PSEN1 and Alzheimer disease: The 5xFAD mouse model of AD overexpresses mutant human amyloid precursor protein (APP) containing the Swedish (K670N, M67IL), Florida (I716V), and London (V717I) Familial Alzheimer’s Disease (FAD) mutations, as well as the human presenilin 1 (PS1) gene with two FAD mutations, M146L and L286V.