RAI1 and Potocki-Lupski syndrome: SMS results from RAI1 haploinsufficiency, typically due to 17p11.2 deletions (most commonly ~3.7 Mb) or pathogenic mutations, whereas PTLS is caused by RAI1 overexpression resulting from 17p11.2 microduplications (0.25–11.2 Mb) (Supplementary Material 3).