As the current most common neurodegenerative disease, Alzheimer's disease (AD) is histopathologically characterized by the presence of two hallmark lesions: extracellular senile plaques consisting of β-amyloid and intracellular neurofibrillary tangles (NFTs) made up of the abnormally hyperphosphorylated tau [1–3]. Here, MAPT is linked to early-onset autosomal dominant Alzheimer disease.