Recently, genome-wide association studies identified a novel psoriasis susceptibility locus tagged by two single-nucleotide polymorphisms (SNPs) rs4795067 and rs28998802, both of which are in the intronic region of inducible nitric oxide synthase (iNOS) gene.
All three loci were also associated with psoriatic arthritis (rs4795067, combined P = 1 × 10⁻⁵; rs10782001, combined P = 4 × 10⁻⁸; and rs12586317, combined P = 6 × 1⁻⁵) and purely cutaneous psoriasis (rs4795067, combined P = 1 × 10⁻⁸; rs10782001, combined P = 2 × 10⁻⁶; and rs12586317, combined P = 1 × 10⁻⁶).
All three loci were also associated with psoriatic arthritis (rs4795067, combined P = 1 × 10⁻⁵; rs10782001, combined P = 4 × 10⁻⁸; and rs12586317, combined P = 6 × 1⁻⁵) and purely cutaneous psoriasis (rs4795067, combined P = 1 × 10⁻⁸; rs10782001, combined P = 2 × 10⁻⁶; and rs12586317, combined P = 1 × 10⁻⁶).