RESUMO
OBJECTIVE: Premature ovarian failure (POF) is a highly heterogenous condition, and its etiology remains unknown in approximately two-thirds of cases. POF can be caused by Turner syndrome, genetic disease, iatrogenic agents such as chemotherapy and radiotherapy, infection and autoimmune disease. X chromosome inactivation is the random process in females during early embryogenesis to achieve dosage compensation with males. But skewed X chromosome inactivation occurs in the female carriers, secondary to cell-autonomous selection against cells in which the abnormal X chromosome is active. Highly skewed X chromosome inactivation is likely to occur in POF which caused by subcytogenetic X chromosome deletion or translocation and X-linked gene mutation. The present study was performed to investigate whether highly skewed inactivation of X chromosome is observed in POF. METHODS: Eighty-six women with premature ovarian failure were studied and eighty-three normal women were enrolled as a control group. X chromosome inactivation pattern were determined by studying methylation pattern of androgen receptor gene. RESULTS: Seventy-six of the 86 POF patients were informative for X chromosome inactivation assay, 8 (10.5%) of them showed highly skewed X chromosome inactivation. In the age matched control group, 3 (4.1%) out of the 74 subjects showed highly skewed X chromosome inactivation. However, this finding is not statistically significant (p=0.2274). Among highly skewed X inactivation, one case of premature ovarian failure revealed 46,XX,del(X)(p21) by high resolution band karyotyping. Therefore highly skewed X inactivation can provide clues to evaluate the causes in POF. CONCLUSION: This study suggests that screening of skewed X chromosome inactivation for the POF will be useful to detect subcytogenetic X chromosome deletion or translocation and X-linked gene mutation associated with POF.