Background and purpose: The alanine/valine (A/V) polymorphism at codon 677 of the 5,10 methylenetetrahydrofolate reductase (MTHFR) gene correlates with elevated levels of plasma homocysteine and with an increased risk of atherosclerotic cardiovascular disease. Our study was designed to assess the frequency of the A and V alleles in patients with asymptomatic severe carotid artery stenosis (CAS) assessed by extracranial duplex examination in comparison with age- and sex-matched subjects without carotid atherosclerosis.
Methods: Consecutive patients (n=48; 28 men, mean+/-SD age 67.1+/-11. 4 years) with asymptomatic severe (>75%) CAS were compared with subjects without CAS (n=26; 15 men, aged 61.2+/-11.5). The MTHFR genotype was analyzed by polymerase chain reaction followed by HinfI digestion. The chi(2) analysis and t test were used to compare the groups.
Results: The frequency of V alleles was significantly higher in the CAS group (0.47) compared with control subjects (0.27, chi(2) test; OR 2.4 [95% CI 1.1 to 5.3]; P<0.02).
Conclusions: Our results indicate that the MTHFR A677V allele is significantly associated with severe CAS.