APP and Alzheimer disease: Indeed, 3xTg-AD mice contain the APP Swedish, the human PSEN1 (M146V), and the MAPT (P301L) mutations and show increased Aβ42 levels at 4 months, Aβ plaques around 9 months, NTF at approximately 12 months, and initial cognitive deficits at 4 months [181,182].