Mutations in the MTHFR genecould reduce its enzymatic activity and cause hyperhomocysteinemia, which is a riskfactor for atherosclerosis due to endothelial dysfunction and OS.71 In HD individuals, there was a strongrelationship between the presence of the C677T polymorphism in the MTHFR gene andVC, as compared to the CC genotype, patients with CT and TT genotypes had VCadjusted odds ratios of 1.39 and 1.58, respectively (p <0.005).72 The gene discussed is MTHFR; the disease is endothelial dysfunction.