Overactivity of angiotensin-converting enzyme (ACE) 1, a component of the classic renin–angiotensin system (RAS), is central to the formation of angiotensin II, a mediator of hypertension, but is also implicated in mechanisms noted in Alzheimer's disease, including neuroinflammation and oxidative stress. Here, AGT is linked to early-onset autosomal dominant Alzheimer disease.