Researchers have discovered a gene mutation that may cause premature ovarian failure, or early menopause. The findings may be useful for further study into, what researchers say, is a poorly understood condition.
Premature ovarian failure is a form of infertility that affects about 250,000 women in the United States. It is diagnosed in one out of every 100 women ages 30 to 39. Investigators created mice that lack both copies of a gene called FOXO3a, which belongs to the forkhead gene family. These genes are believed to control processes related to aging, cancer and diabetes. As the gene-altered mice aged, the females had fewer and smaller litters. By 15 weeks, which is comparable to early adulthood in a woman, they were sterile.
In addition, in the ovaries of the gene-altered mice, the follicles that contain eggs were activated earlier and more widely than in the normal mice. Lead study author Ronald DePinho, M.D., from Dana-Farber, explains: "There is a finite number of grains of sand that are released in a metered way. Similarly, a woman's eggs are gradually released over her reproductive lifespan. Menopause occurs when all the grains of sand have fallen. In mice lacking the FOXO3a gene, all of the grains of sand fall out very quickly, resulting in early menopause."
Researchers say it might be possible in the future to develop a contraceptive that would delay follicular activation. Current oral contraceptives prevent ovulation but do not slow the rate of activation.