Diagnosis of Prader-Willi Syndrome and Angelman Syndrome
Diagnosis of Prader-Willi Syndrome and Angelman Syndrome
In a retrospective study, data were assessed from cases regarding PWS/AS that underwent
 molecular diagnosis at the National Chen-Kung University Hospital, Tainan, Taiwan, between
 January 2001 and December 2014.
Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are two distinct syndromes of
 developmental impairment that result from loss of the expression of imprinted genes on the
 q11-q13 region of chromosome 15 (15q11-q13). Approximately 70%--75% of individuals affected
 with PWS and AS have an interstitial deletion of 15q11-q13. Regarding the remaining
 individuals with PWS, maternal uniparental disomy is the cause in 20% of cases, imprinting
 errors in 3% of cases, and chromosomal translocation in approximately 1% of cases. Regarding
 the remaining cases of AS, paternal uniparental disomy accounts for 2% of cases and mutations
 in the UBE3A gene for 20% of cases.The PWS/AS critical region was examined by fluorescence in
 situ hybridization (FISH), methylation-specific PCR (M-PCR), and methylation-specific
 multiplex-ligation dependent probe amplification(MS-MLPA). In a retrospective study at the
 National Chen-Kung University Hospital,Tainan, Taiwan, data were reviewed from cases that
 were referred for molecular diagnosis between January 1, 2001, and December 31, 2014.
Inclusion Criteria:

 -  Individual with clinical features related to Prader-Willi syndrome or Angelman
 syndrome;

 -  Fetus with suspicious deletion or duplication of chromosome 15q11.2-q13 visible by the
 microscope;

 -  Fetus whose mother or father has chromosomal abnormality involving 15q11.2-q13

 -  Fetus with mosaic trisomy 15

 Exclusion Criteria: