Transmissible spongiform encephalopathies

Keywords Disease name and synonyms Included diseases Definition Pathogenesis Sporadic CJD Genetic forms of TSE Acquired forms of TSE Treatment Conclusion References Abstract Human prion diseases or transmissible spongiform encephalopathies (TSE) are rare transmissible diseases affecting the central nervous system. The infectious agents are composed of an abnormal isoform of a host membrane protein called " prion protein " (PrP). TSE have common features: long duration of incubation, lesions limited to the central nervous system without inflammatory or immunologic reaction but with accumulation of an abnormal form of prion protein (PrPsc) and death without any remission because of the absence of treatment. Sporadic Creutzfeldt-Jakob disease (CJD) is the most frequent form of the disease (85% of all forms of TSE) and its etiology is unknown. Its annual incidence is estimated to only 1.0–1.5 per million. Besides the typical rapidly progressive form, other forms of the disease exist and may give rise to diagnostic difficulties. Periodic electroencephalography or 14-3-3 protein detection in spinal fluid are helpful for clinical diagnosis. Currently there is no presymptomatic or early test for diagnosis. Examination of the brain after autopsy is necessary to confirm diagnosis. The etiology of other forms of TSE is known: genetic TSE (genetic CJD, Gerstmann-Straussler-Scheinker and Fatal Familial Insomnia) are caused by mutations or insertions in the PRNP gene encoding PrP, and acquired TSE (Kuru, iatrogenic CJD, variant CJD (vCDJ)) result from accidental contamination. The last reported form of TSE is vCDJ. Most vCDJ cases are observed in the United Kingdom and are highly likely to be linked to bovine spongiform encephalopathy (BSE). Low age at onset, psychiatric symptoms and/or pain preceding neurological symptoms, MRI anomalies, detection of abnormal prion protein PrPres in lymphoid system, " florid plaques " in the brain are specific of vCJD. To date, treatment of TSE is purely symptomatic.