The levels of Aβ42, the Aβ40/Aβ42 ratio, phosphorylated tau (p-tau), and the results of amyloid PET imaging (such as the uptake of radiotracers) in CSF can reflect the accumulation of amyloid plaques in the brain [291]; however, they do not necessarily predict whether an individual will exhibit clinical symptoms (such as mild cognitive impairment or dementia) in the future, particularly within cognitively normal populations. This evidence concerns the gene MAPT and Cognitive impairment.