LAUSR

Tauopathies are a heterogeneous group of neurodegenerative disorders sharing the neuropathologic hallmark of neuronal and/or glial accumulation of tau (Table 1). They can have genetic, toxic, autoimmune, or environmental bases, although in most cases, the etiology remains unknown. Recent years have seen increasing numbers of movement disorders subsumed under the umbrella of “tauopathies.” Herein we review these entities from clinical, etiological, and pathomechanistic standpoints and conclude by discussing the difficulties in interpreting the relevance of tau deposition in these disorders. Indeed, as the number of disparate disorders bearing tau pathology increases, the less likely it becomes that tau is the primary instigator or mediator of disease in all. Moreover, the recognition of a number of aging-related tauopathies (aging-related tau astrogliopathy; primary age related tauopathy), sometimes in patients without clinical deficits, further supports the theory that on occasion, tau deposition may be a late or secondary phenomenon or may merely reflect processes associated with normal aging and life insults.