MAPT and Alzheimer disease: Experimental transmission in several settings has been convincingly demonstrated in the case of the amyloid beta (Aβ) peptide which features prominently in Alzheimer's disease (AD), the intracytoplasmic protein tau, also involved in AD as well as various neurodegenerative diseases referred to as taopathies, and α-synuclein, the primary constituent of Lewy bodies found in Parkinson's disease (PD) [1], [3].