MAPT and Alzheimer disease: Although the controversy still exists over whether neurofibrillary tangles or Aβ plaques are the first event in AD, evidence suggests that CSF Aβ1-42 may be the first biomarker to change in the progression to AD followed by tau pathology [63, 64], supporting associations between increased plasma Aβ1-42 and worse subjective memory that precede tau-related objective memory changes in normal aging.