The ATIC rs3821353 G/T genotype was significantly associated with non-response to MTX treatment under codominant comparison, with a 0.33-fold chance for a positive response to MTX (OR = 0.33, 95% CI = 0.12−0.9, p-value = 0.034), indicating its bad prognostic significance for MTX treatment in RA patients. Here, ATIC is linked to rheumatoid arthritis.