APP and Alzheimer disease: Multiple familial AD mutations of APP, the interaction between which has not been identifiedUnknown effects of Arctic mutationNo severe behavioral phenotypes, a feature of preclinical ADNo NFTs or neuronal loss, a feature of preclinical ADGenomic homozygosity in order to accelerate pathology and to remove murine endogenous Aβ (heterozygous mice accumulate Aβ, but take longer than homozygous mice.)Overproduction of CTFβ