SNRPN and Prader-Willi syndrome: We demonstrate a unique molecular presentation in a patient with classic PWS associated with a 78 kb microdeletion involving exons 2-3 of the SNURF-SNRPN gene and preserved expression of downstream SNORD116. This result shows that classic PWS is not solely dependent on absent SNORD116 expression and that more work is needed to understand the mechanisms driving the phenotype.