The association to PsA was observed in the presence of polymorphisms: TNF-238 G > A (rs361525), -308 G > A (rs1800629), and -857 C > T (rs1799724); IL12B C > G (rs6887695) and A > C (rs3212227); IL23A A > G (rs2066808) and IL23R G > A (rs11209026).
For both PA and PV, we detected the strongest association with two IL12B single-nucleotide polymorphisms and the corresponding haplotype as reflected by minimal P-values of 10(-7) and highest odds ratios of 1.50 (1.28-1.75) for rs6887695 in PA patients and 1.50 (1.27-1.76) for rs3212227 in the PV cohort, respectively.
Both IL12B SNPs were independently associated with PsA susceptibility, and this association was strongest under a dominant model, with homozygosity for the common allele being more frequent in patients with PsA than in control subjects: for rs3212227, the odds ratio (OR) for carriage of AA versus other genotypes was 1.43 (95% confidence interval [95% CI] 1.17-1.76); for rs6887695, the OR for carriage of GG versus other genotypes was 1.43 (95% CI 1.18-1.74).