Nearly 40,000 study participants helped scientists discover 16 novel genetic markers associated with psoriasis, joining the 47 already-known markers. Psoriasis, an immunological disease that causes “raised, red, scaly patches” on areas of the skin such as the elbows, knees, and scalp, is rare - it affects just one to two percent of the population.
The University of Michigan study is, according to first author Alex Tsoi, PhD, the “largest psoriasis meta-analysis to date in terms of sample size.” Tsoi and the research team conducted tests of entire genomes, looking to compare genetic variant frequencies between people with and without psoriasis.
"We've been able to pinpoint pathways related to the disease as well as pointing to the right directions for the gene targets,” Tsoi explained.
Researchers looked for and analyzed the interleukin (IL)-23 and HLA gene pathways during their study, which ultimately led to the discovery of the novel genetic markers in association with psoriasis. Current therapies target IL-23 as well as IL-17, a byproduct of IL-23 activity.
HLA is also an infamous subject when studying psoriasis genetics. Based on the results from the new study though, HLA’s structure, explained senior author James T. Elder, MD, PhD, is “more complicated than ever suspected.”
For the psoriasis-associated genes of which scientists are aware, there is still a need for drug targets to be developed that target these known genes, and there are still psoriasis-associated genetic markers left to be uncovered. "We know there are a lot of genes, each with a relatively small effect, in play,” Elder said. “Those genes combined with the environment lead people to develop psoriasis. Better treatments will come out of understanding these other untouched genes."
More about psoriasis
Psoriasis, an autoimmune disorder, can be characterized by any of the five types: plaque psoriasis (the most common), guttate (triggered by Streptococcal infections), inverse (red lesions in body folds I.E. behind the knee), pustular (white pustules surrounded by red skin), erythrodermic (particularly severe, effects most of the body).
The present study was published in the journal Nature Communications.