RESUMO
Individuals belonging to six different Amerindian tribes and two African groups of Costa Rica were genotyped for factor V Leiden (FV), factor V haplotype HR2 (FV HR2), Factor II 20210G>A (FII), the methylenetetrahydrofolate reductase (MTHFR), factor VII polymorphisms (FVII IVS7, FVII R353Q), factor XIII (FXIII V34L), and the insertion/deletion (I/D) polymorphism of the gene of angiotensin converting enzyme (ACE). Clear differences in the prevalence were found and are first reported. The prevalence of some of the established genetic risk factors was low in Amerindians of Costa Rica (ACE) or even absent (FVL, FII), and others (MTHFR, FVHR2) had an extremely high prevalence. People of African origin carried very rare FVL or FII polymorphisms, but the DD genotype of ACE is the highest reported. Concerning the protective factors, the QQ genotype of FVII R353Q was absent in Amerindians, but the protective 7/7 genotype of FVII IVS7 frequently found. Novel alleles of FVII IVS7 (4, 8, and 9 monomers) were found. Intertribal heterogeneity was observed that may reflect the evolutionary history of these tribal groups and their admixture with other populations.