MAPT and early-onset autosomal dominant Alzheimer disease: Jiang et al. found that cerebrospinal fluid and positron emission tomography β-amyloid discordant individuals have distinct cortical tau deposition patterns in non-demented elderly adults, indicating different cerebrospinal fluid β-amyloid positive-first and positron emission tomography β-amyloid positive-first individuals may have initial tau tangles in distinct cortical regions in early amyloidosis stage of Alzheimer's disease.