Hypertension treatment guidelines developed recently have used five main classes of antihypertensive medicine – angiotensin converting enzyme (ACE) inhibitors (ACEIs), angiotensin II receptor blockers (ARBs, also termed angiotensin II receptor antagonists in other sources), beta-blockers (BBs), calcium channel blockers (CCBs, also termed calcium antagonists in other sources) and diuretics. The gene discussed is ACE; the disease is Hypertension.