RELATION OF 3 GENETIC-TRAITS TO VENOUS THROMBOSIS IN AN AFRICAN-AMERICAN POPULATION

A mutation in the Factor V gene (Factor V Leiden), a variant in the 5, 10-methylenetetrahydrofolate reductase gene (MTHFR), and an insertion /deletion polymorphism of the angiotensin I-converting enzyme gene (AC E) may be related to abnormal blood clotting. The authors examined the associations between these genetic traits and venous thrombosis among African Americans, This study comprised 93 patients with venous throm bosis and 185 control subjects attending clinics at an urban, public h ospital in Atlanta, Georgia, in 1995-1996, Subjects' DNA was extracted from blood and assayed for these genetic traits, Odds ratios were obt ained from logistic regression and used as a measure of association be tween each genetic trait and venous thrombosis. Factor V Leiden was un related to venous thrombosis, but the mutation was too rare among our African-American subjects to evaluate adequately its relation to venou s thrombosis, The homozygous and heterozygous genotypes for the V alle le of the MTHFR gene were unrelated to venous thrombosis (odds ratio = 0.9, 95% confidence interval 0.5-1.8). Subjects with the deletion/del etion ACE polymorphism experienced a moderate increase in venous throm bosis risk compared with persons with the other genotypes (odds ratio = 1.5, 95% confidence interval 0.9-2.6). However, women with this ACE genotype experienced no increased risk (odds ratio = 0.9, 95% confiden ce interval 0.5-1.9), whereas men with this genotype had nearly three times the risk (odds ratio = 2.8, 95% confidence interval 1.2-6.2; p v alue for interaction = 0.06), These data indicate that the prevalence of Factor V Leiden and the V allele of the MTHFR gene is low among Afr ican Americans, The D allele of the ACE gene is equally prevalent amon g African Americans and whites and may be related to venous thrombosis among African-American men.