In summary, we described a novel Thr119Arg mutation in HDAC8 in a patient displaying the chief phenotypical characteristics of the CdLS, that is, brachycephaly, low anterior hairline, arched eyebrows with synophrys, long eyelashes, broad nasal tip, smooth philtrum, low‐set ears, short neck, small hands and feet, and a low‐pitched growling cry and developmental delay. This evidence concerns the gene HDAC8 and Cornelia de Lange syndrome.