RAD21 and Cornelia de Lange syndrome: Mutations in Nippe-B-like (NIPBL), Structural maintenance of chromosomes 1A (SMC1A), Structural maintenance of chromosomes 3 (SMC3), and other genes involved in the cohesin pathway, such as RAD21, HDAC8, and BRD4, have been implicated in CdLS [8,9,10,11].