Since CdLS and tumors share same types of mutations in cohesin genes (for NIPBL heterozygous mutations, mainly non-sense, leading to haploinsufficiency; for SMC1A hemizygous mutations, mainly missense, probably leading to a dominant negative effect) (Mannini et al., 2013; Singh and Gerton, 2015), it has been hypothesized that they differ in their physiopathological contest. The gene discussed is NIPBL; the disease is Cornelia de Lange syndrome.