PRTN3 and rheumatoid arthritis: After adjustment, with the CC genotype as the reference, the ACPA-positive RA group showed statistically significant differences in the CT genotype and dominant model (CT + TT) of MTHFR 677C/T when compared with the healthy control group [(p = 0.040, OR = 6.504, 95% CI = 1.087–38.935) and (p = 0.025, OR = 6.556, 95% CI = 1.272–33.799)].