The gene in the study is the blueprint for a protein called thrombomodulin, which is found in the lining of the blood vessel walls. The protein converts the enzyme thrombin from a clotting agent into an anti-clotting agent. This shift in gene structure has been previously associated with heart attack risk.
Genes give instructions on how amino acids link together to form proteins.
Any shift in the order in which amino acids are linked can cause the protein to function abnormally. Reduced levels of normal thrombomodulin as a result of the altered gene may cause an increased tendency for blood vessel damage and blood clots. We have identified a genetic marker for predicting increased heart attack risk in African-Americans. The same small shift in the structure of the thrombomodulin gene was not associated with coronary heart disease risk in white individuals. Baseline examinations, including blood pressures and samples of blood and DNA, were conducted between 1987 and 1989.