For some women, the "change" happens all too soon. An estimated one in 100 women under age 40 and one in 1,000 under 30 suffer from what is known as Premature Ovarian Failure (POF); some teenagers are even affected. And as their estrogen levels wane, these women experience the classic symptoms of menopause, including hot flashes, mood swings and, often most devastating, a loss of fertility. Now scientists from the University of Auckland have identified a gene mutation that may be associated with POF. The results, published in today's issue of Human Reproduction, are preliminary. But "if the mutation is found in a family with a history of premature menopause," team member Ingrid Winship says, "screening younger women members would provide valuable information to help them plan their families."
Lead researcher Andrew Shelling and his colleagues collected medical histories and DNA samples from 43 women with POF. They discovered that 7 percent--three women in total--had a mutation in one of three inhibin genes, the alpha inhibin gene. In a control group, mutations in this gene were much rarer, occurring at a rate of only one in 150. Inhibin itself is a glycoprotein involved in regulating follicle stimulation hormone and so is crucial to the normal functioning of a woman's reproductive system. Of interest, the three women in the study with the mutation were all exceptionally young--aged 16, 20 and 24--when they ceased menstruating. "We think that mutations in the inhibin alpha gene may be responsible for premature menopause in very young women," Shelling notes, "but that more subtle changes in gene function could cause premature menopause in older women."
The scientists are planning additional work, involving larger groups of subjects, analyses of other genes in the inhibin pathway and other reproductive disorders involving inhibin--namely polycystic ovarian syndrome and ovarian cancer. "To verify our findings, there needs to be more good biochemical research and population studies from different parts of the world with ethnically matched controls," Shelling adds. "If that research also turns out to be significant, then we will definitely have identified a new molecule involved in premature menopause and possibly other reproductive disorders. That could lead to new treatments in the future, either by replacing the defective inhibin molecule through some form of hormone replacement therapy or possibly even a gene therapy."