MAPT and Alzheimer disease: Tau aggregates form intracellular neurofibrillary tangles (NFTs), which progressively accumulate in the central nervous system (Cipriani et al., 2011), and propagate along synaptically connected regions (Braak and Braak, 1991; Hoenig et al., 2018; Vogel et al., 2020) in a well-defined, staged pattern that correlates with the cognitive decline seen in AD patients (Braak et al., 2006).