Determination of the allele frequencies of three polymorphisms in the promoter region of the human protein C gene in three Brazilian ethnic groups.

The frequencies of three polymorphisms in the promoter region of the human protein C gene have been determined in three ethnic groups of the Brazilian population. The allele frequencies observed in south-eastern Brazilian Caucasians and Blacks were similar to the values obtained for the Dutch population and were different from those observed in Amazonian Indians living in the north of the country. The most frequent genotypic combination found in this latter group was the CC/GG/AA genotype, which is very rare among Caucasians. The complete heterozygous genotype CT/AG/AT was the most frequent both in Brazilian Caucasians and Blacks. Among 27 possible genotypic combinations, 21 were found in the Caucasian group and 15 in Blacks, revealing a high degree of genetic diversity in south-eastern Brazilian populations.