In WTCCC AUCs for the SNP, HLA, HLA-SNP, HLA-smoking and HLA-SNP-smoking models in discriminating between ACPA-positive RA and controls comprised 0.660 (95% CI 0.638–0.681), 0.764 (95% CI 0.746–0.782), 0.796 (95% CI 0.779–0.813), 0.813 (95% CI 0.784–0.841) and 0.837 (95% CI 0.810–0.865), respectively (Figure 3). This evidence concerns the gene PRTN3 and rheumatoid arthritis.