Sporadic fatal insomnia: A case study

A 58-year-old man died after a 27-month illness characterized by insomnia, confirmed by polysomnography. He was homozygous for methionine at codon 129 of the prion gene but had no mutation in the prion gene. Neuropathology sh owed thalamic and olivary atrophy and no spongiform changes. Paraffin-embed ded tissue blotting demonstrated abnormal prion protein in the brain. This is the first case of the sporadic form of fatal familial insomnia with demo nstration of the disorder by polysomnography.