Recent studies have also implicated tau-related pathology in neurodegenerative diseases not traditionally known as tauopathies, such as PD; about 50% of PD patients show tau tangles (Zhang et al., 2018; Henderson et al., 2019), and single-nucleotide polymorphisms in the tau gene have been identified as risk factors for PD (Edwards et al., 2010). Here, MAPT is linked to neurodegenerative disease.