Fatal familial insomnia is a prion disease characterized by loss of sleep, oneiric stupors with dream enactment, autonomic activation, and somatomotor abnormalities. The latter may include diplopia, pyramidal signs, myoclonus, dysarthria or dysphagia, and ataxia. PET shows marked thalamic hypometabolism, and neuropathology invariably reveals a moderate to severe neuronal loss and gliosis in the anteromedial thalamic and inferior olivary nuclei. The disease is usually linked to the D178N mutation in the PRNP gene co-segregating with methionine at the polymorphic codon 129. However, sporadic cases of fatal insomnia, lacking the PRNP mutation, may also occur. Fatal familial insomnia represents a model disease for the study of sleep, emphasizing the role of the thalamo-limbic circuits in sleep regulation.
In this article, Dr. Piero Parchi, Dr. Samir Abu-Rumeileh, and Dr. Pietro Cortelli of the University of Bologna discusses the manifestations and diagnosis of fatal familial insomnia.
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