Genetic aspects of the blood pressure control system.

Utilization of several genetic models (twins, families of monozygotic twins, characterized hypertensives and normotensive first-degree-relatives of essential hypertensives) has permitted us to probe for evidence of genetic mediation of several components of the blood pressure control system in humans. These studies have identified evidence for genetic mediation of systolic blood pressure in a cross-sectional study of normotensive subjects covering a wide age span. Further, this effect was independent of body size. The twin model, studied under conditions of sodium loading and sodium and volume depletion, demonstrated a genetic component in the response of plasma renin activity, aldosterone, norepinephrine and renal sodium excretion to these maneuvers. Among hypertensive subjects and unexpected abnormality in the distribution of a specific MNS blood group pattern was seen in renal vascular hypertensives. This may provide a new genetic marker for identifying individuals at increased risk to develop this abnormality.