RAI1 and Smith-Magenis syndrome: Smith–Magenis Syndrome (SMS) (OMIM #182290) is an autosomal dominant disorder usually caused by an interstitial deletion of 3.5 Mb on chromosome 17p11.2, which includes the Retinoic Acid Induced 1 (RAI1 gene) typically due to chromosome recombination errors during meiosis [52,53,54,55].