A novel deletion of SNURF/SNRPN exon 1 in a patient with Prader-Willi-like phenotype

Yang Cao, Susan S. AlHumaidi, Eissa A. Faqeih, Beth A. Pitel, Patrick Lundquist, Umut Aypar

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Here we report the smallest deletion involving SNURF/SNRPN that causes major symptoms of Prader-Willi syndrome (PWS), including hypotonia, dysmorphic features, intellectual disability, and obesity. A female patient with the aforementioned and additional features was referred to the Mayo Clinic Cytogenetics laboratory for genetic testing. Chromosomal microarray analysis and subsequent Sanger sequencing identified a de novo 6.4 kb deletion at 15q11.2, containing exon 1 of the SNURF gene and exon 1 of the shortest isoform of the SNRPN gene. SNURF/SNRPN exon 1, which is methylated on the silent maternal allele, is associated with acetylated histones on the expressed paternal allele. This region also overlaps with the PWS-imprinting center (IC). Subsequent molecular methylation analysis was performed using methylation-specific MLPA (MS-MLPA), which characterized that the deletion of SNURF/SNRPN exon 1 was paternal in origin, consistent with the PWS-like phenotype. Since SNURF/SNRPN gene and the PWS-IC are known to regulate snoRNAs, it is likely that the PWS-like phenotype observed in patients with paternal SNURF/SNRPN deletion is due to the disrupted expression of SNORD116 snoRNAs.

Original languageEnglish
Pages (from-to)416-420
Number of pages5
JournalEuropean Journal of Medical Genetics
Issue number8
StatePublished - Aug 2017


  • Chromosomal microarray
  • PWS-IC
  • Prader-Willi syndrome


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