APP and Alzheimer disease: In the 5xFAD mouse model, transgenes for human β-Amyloid precursor protein (APP) and PSEN1 (a core protein in the γ-secretase complex) are expressed, encompassing a total of five mutations associated with Alzheimer’s disease: Swedish (K670N/M671L), Florida (I716V), and London (V717I) mutations in APP, along with M146L and L286V mutations in PSEN1 (Oakley et al., 2006).