By: Taylor Eisenstein
BSE and vCJD are just some examples of transmissible spongiform encephalopathies, or prion diseases. Prions are pathogenic agents composed of protein material and are capable of causing neurodegenerative diseases that can affect both humans and animals. Prions can cause normal prion proteins, primarily found in the brain, to fold abnormally. This can have severe consequences, since the structure of a protein determines its function. The way that a protein is shaped determines that protein’s functional abilities, which can be essential for life. While functions of normal prion proteins are not yet entirely understood, researchers have proposed that they play a role in neuroprotection and assist in communication between neurons.
In particular, the abnormal, mis-folded proteins can clump in the brain, which can result in neuronal loss, tiny holes in the brain, and consequent brain damage. These factors can ultimately lead to impaired brain function, declined intellectual function, and difficulty in coordinating movements. Symptoms of prion diseases include muscle stiffness, fatigue, difficulty speaking, confusion, and dementia. Prion diseases are usually progressive, fatal, and extremely rare. Risk factors include consumption of infected meat, contact with contaminated medical equipment, or even family history.
Creutzfeld-Jakob disease (CJD) is the most common human prion disease. This disease is different from vCJD since it is not acquired and is either sporadic or inherited. CJD has an annual incidence of approximately one case per million in a population. This means that, in the United States, approximately 300 cases may occur per year. While duration of the disease can vary, CJD is usually fatal within a year—or within a matter of months. Other human prion diseases include Gerstmann-Straussler-Scheinker disease (GSS), fatal familial insomnia (FFI), and Kuru. GSS and FFI are genetic and inherited in an autosomal dominant manner. In contrast, Kuru is a prion disease often associated with cannibalistic practices. The disease was transmitted amongst members of the Fore people in New Guinea when they consumed brain tissues of infected, deceased family members. Other animal prion diseases include chronic wasting disease (CWD) and scrapie.
There is no cure for prion diseases. Most treatments are aimed at simply alleviating symptoms and making individuals with such diseases feel as comfortable as possible for the duration of their illness. However, there is ongoing research to find an effective therapy for prion diseases. For instance, antibodies aimed at inhibiting prion replication have been proposed as a potential means of treatment. In the future, perhaps research into such treatments will advance and eventually prove to be more effective.
1. White, A. R., Enever, P., Tayebi, M., Mushens, R., Linehan, J., Brandner, S., ... & Hawke, S. (2003). Monoclonal antibodies inhibit prion replication and delay the development of prion disease. Nature, 422(6927), 80-83.