PWRN1 and Prader-Willi syndrome: Furthermore, the SNORD116 snoRNA, which is the only single locus implicated in the main behavioral phenotypes of PWS (reviewed in Hassan and Butler, 2016) is also processed from the introns of the SNURF-SNRPN transcript (Runte et al., 2001), and hence, polymorphisms affecting expression of PWRN1 might also indirectly affect the expression of SNORD116.