In the largest genetic study of psoriasis to date, researchers at the University of Michigan in Ann Arbor have identified new variants associated with the chronic skin disease, bringing
the total number of variants associated with psoriasis to over 60.
The findings reveal more about the genetic architecture of the disease, pointing to the process within the body’s immune response involved in the development of the disease.
“We know there are a lot of genes, each with a relatively small effect, in play,” Dr. James T. Elder, professor of dermatology at U-M Medical School, said in a press release. “Those genes combined with the environment lead people to develop psoriasis. This study identified 16 more genetic markers, bringing the total to 63 loci linked to psoriasis.”
Impact of Psoriasis
Psoriasis, which is estimated to affect about 3 percent of the population, is complex, unpredictable and hard to treat. Symptoms include red itchy and scaly patches of skin often seen on the knees, elbows and scalp. But flare-ups can also impact the torso, palms and soles of the feet. In its mildest form, psoriasis can be a nuisance, but in severe cases the disease can be painful and disfiguring.
For this study, scientists used data from eight different groups, including 23andMe customers who consented to participate in research. In all, the meta-analysis included data from more than 39,000 people, all of European ancestry. The researchers found 63 genetic variants associated with the condition, including 16 that were identified for the first time.
Biological Pathways
After identifying the variants associated with the condition, the researchers applied a recently developed algorithm known as MEAGA used to help identify biological functions and pathways, as well as protein-to-protein interactions. This gives researchers an important added layer of information for the genetic associations that were found by suggesting how they may act in the body to influence the development of the disease. In this case, the researchers matched the variants to dozens of pathways and functions. Many of these pathways are involved in the immune response, and have important functions including regulation of certain immune cells and inflammatory signals.
The researchers also screened drug databases for existing drugs that target specific genes in which novel variants were discovered. They found 18 different drugs that regulate seven genes containing novel variants. Some of those drugs — aminosalicylic acid, mesalazine and sulfasalazine — have been used to treat psoriasis, the researchers said.
The findings from the paper “will serve as an important framework guiding future research into the pathogenesis and treatment of psoriasis,” according to the study.
You can find the study at Nature Communications.