['Methotrexate (MTX), widely used in the treatment of rheumatoid arthritis (RA), inhibits dihydrofolate reductase and folate-dependent enzymes. Methylenetetrahydrofolate reductase (MTHFR) is involved in folate metabolism and has been shown to be polymorphic, affecting the enzyme activity.', 'To examine the association between 677C>T and 1298A>C MTHFR polymorphisms and MTX efficacy in the treatment of RA, a total of 174 RA patients, treated with MTX plus methylprednisone 4 mg and folic acid 5 mg were analyzed.', 'In univariate regression analysis model, the MTHFR 677T allele was associated with significantly higher frequency of remission, whereas in the case of the 1298C allele, a tendency for higher remission rate was observed. In multivariate regression analysis, the presence of both 677T and 1298C alleles was associated with an increased frequency of remission.'] Do 677C > T and 1298A > C MTHFR polymorphisms affect methotrexate treatment outcome in rheumatoid arthritis?