For each AD case we isolated both (i) SARK tau, corresponding to more fibrillar species of tau using the well-characterized sarkosyl-insoluble extraction method [22, 42], and (ii) HMW tau, corresponding to tau oligomers using size-exclusion chromatographyon PBS-soluble tissue fractions [17, 57] (Fig. 1a). The gene discussed is MAPT; the disease is Alzheimer disease.