GenHAT, a prospective study ancillary to ALLHAT, will characterize hypertension genetic variants and determine their interaction with antihypertensive treatments in relation to coronary heart disease (CHD). DNA from frozen clots stored at the ALLHAT Central Laboratory will be used to genotype variants of hypertension genes (angiotensinogen -6, angiotensin converting enzyme insertion/deletion, angiotensin type- 1 receptor, alpha-adducin, beta2 adrenergic receptor, lipoprotein lipase, and 10 new hypertension variants expected to be discovered during the course of the study). In addition to the primary aim, a number of secondary aims will be undertaken to evaluate gene- treatment interactions in relation to other endpoints, including all-cause mortality, stroke, heart failure, left ventricular hypertrophy, decreased renal function, peripheral arterial disease, and blood pressure lowering. Because of the ethnic and gender diversity of ALLHAT, an assessment will be made of the effects of these variants on outcomes in key subgroups (age >65 years, women, African Americans, Type II diabetics), and whether the gene-treatment interactions in relation to outcomes are consistent across subgroups.