Because it is generally believed that the onset of AD relates to the deposition of amyloid-β (Aβ) in extracellular plaques, aggregation of tau into neurofibrillary tangles in neurons, and abnormal phosphorylation of tau, the measurements of Aβ1–42, hyperphosphorylated tau, and total tau proteins are options for AD early diagnosis (Hersi et al., 2017; Park et al., 2020). This evidence concerns the gene MAPT and Alzheimer disease.