The most prevalent, Alzheimer’s disease, is a complex and heterogeneous neurodegenerative disease of the CNS, first presented by German psychiatrist Alois Alzheimer (Alzheimer, 1907), typically characterized by the deposition of extracellular β-amyloid plaques and intracellular tau neurofibrillary tangles (NFTs). Here, MAPT is linked to early-onset autosomal dominant Alzheimer disease.