The exact etiopathogenetic mechanisms leading to dementia have not yet been completely identified and the ongoing therapeutic strategies are generally based on the different aspects of dementia: to reduce protein aggregation, including β-amyloidosis and abnormal Tau phosphorylation in AD, and α-Syn deposition in DLB; to prevent further cerebrovascular and ischemic events in VaD and FTD; to restore specific neurotransmitter impairment, including cholinergic abnormalities in AD, and dysfunction of glutamatergic and dopaminergic system in DLB. The gene discussed is MAPT; the disease is Alzheimer disease.