Autoimmune diseases occur when the immune system, which is meant to defend your body, actually attacks it. These diseases affect about 7.5 percent of the U.S. population, but for reasons unknown, they are far more likely to occur in women than men. While doctors have long suspected that this difference may be caused by hormones, new research suggests there may actually be a genetic component.

The study, now published online in Nature Immunology, revealed specific gene expression differences between the sexes that are associated with increased susceptibility to autoimmune diseases. In total the team of researchers from the University of Michigan found 661 genes that were expressed differently between the sexes, many of which had immune function and overlapped with genetic pathways and risk genes related to autoimmune diseases. Ultimately, the team identified what they are calling VGLL3, a master regulator of the female-biased immune network.

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"This previously unknown inflammatory pathway promotes autoimmunity in women," says senior author Johann Gudjonsson in a recent statement.

For the study, the team focused on examining how autoimmune diseases affected the skin. To do this they took skin biopsies from 31 females and 51 males. In doing so, they were able to see striking genetic differences between the two genders. This approach is different from past research on how autoimmune diseases affect the sexes, as it looks at genetic not hormonal factors.

"We found no evidence of involvement of estrogen or testosterone in the immune differences we observed between women and men," added Gudjonsson. "Identifying a separate regulatory mechanism could be a huge advance in gender-focused autoimmune research."

According to Healthline, there are as many as 80 types of autoimmune diseases, ranging from psoriasis which causes skin inflammation, to lupus which can cause organ failure. What’s more, it’s possible to have more than one autoimmune disease at the same time. However, despite the type of condition, women are always affected at a higher rate. The team hopes that identifying the true reason for this difference in diagnosis may eventually lead to better treatment options.

Source: Liang Y, Tsoi L, Xing X, et al. A gene network regulated by the transcription factor VGLL3 as a promoter of sex-biased autoimmune diseases. Nature Immunology. 2016

See Also:

5 Things To Know About Misunderstood Immune Disease

Autoimmune Disease Biomarkers