All pathologically examined cases of a clinical MND/dementia that came to my knowledge during the last 15 years in Cambridge were characterized by the same combination of the classical pathological features of MND (such as neuronal loss in the anterior horn of the spine and bulbar nuclei, particularly the hypoglossal nucleus) with frontotemporal atrophy and ubiquitin-positive, tau-negative intraneuronal inclusions in the dentate fascia of the hippocampus. The gene discussed is MAPT; the disease is mild neurocognitive disorder.