Gene Linked to Lupus in Men
Lupus most often affects women, but a new study finds that a variant form of a specific gene puts men at particular risk of developing the autoimmune disease. The gene linked to lupus in men—and women—is called Toll Like Receptor 7 (TLR7), and has previously been studied in animal cells.
Systemic Lupus Erythematosus
Systemic lupus erythematosus (SLE, or lupus) is a chronic, autoimmune disease that affects at least 1.5 million Americans. Lupus mostly affects women ages 15 to 44, although men and children develop the disease as well. Women of color are two to three times more likely to develop lupus.
Individuals who have lupus can experience symptoms ranging from mild to life-threatening, and the symptoms can come and go. The disease impacts the organs, such as the heart, lungs, kidneys, and skin, and symptoms can include rash, sores in the mouth, arthritis, photosensitivity, blood disorder (anemia, leucopenia, lymphopenia), seizures or psychosis, and kidney disorder, among others.
New Lupus Study
Prior to the new study, research had shown that TLR7 and TLR9 were important in animal models of lupus, but evidence in people was lacking. Now Betty Tsao, PhD, at the University of California Los Angeles (UCLA), has found that humans, and especially males, who have a variant form of TLR7 are at increased risk of developing the disease.
Only about 10 percent of people who develop lupus are males, but the disease is typically more severe in men. Tsao and her colleagues discovered that men who have an extra X (female) chromosome have a higher risk for lupus, and predicted that genes on that chromosome could be instrumental in male lupus.
The research team evaluated blood samples from more than 4,000 people with lupus from East Asia and found a variant form of the TLR7 gene associated with lupus. The association was stronger in men who were of Chinese and Japanese ethnicity. Tsao noted that “Now that we know the sex-specific genetic contributions to lupus, we can proceed to find more targeted therapies than currently exist.”
Current treatment of lupus focuses largely on relieving individual symptoms, which means patients are typically prescribed drugs such as corticosteroids, diuretics, anticonvulsants, anti-inflammatories, the antimalarial drug hydroxychloroquine, and other medications based on an individual’s needs.
Results of the new study provide the first evidence that changes in the TLR7 gene promote lupus in people, and that men with a variant form of the gene are at increased risk of developing the disease.
Lupus Foundation of America
University of California, Los Angeles, Sept. 3, 2010 news release