These CSF biomarkers are now included in research diagnostic criteria for both prodromal and dementia stages of Alzheimer’s disease (AD) due to reduced levels of amyloid and elevated levels of tau on threonine 181 in CSF showing 85–95% sensitivity and specificity for AD at the stage of dementia or earlier mild cognitive impairment stage [34,35]. This evidence concerns the gene MAPT and early-onset autosomal dominant Alzheimer disease.