In particular, three cerebrospinal fluid (CSF) biomarkers (β-amyloid 1–42 [Aβ1–42], total Tau [t-Tau] and its phosphorylated form [p-Tau]) have been extensively studied due to their high diagnostic accuracy for the diagnosis of Alzheimer disease (AD)1. This evidence concerns the gene MAPT and early-onset autosomal dominant Alzheimer disease.