MAPT and Alzheimer disease: Neuropathologically, the AD brain is characterized by extra-cellular depositions of oligomerized and fibrilar amyloid beta peptide 42 (Aβ42) surrounded by dystrophic neurites called neuritic plaques, as well as intra-neuronal formation of neurofibrillary tangles composed of phosphorylated tau protein (Serrano-Pozo et al., 2011; Chakrabarti et al., 2015).