In AD, CSF levels of total tau are elevated (Vandermeeren et al. 1993; Blennow et al. 1995; Vigo-Pelfrey et al. 1995), although total tau is also increased in the CSF in vascular dementia (Andreasen et al. 1998; Nagga et al. 2002) and in fronto-temporal dementia (Green et al. 1999). The gene discussed is MAPT; the disease is frontotemporal dementia.