Ethnic heterogeneity of the factor XIII Val34Leu polymorphism

A polymorphism in the coagulation factor XIII gene (FXIII Val34Leu) has bee n recently described to confer protection for arterial and venous thrombosi s and to predispose to intracerebral hemorrhage. At present it is known tha t FXIII Val34Leu is prevalent in Caucasians, but information upon its distr ibution in different ethnic groups is scarce. We investigated the prevalenc e of FXIIIVal34Leu in 450 unrelated subjects of four ethnic groups: 97 Cauc asians (Brazilians of European descent and Portuguese), 149 Blacks (Brazili ans, and Africans from Cameroon, Zaire and Angola), 40 Asians (Japanese des cendents) and 164 Amerindians from South America. PCR amplification of exon 2 of FXIII gene followed by MseI restriction-digestion was employed to def ine the genotypes. FXIIIVal34Leu was detected in 44.3% of the Caucasians, i n 28.9% of the Blacks, in 2.5% of the Asians and in 51.2% of the Amerindian s. These data confirm that FXIII Val34Leu is highly prevalent in Caucasians and indicate that it is rarer in populations of African origin. The very h igh frequency among Amerindians indicates that FXIII Val34Leu is not absent among Asians, and since it has a very low prevalence in Japanese, a hetero geneity in its distribution in Asia may be inferred. Taken together, our da ta showed that FXIII Val34Leu exhibits a significant ethnic heterogeneity, a finding that is relevant for studies relating this polymorphism with thro mbotic and bleeding disorders.