MAPT and red-green color blindness: In AD and chronic traumatic encephalopathy (CTE), both 3R and 4R isoforms make up the neuronal inclusions [13,14]; 3R tau is found in PiD, whereas 4R tau isoforms are present in the filaments of PSP, CBD, argyophilic grain disease (AGD), and globular glial tauopathy (GGT) [15,16,17].