Study shows that seven genes may cause psoriasis

NEW YORK Seven genes may cause the skin disease psoriasis, according to a study published in the online edition of the journal Nature Genetics.

The study's researchers, led by University of Michigan dermatology professor James Elder, enlisted 1,409 psoriasis patients and a control group of 1,436 healthy people, all of European ancestry. They later expanded the two groups by 5,048 and 5,041 people, respectively.

They found variations in seven genes underlying the autoimmune response that causes the disease, characterized by red, scaly skin and soreness. Psoriasis affects as many as 7.5 million people in the United States, according to the National Psoriasis Foundation.