A translocation breakpoint cluster disrupts the newly defined 3' end of the SNURF-SNRPN transcription unit on chromosome 15

Hum Mol Genet. 2001 Feb 1;10(3):201-10. doi: 10.1093/hmg/10.3.201.


Balanced translocations affecting the paternal copy of 15q11--q13 are a rare cause of Prader-Willi syndrome (PWS) or PWS-like features. Here we report on the cytogenetic and molecular characterization of a de novo balanced reciprocal translocation t(X;15)(q28;q12) in a female patient with atypical PWS. The translocation breakpoints in this patient and two previously reported patients map 70-80 kb distal to the SNURF-SNRPN gene and define a breakpoint cluster region. The breakpoints disrupt one of several hitherto unknown 3' exons of this gene. Using RT--PCR we demonstrate that sequences distal to the breakpoint, including the recently identified C/D box small nucleolar RNA (snoRNA) gene cluster HBII-85 as well as IPW and PAR1, are not expressed in the patient. Our data suggest that lack of expression of these sequences contributes to the PWS phenotype.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Alternative Splicing
  • Autoantigens / genetics*
  • Base Sequence
  • Chromosome Banding
  • Chromosome Breakage / genetics
  • Chromosomes, Human, Pair 15 / genetics*
  • Cytogenetic Analysis
  • DNA / genetics
  • DNA / metabolism
  • DNA Methylation
  • DNA, Complementary / chemistry
  • DNA, Complementary / genetics
  • Exons / genetics
  • Female
  • Gene Expression
  • Humans
  • In Situ Hybridization, Fluorescence
  • Male
  • Molecular Sequence Data
  • Nuclear Proteins*
  • Prader-Willi Syndrome / genetics
  • Prader-Willi Syndrome / pathology
  • Proteins / genetics*
  • Ribonucleoproteins, Small Nuclear*
  • Sequence Analysis, DNA
  • Transcription, Genetic
  • Translocation, Genetic*
  • X Chromosome / genetics
  • snRNP Core Proteins


  • Autoantigens
  • DNA, Complementary
  • Nuclear Proteins
  • Proteins
  • Ribonucleoproteins, Small Nuclear
  • SNRPN protein, human
  • SNURF protein, human
  • snRNP Core Proteins
  • DNA

Associated data

  • GENBANK/AF319522
  • GENBANK/AF319523
  • GENBANK/AF319524