Recently, the National Institute on Aging–Alzheimer’s Association (NIA-AA) proposed the AT(N) research framework in which Alzheimer’s disease (AD) is defined as a biological entity based on a dichotomous classification of normal (−) or abnormal (+) β-amyloid deposition (A), pathological tau (T), and neurodegeneration (N) biomarkers in living persons. The gene discussed is MAPT; the disease is Alzheimer disease.