A single tau PET scan may preclude the need for Aβ PET or CSF AD biomarkers, as well as fluorodeoxyglucose F 18 PET, in the diagnostic workup of amnestic dementia (eFigure 15 in the Supplement) given the finding that tau PET positivity was virtually confined to Aβ-positive cases and studies showing a high overlap between tau PET and hypometabolism.52,53. The gene discussed is MAPT; the disease is Alzheimer disease.