MTHFR and rheumatoid arthritis: As for the MTHFR polymorphisms, anti-CCP positive, but not anti-CCP negative RA patients following adjustment for age and gender, depicted increased frequency of the MTHFR 1298 CC genotype compared to HC (OR [95% CI]: 1.87 [1.01–3.47], p-value: 0.05, recessive model, Table 5 and Suppl.