In Alzheimer’s Disease (AD) the correlation of three biomarker levels (beta-amyloid 42, Aβ42, 4.4 kDa; total tau protein, t-tau, 40–60 kDa; and tau phosphorylated at position threonine 181, p-tau, 46–68 kDa) identifies the very early onset of the disease [8]. The gene discussed is MAPT; the disease is early-onset autosomal dominant Alzheimer disease.