Genetics of essential hypertension. From the unimodal-bimodal controversy to molecular technology.

THE aim of this brief review is to provide researchers involved in investigating the pathogenesis of essential hypertension with a historical perspective of genetic studies on the subject and to list some of the problems that should be taken into account when considering the hypothesis that a given biochemical mechanism may be involved in causing essential or genetic types of hypertension. Because of obvious space limitations and the wide variety of problems involved, it will not be possible to provide a detailed, comprehensive review of all the published work on this topic. However, we will try to focus on some common beliefs that have been dominant in the literature and continue to influence the thinking of many students of hypertension, at least as indicated by discussions at scientific meetings and articles in the specialist journals. We will also briefly discuss the criteria for allocating a given biochemical finding to its probable position in the chain of events leading from a gene abnormality to increased blood pressure. Such criteria appear to be missing in most of the published work on genetic rat models aimed at elucidating differences in biochemical systems of blood pressure regulation between hypertensive strains and their various normotensive controls.