Scientists have identified several new genetic variants that affect risk of psoriasis, a common inflammatory disease of the skin and joints, according to three studies published online this week in Nature Genetics.

Psoriasis affects approximately 1% of individuals, and is usually characterized by red scaly patches on the skin. Gon?alo Abecasis and colleagues carried out a genome-wide association study of affected individuals of European ancestry, and report association with seven genes, five of which cluster in two pathways. These pathways involve signaling by the IL-23 and NF-kappaB proteins, and antibodies targeting them have proven to be effective treatments for many individuals with the disease.

Xue-Jun Zhang and colleagues carried out a genome-wide association study of Chinese individuals with psoriasis, and report variants within the LCE cluster as protecting against the disease.

A third study by Xavier Estivill and colleagues shows that individuals in whom two of the LCE genes are deleted are at higher risk of psoriasis. They show that LCE proteins are induced in normal skin by disruption of the skin barrier, suggesting that compromised skin barrier function after injury may predispose to psoriasis.