Advances in the field of biomarkers have pushed forward a redefinition of Alzheimer's disease (AD) as a biological construct.1 Under this definition, the ATN classification system recognizes three general groups of biomarkers for AD: biomarkers of β‐amyloid plaques (A), biomarkers of fibrillar tau (T) and biomarkers of neurodegeneration or neuronal injury (N).1 These categories can be assessed by using different modalities, but those that are more widely implemented are cerebrospinal fluid (CSF) biomarkers and imaging techniques. The gene discussed is MAPT; the disease is Alzheimer disease.