The Reducing pathology in Alzheimer's Disease through Angiotensin TaRgeting (RADAR) trial was designed to test the hypothesis that blockade of angiotensin II signalling by losartan would slow brain volume loss, as a measure of disease progression, in clinically diagnosed mild-to-moderate probable Alzheimer's disease by reducing brain volume loss as a measure of disease progression. The gene discussed is AGT; the disease is Alzheimer disease.