In AD, both 3-repeat (3R) and 4-repeat (4R) tau isoforms are accumulated as filamentous aggregates (PHFs) [16], whereas only 3R tau isoforms are deposited in PiD [10], and 4R tau isoforms are primarily accumulated in PSP and CBD [2, 32, 37]. The gene discussed is MAPT; the disease is red-green color blindness.