Background: Rheumatoid arthritis is a chronic inflammatory disorder that mainly affects the peripheral joints and surrounding tissue. Genetic and environmental factors have important roles in pathogenesis. The role of oxidative stress and the enzymes involved in the pathogenesis of rheumatoid arthritis have been studied in these years. A predominant role in counteracting reactive oxygen spieces is played by endogenous antioxidant enzymes, and glutathion peroxidase (GPx). An alteration of CTC codon to CCC codon which results in substitution of leucine instead of proline in 198th amino acid location is one of the important polymorphisms of this gene. The aim of this study was to evaluate the association of GPx1 gene polymorphism in patients with rheumatoid artheritis.

Materials and Methods: The case-control study included 130 patients with rheumatoid artheritis and 126 healthy individuals. Genomic DNA was extracted from white blood cells and the genotypes were identified using polymerase chain reaction-restriction fragment length polymorphism (PCR - RFLP). Statistical analysis was carried using the MedCalc (version 12.1).

Results: The frequencies of CC, CT and TT genotypes of GPx1gene were 32.31%, 43.08% and 24.61% respectively, in rheumatoid arthritis patients, whiles in healthy volunteers were 42.62%, 54.10% and 3.28%. Statistical results showed significant relationship between TT genotype of GPx1 gene and Rheumatoid arthritis (p=0.002, &chi2 =11.715, OR: 9.90 95% CI (2.04 to 48.01)).

Conclusion: In conclusion, these results indicate that TT genotype of GPx1 gene may be associated with the risk of rheumatoid artheritis in the studied population. However, further research is required to clarify the role of gene polymorphism in rheumatoid arthritis.