HDAC8 and Cornelia de Lange syndrome: Heterozygous c.490C>T (p.R164X) pathogenic variant in the HDAC8 gene previously reported to cause Cornelia de Lange syndrome 5 (CDLS5) (Deardorff et al 2012), an X-linked dominant developmental disorder. Phenotypes include facial dysmorphisms, abnormal hands and feet, and growth and developmental delay [49].