While in Alzheimer's disease (AD) tau aggregates preferentially are formed in neurons, in frontotemporal dementias, such as Pick's disease, progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD), tau-positive inclusions are consistent features not only in neurons but also in glia [5–8]. This evidence concerns the gene MAPT and early-onset autosomal dominant Alzheimer disease.