Novel mosaic variants in two patients with Cornelia de Lange syndrome

Cornelia de Lange syndrome (CdLS) is a dominantly inherited developmental disorder caused by mutations in genes that encode for either structural ( SMC1A , SMC3 , RAD21 ) or regulatory ( NIPBL , HDAC8 ) subunits of the cohesin complex. NIPBL represents the major gene of the syndrome and heterozygous mutations can be identified in more than 65% of patients. Interestingly, large portions of these variants were described as somatic mosaicism and often escape standard molecular diagnostics using lymphocyte DNA.