Specifically, the guidelines endorse the view that there is a higher prevalence of low-renin hypertension in individuals of African ancestry or Black ethnic backgrounds (Materson 2007, Gupta et al. 2010), attenuating response to beta-blockers and angiotensin-converting enzyme inhibitors (which work primarily by suppressing the renin–angiotensin system) and increasing the likelihood of response to calcium channel blockers (which work primarily by vasodilation). This evidence concerns the gene REN and hypertensive disorder.