PWS is a contiguous gene disorder caused by paternal loss of the maternally imprinted 15q11-q13 chromosomal region containing 6 small nucleolar RNA genes and 6 protein-coding genes (MKRN3, NDN, NPAP1, SNURF-SNRPN, and melanoma antigen gene family member L2; MAGEL2) (1). This evidence concerns the gene MAGEL2 and Prader-Willi syndrome.