5xFAD mice overexpress the K670N/M671L (Swedish), I716V (Florida), and V717I (London) mutations in human APP (695) and the M146L and L286V mutations in human PS1 associated with familial early-onset AD and accumulate elevated levels of Aβ42 beginning around 2 months of age [126]. Here, PSEN1 is linked to Alzheimer disease.