A field on fire: the biochemistry of mad cows

Prion diseases are neurodegenerative diseases that have been linked together because they may potentially have the same cause. These include the diseases scrapie of sheep and BSE (bovine spongiform encephalopathy) of cattle, and also several human diseases that include sporadic CJD (Creutzfeldt-Jakob) disease and a variety of inherited forms. The inherited forms of prion diseases are linked to mutations within the gene for the prion protein. Around 85% of all human cases of prion disease are sporadic CJD, which is a disease affecting people of around 60 years of age. The cause of this disease remains unknown. Unfortunately, the name of this disease causes some confusion, as it is similar to vCJD (variant CJD), a related disease of much younger people.