Frequency of the fragile X syndrome in Chinese mentally retarded populations is similar to that in Caucasians.
Fragile X syndrome is recognized as the most common inherited cause of mental retardation in western countries. The prevalence of the fragile X syndrome in Asian populations is uncertain. We report a multi-institutional collaborative study of molecular screening for the fragile X syndrome from 1,127 Chinese mentally retarded (MR) individuals. We found that 2.8% of the Chinese MR population screened by DNA analysis had the fragile X full mutation. Our screening indicated that the fragile X syndrome prevalence was very close to that of Caucasian subjects. In addition, we found that 62.5% of fragile X chromosomes had a single haplotype for DXS548-FRAXAC1 (21-18 repeats) which was present in only 9.7% of controls. This unique distribution of microsatellite markers flanking the FMR1 CGG repeats suggests that the fragile X syndrome in Chinese populations, as in the Caucasian, may also be derived from founder chromosomes.
Zhong
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N
Department of Human Genetics, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York 10314, USA. omrddzhong@aol.com
Ju
W
W
Xu
W
W
Ye
L
L
Shen
Y
Y
Wu
G
G
Chen
S H
SH
Jin
R
R
Hu
X F
XF
Yang
A
A
Liu
X
X
Poon
P
P
Pang
C
C
Zheng
Y
Y
Song
L
L
Zhao
P
P
Fu
B
B
Gu
H
H
Brown
W T
WT
D000483:Alleles; D002681:China / Q000453:epidemiology; D005260:Female; D018703:Founder Effect; D005600:Fragile X Syndrome / Q000453:epidemiology* / Q000235:genetics*; D005820:Genetic Testing; D006239:Haplotypes; D006801:Humans; D008607:Intellectual Disability / Q000453:epidemiology* / Q000235:genetics*; D008297:Male; D044465:White People; D014960:X Chromosome / Q000235:genetics