In the past decade, AD transgenic mice have been used as a standard preclinical model for testing candidate AD drug targets, which are pre-selected by basic mechanistic studies or by the chemical/peptide library screening using a simple biochemical or cellular model (i.e., APP processing, synthetic Aβ aggregation, tau phosphorylation and etc.)(Fig. 2). The gene discussed is MAPT; the disease is Alzheimer disease.