ABSTRACT
Multiple polymorphic loci have been linked directly to heart disease, or to a susceptibility to heart disease. Limited phenotypic response of the cardiovascular system accounts for similar pathology from different gene defects, and many of these polymorphisms have variable phenotypic expression in other systems apart from the heart. These single-gene defects fall into one of four broad classes based on their phenotypic expression, including polymorphisms associated with: (1) coronary artery disease such as lipid disorders and hypertension; (2) defects in cardiovascular structure; (3) cardiomyopathy; and (4) defects in cardiac rhythm. Although environmental factors influence the expression of many of these diseases, it is clear that single-gene defects have been identified which cause heart disease.
