PSEN1 and Alzheimer disease: Mitochondrial dysfunction is an established feature of Alzheimer’s disease (101, 102) and in the frequently utilized 5xFAD mouse model, a model that has a total of five Alzheimer’s disease–linked mutations: the Swedish (K670N/M671L), Florida (I716V), and London (V717I) mutations in APP and the M146L and L286V mutations in PSEN1 (103).