Abstract
Intellectual disability (ID) is a neurodevelopmental disorder in which genetics play a key aetiological role. GATA zinc finger domain-containing 2B (GATAD2B) gene encodes a zinc-finger protein transcriptional repressor which is a part of the methyl-CpG binding protein-1 complex. Pathogenic variants in this gene are linked to ID, dysmorphic features, and cognitive disability. To date, only 18 cases are reported worldwide and only one case is reported from India. A 12-year-old girl presented with a heterozygous nonsense variation in exon 8 of the GATAD2B gene (chr1:153785737G>A). She has severe ID and significant delayed developmental milestones along with clinical features including broad arched eyebrows, low-set ears, a bulbous nose tip, thin upper lip, and wide mouth with downturned corners. This is the second report of a heterozygous mutation in the GATAD2B gene from India with a novel phenotype. To substantiate the association of GATAD2B mutation with ID, we performed DNase I footprint analysis of wild and mutant DNA sequences to establish k-mer binding profile and deduced GATA binding affinity using human ENCODE experimental data of foetal brain. We observed that in the presence of variation, GATA zinc finger domain was altered thus contributing to ID. Our findings support the importance of the GATAD2B gene in the study of neurodevelopmental disorders.
