MAPT and red-green color blindness: Intraneuronal accumulation of neurofibrillary tangles (NFT) made of abnormally hyperphosphorylated tau is centrally involved in the pathogenesis of primary tauopathies, such as supranuclear palsy (PSP), corticobasal degeneration (CBD), Pick’s disease (PiD), and frontotemporal dementia with Parkinsonism linked to chromosome 17 (FTDP-17), and secondary tauopathies such as Alzheimer’s disease (AD) [1].