In contrast to t-tau, which is included in the AT(N) criteria for AD diagnosis as a general marker of neurodegeneration and neuronal injury, there is no change in CSF p-tau concentrations in other tauopathies and neurological conditions (Hesse et al., 2001; Parnetti et al., 2001; Riemenschneider et al., 2003). The gene discussed is MAPT; the disease is Alzheimer disease.