Iniesta R, et al. - Researchers investigated the extent to which variation in blood pressure (BP) response across different ethnicities may be explained by genetic factors: genetically defined ancestry and gene variants at loci known to be linked to blood pressure (BP). They assessed data from fives trials in which genotyping had been performed (n=4,696) and in which treatment responses to β-blockers, angiotensin-converting enzyme inhibitors, angiotensin receptor blocker, thiazide or thiazide-like diuretic and calcium channel blocker were available. In all, variations in response to the thiazide diuretic hydrochlorothiazide, the β-blockers atenolol and metoprolol, the angiotensin-converting enzyme inhibitor lisinopril, and the angiotensin receptor blocker candesartan were more closely linked to genetically defined ancestry than self-defined ethnicity in admixed participants. A small number of gene variants related to loci associated with drug-signaling pathways with large effect size and differing allele frequencies in black vs white individuals explained a significant proportion of the variation in response to candesartan and hydrochlorothiazide between these groups. According to findings, a genomic precision medicine approach can be used to personalize antihypertensive treatment within and across populations without recourse to surrogates of genetic structure, including self-defined ethnicity.