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Prion Diseases



Prion is a term used to describe the mysterious infectious agent responsible for several neurodegenerative diseases such as Creutzfeldt-Jakob disease.

The word refers to Dr Stanley Prusiner’s hypothesis of the infectious agent causing these diseases. This hypothesis explains why the infectious agent is resistant to ultraviolet light, which would typically kill the agent by damaging the DNA/RNA, but is instead susceptible to substances that disrupt proteins. 


Prion diseases include Creutzfeldt-Jakob Disease and Kuru in humans, as well as Bovine Spongiform Encephalopathy and Scrapie in animals. They are distinguished by characteristic spongiform changes associated with neuronal loss and failure to induce inflammatory response. 


The prion protein was discovered to be encoded by a gene (PrP gene) found in all animals examined, including humans. The infectious prion protein was caused by a mutation in the PrP gene. These studies argued that prion diseases can be inherited and infectious, which is an unprecedented concept. 


However, there is no chemical difference that distinguishes normal PrP from the disease form. Instead, the only difference between the two proteins was its conformation. The disease form of PrP acts as a template for the refolding of normal PrP into the disease form, resulting in the “spread” of the disease. Prion diseases are thus also diseases of protein conformation. 


For his discovery of prions and his work on the subject, Dr Stanley Prusiner was awarded The Nobel Prize in Physiology of Medicine 1997.


Sources:

https://www.cdc.gov/prions/index.html

https://www.scientificamerican.com/article/what-is-a-prion-specifica/

https://www.hopkinsmedicine.org/health/conditions-and-diseases/prion-diseases

http://www.laskerfoundation.org/awards/show/prions-as-a-cause-of-chronic-neurodegenerative-diseases/

https://www.nobelprize.org/prizes/medicine/1997/prusiner/facts/

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