Tau pathology is also present in a large number of conditions whose cause cannot be traced to mutations in the gene encoding tau, including traumatic brain injury and repeated head trauma (dementia pugilista) from contact sports [5]–[7] as well as Alzheimer's disease, and has been observed with and without amyloid-beta pathology. The gene discussed is MAPT; the disease is early-onset autosomal dominant Alzheimer disease.