Prader-Willi syndrome in Taiwan.
BACKGROUND
Prader-Willi syndrome (PWS) is a congenital disorder caused by absent expression of paternal genes in 15q11-13 affecting multiple systems. The information concerning the clinical features of this genetic disorder is incomplete in Taiwan.


METHODS
A retrospective analysis was carried out of 70 PWS patients (39 male, 31 females; age range, 1 month-22 years) seen in four major medical centers in Taiwan from January 1980 through June 2005. All cases were confirmed by methylation-specific polymerase chain reaction. The molecular characteristics, birth history, clinical presentation and laboratory studies were analyzed.


RESULTS
Complete genetic analysis was performed in 52 of the 70 patients with PWS. The abnormalities found included deletions in 45 (87%), maternal uniparental disomy (UPD) in five (10%), and a probable imprinting center deletion or an imprinting defect in two (4%). The average weight of the patients at birth was 2588 +/- 540 g. Bone age delay of >2 years and growth hormone (GH) deficiency were noted in 11/40 (28%) and 12/20 (60%), respectively. In the 18 in whom both bone age and GH were assessed, abnormalities of both were found in two (11%). In 2000, Taiwan instituted the Rare Diseases and Orphan Drugs Act and mandated a three-phase screening protocol for PWS. Of the 41 patients diagnosed with PWS before 2000, only four (10%) were diagnosed before the age of 3 months; in the 29 patients diagnosed after 2000, in 15 (52%) the syndrome was confirmed before 3 months of age (P < 0.001).


CONCLUSIONS
The present finding is in contrast to that of most previous reports that indicated a higher incidence of UPD in PWS. It is unclear whether this discrepancy in the incidence of UPD arises from under-diagnosis or because of ethnic differences, a question worthy of further study. The three-phase screening protocol has generated notable improvement in the early diagnosis of PWS in Taiwan.
Lin
Hsiang-Yu
HY
Department of Pediatrics, Mackay Memorial Hospital, and Mackay Medicine, Nursing and Management College, Taipei, Taiwan.
Lin
Shuan-Pei
SP
Yen
Jui-Lung
JL
Lee
Yann-Jinn
YJ
Huang
Chi-Yu
CY
Hung
Han-Yang
HY
Hsu
Chyong-Hsin
CH
Kao
Hsin-An
HA
Chang
Jui-Hsing
JH
Chiu
Nan-Chang
NC
Ho
Che-Sheng
CS
Chao
Mei-Chyn
MC
Niu
Dau-Ming
DM
Tsai
Li-Ping
LP
Kuo
Pao-Lin
PL
D000293:Adolescent; D000328:Adult; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D015870:Gene Expression; D020022:Genetic Predisposition to Disease; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009017:Morbidity / Q000639:trends; D016133:Polymerase Chain Reaction; D011218:Prader-Willi Syndrome / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics; D011379:Prognosis; D023121:RNA, Messenger, Stored / Q000235:genetics*; D013624:Taiwan / Q000453:epidemiology
D023121:RNA, Messenger, Stored