Reduced Folate Carrier Gene-1 G80A Polymorphism is Not Related to Methotrexate Response in Egyptian Rheumatoid Arthritis Patients

Abstract

Background: Methotrexate (MTX) is considered the prime drug in rheumatoid arthritis (RA) treatment. However, response to MTX varies considerably among patients. Single nucleotide polymorphisms (SNPs) in the genes coding for MTX cellular pathway could be used to predict MTX response which would be clinically beneficial. The reduced folate carrier-1 (RFC-1) is an anion exchanger which plays a significant role in the transport of MTX and folates into the cells. RFC-1 G80A SNP is reported to affect MTX response in some ethnic populations. Aim: aimed to examine the relation between RFC-1 G80A SNP with MTX response in Egyptian RA patients. Patients and Methods: 74 newly diagnosed RA patients within the first month of MTX therapy and 78 healthy controls were included in the present study. Patients’ clinical data and laboratory investigations were recorded. The response to MTX in RA patients was evaluated after 3 months of MTX therapy using the European League Against Rheumatism (EULAR) response criteria. RA patients were then classified into MTX responders and MTX non-responders. RFC-1 G80A SNP was investigated using polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP). Results: The results of the present study showed no statistically significant differences between MTX responders and non-responders regarding genotype and allele frequencies of RFC-1 G80A SNP (p>0.05) in Egyptian RA patients, in addition to recessive, dominant, codominant, homozygotic, and per-allele genetic models (p>0.05). Conclusions: The current study revealed no association between RFC-1 G80A SNP and MTX response. Moreover, RFC-1 A80G SNP was not associated with susceptibility to RA.