD repeat domain containing 3) is an X-linked gene that encodes a protein containing bromodomain and WD40 repeat domains, which are involved in chrX remodeling and transcriptional regulation 1. The protein plays a critical role in neurodevelopment, with pathogenic variants causing X-linked intellectual developmental disorder 93 2. Loss-of-function variants typically result in moderate to mild intellectual disability (65% and 35% respectively), postnatal macrocephaly (mean +2.8 SD), obesity (mean BMI +2.0 SD), speech delay, and behavioral issues including aggressive behavior and autism spectrum disorders 3. The clinical phenotype shows genotype-phenotype correlation: null variants and deletions cause intellectual disability with overgrowth features 3, while specific missense variants in the WD40 repeat and bromodomain regions are associated with X-linked partial epilepsy without intellectual disability 1. BRWD3 has also been implicated in cancer biology, where it shows high expression in lung adenocarcinoma and regulates cell proliferation and apoptosis through p53 and p65 pathways 4. The gene's involvement in chrX regulation and transcriptional control underlies its diverse roles in neurodevelopment and cellular growth control.