Feb. 28, 2002 -- Doctors already suspected that endometriosis runs in families. Now, there's convincing new evidence to support the theory of a genetic link.
Endometriosis is a condition in which uterine tissue grows outside the womb, attaching to various organs and ligaments in the abdominal cavity. This tissue acts like normal uterine tissue, growing and disintegrating with each menstrual cycle. This can cause pain, bleeding, and in some cases, infertility.
In Iceland, every citizen's family and health records are stored in a comprehensive database, allowing for large, highly-detailed population studies. For this investigation, researchers from deCODE Genetics and Landspitalinn University Hospital, both in Reykjavík, looked at records for all 750 women diagnosed with endometriosis between 1981 and 1993.
Their findings appear in the most recent issue of the European medical journal Human Reproduction.
They found that women with endometriosis were significantly more likely to be related to each other than were healthy women in a control group. Not only did a woman have more than five times the normal risk of developing endometriosis if her sister had it, she was also 50% more likely than normal to develop endometriosis if a cousin had it. This clinched the fact that genes were involved. It also revealed that fathers could pass the faulty genes along to their daughters.
Now the challenge is figuring out precisely which gene or genes are to blame.
"By using our populationwide genealogical resources and statistical models for measuring kinship, we have for the first time demonstrated the existence of a hereditary component to endometriosis that can be traced beyond first-generation relatives," says study co-author Kari Stefansson, MD, president and chief executive officer of deCODE.
These findings have begun "a genomewide scan to identify key genes that contribute to the disease," says Stefansson in a news release. By pinpointing the particular genes involved, scientists can better focus prevention and treatment efforts.
The team is already attempting to create a DNA-based screening test. "Such a test would assist in diagnosing the disease and in identifying women at particular risk of endometriosis, without the need for invasive procedures," he says.