These loci were identified by previous psoriasis genome-wide association studies and include variants within or near the HLA locus, IL23R, IL12B, TNIP1, TNFAIP3, IL23A, IL13, TRAF3IP2, LCE3B/3C, RNF114, IFIH1, ERAP1, REL, TYK2, NFKBIA, NOS2, IL28RA, SDC4, FBXL19, and RPS26. This evidence concerns the gene NOS2 and psoriasis.