Tau accumulation in a patient with pallidonigroluysian atrophy

We studied the brain of a patient with pallidonigroluysian atrophy (PNLA) in whom argyrophilic and abnormally phosphorylated tau positive neurons and glia were identified in the brain on Gallyas-Braak silver staining and immunohistochemical analysis although neurofibrillary tangles were not seen by Bodian silver stain. Immunohistochemical studies using six anti-tau antibodies that recognize the different phosphorylated epitopes of tau protein revealed that these epitopes in neurons and glial cells share common characteristics with neurofibrillary tangles in Alzheimer's disease. Immunoblot analysis of phosphorylated tau protein showed major bands of 64 and 68 kDa and after dephosphorylation, tau consisted mainly of 4 repeat tau. No mutations were detected in the coding exons and their flanking intronic regions of the tau gene. This study suggests that PNLA is one of tauopathy and the biochemical characteristics of phosphorylated tau are similar to those found in progressive supranuclear palsy and corticobasal degeneration.