Fourteen of 41 patients with MND (34 %) (patients #1–14), 9/16 with FTD + MND (56 %) (patients #42–52) and 11/23 (48 %) patients with FTD (patients #58–68) showed neither amyloid nor tau pathology in any region of the brain examined. The gene discussed is MAPT; the disease is frontotemporal dementia.