Association of the MTHFR Gene Polymorphisms with Efficacy and Toxicity of Methotrexate in Patients with Juvenile Idiopathic Arthritis

Abstract

The aim of this study was to investigate whether the C677T and A1298C polymorphisms of methylenetetrahydrofolate reductase (MTHFR) gene might be related to the prediction of toxicity and efficacy of methotrexate (MTX) in juvenile idiopathic arthritis (JIA) in clinical practice. Sixty-three patients (50 girls and 13 boys) fulfilling the International League of Associations for Rheumatology (ILAR) criteria for JIA were included in the study. Patients were divided into two groups – those undergoing treatment with MTX monotherapy and putative optimal response ($$n = 28$$), and those with poor response to therapy with MTX and therefore shifted to treatment with MTX and a biological agent ($$n = 35$$). DNA for SNP analysis was automatically isolated from whole blood through chemagic Magnetic Separation Module I instrument (PerkinElmer chemagen Technologie GmbH, Baesweiler, Germany). The following SNPs in MTHFR gene – 677C>T (rs1801133) and 1298A>C (rs1801131) – were analyzed using High Resolution Melt (HRM) analysis. A real-time PCR (RotorGene 6000, Qiagen, USA) was performed for amplification of DNA prior to HRM analysis. We did not find any significant difference in the distribution of genotype ($$\chi2 = 1.04$$;  df $$= 2/\chi2 = 0.60$$; df = 2) and allele ($$\chi2 = 0.11$$; df = $$1/\chi 2 = 0.03$$; df = 1) frequencies of polymorphisms C677T and A1298C between the two groups. Adverse events (nausea, dizziness, headache, hepatotoxicity) due to MTX were noted among four of the patients. It was found that all of the patients who experienced side effects of the treatment carry the allelic variant C677T (three CT heterozygotes and one TT homozygote). The variant allele A1298C was found in one of these four patients. We did not find any significant association between the C677T and A1298C polymorphisms of MTHFR and the efficacy and toxicity of methotrexate.