Neurofibrillary tangle parkinsonian disorders--tau pathology and tau genetics.

A number of related conditions, including progressive supranuclear palsy (PSP), corticobasal degeneration, Pick's disease, and the parkinsonism dementia complex of Guam, are characterized by the deposition of tau neurofibrillary tangles in the absence of amyloid pathology. These diseases share some overlap in their topography and clinical features but can be subdivided into three main groups according to the isoforms of the alternatively spliced tau gene that are deposited. The recent description of mutation in tau in frontotemporal dementia, and a common variant of tau that predisposes to PSP, and the relationship of these changes to the tau protein subgroups offers new insights into the pathogenesis of these disorders.