Rubinstein–Taybi syndrome (RSTS) is a rare autosomal dominant neurodevelopmental disorder divided into two main types: Type 1 (RSTS1; OMIM #180849) and Type 2 (RSTS2; OMIM #613684), which respectively result from mutations in the paralogous genes CREBBP and EP300 [1, 2]. This evidence concerns the gene EP300 and Rubinstein-Taybi syndrome due to CREBBP mutations.