title: Methylation-specific multiplex ligation-dependent probe amplification and identification of deletion genetic subtypes in Prader-Willi syndrome.
abstract: OBJECTIVE
  Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are complex neurodevelopmental disorders caused by loss of expression of imprinted genes from the 15q11-q13 region depending on the parent of origin. Methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) kits from MRC-Holland (Amsterdam, The Netherlands) were used to detect PWS and AS deletion subtypes. We report our experience with two versions of the MS-MLPA-PWS/AS kit (original A1 and newer B1) in determining methylation status and deletion subtypes in individuals with PWS.
  
  
  METHODS
  MS-MLPA analysis was performed on DNA isolated from a large cohort of PWS subjects with the MS-MLPA-PWS/AS-A1 and -B1 probe sets.
  
  
  RESULTS
  Both MS-MLPA kits will identify deletions in the 15q11-q13 region but the original MS-MLPA-A1 kit has a higher density of probes at the telomeric end of the 15q11-q13 region, which is more useful for identifying individuals with atypical deletions. The newer B1 kit contains more probes in the imprinting center (IC) and adjoining small noncoding RNAs useful in identifying small microdeletions.
  
  
  CONCLUSIONS
  The A1 kit identified the typical deletions and smaller atypical deletions, whereas the B1 kit was more informative for identifying microdeletions including the IC and SNORD116 regions. Both kits should be made available for accurate characterization of PWS/AS deletion subtypes as well as evaluating for IC and SNORD116 microdeletions.
authors: Department of Psychiatry and Behavioral Sciences and Pediatrics, University of Kansas Medical Center, Kansas City, Kansas 66160, USA.
authors: Rebecca S
authors: RS
authors: Henkhaus
authors: Soo-Jeong
authors: SJ
authors: Kim
authors: Virginia E
authors: VE
authors: Kimonis
authors: June-Anne
authors: JA
authors: Gold
authors: Elisabeth M
authors: EM
authors: Dykens
authors: Daniel J
authors: DJ
authors: Driscoll
authors: Merlin G
authors: MG
authors: Butler
mesh_terms: D017204:Angelman Syndrome / Q000175:diagnosis / Q000235:genetics*; D002884:Chromosomes, Human, Pair 15; D019175:DNA Methylation; D015342:DNA Probes; D005260:Female; D018392:Genomic Imprinting; D006801:Humans; D008297:Male; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D011218:Prader-Willi Syndrome / Q000175:diagnosis / Q000235:genetics*; D011933:Reagent Kits, Diagnostic; D017384:Sequence Deletion; D016615:Telomere / Q000235:genetics
chemical_list: D015342:DNA Probes; D011933:Reagent Kits, Diagnostic