Of thesesites, about 20 residues undergo phosphorylation in tau from bothhealthy and AD brains, while about 40 phosphorylated residues occuronly in AD brain.10 The different phosphorylationsites and their combinations (namely, multi-site phosphorylation)have different effects on tau aggregation and MT binding affinity.Tau phosphorylation at Thr175 leads to fibril formation and enhancescell death.11 Pseudo-phosphorylation oftau at Thr212,12 Ser202, and Thr20513 promotes tau filament formation. This evidence concerns the gene MAPT and Alzheimer disease.