SNRPN and Prader-Willi syndrome: The Small Nuclear Ribonucleoprotein Polypeptide N (SNRPN) gene is located within the central region associated with PWS and has an important regulatory role over the imprinted genes located in chromosome 15 (113, 114), while the SNRPN Upstream Reading Frame (SNURF) gene is encoded by an evolutionarily-conserved upstream open reading frame and is localized to the nucleus (115).