MAPT and Alzheimer disease: An example of a pathobiological phenotype that has been associated with favorable outcomes in AD is reduced levels of activated microglia, as these are associated with neuronal death, increased plaque formation and tau pathology (Colonna and Butovsky, 2017; Pearce and Pearce, 2017; Spangenberg and Green, 2017; Perea et al., 2020).