Little is known of the genetics of glomerular damage in essential hypertension in humans. The prevalence of end-stage renal disease due to primary hypertension varies from 20% to 30% of all cases of renal failure to as low as 0.002%. This depends not only on differences in diagnostic criteria but also on different racial susceptibility to the disease as well as on different genetic backgrounds in different subsets of individuals of the same race. A review of the literature is provided, together with an example of how a point mutation that causes hypertension in Milan hypertensive rats can provide a model to analyze this issue correctly.