Dystrophic neurites around amyloid plaques of human patients with Gerstmann-Sträussler-Scheinker disease contain ubiquitinated inclusions.

Dystrophic neurites have been previously observed around prionic protein-derived amyloid plaques of Gerstmann-Sträussler-Scheinker (GSS) disease. Ubiquitin (Ubq) immunohistochemistry reveals the presence of dot-like stainings around many of these plaques. In order to determine the nature of ubiquitinated deposits, we performed an immunogold electron microscope study on autoptic samples from the cerebellum of a GSS patient. Both pre- and post-embedding staining methods showed Ubq-positive dense bodies and filamentous structures, belonging to dystrophic neurites. They are analogous to ubiquitinated neuritic processes described around cerebellar amyloid plaques of Alzheimer's disease (AD). These results suggest that amyloid deposition is responsible for the degeneration of adjacent axon terminals in both AD and GSS.