Genes encoding fibrinogen and cardiovascular risk.

The role of fibrinogen in cardiovascular disease has been extensively studied, and meta-analyses have definitively confirmed that high levels of fibrinogen are associated with an increased risk of the disease. In recent years, several polymorphisms have been identified in the fibrinogen chain genes that contribute to determine the levels of fibrinogen in the general population. The fibrinogen beta-chain gene has been more extensively studied because the beta-chain synthesis is the limiting step in the production of mature fibrinogen. Overall, the studies show an association between beta-fibrinogen chain polymorphisms and the levels of fibrinogen. In contrast, the majority of the studies did not find any relation with the risk of cardiovascular disease. The individual responses to gender or to environmental stimuli such as smoking, physical exercise, or infections may be genetically determined, and genetic variability underlies changes in biological reactions that contribute to differences in cardiovascular risk. In the future, gene-environment interactions should be considered in evaluating the relevance of genetic variations on the risk of cardiovascular disease.