The genomic technology of array Comparative Genomic Hybridisation (aCGH), which monitors losses or gains in chromosome regions that may harbour novel candidate genes, is not yet a standard test for investigation of NIPBL- and SMC1A-mutation-negative CdLS patients [11,18,34,35], but results obtained with the technique to date are consistent with those of > 30 conventional cytogenetic and FISH-targeted studies that have shown chromosomal abnormalities associated with the CdLS phenotype involving almost all of the chromosomes (reviewed [36]). This evidence concerns the gene NIPBL and Cornelia de Lange syndrome.