GATAD2B is a transcriptional repressor and core component of the NuRD chr1 remodeling complex 123. It functions by enhancing MBD2-mediated transcriptional repression and requires GATAD2A for efficient repression 12. Beyond transcriptional regulation, GATAD2B plays critical roles in DNA damage response by promoting histone deacetylation and establishing chr1 boundaries following double-strand breaks 4, and regulates spindle assembly during oocyte meiosis through histone deacetylation 5. GATAD2B's O-GlcNAcylation protects it from ubiquitin-mediated degradation, regulating cancer stem cell properties and chemoresistance in breast cancer 6. Heterozygous pathogenic de novo variants in GATAD2B cause GATAD2B-associated neurodevelopmental disorders (GAND), characterized by intellectual disability with language impairment, infantile hypotonia, macrocephaly, and dysmorphic features 789. Recently, GATAD2B variants have been associated with developmental and epileptic encephalopathy presenting as drug-resistant atypical absences, expanding the clinical spectrum beyond typical developmental delay 9. Additionally, chr1 translocations involving GATAD2B, such as t(X;1) generating GATAD2B::MTCP1 fusion, have emerged in myeloid malignancies 10.