It would be extremely useful to develop methods employing cerebrospinal fluid biomarkers combined with total tau, phosphorylated tau, tau oligomers, and other biomarker measurements to differentially diagnose dementias, such as AD, frontotemporal lobar degeneration, progressive supranuclear palsy, corticobasal degeneration, dementia with Lewy bodies, vascular dementia, and prion disease. The gene discussed is MAPT; the disease is frontotemporal dementia.