NIPBL and Cornelia de Lange syndrome: A recent study identified NIPBL mutations in buccal epithelial cells of patients with classical CdLS who had been scored negative by sequencing of blood-derived DNA.6 Saliva-derived DNA has several advantages in the analysis of CdLS; first, it is easy to collect and second it is of multitissue origin (bone marrow derived and buccal epithelial cells).