An aberrant variety of one of the proteins, called PrP, in a brain cell. The result of a gene mutation (see GENES), prions are stable, resistant to radiation and impervious to the normal cellular processes of degradation. They seem to react with normal PrP, turning it into an abnormal type that then accumulates in brain tissue. Prions are believed to be the infectious agents that cause a group of serious neurological disorders called spongiform encephalopathies. CREUTZFELDT-JAKOB DISEASE (CJD), the new variant of CJD linked with BOVINE SPONGIFORM ENCEPHALOPATHY (BSE), and KURU – a neurological disorder once related to cannibalism in New Guinea – are all diseases in this group that occur in humans. The prion disorders have a long latent period between infection and manifestation of symptoms; they are hard to diagnose until autopsy and there is no effective curative treatment.