Commonly used transgenic mouse models generated using FAD genes such as a forced expression of mutant amyloid precursor protein (APP) and/or Aβ cascade genes do not accurately mimic late-onset sporadic AD in multiple aspects, including the trigger, origin, and time course of Aβ production as well as the lack of neuronal loss and tau pathology in some widely used FAD mice [37–39]. This evidence concerns the gene APP and Alzheimer disease.