Some studies suggested that RSTS patients carrying the EP300 gene variant have a mild clinical phenotype [19], but Fergelot et al. previously conducted a comparative study on 52 children carrying the variants in the EP300 gene and 308 children carrying the variants in CREBBP gene and found that the clinical manifestations of the two types were similar [6]. This evidence concerns the gene EP300 and Rubinstein-Taybi syndrome.