MAPT and Alzheimer disease: While the presence of different fibrillar protein aggregates such as amyloid plaques (Aβ), neurofibrillary tangles (tau), and Lewy bodies (a-syn) are characteristic and defining pathological features of individual neurodegenerative diseases such as AD, PD, FTLD and DLB, they may not represent the most effective early stage pathological markers for neurodegenerative disease.