Chromosomal abnormalities and FMR1 gene premutation in Chinese women with premature menopause.

OBJECTIVE To study the prevalence of chromosomal abnormalities and FMR1 gene premutation in Chinese women with premature menopause in Hong Kong. DESIGN Retrospective study. SETTING Clinical Genetic Service, Hong Kong. PARTICIPANTS Chinese women with premature menopause referred for cytogenetic study from January 1983 to November 2003. MAIN OUTCOME MEASURES Chromosomal abnormalities, FMR1 gene premutation. RESULTS Chromosomal abnormalities were present in 15.6% of Chinese women who suffered premature menopause. X-chromosome abnormality was involved in over 80% of cases. FMR1 gene premutation was present in 0.86% of 116 cases screened for this abnormality. The predominance of X-chromosome abnormality accounted for the shorter stature, younger menopausal age, and higher prevalence of dysmorphic features among the cytogenetically abnormal patients. However, on logistic regression, no clinical feature was significantly correlated with cytogenetic abnormality. CONCLUSIONS The prevalence of chromosomal abnormalities among Hong Kong Chinese women who suffer premature menopause was comparable with that of Caucasian and Chinese populations elsewhere. Because clinical features are poor predictors of cytogenetic abnormality, a pragmatic approach to screening is advocated. The carrier rate of fragile X premutation in these women appeared lower than that of Caucasians. Nevertheless, a search for FMR1 gene premutation, in addition to conventional chromosomal study, has important implication for prenatal diagnosis and fertility management for the extended family.