X chromosome inactivation patterns in patients with idiopathic premature ovarian failure

BACKGROUND: X chromosome aberrations have been reported as the cause of extremely skewed X chromosome inactivation (XCI). The purpose of this study was to investigate whether skewed XCI is associated with idiopathic premature ovarian failure (POF). METHODS: The XCI status was evaluated in Korean women by the methylation assay of androgen receptor locus in 126 idiopathic POF patients (35.3 +/- 13.9 years old, mean +/- SD) and 126 age-matched controls (35.2 +/- 13.9 years). The incidence of skewed XCI in POF group was compared with that of control. The correlation between age and skewed XCI was also evaluated within both groups. RESULTS: The incidence of extremely skewed XCI (>or=90%) was 3.9 versus 2.7% (P = 0.710) in POF and control group, respectively. No significant differences were found in the incidence of skewed XCI on all three levels (>or=90, >or=80 and >or=70%) compared between these two groups. The calculation of correlation coefficients showed that, in both POF and control group, there were no significant correlations between age and XCI ratio. Neither was there increasing tendency of skewed XCI according to the increase of age in both groups. Furthermore, there were no significant differences when the XCI ratios were analysed according to the age of onset of ovarian failure. CONCLUSIONS: The incidence of skewed XCI in Korean POF population was not significantly different from control, implying that skewed XCI may not be associated with idiopathic POF. There were also no significant correlations between age and skewed X-inactivation patterns in both groups.This study was supported by a grant (01-PJ10-PG6-01GN13- 0002) from the Korea Health 21 R&D Project, Ministry of Health & Welfare, Republic of Korea