Distinct from Alzheimer’s disease, there are dementias which are exclusively tauopathy (69), supporting the belief that Tau abnormalities are directly responsible of dementia activity of the brain in Alzheimer’s disease (72); the tauopathic diseases without Aβ abnormality could be called “pure tauopathies”: some are FTDP17: frontotemporal dementias and parkinsonism linked to chromosome 17; progressive supra-nuclear palsy; Pick diseases, etc. The gene discussed is MAPT; the disease is dementia.