CDK16 and cask-related x-linked intellectual disability: In our recent study of 405 families with XLID investigated by X chromosome exome sequencing, we identified a variant in CDK16/PCTAIRE-1 in a family with four affected males who all carry the variant and their mothers are heterozygous carriers [chrX:47086041-47086043, delTG, Q00536-2 (isoform 2): p.Trp400ValfsVPAP].