On exome analysis, a mosaic mutation in NIPBL coding exon 8 (c.[=/1435C>T] p.[=/(Arg479*]) was identified in a male CdLS case (Family 3061, individual II:1) (figure 2A), who had previously been scored negative following Sanger sequencing of NIPBL. This nonsense mutation was found in 15% of the reads (31 out of 206 reads). This evidence concerns the gene NIPBL and Cornelia de Lange syndrome.