MTHFR and rheumatoid arthritis: Interestingly, RA patients carrying the C allele of the MTHFR 1298 A>C gene polymorphism (patients with MTHFR 1298CC and MTHFR 1298AC genotypes) presented a statistically significant increased risk of suffering CV events compared with those homozygous for MTHFR 1298AA (MTHFR 1298CC + MTHFR 1928AC genotype frequency, 62.3% in RA patients with CV events versus 49.7% in those RA patients without CV events; OR = 1.67; 95% CI = 1.00 to 2.82; P = 0.04).