The majority of these studies have been conducted in mice, including transgenic models of AD (APP/PSI, 3xTg-AD, SAMP8, 5XFAD, and APP knock-in mice), mice in which AD-like symptoms have been induced by the injection of a specific substance (beta amyloid peptides, D-galactose, or scopolamine), and aged mice. The gene discussed is APP; the disease is Alzheimer disease.