The prevalence of CGG repeat expansion mutation in FMR1 gene in the northern Chinese women of reproductive age

Background The prevalence of CGG repeat expansion mutation in FMR1 gene varies among different populations. In this study, we investigated the prevalence of this mutation in women of reproductive age from northern China. Methods A total of 11,891 pre-conceptional or pregnant women, including 5037 pregnant women and 7357 women with the history of spontaneous abortion or induced abortion due to delayed growth of the embryos, were recruited. The number of CGG repeats in FMR1 was measured by the TRP-PCR method. We also offered genetic counseling and prenatal diagnosis to the women carrying pre-mutation or full mutation alleles. Results The prevalence of pre-mutation in reproductive women in northern China was 1/410, higher than that in southern China and Korea but lower than that in western countries. We also found that the prevalence of pre-mutation was relatively high (1/320) in women with abortion history. Conclusion Screening for CGG repeat expansion mutation in FMR1 should be recommended to the women with the history of spontaneous abortion or induced abortion due to delayed growth of the embryos.