Prader-Willi syndrome(PWS) is an important,wellrecognized syndromic form of neurodevelopmental disorder. The incidence is about 1 in 15,000-25,000 live births,and it affects both males and females(Vogels et al.,2004).The underlying genetic defects occur at an imprinted region on chromosome 15q11-13.Within this region,some genes only express on the maternally inherited chromosome 15,like UBE3A and ATP10C;while other genes only express on the paternally inherited chromosome 15,like MKRN3,MAGEL2, NDN,C15orf2,SNURF-SNRPN,and a number of small The incidence is about 1 in 15,000-25,000 live births, and it affects both males and females (Vogels et al., 2004). The underlying genetic defects (Prado-Willi syndrome (PWS) is an important, wellrecognized syndromic form of neurodevelopmental disorders. occur at an imprinted region on chromosome 15q11-13.Within this region, some genes only express on the maternally inherited chromosome 15, like UBE3A and ATP10C; while other genes only express on the paternally inherited chromosome 15, like MKRN3, MAGEL2, NDN, C15orf2, SNURF-SNRPN, and a number of small