Association of *14 Allele with Poor Response to Methotrexate in Juvenile Idiopathic Arthritis Patients.

Objective: Variants in the gene, encoding a hepatic methotrexate (MTX) transporter, affect clearance of high-dose MTX. We tested whether in the *14 and *15 alleles of influenced the response to low-dose MTX in juvenile idiopathic arthritis (JIA) patients.

Methods: The study included 310 JIA patients genotyped for three single nucleotide polymorphisms (SNPs) in (rs4149056, rs2306283, and rs11045819).