Tau mutations are responsible for a diverse group of neurodegenerative dementias that include Pick’s disease, progressive supranuclear palsy (PSP) [18,19], corticobasal degeneration (CBD) [20-22], and fronto-temporal dementia with parkinsonism linked to chromosome-17 (FTDP-17), a rare but devastating disease [23]. This evidence concerns the gene MAPT and semantic dementia.