This implies that the predominantly straight filaments of 4-repeat tau that constitute the pathology of progressive supranuclear palsy and corticobasal degeneration, and the 3-repeat tau of intraneuronal Pick bodies, lead to less intense binding than that seen in Alzheimer’s pathology, with its balanced 3-/4-repeat tauopathy in the form of paired helical filaments. This evidence concerns the gene MAPT and Classical progressive supranuclear palsy.