In the United States, more people die from CAD than any other disease, with African Americans, particularly women and young men, being more affected by CAD than European Americans. One cause of CAD is atherosclerosis, a condition in which deposits of fat, cholesterol, and other substances build up along the inner walls of arteries. Coronary artery calcification occurs as a result of atherosclerosis and is characterized by calcium build up in the arteries. Non-invasive imaging, including computed tomography (CT) scans, of coronary artery calcification is an effective way to assess CAD risk. The Genetic Epidemiology Network of Arteriopathy (GENOA) study, which is part of the Family Blood Pressure Program (FBPP), is a study that examined siblings with high blood pressure during two exams conducted between 1995 and 2004. The purpose of this new GENOA study, which will enroll past GENOA participants, is to identify genetic factors that may lead to the development of coronary artery calcification in African Americans. Conducting genetic studies in the African American population will result in greater understanding of the mechanisms of atherosclerosis, and may lead to improved strategies for the early identification of people at risk for CAD and the development of new treatments for CAD.