MAPT and Alzheimer disease: All six isoforms are found in the insoluble Tau deposits of Alzheimer disease (AD) and chronic traumatic encephalopathy (CTE), whereas only 3R-Tau isoforms are found within those of Pick disease (PiD) and only 4R-Tau isoforms in the deposits of other diseases such as progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) [20, 24, 26, 27].