The evolution of views on the nosological position of transmissible spongiform encephalopathies.

We report here on the evolution of view on the nature of transmissible spongiform encephalopathies or prion disease. While the nosological position of these diseases is well understood, the nature of the agent is still a matter of dispute. There is no doubt, however, that the gene for PrP plays a major role in the whole group of neurodegenerations.