This finding raises the possibility that the neuropsychological symptoms in Williams syndrome are not only caused by haploinsufficiency of genes like GTF2I, GTF2IRD1, LIMK1, and CLIP2 (2, 11, 22), but also by that of the WSCR gene(s) implicated in structure and function of the vasculature. This evidence concerns the gene GTF2IRD1 and Williams syndrome.