The gene in the study is the blueprint for a protein called thrombomodulin, which is found in the lining of the blood vessel walls.
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. The normal gene occurs in about 80 percent of people, said Dr. Kenneth Wu, lead author of the study and professor and director of the Hematology and Vascular Biology Research Center at the University of Texas, Houston Health Science Center. Maybe the expression of the gene is different in blacks and whites and plays a greater role in blacks than in whites. It is not clear why this would be the case. The gene is expressed on the surface of cells that line blood vessels, said Wu.