MAPT and Alzheimer disease: These neurodegenerative diseases result from the gradual and progressive loss of neural cells because of abnormal deposits of β-amyloid and tau protein in patients with AD and α-synucleinopathy in dopaminergic neurons of the substantia nigra in patients with PD, leading to nervous system dysfunction (Gelb et al., 1999; Reitz and Mayeux, 2014).