http://www.sciencedaily.com/releases/2012/04/120419121436.htm

First Gene Linked to Common Form of Psoriasis Identified

(snip...) "The research shows that rare mutations in the CARD14 gene, when activated by an environmental trigger, can lead to plaque psoriasis. This type of psoriasis accounts for 80 percent of all cases and is characterized by dry, raised, red patches covered with silvery scales that can be itchy and painful.
The new findings also indicate that mutations in CARD14 can be involved in the pustular form of psoriasis and in a debilitating arthritis linked to the psoriasis. The discovery may lead to more effective, targeted therapies for plaque psoriasis and other forms of the disease.
The research is published May 4 in two separate papers in The American Journal of Human Genetics" (more...)