PSEN1 and Alzheimer disease: We next generated an AD mouse model lacking the APMAP gene (APMAP-KO/AD) by cross-breeding the APMAP-KO mice with APP/PS1 mice coexpressing the KM670/671NL Swedish mutation of human amyloid precursor protein (APP) and the dE9 mutation of human presenilin 1 (PS1), which develops parenchymal Aβ plaques starting at the age of 6 months [30, 35].