The majority of cases are characterized by the accumulation of either tau (either 3 or 4 repeat tau, as opposed to the combination of 3 and 4 repeat isoforms present in AD), TDP-43 (with its subtypes TDP types A, B, C, and D), or fused in sarcoma (FUS) protein [4]. The gene discussed is MAPT; the disease is Alzheimer disease.