Genetic Discovery Could Lead to New Treatments

A significant advance in the understanding of the genetic basis of psoriasis was reported by an international team of researchers in two studies published in the February 2009 issue of the journal Nature Genetics. The research involved thousands of DNA samples, including samples from the National Psoriasis Foundation Tissue Bank, predecessor of the National Psoriasis Victor Henschel BioBank.
Psoriasis: Genetic Discovery Could Lead to New Treatments

The first study was a collaborative effort of Foundation-supported researchers at Washington University in St. Louis, Mo., the University of Michigan, the University of Utah and colleagues in Canada and Europe. This study focused on common sites within the human genome where a single unit of DNA is changed. It’s called single nucleotide polymorphism (SNP or “snip”). The researchers scanned nearly 450,000 SNPs in each of 1,409 psoriasis patients and compared the DNA variations to those in 1,436 healthy controls.

They initially selected 21 of the most promising “suspect variants” associated with psoriasis. The investigators then went on to validate the authenticity of these variants in another group of 5,048 psoriasis patients and 5,041 controls. The validation step revealed seven confirmed variants, all of which appear to increase the risk of psoriasis.

All seven variants, the study noted, likely play a role in immune system regulation, which is involved in the development of psoriasis. Some of the genes identified in this study are already targeted by effective psoriasis treatments, while others may become targets for future psoriasis treatments.

A second study of 2,831 patients with psoriasis looked for links between the disease and another genetic variation called a “copy number variation.” In using this technique, National Psoriasis Foundation researcher Anne Bowcock and colleagues at Washington University found that the absence of two skin genes — LCE3B and LCE3C — increases the risk of psoriasis. Normally, both genes are activated after an injury to the skin. The researchers suspect the absence of the genes could lead to an inappropriate immune response, which may cause the inflammation that characterizes psoriasis.

The new variants discovered in these two studies have significantly advanced our understanding of the genetic cause of psoriasis, and have revealed important new insights that lead us closer to a cure.

However, there is still much more to discover before we have a complete understanding of psoriasis genetics. You can do your part by donating your DNA (blood and tissue samples) for the study of psoriasis genetics to the National Psoriasis Victor Henschel BioBank. To donate your DNA, visit www.stoppsoriasis.org or call 1-800-723-9166, ext. 372, to learn more.