PSEN1 and Alzheimer disease: The 5xFAD mouse, a widely used AD mouse model, has 5 familiar AD-linked mutations, i.e., the Swedish (K670 N/M671 L), Florida (I716V), and London (V717I) mutations in amyloid precursor protein (APP) and the M146 L and L286 V mutations in presenilin-1 (PSEN1) [2].