MAPT and Alzheimer disease: • Tau aggregates associated with severity of symptoms and disease progression (34, 35). • Presence of NFTs in several AD brain regions: transentorhinal region, hippocampus, neocortex (36). • Transcellular propagation of tau in vitro (37, 38) and spread between brain regions in vivo (39–41). • Propagation and deposition of tau inclusions in a sequential pattern in AD patients, from transentorhinal (stage I) to the isocortex (stage V–VI) (36).