RAI1 and Smith-Magenis syndrome: SMS is associated with deletions of the 17p11.2 locus, which covers many genes, including RAI1. Despite having similar overlap in phenotype, outcome differences have been reported for SMS patients with 17p11.2 deletions compared to SMS patients with mutations—such as frameshift and missense variations, including p.P242L, p.D969D, p.S1808N, and other variants (Table 2)—that only affect RAI1 [47,85,86,90,91,92,93,94].