Rubinstein-Taybi syndrome (RSTS) is a neurodevelopmental disorder associated to mental retardation and caused by mutations in the genes CREBBP and EP300 encoding for the transcriptional regulators CBP and p300, respectively. These proteins regulate the acetylation state of the chromatin and consequently affect gene expression. Previous studies have shown that neuronal histone acetylation is reduced in mouse models of RSTS. In this article, Lopez-Atalaya and colleagues identify a number of new mutations into the CREBBP gene associated to RSTS widening the spectrum of mutations associated to this disorder and investigate for possible histone acetylation deficits in lymphoblastoid cell lines derived from some of these patients. The confirmation of the existence of similar biochemical deficits in cell lines from patients and mouse models of the disease and the efficacy of HDAC inhibitors to reverse these deficits opens new therapeutic possibilities.  (By Dr. Angel Barco, http://jmg.bmj.com/content/early/2011/10/07/jmedgenet-2011-100354.abstract?papetoc )