Objective: The aim of this study is to determine the prevalence of C677T methylenetetrahydrofolate reductase (MTHFR) polymorphism and correlate it with plasma homocysteine levels in coronary artery disease (CAD).
Methods: Ninety-three patients with documented CAD from Hospital Universitário Oswaldo Cruz (Recife, PE, Brazil) and 108 healthy controls were evaluated. Homocysteine and folate levels were determined by HPLC and chemoluminescence, respectively, and lipid profile was considered. Genotyping was done by RFLP/PCR.
Results: The groups were homogeneous for the C677T polymorphisms. The homocysteine level in cases (11.7 micromol/L) was statistically different from that observed in controls (8.84 micromol/L, p< 0.05). It was also observed that 72% of the patients had homocysteine values above 12 micromol/L while the control group presented only 32% in this range. There was no relationship between homozygosity for the C677T polymorphism and the homocysteine level (p= 0.634). We noticed statistical differences between folate levels from patients and controls (6.22 and 7.69 ng/dL, p< 0.05, respectively). However, there was no correlation between homocysteine and folate concentrations in the entire group (r= -0.202). Comparing cases and controls, the odds ratio (OR) when homocysteine is high and folate is low was OR= 11.9; CI 95%= 4.16-34.42, p< 0.01.
Conclusion: A lack of correlation between C677T mutation and homocysteine level suggests that environmental factors and others genetic factors seem to exert more influence on homocysteine level in this population.