PSEN1 and Alzheimer disease: A well-established and extensively utilized animal model for AD is the double transgenic APPswe/PS1L166P mouse which overexpresses familial AD mutations of human amyloid precursor protein and presenilin-1, resulting in increased Aβ42 levels and thus representing a model of cerebral amyloidosis for AD, with early onset of the amyloid plaque deposition [5].