MAPT and Alzheimer disease: Transmission of the AD pathology and related tauopathies is not fully understood, but is believed to be through “prion-like seeding” mechanisms that ultimately yield intercellular spreading of toxic tau aggregates (Guo and Lee, 2011, Guo et al., 2016; Swanson et al., 2017; Gibbons et al., 2019; Vaquer-Alicea and Diamond, 2019; Goedert, 2020).