Why the mitochondrial study in the AD had these contradictory reports, we speculated that, though Aβ and tau aggregation are associated with mitochondrial damage, oxidative stress as well as structural and functional alterations of neurons in AD [32-34], it seems that Aβ and tau proteins induces mitochondrial dysfunction and mitochondrial number with different mechanisms, which waiting for further study. The gene discussed is MAPT; the disease is Alzheimer disease.