This classification based on the handedness of specific repeats agrees with the isoform composition of tau inclusions (3R + 4R tauopathy and 3R tauopathy) and four-layered (CBD and AGD) and three-layered (PSP, GGT and GPT) folds2, but it also distinguishes GPT from PSP. The gene discussed is GPT; the disease is argyrophilic grain disease.