In AD, tau is hyperphosphorylated (it contains 9–10 moles of phosphate per mol of tau while normal tau contains 2–3 moles of phosphate) (19, 20), undergoes conformational changes (21) and is converted into toxic oligomers and fibrillar aggregates, the straight (SFs) and paired helical filaments (PHFs) (22, 23). This evidence concerns the gene MAPT and Alzheimer disease.