MAPT and red-green color blindness: The primary tauopathies include frontotemporal lobar degeneration (FTLD) with tau, corticobasal degeneration (CBD), Pick’s disease (PiD) and progressive supranuclear palsy (PSP), each of which can express various isoform ratios (3R and 4R), conformations and subcellular localization of tau pathology.