STAG1 and Cornelia de Lange syndrome: Variants in genes encoding various structural or functional components of the cohesin complex, including RAD21, SMC1A, SMC3, BRD4, STAG1/2, NIPBL, HDAC8, WAPL, ANKRD11 and in single individuals PDS5A and ESPL1, have been implicated in Cornelia de Lange Syndrome (CdLS) (Ansari et al. 2014; Kline et al. 2018; Woods et al. 2014; Yuan et al. 2019).