Genetic Factors in Hypertension – What is Known and What Does It Mean?

AbstractThe cause of primary hypertension is unknown but the normal distribution of blood pressure in the population, of which hypertension represents the upper tail, suggests a multifactorial aetiology. Approximately 30%–60% of the blood pressure variation in the population is accounted for by genetic factors whereas environmental exposure explain the remaining part [1, 2]. Primary hypertension is likely to be the result of the net effect of various environmental factors and number of common variants in different genes, each of which will have a moderate effect on blood pressure [3]. Thus hypertension susceptibility genes will occur also in the normotensive segment of the population, although less frequently than in hypertensive patients. The exact genetic defects of a number of rare salt sensitive monogenic forms of hypertension have been described [4–6]. The causative mutations all lead to increased reabsorption of sodium in the renal tubules. These discoveries have highlighted the clinical relevance of searching for hypertension genes as they have allowed for early diagnosis, prevention with salt restriction and specific and effective pharmacological treatment of these monogenic forms of hypertension. The genetic background of primary hypertension is more complex and considerably harder to dissect as the number of genes and environmental factors involved are greater, resulting in a "non-Mendelian" inheritance pattern. However, thanks to the recent enormous development of molecular genetics [7], genetic statistics [8, 9] as well as of advances in clinical hypertension research, identification of primary hypertension susceptibility genes now seems feasible. This article reviews the strategies that can be used for hypertension susceptibility gene identification and gives an overview of the as yet most important findings in the field of genetics of hypertension. Finally, views on what we can expect from this research field in the future and what impact it will have on clinical medicine are put forward.