Intracerebral injection of human AD brain extracts or extracts prepared from human amyloid precursor protein (APP) transgenic mouse brains containing aggregated amyloid-β into the brains of APP transgenic mice induces the formation of amyloid-β plaques in the host brains (Eisele et al. 2010; Meyer-Luehmann et al. 2006). This evidence concerns the gene APP and Alzheimer disease.