CREBBP and Rubinstein-Taybi syndrome: While CREBBP variants in exons 30–31 have been associated with Rubinstein-Taybi syndrome, the CBP TAZ2 domain spanning amino acid residues 1772–1840 is a functionally distinct region, as variants within TAZ2 are now consistently linked with MKHK and a specific DNA methylation signature (Haghshenas et al., 2024; Nishi et al., 2022; Sima et al., 2022).