Endometriosis and Uterine Fibroids May Stem From the Same Genes, Study Says

Endometriosis and Uterine Fibroids May Stem From the Same Genes, Study Says

Scientists have found that the same genes may be involved in the development of both endometriosis and uterine fibroids, and that understanding the underlying genetics may help pave the way for new treatment strategies.

Their study, titled “Genome-wide association and epidemiological analyses reveal common genetic origins between uterine leiomyomata and endometriosis,” was published in Nature Communications.

Uterine fibroids — also called leiomyomata or leiomyomas — are benign or noncancerous growths in the uterus. The disease does not usually cause any symptoms, but about 25% of women with fibroids have symptoms that include heavy periods, and pelvic and back pain, among others. The only “curative” treatment currently is hysterectomy (surgical removal of the uterus).

Research has suggested that people with endometriosis are more likely to develop fibroids, but the reasons for this association haven’t been clear.

The researchers behind the new study first performed a genome-wide association study (GWAS) for fibroids. GWAS involves looking throughout the genome for regions where variations are associated with an increased or a decreased likelihood for a particular disease. Importantly, these studies are most useful when they include data on many people, which gives the analysis greater statistical power.

This GWAS combined data from several databases, both public and commercial, and included data for 35,474 female individuals with fibroids and 267,505 without. This sample size “more than doubles the case sample size of previously reported GWAS,” the researchers wrote.

However, because all the people included were women of white European ancestry, this likely limits the generalizability of the researchers’ findings, particularly since uterine fibroids are more common in people of African descent.

The researchers identified 29 genomic regions associated with an increased risk of uterine fibroids. Of these, 21 had been previously reported, and eight were new. Many of these regions contained genes that had been previously implicated in the development of cancer and/or how cells respond to hormones, which is thought to be a major regulator of fibroid development.

A subsequent analysis of a sample subset identified three genomic regions that are specifically associated with fibroids and heavy menstrual bleeding. These may open avenues for future studies as heavy periods are by far the most common symptom of fibroids and can affect quality of life. As such, “[genetic] variants specifically associated with this symptom are of particular interest for drug target development,” the researchers wrote.

“These findings are interesting in consideration of further research because only one in four fibroid cases causes symptoms, namely heavy periods,” said Outi Uimari, PhD, a professor at the University of Oulu and co-author of the study, in a press release.

The researchers also noticed that many of the fibroid-associated genome regions have also been linked to endometriosis. Subsequent statistical analyses revealed four regions of the genome that are strongly associated with both conditions. While the exact biological mechanisms behind this association have yet to be determined, this finding suggests that genetic variants that predispose people to endometriosis could also predispose them to uterine fibroids.

Further supporting this idea, the researchers performed an epidemiological meta-analysis that included data for 402,868 individuals, finding that people with endometriosis were 2.17 times more likely to have uterine fibroids — validating previous research and, again, supporting the notion that the two conditions are linked.

“We were able to identify several genes underlying fibroids as well as gain valuable information on the shared biological mechanisms underlying both fibroids and endometriosis,” Uimari said.

Overall, the researchers hope that further study of these genetic regions could identify probable treatment targets, ultimately paving the way for more effective therapies for endometriosis and uterine fibroids.

“Further characterization of the mutual pathogenic [disease-causing] mechanisms of [uterine fibroids] and endometriosis has the capacity to discover not only a deeper understanding of the underlying biology, but also treatments for two diseases that cause significant morbidity in roughly one-third of the world’s population,” they said.