HDAC8 and Cornelia de Lange syndrome: Since then, cohorts of individuals with classic, non-classic and overlapping phenotypes have been screened for gene variants of other cohesin core and regulatory proteins, leading to the detection of variants in six additional genes causal of CdLS: SMC1A, SMC3, RAD21, BRD4, HDAC8 and ANKRD11 (R4).