Rheumatoid arthritis risk associates with DNA repair gene XRCC1 Arg399Gln polymorphism in Turkish patients.

Rheumatoid arthritis (RA) is an autoinflammatory disease with a genetic background. The synoviocytes in RA shows cellular transformation with tumor-like features, and RA patients have genomic instability and relaxation of DNA repair mechanisms. The polymorphisms in BER repair pathway genes, XRCC1 and OGG1, may change the response to inflammation via altered DNA repair capacity. In this study, we aimed to investigate the relationship between the risk of RA and XRCC1 Arg194Trp, Arg399Gln, and OGG1 Ser326Cys polymorphisms in a group of Turkish RA patients. XRCC1 Arg194Trp, Arg399Gln, and OGG1 Ser326Cys polymorphisms were investigated by PCR-RFLP method in 100 RA patients and 158 healthy control subjects. The results were statistically analyzed by calculating the odds ratios (OR) and their 95% confidence intervals (95% CI) using the χ(2)-tests. RA patients in this study had significantly higher frequencies of XRCC1 Arg399Gln polymorphism in both homozygote (GG) (35%, OR: 7.78 [95% CI: 3.65-16.59], P < 0.001) and heterozygote (AG) forms (41%, OR: 2.17 [95% CI: 1.19-3.96], P < 0.01) and also increased frequency of 399Gln (G) allele (55%, OR:2.99 [95% CI: 1.67-5.37], P < 0.001). We conclude that XRCC1 Arg194Trp, and OGG1 Ser326Cys polymorphisms are not associated with RA; however, Arg399Gln polymorphism is a significant risk factor of RA, and carriers of 399Gln (G) allele have greater risk of RA.