MAPT and Alzheimer disease: Previously, our lab has developed tau RT-QuIC assays optimized to detect the mainly 3R aggregates of Pick disease (PiD) [27]; the 3R/4R aggregates of Alzheimer disease (AD) and chronic traumatic encephalopathy (CTE) [21]; or the 4R aggregates of progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), frontotemporal dementias associated with MAPT mutations (FTDP 17 MAPT) and others [29].