MAPT and red-green color blindness: We evaluated two different tau variants, one, the P301S mutation, is a disease associated variant that has been linked to multiple tauopathies in humans, including frontotemporal dementia (FTD), corticobasal degeneration (CBD), and progressive supranuclear palsy (PSP) (Bugiani et al., 1999; Kametani et al., 2020).