C677T MTHFR mutation and factor V Leiden mutation in patients with TIA Minor stroke: A case-control study

A common C677T mutation in the gene for the enzyme 5,10-methylenetetrahydro folate reductase (5,10-MTHFR) has been linked to elevated levels of homocys teine and was therefore suspected to be a candidate genetic risk factor for arterial occlusive disease. Another mutation, factor V Leiden, has been es tablished as a common hereditary risk factor for venous thrombosis, but its role in arterial disease remains controversial. We investigated the preval ence of both the C677T MTHFR mutation and the factor V Leiden mutation in 8 1 patients with transient ischemic attack (TIA) or minor stroke (MS) and in 81 age- and sex-matched control subjects free from clinically manifest vas cular disease. We further compared clinical and laboratory data as well as clinical course of patients carrying the factor V Leiden mutation alone or in combination with the C677T MTHFR mutation and mutation-free patients. Th e prevalence of the MTHFR mutation did not differ between patients and cont rol subjects with 11.1% homozygous carriers in both groups (OR for homozygo us carriers 1.0;95% CI 0.38-2.66). However, there was a trend towards a hig her prevalence of carriers of factor V Leiden in patients (12.3%) than in c ontrol subjects (4.9%) (OR 2.75; 95% CI 0.83-9.17; p=0.09). Furthermore, we found some evidence that the combined occurrence of the C677T MTHFR mutati on and factor V Leiden might unfavorably affect the clinical course of the disease, but the number of respective patients was small. Larger studies wi th a greater number of carriers of both the C677T MTHFR mutation and factor V Leiden seem therefore warranted. (C) 1999 Elsevier Science Ltd. All righ ts reserved.