The expression of many genes known to be associated with psoriasis, including Lce3f, Sprr2b, Krt15, S100a8, S100a9, Il17a, Il17f, Il18, Il20, Il22, and Ccl20, was downregulated in the skin of IMQ-treated Camk4−/− mice compared with those of IMQ-treated Camk4+/+ mice. The gene discussed is IL20; the disease is psoriasis.