MAGEL2 and Prader-Willi syndrome: MAGEL2 is a gene that is involved in Prader–Willi (PWS) [11] and Schaaf-Yang (SYS) syndromes [12] and is classified as one of the highest relevant gene to ASD risk (SFARI gene scoring), indeed 75–80% of SYS patients meet the formal clinical diagnostic criteria of ASD [13, 14].