Background: The relationship between haemostatic gene polymorphisms and arterial disease remains unclear. Much of the evidence gathered so far has been obtained from small heterogeneous studies, resulting in inconsistencies. This study focuses on the South African Indian population which not only represents the largest Indian population outside the Indian subcontinent, but also constitutes a genetically discrete group in whom a high incidence of coronary heart disease occurs.
Material/methods: We investigated the relationship between polymorphisms in the Factor V (Leiden), prothrombin (20210 GgA) and thrombomodulin (Ala455Val) genes in patients with a myocardial infarction (MI) <45 years of age (n=195) and in unaffected siblings (n=107) and unrelated healthy race-matched individuals drawn from the same community (n=300).
Results: The Factor V Leiden mutation was found to occur with a frequency of less than 1%, while the prothrombin 20210 GgA polymorphism was not observed in any of the individuals in this study. In contrast, the variant thrombomodulin Val allele occurred with a frequency similar to that reported in Caucasians. The frequency of this allele in both patients with MI and their siblings was marginally higher than in healthy controls, but the difference did not reach statistical significance. However, in patients who smoked, the thrombomodulin variant allele occurred significantly more frequently than in the non-smoking group (p=0.044).
Conclusions: The Leiden Factor V and prothrombin 20210 GgA polymorphisms have no value in disease association studies in the Indian Asian population. In smokers, the thrombomodulin Ala455Val variant allele emerges as a significant risk factor for coronary heart disease.