摘要
Background Fragile X syndrome(FXS).caused by CGG-repeat expansion in FMR1 promoter,is one of the most common causes of mental retardation.Individuals with full mutation and premutation alleles have a high risk of psychophysiological disorder and of having affected offspring.Frequencies of FMR1 alleles in general newborns have been reported in Caucasians but have not been investigated in the large-scale population in the mainland of China.Methods The sizes of FMRI CGG-repeats were analyzed in 51,661 newborns(28,114 males and 23,547 females)and also in a cohort of 33 children diagnosed with developmental delay using GC-rich polymerase chain reaction(PCR)and triple repeat primed PCR.Results The frequency of CGG repeats>100 was 1/9371 in males and 1/5887 in females,and the frequency of CGG repeats>54 was 1/1561 in males and 1/1624 in females.FMRJ full mutation and premutation were identified in 27.27%of children who had Ages and Stages Questionnaire scores less than two standard deviations from the cutoff value.Conclusions Our study revealed the prevalence of FXS in China and improved the sample databases of FXS,suggesting that the prevalence of FXS in Chinese is higher than estimated previously and that FXS screening can be advised to high-risk families.
基金
supported by the Key Research and Development Program of Zhejiang Province(2017C03009 to Q.S.)
the National Key Research and Development Program of China(2017YFC1001703 to Q.S.)
Q.S.was also supported by the Fundamental Research Funds for the Central Universities(2014QNA6002).
