The aggregation of the microtubule (MT)-associated protein tau, which is heat stable and normally exhibits a random coil conformation in aqueous solution, plays a central role in the neurodegeneration seen in Alzheimer’s disease and non-Alzheimer’s tauopathies that form the core of the paired helical filament (PHF) (8, 9). This evidence concerns the gene MAPT and early-onset autosomal dominant Alzheimer disease.