KAT6B is a histone lysine acetyltransferase that catalyzes acetylation of histone H3, particularly at H3K23 and H3K14 positions 1. It functions as a component of the BRPF1-KAT6B complex and the MOZ/MORF histone acetyltransferase complex, which regulate chr10 structure and transcription 2. KAT6B plays critical roles in developmental processes including forebrain and cerebral cortex development, skeletal patterning, hematopoiesis, and maintenance of stem cells 3. Beyond histone modification, KAT6B acetylates non-histone proteins involved in transcription, DNA repair, cell cycle progression, and signal transduction 3. Germline KAT6B mutations cause neurodevelopmental syndromes including genitopatellar syndrome and Say-Barcher-Biesecker-Young-Simpson (SBBYS) syndrome, characterized by intellectual disability, cerebral anomalies, optic nerve hypoplasia, and limb anomalies 4. Clinically, KAT6B has dual roles in cancer. Somatic KAT6A/KAT6B overexpression drives ER+ breast cancer and leukemia 5, while KAT6B::KANSL1 fusions define an aggressive uterine sarcoma 6. Pharmacologic KAT6A/KAT6B inhibition demonstrates therapeutic efficacy in ER+ breast cancer and shows promise in MLL-fusion leukemia when combined with menin inhibitors 78.