Unlike various Aβ-depositing models such as APP/PS1 transgenic mouse models (Drummond and Wisniewski, 2017), PS cDKO mice lacked amyloid aggregation but recapitulated key features of AD, and presented with significant early-onset neuroinflammation, which preceded the appearance of other neurodegenerative symptoms. Here, PSEN1 is linked to Alzheimer disease.