ABSTRACT
Many neurodegenerative diseases, previously classified according to clinical and morphological criteria, are characterized by distinct brain lesions that have in common the formation of filamentous deposits of abnormal proteins. This allows a biochemical re-classification of neurodegenerative diseases. A group of heterogeneous dementias and movement disorders are hallmarked by prominent intracellular accumulations of abnormal filaments formed by the microtubule-associated protein tau that appears to share common mechanisms of disease. They are summarized as neurodegenerative tauopathies (Table 41.1). Despite their diverse phenotypic manifestation, brain dysfunction and degeneration are linked to the progressive accumulation of tau inclusions in neurons and glia, implicating their pathogenic importance. Some of these disorders are due to various mutations of the tau gene,1,2 while novel tau polymorphisms have been observed in various frontotemporal dementias,3 thus broadening the molecular genetic aspects of the tauopathies.4,5
These findings have opened up new ways for understanding the role of tau abnormalities in neurodegeneration.
