prion

¹ American  

[prahy-on] / ˈpraɪ ɒn /

noun

1. any of several petrels of the genus Pachyptila, located in the oceans of the Southern Hemisphere and having serrated edges on the bill.

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prion ² American  

[pree-on, prahy‑] / ˈpri ɒn, ˈpraɪ‑ /

noun

1. a tiny proteinaceous particle, likened to viruses and viroids, but having no genetic component, thought to be an infectious agent in bovine spongiform encephalopathy, Creutzfeldt-Jakob disease, and similar encephalopathies.

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prion ¹ British  

/ ˈpriːɒn /

noun

1. a protein in the brain, an abnormal form of which is thought to be the transmissable agent responsible for certain spongiform encephalopathies, such as BSE, scrapie, Creutzfeldt-Jakob disease, and kuru

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prion ² British  

/ ˈpraɪən /

noun

1. any of various dovelike petrels of the genus Pachyptila of the southern oceans that have a serrated bill

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prion Scientific  

/ prē′ŏn,prī′- /

1. A particle of protein that is thought to be able to self-replicate and to be the agent of infection in a variety of diseases of the nervous system, such as mad cow disease. Prion replication (in which strings of amino acids are reproduced) stands as an exception to a central tenet of biology stating that only nucleic acids, such as DNA, can self-replicate. The mechanism of prion replication is not clearly understood.

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prion Cultural  

1. A protein that not only folds into an unusual shape itself, but also seems to have the ability to cause other proteins to change their shape as well. For a long time, scientists were skeptical that prions existed, but now most accept them.

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Closer Look

In 1997 Stanley Prusiner was awarded the Nobel Prize for physiology or medicine for his theory that a deviant form of a harmless protein could be an infectious agent, a transmitter of disease. Named prions (short for proteinaceous infectious particle), these misshapen proteins cause healthy proteins to misfold, fatally clumping together in the brain. Unlike other disease-causing agents, prions lack genetic material (DNA and RNA). Neurodegenerative prion diseases are often called spongiform encephalopathies because they leave the brain riddled with holes like a sponge. In animals, prion diseases include scrapie in sheep and bovine spongiform encephalopathy, commonly known as mad cow disease in cattle. In humans, diseases such as kuru and Creutzfeldt-Jakob disease (CJD) are also thought to be caused by prions. All the diseases are characterized by loss of motor control, dementia, paralysis, and eventual death due to massive destruction of brain tissue. Humans are thought to contract prion disease most commonly by eating prion-contaminated flesh. Kuru, a rare and fatal brain disorder, brought prion disease to the forefront. First described in the 1950s, kuru was most common among the Fore people of Papua New Guinea, who had a custom of eating the brains of their dead during funeral feasts. It is speculated that a tribe member developed CJD, his or her contaminated brain tissue was ingested, and the disease spread. Kuru reached epidemic levels in the 1960s, but the disease declined after the government discouraged the practice of cannibalism and now it has almost completely disappeared.

Discover More

Prions are thought to be the cause of mad cow disease.

Etymology

Origin of prion¹

1840–50; < New Latin < Greek príōn a saw

Origin of prion²

1980–85; pr(oteinaceous) ( def. ) + i(nfectious) + -on ¹

Explanation

In microbiology, a prion is a tiny particle, a misshaped protein that causes a particular type of disease. Prions are the cause of many brain illnesses in humans and animals. So-called mad cow disease is caused by prions, as is chronic wasting disease, which affects deer, and Creutzfeldt-Jakob disease in humans. These are all extremely serious illnesses that aren't fully understood by scientists. Prions are pathogens, like viruses and bacteria, but they exist as proteins within normal cells. It's only when they become strangely folded that they begin to infect the proteins around them, ultimately causing brain damage. The word was formed in the 1980s, from pro(teinaceous) in(fectious particle).

Example Sentences

See Examples For:

prion

According to the researchers, this ability to change makes prion diseases especially challenging to forecast and manage.

From Science Daily ● Jun. 16, 2026

Chronic wasting disease is caused by a misfolded protein known as a prion and can be transmitted through predator and prey interaction, such as a panther eating a deer that has the disease.

From Science Daily ● Nov. 21, 2024

"When we think about gene therapy for a whole-brain disease like prion disease, you need really systemic delivery and broad biodistribution in order to achieve anything," said Minikel.

From Science Daily ● May 16, 2024

Cases acquired from contaminated meat, blood transfusions, neurosurgical instruments and grafts now account for less than 1% of all prion disease.

From Science Magazine ● Mar. 21, 2024

Hadn't he, in his disconnection, looked like a man suffering from some neuron-entangled nervousness, heavy neurosis, or a bad prion making the holes in his head to match the holes of his being.

From Tokyo to Tijuana: Gabriele Departing America by Sills, Steven (Steven David Justin)