Study of the Association between MTHFR Polymorphism (rs1801133) and the Outcome of Methotrexate Treatment in Rheumatoid Arthritis Patient

Abstract Background Rheumatoid arthritis is a chronic systemic autoimmune disease that causes loss of joint function and significantly reduces the quality of life. Methotrexate is one of the disease- modifying anti-rheumatic drugs that can influence treatment efficacy and toxicity. Methotrexate is used as an anchor drug for the treatment of rheumatoid arthritis and there may be differences in drug action between genotypes. Aim of the Work The present study was aimed to evaluate the impact of methylenetetrahydrofolate reductase (MTHFR) gene C677T (rs1801133) polymorphism on the clinical outcome of methotrexate treatment as regards treatment efficacy or toxicity in Egyptian rheumatoid arthritis patients. Subjects and Methods This study conducted on 45 patients diagnosed with rheumatoid arthritis receiving methotrexate as a first line of treatment. Subjects were classified into two groups; group I (responders, n = 25) and group II (non-Responders, n = 20) according to clinical response to methotrexate by using disease activity score (DAS28). Complete blood count, erythrocyte sedimentation rate, liver function, renal function, C- reactive protein, cyclic citrullinated peptide antibody and rheumatoid factor were done for all patients. Determination of methylenetetrahydrofolate reductase gene C677T (rs1801133) polymorphism was carried out using Real-time polymerase chain reaction. Results The present study did not confirm the presence of a significant association between the genotypic frequencies of the methylenetetrahydrofolate reductase gene C677T (rs1801133) polymorphism among the responders and the non-responders group in patients with rheumatoid arthritis. In addition, the methylenetetrahydrofolate reductase gene C677T (rs1801133) polymorphism did not show significant difference between disease complications among the responders and the non-responders groups. On the other hand, our findings suggested that a statistically significant difference was found between two groups of patients regarding disease activity score (DAS 28). Conclusion The current study revealed that there is no significant association between the genotypic frequencies of the methylenetetrahydrofolate reductase gene C677T (rs1801133) polymorphism among the responders and the non-responders groups of patients with rheumatoid arthritis. Moreover, the methylenetetrahydrofolate reductase gene C677T (rs1801133) polymorphism did not show significant difference between disease complications among the responders and the non-responders groups in patients with rheumatoid arthritis.