The core CSF biomarkers (β-amyloid [Aβ]42/Aβ40 ratio, phosphorylated tau 181 [p-tau], and total tau) jointly perform excellently to provide biological evidence of AD, in agreement with the principal pathological features of the disease – Aβ plaques, phosphorylated tau, and neurodegeneration respectively [5–7]. This evidence concerns the gene MAPT and Alzheimer disease.