Evidence for PTPN22 R620W Polymorphism As the Sole Common Risk Variant for Rheumatoid Arthritis in the 1p13.2 Region

Item does not contain fulltextOBJECTIVE: The PTPN22 rs2476601 genetic variant has been associated with rheumatoid arthritis (RA) and other autoimmune diseases. Some reports suggest that this single-nucleotide polymorphism (SNP) may not be the only causal variant in the region of PTPN22. Our aim was to identify new independent RA-associated common gene variants in the PTPN22 region. METHODS: We analyzed Wellcome Trust Case-Control Consortium genome-wide association study data for associations in the 397.2 kb PTPN22 region and selected 9 associated SNP (with p < 5 x 10(-3)) for replication and dependence analysis. The replication cohorts comprised 2857 patients with RA and 2994 controls from Spain, Netherlands, and Norway. RESULTS: We found that 6 of the 9 selected SNP were associated in the Spanish cohort. Of these, 4 were also associated in the Dutch and Norwegian cohorts, and all 6 were associated with RA in the combined analysis. Conditional analyses showed that none of these associations was independent of rs2476601. CONCLUSION: The SNP rs2476601 located in the PTPN22 gene is the sole common genetic variant associated with RA in the 1p13.2 region, suggesting that neighbor genes of PTPN22 do not have a major influence in RA