MAPT and Alzheimer disease: For example, in a recent study by Ossenkoppele et al. (2022), among CN subjects identified with both amyloid and tau pathology (A+T+), as measured by amyloid-PET and tau-PET, which indicates a high likelihood of progression to MCI or AD, a substantial proportion (~36%, 40 out of 111) remained CN after an average of 42 months of follow-up86.