Starting from the evidence that cohesin depletion causes a reduction in the looping interactions in the IGF2/H19 imprinted domain [29], we studied the 3D chromatin structure of this locus in LCLs from CdLS patients with mutations in the SMC1A or NIPBL genes, and evaluated whether constitutive genetic mutations in the cohesin subunit genes can alter chromatin architecture and, consequently, gene expression. The gene discussed is H19; the disease is Cornelia de Lange syndrome.