RAD21 and Cornelia de Lange syndrome: Cornelia de Lange syndrome (CdLS, OMIM # 122470, #614701, #610759, #300590, and #300882) is a rare genetic disorder caused by variants in cohesion complex genes including NIPBL (NM_133433.3), SMC1A (NM_006304.4), SMC3 (NM_005445.3), HDAC8 (NM_018486.2), and RAD21 (NM_006265.3) (1).