With the aim of determining whether this discrepancy can be attributed to the binding properties of specific compounds, different compound classes, or to the tau binding site(s), we carried out a microscopic neuropathological evaluation in post-mortem human brain tissue of cases with Alzheimer’s disease, a range of primary tauopathies and non-demented controls with and without tau pathology. The gene discussed is MAPT; the disease is early-onset autosomal dominant Alzheimer disease.