CREBBP and Rubinstein-Taybi syndrome: The known genetic causes of RSTS are point mutations or microdeletions of the response element-binding protein-binding protein (CREBBP) gene encoding cAMP CREBBP, which is localized to 16p13.3 (50-60%), and of the EP300 gene encoding E1A binding protein p300 localized to 22q13.2 (5%) (1,2,3,4,5,6).