MAPT and Parkinson disease: It may be closely related to the massive accumulation of α-synuclein (α-syn) and the aberrant expression of the microtubule-associated protein tau (Bassil et al., 2021; Han et al., 2021), both of which have been identified as the first two genes of the population attributable risk underlying PD in genome-wide association studies (Simon-Sanchez et al., 2009).