MAPT and early-onset autosomal dominant Alzheimer disease: Although these soluble p-tau analytes in CSF and plasma are tau biomarkers, they may indicate that the patient already has moderate/frequent amyloid plaques (high CERAD score, Consortium to Establish a Registry for Alzheimer’s Disease) and most of these cases are also in Braak stages III to VI, meeting the criteria for intermediate/high AD neuropathological change4.