New genetic variants found to influence psoriasis risk

May 28, 2017 – ANN ARBOR. A study at the University of Michigan has identified new genetic pathways and potential treatment targets for psoriasis.

Researchers aimed to find the genetic causes of psoriasis, one of the most common immune-mediated diseases in the United States.

“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.”

Researchers conducted genome-wide tests, comparing frequencies of genetic variants of people with psoriasis to control subjects and examined data from eight different cohorts for a sample of more than 39,000.

The study focused on participants of European origin and on the loci they have already identified and found two notable pathways including the IL-23 and HLA genes.

Current treatment for psoriasis target IL-23 and IL-17, a cytokine that is produced in response to IL-23.

“This is by far the largest psoriasis meta-analysis to date in terms of sample size,” Alex Tsoi, research assistant professor in dermatology, biostatistics and computational medicine and bioinformatics at U-M Medical School said. “We’ve been able to pinpoint pathways related to the disease as well as pointing to the right directions for the gene targets.”

Current treatments for psoriasis focus only on about 5 percent of the genes identified so far.

Researchers analyzed data from specialist-diagnosed psoriasis along with self-reported cases from the consumer genetics company 23andMe, to identify the 16 new loci.

“Adding that chunk of data really gave us power to see more signals than we had seen in the past,” Elder said. “Better treatments will come out of understanding these other untouched genes.”

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.

Source: University of Michigan

Large scale meta-analysis characterizes genetic architecture for common psoriasis associated variants. Nature Communications 8. Published online: 24 May 2017.