An atypical case of sporadic fatal insomnia

Fatal insomnia is a rare human prion disease characterised by sleep–wake disturbances, thalamic degeneration and deposition of type 2 disease-specific prion protein (PrP^Sc). This report details a patient with sporadic fatal insomnia who exhibited cerebral deposition of type 1 PrP^Sc and neuropathological changes largely in the basal ganglia. Previous damage of this brain region by a surgically removed colloid cyst and the insertion of two intracerebral shunts may have influenced the distribution of PrP^Sc through a chronic inflammatory process. These findings add to our knowledge of the phenotypic variability of human prion diseases with prominent sleep disturbances.