Over the past two decades, this approach has yielded several dozen mouse models of Alzheimer’s disease in which transgenic expression of the amyloid precursor protein (APP) is controlled by promoters such as the prion protein, Thy-1 cell surface antigen, or platelet-derived growth factor B chain that drive high-level transgene expression in the adult [1-5]. Here, APP is linked to early-onset autosomal dominant Alzheimer disease.