Approximately 1% of all women are affected with a medical condition known as primary ovarian insufficiency (POI), a condition that often renders a woman infertile. The condition, also known as premature ovarian failure (POF) or premature menopause, affects the ovaries in ways that cause delayed or impaired sexual development or cessation of the menses at an abnormally early age. The cause of POI often remains elusive but a team of researchers at Tel Aviv University (TAU) in Israel has recently discovered a link between POI and a specific gene mutation.
Within the ovary, POI affects its ability to properly secrete estrogen and causes malfunction or depletion of ovarian follicles. Girls who have POI may never exhibit any of the classic signs of puberty. If they menstruate, their cycles are often irregular. Because estrogen is so vital to a woman’s overall health, POI affects women in other ways, too, that are not so closely related to menstruation and pregnancy. When the ovaries never function properly or cease to function before the age of 40, POI is often diagnosed. Most women experience natural menopause around age 50.
Some known causes of POI include Turner’s syndrome (only one X chromosome instead of two), chemotherapy, and radiation treatments but the cause is unknown about 90% of the time. At TAU, Dr. Liat de Vries and Prof. Lina Basel-Vanagaite delved into the role a specific mutation in a gene known as SYCE1 might play. This mutation is known to cause POI in animals but has never before been associated with POI in humans.
The study was prompted when de Vries was approached by an extended family in which two daughters were diagnosed with POI. Family composition included:
- Two sets of parents
- Two parents were first cousins
- The two families included 13 individuals
- A daughter in each family had POI
One daughter had reached puberty and appeared to be fully developed sexually but she never menstruated. The other daughter, 16, showed no symptoms at all of sexual maturity.
Of the 13 family members, genetic testing was done on:
- Both girls with POI
- All four parents
- Three sons
- One daughter with no symptoms of POI
Their tests were compared with an ethnically matched control group of 90 individuals. Testing revealed:
- The two daughters with POI had inherited two copies of the gene mutation, one copy from each parent.
- Each of the four parents carried one DNA copy of the gene mutation.
- Each of the three sons carried one copy.
- The POI-free daughter did not carry the mutation at all.
- The gene mutation was not found in any of the control group.
Although the TAU findings indicate no way to overcome the girls’ POI diagnoses, de Vries said: “we saved the family a lot of heartache by presenting evidence that any chance of inducing fertility in these two girls is slight.” He suggests the family might want to forego standard fertility treatments if pregnancy is desired and try egg donation as the first approach to child-bearing.
Sources:
- “Genetic Mutation Found to Cause Ovarian Failure.” Tel Aviv University / American Friends: Newsroom. American Friends of Tel Aviv University, 17 Dec. 2014. Web. 2 Jan. 2015.
- Nelson, Lawrence M. "Primary Ovarian Insufficiency." NCBI. US National Library of Medicine / National Institutes of Health, 5 Feb. 2009. PMC. Web. 2 Jan. 2015.