Because of the high incidence of hypertension in indigenous South Africans (for example up to 25% in urban Zulu individuals [52]), of which up to 50% show suppressed plasma renin activity, an indirect measure of salt sensitivity [13], it is however likely that a genetic predisposition to this disease is represented in a fair proportion of the population, and that the evidence for this can be found in our sample set when compared to Caucasians. The gene discussed is REN; the disease is hypertensive disorder.