MAPT and Alzheimer disease: Alzheimer's disease (AD) and related tauopathies are neurodegenerative disorders pathologically defined by the presence of abundant and highly phosphorylated forms of the microtubule-associated tau protein which later aggregates into fibrils and finally forms the neurofibrillary tangles (NFTs).1 Although it is known that the presence and abundance of NFTs correlates with the severity of dementia and neuronal loss,2, 3 the mechanisms leading to the abnormal high phosphorylation of tau in the brain of these patients remain unclear.