PWS is also characterized by thermosensory abnormalities [19,20] as well as Schaaf-Yang syndrome (SYS), which has several overlapping features with PWS but is caused by pathogenic/truncating variants of the melanoma antigen L2 gene (MAGEL2), and a diagnosis of ASD is more frequent [21,22]. The gene discussed is MAGEL2; the disease is Schaaf-Yang syndrome.