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Recently a new identified genetic variant in the 3'-untranslated region of the prothrombin gene (G20210A allele) associated with increased plasma prothrombin levels has been linked to an increased risk of venous thromboembolism (VTE). To determine the importance of this G20210A allele as a causative risk factor for VTE in the general population, we analysed the data of an epidemiologic investigation on thrombophilia in young people, the Oporto Thrombophilia Study (PORtromb). Forty cases (mean age: 27 yr old) with a first episode of VTE under 40 yr old, and 100 healthy subjects, were evaluated. Heterozygosity for the G20210A allele was present in 12.5% of VTE cases and in 5% of controls, indicating a possible marginal increase of VTE risk in carriers of the allele (odds ratio: 2.71: 95% CI 0.74-9.95).

Objective: We investigate whether each of the following: HPA-1, Factor V Leiden, prothrombin gene variant and the methylene tetrahydrofolate reductase gene (MTHFR) mutation, are risk factors for acute coronary disease in Portuguese patients., Material and Methods: 100 blood donors and 52 patients with an established diagnosis of myocardial infarction or unstable angina were evaluated for genetic risk factors, by determining HPA-1 genotype, Factor V Leiden, Prothrombin 20210 variant and MTHFR mutation., Results: We found a prevalence of 2.0% for Factor V Leiden, 5.0% for the Prothrombin 20210 variant and 66% for the MTHFR mutation in blood donors. These values are similar to those found in the patients (1.9, 3.8 and 58%, respectively). We found that 28/100 controls had the PI(A2) polymorphism, a frequency statistically different from that in the patients (23/52). This difference was even more pronounced in patients less than 60 years old (27/96 vs. 13/24)., Conclusion: Factor V Leiden, Prothrombin 20210 variant and MTHFR mutation do not seem to represent risk factors for acute coronary disease. However, the PI(A2) polymorphism could have a role in the pathogenesis of this disease. The presence of multiple genetic factors, more than single ones, could influence the development and outcome of myocardial infarction and unstable angina. Larger studies are needed in order to have a better insight into the pathophysiological mechanisms of this disease, along with its prevention and the development of new treatments., (Copyright 2000 S. Karger AG, Basel)