To examine whether the trypsin-resistant tau band patterns are characteristic for each disease, we prepared sarkosyl-insoluble fractions from brains of five cases with AD, two cases with PiD, two cases with CBD, four cases with PSP and four cases with MAPT. Trypsin treatment followed by immunoblotting with TauC4 confirmed that each disease showed a consistent, characteristic band pattern of trypsin-resistant tau (Fig. 2e). This evidence concerns the gene MAPT and Alzheimer disease.