In addition to tau protein and Aβ peptides, recent studies indicate that levels of certain phosphorylated forms of tau increase significantly in CSF of AD patients (Ewers et al. 2007; Brys et al. 2007; Kohnken et al. 2000; Arai et al. 2000; Vanmechelen et al. 2000; Hampel, 2003), but not in vascular dementia, frontotemporal dementia (Sjögren et al. 2000), Lewy body dementia, (Parnetti et al. 2001) or geriatric major depression (Buerger et al. 2003). This evidence concerns the gene MAPT and Alzheimer disease.