RAI1 and Smith-Magenis syndrome: To shed light on the mechanisms through which RAI1 haploinsufficiency causes disease, we collected skin biopsies from two heterozygous female SMS patients carrying two CNVs, one with the canonical deletion of 3.6 Mb, which includes 72 genes (hereafter referred to as RAI1-del1), and the other with a 1-Mb deletion that includes 2 genes, FLCN (folliculin) and RAI1 (RAI1-del2).