The largest genetic study of eczema ever performed permitted a team of international researchers to identify ten previously unknown genetic variations that contribute to the development of the condition. [University of Gothenburg]

With cold winter temperatures looming around the corner for much of the northern hemisphere, the arid frigid air seemingly brings along with it dry, itchy skin. Yet, for a fair number of people this type of skin malady is a constant part of life, regardless of the season.

Atopic dermatitis—commonly known as eczema—is a common inflammatory skin disorder that affects one out of every five children and between 5-10% of the adult population. While inheritability patterns and some genetic markers have been identified for the disease, most of the genes responsible for the skin condition have yet to be determined.

Now, an international team of scientists from clinical researcher centers across the globe have conducted the largest study to date of atopic dermatitis, pooling data obtained from 377,000 subjects in 40 different projects around the world.     

“We identified ten new genetic variations, making a total of 31 that are currently known to be associated with atopic dermatitis,” explained co-author Bo Jacobsson, M.D., Ph.D., professor and chief physician in the department of obstetrics and gynecology at the Sahlgrenska Academy, a division of the University of Gothenburg. “Of particular interest is that each of the new ones has a role to play in regulation of the immune system.”

The findings from this study were published recently in Nature Genetics through an article entitled “Multi-ancestry genome-wide association study of 21,000 cases and 95,000 controls identifies new risk loci for atopic dermatitis.”

Among the new candidate genes for eczema, the researchers came upon loci that are important for the innate immune system and for the development and function of T-cells, which play an important role in various immune responses.

“We identified ten new risk loci, bringing the total number of known atopic dermatitis risk loci to 31 (with new secondary signals at four of these loci),” stated the researchers. “Notably, the new loci include candidate genes with roles in the regulation of innate host defenses and T cell function, underscoring the important contribution of autoimmune mechanisms to atopic dermatitis pathogenesis.”

Interestingly, the newly identified genetic regions show a robust correlation with known risk loci for other immune disorders such as asthma, allergies, and other chronic inflammatory diseases like Crohn's disease and psoriasis, as well as with autoimmune diseases.

“While the new variations contribute in only a small way to the risk of developing atopic dermatitis, knowing about them will raise our awareness of the mechanisms for the various diseases,” noted Dr. Jacobsson. “Our ultimate hope is that additional treatment methods will emerge as a result.”

For this study, the researchers incorporated a total of 21,399 cases of European, African, Japanese, and Latino ancestry in 22 different studies comparing them with 95,464 controls. Moreover, the findings were then replicated in 18 studies of 32,059 cases and 228,628 controls.

“While not detracting from the importance of maintaining the skin barrier in the prevention and treatment of atopic dermatitis, our findings lend support to new therapeutic approaches targeted at immune modulation,” concluded the investigators.

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