STAG2 and Cornelia de Lange syndrome: It remains uncertain whether duplication of the whole gene can lead to a CdLS phenotype, as demonstrated for duplications in STAG2 and SMC1A (Baquero-Montoya et al. 2014; Mullegama et al. 2019), as all duplications we retrieved, were either including several other genes or pathogenicity could not be confirmed.