Thalamic degeneration with negative prion protein immunostaining

A 34-year-old woman presented with an insidious 5-year history of cognitive decline and apathy, associated with hypersomnia, ataxia, and dysarthria. M agnetic resonance imaging of the brain showed cortical and subcortical atro phy. At autopsy we found abnormalities in the subcortical grey matter and b rainstem, with a relatively preserved cerebral cortex. The thalami showed s ymmetrical neuronal loss and astrocytosis, particularly severe in the dorsa l medial nucleus, followed by the lateral nuclei group. Prion protein immun ostaining was negative, and there was no spongiform change. No mutations we re detected in the prion protein gene.