Epidemiological studies have consistently reported a higher prevalence of essential hypertension in black people. Other data indicate that black people may have salt regulatory systems with low reserves which are unable to cope with moderate quantities of salt and respond to salt loading by increasing their bloodpressures. Black people are therefore susceptible to the deleterious effects of salt. As some forms of EH may be related to defects in salt regulatory systems, we investigated association of the reningene locus (the rate limiting enzyme in an important salt regulatory system) with EH in an ethnically homogenous group of black people of African origin (Summary)