[Genetic aspects of heart and circulatory diseases].

Cardiovascular diseases (CVD) are common, heterogenous and of multifactorial origin with a variety of more or less known environmental risk factors interacting with a certain genetic predisposition. Beside some rare monogenic conditions the hereditary risk factors are polygenic and acting either on a given CVD or again on particular predisposing conditions. This is well known for type II hyperlipoproteinemia, which can be observed as a rare monogenic metabolic disorder or as the more common polygenic variant. The relative proportions of genetic and environmental risk factors for CVD can be estimated only approximately due to the various interactions. The current methods are investigations for a given phenotype (e.g. LDL-cholesterol) in first-degree relatives of index patients and studies of concordance rates in mono- and dizygotic twins. The results of a large number of epidemiological studies are indicating that there is a considerable genetic component in the liability for ischemic heart disorders (especially for cardiac infarction in younger age groups), as well as for essential hypertension.