Prion diseases are transmissible, untreatable, and fatal brain diseases of mammals. Their cause is highly unusual: The host’s normal prion protein can, for unknown reasons, malfunction and assemble into structured aggregates called prions that cause infectious brain disease. This process – which can be underway for years before symptoms appear – likely causes the most common form of prion disease in people, sporadic Creutzfeldt-Jakob disease (CJD). Other forms of human prion diseases include variant CJD, fatal familial insomnia, Gerstmann-Straussler-Scheinker Syndrome and Kuru.

In livestock and wildlife, prion diseases such as scrapie (sheep), chronic wasting disease (deer, elk, moose), and mad cow disease (cattle) can spread by casual contact or contamination of feeds or the environment. Prions also can be infectious if inadvertently transferred from person to person by invasive medical procedures.

Prion disease symptoms reflect the brain being destroyed and can range from memory loss and unstable movement to being unable to sleep or realize the need to eat.

Prion disease represents a group of conditions that affect the nervous system in humans and animals. In people, these conditions impair brain function, causing changes in memory, personality, and behavior; a decline in intellectual function (dementia); and abnormal movements, particularly difficulty with coordinating movements (ataxia). The signs and symptoms of prion disease typically begin in adulthood and worsen with time, leading to death within a few months to several years.

What are transmissible spongiform encephalopathies?

Transmissible spongiform encephalopathies (TSEs), also known as prion diseases, are a group of rare degenerative brain disorders characterized by tiny holes that give the brain a "spongy" appearance. These holes can be seen when brain tissue is viewed under a microscope.

Creutzfeldt-Jakob disease (CJD) is the most well-known of the human TSEs. Other human TSEs include:

• Kuru
• Fatal Familial Insomnia (FFI)
• Gerstmann-Straussler-Scheinker Disease (GSS)

A relatively new type of CJD known as variant CJD (vCJD) was first described in 1996. Research suggests that vCJD may have resulted from human consumption of beef from cattle with a TSE disease called bovine spongiform encephalopathy (BSE), also known as Mad Cow Disease. Other TSEs found in animals include:

• Scrapie, which affects sheep and goats
• Chronic wasting disease, which affects elk and deer
• Transmissible mink encephalopathy

In a few rare cases, TSEs have occurred in other mammals such as zoo animals. These cases are probably caused by contaminated feed. CJD and other TSEs also can be transmitted experimentally to mice and other animals in the laboratory.

Research suggests that TSEs are caused by an abnormal version of a protein called a prion (short for proteinaceous infectious particle). Prion proteins occur in both a normal form, which is a harmless protein found in the body's cells, and in an infectious form, which causes disease.

Human TSEs can occur three ways:

1. Sporadically—Sporadic TSEs may develop because some of a person's normal prions spontaneously change into the infectious form of the protein and then alter the prions in other cells in a chain reaction.
2. As hereditary diseases—Inherited cases arise from a change, or mutation, in the prion protein gene that causes the prions to be shaped in an abnormal way. This genetic change may be transmitted to an individual's offspring.
3. Through transmission from infected individuals—Transmission of TSEs from infected individuals is relatively rare. TSEs cannot be transmitted through the air or through touching or most other forms of casual contact. However, they may be transmitted through contact with infected tissue, body fluids, or contaminated medical instruments. Normal sterilization procedures such as boiling or irradiating materials do not prevent transmission of TSEs.

Symptoms of TSEs vary, but they commonly include:

• Personality changes
• Psychiatric problems such as depression

• Lack of coordination
• An unsteady gait

Individuals also may experience involuntary jerking movements called myoclonus, unusual sensations, insomnia, confusion, or memory problems. In the later stages of the disease, patients have severe mental impairment and lose the ability to move or speak.

There is currently no treatment that can halt progression of any of the TSEs. Treatment is aimed at alleviating symptoms and making the individual as comfortable as possible. TSEs tend to progress rapidly and usually culminate in death over the course of a few months to a few years.

How can I or my loved one help improve care for people with transmissible spongiform encephalopathies?

Consider participating in a clinical trial so clinicians and scientists can learn more about TSEs and related disorders. Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.

For information about participating in clinical research visit NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with TSEs at Clinicaltrials.gov.

Prion diseases or transmissible spongiform encephalopathies (TSEs) are a family of rare progressive neurodegenerative disorders that affect both humans and animals. They are distinguished by long incubation periods, characteristic spongiform changes associated with neuronal loss, and a failure to induce inflammatory response.

The causative agents of TSEs are believed to be prions. The term “prions” refers to abnormal, pathogenic agents that are transmissible and are able to induce abnormal folding of specific normal cellular proteins called prion proteins that are found most abundantly in the brain. The functions of these normal prion proteins are still not completely understood. The abnormal folding of the prion proteins leads to brain damage and the characteristic signs and symptoms of the disease. Prion diseases are usually rapidly progressive and always fatal.

Identified Prion Diseases

Listed below are the prion diseases identified to date. CDC does not currently offer information on every prion disease listed below.

Human prion diseases

• Creutzfeldt-Jakob Disease (CJD)
• Variant Creutzfeldt-Jakob Disease (vCJD)
• Gerstmann-Straussler-Scheinker Syndrome
• Fatal Familial Insomnia
• Kuru

Animal prion diseases

• Bovine Spongiform Encephalopathy (BSE)
• Chronic Wasting Disease (CWD)
• Scrapie
• Transmissible mink encephalopathy
• Feline spongiform encephalopathy
• Ungulate spongiform encephalopathy

Creutzfeldt-Jakob disease (CJD) is a rare fatal brain disorder that usually occurs later in life and runs a rapid course. In the early stages of the disease, patients may have failing memory, behavior changes, impaired coordination, and vision problems. As CJD progresses, mental deterioration becomes severe, and they can have uncontrolled movements, blindness, weakness, and go into a coma.

CJD can be very difficult to diagnose because it is similar to other forms of dementia. The only way to confirm the diagnosis is to test a small sample of brain tissue, which can be done by brain biopsy or autopsy. CJD is caused by the build up of abnormal prion proteins in the brain. For most patients, the reason for the abnormal prions is unknown (sporadic CJD). About 5 to 10 percent of cases are due to an inherited genetic change associated with CJD (familial CJD). This condition can also be acquired through contact with infected brain tissue (iatrogenic CJD) or consuming infected beef (variant CJD).

Variant Creutzfeldt-Jakob disease (vCJD) is a prion disease that was first described in 1996 in the United Kingdom. There is now strong scientific evidence that the agent responsible for the outbreak of prion disease in cows, bovine spongiform encephalopathy (BSE or ‘mad cow’ disease), is the same agent responsible for the outbreak of vCJD in humans.

Variant CJD (vCJD) is not the same disease as classic CJD (often simply called CJD). It has different clinical and pathologic characteristics from classic CJD. Each disease also has a particular genetic profile of the prion protein gene. Both disorders are invariably fatal brain diseases with unusually long incubation periods measured in years, and are caused by an unconventional transmissible agent called a prion.

Fatal familial insomnia (FFI) affects the thalamus, the part of the brain that controls the sleep-wake cycle. The most common symptoms are sleep disturbance, psychiatric problems, weight loss, and balance problems. Other symptoms include high blood pressure, excess sweating, and difficulty controlling body temperature. These symptoms tend to get worse over time. Almost all cases of FFI occur due to a specific variant in the PRNP gene and are inherited in an autosomal dominant pattern. Diagnosis is based on the symptoms, clinical exam, sleep study, and imaging studies. The results of genetic testing can help confirm the diagnosis.

Gerstmann-Straussler-Scheinker disease (GSS) is a type of prion disease. Prion diseases are a group of conditions that affect the nervous system. The main feature of GSS is a progressive degeneration of the cerebellum (a part of the brain that controls coordination, balance, equilibrium and muscle tone), as well as different degrees of dementia. It is caused by changes in the PRNP gene and inheritance is autosomal dominant.

Kuru is a rare and fatal brain disorder that occurred at epidemic levels from the 1950s to 1960s among the Fore people in the highlands of New Guinea. The disease was the result of the practice of ritualistic cannibalism among the Fore, in which relatives prepared and consumed the tissues (including brain) of deceased family members. Brain tissue from individuals with kuru was highly infectious, and the disease was transmitted either through eating or by contact with open sores or wounds. Kuru is the Fore word for shiver.

Government discouragement of the practice of cannibalism led to a continuing decline in the disease, which has now mostly disappeared.

Kuru belongs to a class of infectious diseases called transmissible spongiform encephalopathies (TSEs), also known as prion diseases. The hallmark of a TSE disease is misshapen protein molecules that clump together and accumulate in brain tissue. Scientists believe that misshapen prion proteins have the ability to change their shape and cause other proteins of the same type to also change shape.

Other TSEs include:

• Creutzfeldt-Jakob disease and fatal familial insomnia in humans
• Bovine spongiform encephalopathy in cattle (also known as "mad cow" disease)
• Scrapie in sheep and goats
• Chronic wasting disease in deer and elk

There were no treatments that could control or cure kuru, other than discouraging the practice of cannibalism. Currently, there are no cures or treatments for any of the other TSE diseases.

Similar to other the TSEs, kuru has a long incubation period; it was years or even decades before an infected person showed symptoms. Because kuru mainly affected the cerebellum, which is responsible for coordination, the first symptoms were usually an unsteady gait, tremors, and slurred speech. Unlike most of the other TSEs, dementia was either minimal or absent. Mood changes were often present. Eventually, individuals became unable to stand or eat, and they died in a comatose state from six to 12 months after the first appearance of symptoms.

Between 10 and 15 percent of all cases of prion disease are caused by mutations in the PRNP gene. Because they can run in families, these forms of prion disease are classified as familial. Familial prion diseases, which have overlapping signs and symptoms, include familial Creutzfeldt-Jakob disease (CJD), Gerstmann-Sträussler-Scheinker syndrome (GSS), and fatal familial insomnia (FFI).

The PRNP gene provides instructions for making a protein called prion protein (PrP). Although the precise function of this protein is unknown, researchers have proposed roles in several important processes. These include the transport of copper into cells, protection of brain cells (neurons) from injury (neuroprotection), and communication between neurons. In familial forms of prion disease, PRNP gene mutations result in the production of an abnormally shaped protein, known as PrPSc, from one copy of the gene. In a process that is not fully understood, PrPSc can attach (bind) to the normal protein (PrPC) and promote its transformation into PrPSc. The abnormal protein builds up in the brain, forming clumps that damage or destroy neurons. The loss of these cells creates microscopic sponge-like holes (vacuoles) in the brain, which leads to the signs and symptoms of prion disease.

The other 85 to 90 percent of cases of prion disease are classified as either sporadic or acquired. People with sporadic prion disease have no family history of the disease and no identified mutation in the PRNP gene. Sporadic disease occurs when PrPC spontaneously, and for unknown reasons, is transformed into PrPSc. Sporadic forms of prion disease include sporadic Creutzfeldt-Jakob disease (sCJD), sporadic fatal insomnia (sFI), and variably protease-sensitive prionopathy (VPSPr).

Acquired prion disease results from exposure to PrPSc from an outside source. For example, variant Creutzfeldt-Jakob disease (vCJD) is a type of acquired prion disease in humans that results from eating beef products containing PrPSc from cattle with prion disease. In cows, this form of the disease is known as bovine spongiform encephalopathy (BSE) or, more commonly, "mad cow disease." Another example of an acquired human prion disease is kuru, which was identified in the South Fore population in Papua New Guinea. The disorder was transmitted when individuals ate affected human tissue during cannibalistic funeral rituals.

Rarely, prion disease can be transmitted by accidental exposure to PrPSc-contaminated tissues during a medical procedure. This type of prion disease, which accounts for 1 to 2 percent of all cases, is classified as iatrogenic.

Normal Function

The PRNP gene provides instructions for making a protein called prion protein (PrP), which is active in the brain and several other tissues. Although the precise function of this protein is unknown, researchers have proposed roles in several important processes. These include the transport of copper into cells and protection of brain cells (neurons) from injury (neuroprotection). Studies have also suggested a role for PrP in the formation of synapses, which are the junctions between nerve cells (neurons) where cell-to-cell communication occurs.

Different forms of PrP have been identified. The normal version is often designated PrPC to distinguish it from abnormal forms of the protein, which are generally designated PrPSc.

Health Conditions Related to Genetic Changes

Huntington's disease-like syndrome

A particular type of variant (also called a mutation) in the PRNP gene has been found to cause signs and symptoms that resemble those of Huntington's disease, including uncontrolled movements, emotional problems, and loss of thinking ability. Researchers have proposed that this condition be called Huntington's disease-like 1 (HDL1).

The PRNP gene variants associated with HDL1 involve a segment of DNA called an octapeptide repeat. This segment provides instructions for making eight protein building blocks (amino acids) that are linked to form a protein fragment called a peptide. The octapeptide repeat is normally repeated five times in the PRNP gene. In people with HDL1, this segment is repeated eleven or thirteen times. An increase in the size of the octapeptide repeat leads to the production of an abnormally long version of PrP. It is unclear how the abnormal protein damages and ultimately destroys neurons, leading to the characteristic features of HDL1.

Prion disease

Many variants in the PRNP gene have been identified in people with familial forms of prion disease, including Creutzfeldt-Jakob disease (CJD), Gerstmann-Sträussler-Scheinker syndrome (GSS), and fatal familial insomnia (FFI). The major features of these diseases include changes in memory, personality, and behavior; a decline in intellectual function (dementia); and abnormal movements, particularly difficulty with coordinating movements (ataxia). The signs and symptoms worsen over time, ultimately leading to death.

Some of the PRNP gene variants that cause familial prion disease change single amino acids in PrP. Other variants insert additional amino acids into the protein or result in an unusually short version of the protein. These changes alter the structure of PrP, leading to the production of an abnormally shaped protein, known as PrPSc, from one copy of the PRNP gene. In a process that is not fully understood, PrPSc can attach (bind) to PrPC and promote its transformation into PrPSc. The abnormal protein builds up in the brain, forming clumps that damage or destroy neurons. The loss of these cells creates microscopic sponge-like holes (vacuoles) in the brain, which leads to the signs and symptoms of prion disease.

Researchers have identified several common variations (polymorphisms) in the PRNP gene that affect single amino acids in PrP. These polymorphisms do not cause prion disease, but they may affect a person's risk of developing these disorders. Studies have focused on the effects of a polymorphism at position 129 of PrP. At this position, people can have either the amino acid methionine (Met) or the amino acid valine (Val). This polymorphism is written as Met129Val or M129V. Because people inherit one copy of the PRNP gene from each parent, at position 129 an individual can receive methionine from both parents (Met/Met), valine from both parents (Val/Val), or methionine from one parent and valine from the other (Met/Val).

The Met129Val polymorphism appears to influence the risk of developing prion disease. Most affected individuals have the same amino acid at position 129 (Met/Met or Val/Val) instead of different amino acids (Met/Val). Having Met/Met at position 129 is also associated with an earlier age of onset and a more rapid worsening of the disease's signs and symptoms.

Wilson disease

The Met129Val polymorphism has been reported to influence the onset of Wilson disease, an inherited disorder in which excessive amounts of copper accumulate in the body. Wilson disease is caused by variants in the ATP7B gene, but studies suggest that symptoms of Wilson disease begin several years later in people who have Met/Met at position 129 in PrP compared with those who have Met/Val or Val/Val. Other research findings indicate that this polymorphism may also affect the type of symptoms that develop in people with Wilson disease. Having Met/Met at position 129 appears to be associated with an increased occurrence of symptoms that affect the nervous system, particularly tremors.

Other disorders

The Met129Val variation has been associated with differences in performance on long-term memory tasks among healthy young adults. In one study, people who had either Met/Met or Met/Val at position 129 performed better at long-term memory tasks than those who had Val/Val. It is unclear how these differences may be related to memory.

Other Names for This Gene

• AltPrP
• ASCR
• CD230 antigen
• CJD
• GSS
• MGC26679
• PRIO_HUMAN
• prion protein (p27-30) (Creutzfeldt-Jakob disease, Gerstmann-Strausler-Scheinker syndrome, fatal familial insomnia)
• PRIP
• PrP
• PrP27-30
• PrP33-35C
• PrPc
• PrPSc

Genomic Location

Scientists at NIAID’s Rocky Mountain Laboratories (RML) in Hamilton, Montana, have studied prion diseases since the 1960s when Dr. William Hadlow spearheaded work on the sheep brain disease known as scrapie, which was later shown to be a prion disease. RML is one of the world's premier laboratories for studying prion diseases. Primary to their mission is understanding how abnormal prion protein cause disease at the molecular, biochemical, cellular, and animal-model levels.

NIAID scientists at RML are studying how cells in the nervous system interact with prion protein and whether those interactions affect disease progression. These studies have shown how prions move through the brain and how cells in the brain called microglia help slow down disease.

Other studies at RML have looked at different types of CJD in human tissue and how different types of CJD may occur. These studies have shown how human prions interact with cells. They have also shown that prions derived from slightly different forms of the prion protein gene can influence how prions accumulate in the brain.

NIAID scientists at RML also have shown that, in response to damage to the brain, normal prion protein acquires properties similar to those of infectious prion protein. These studies show that prion protein, like the tau protein in chronic traumatic encephalopathy (CTE), acts abnormally following brain injury. They also suggest that damage to the brain might be a way in which CJD infection starts in some people.

RML chronic wasting disease studies have focused on whether infectious prions can cross species from cervids, like deer and elk, into people. During research that took 13 years of observation, NIAID scientists published a series of studies, the latest in 2018, showing that CWD from deer or elk does not cause disease in prion models that are susceptible to infection by human prions. These studies reinforce the belief that a strong barrier to CWD infection exists between cervids and people.

Studies of prion disease infection of cerebral organoid (“minibrain”) cultures in incubators began at RML in 2017. These studies could provide a new model for scientists to study how prion diseases affect the human brain. Cerebral organoids are small balls of human brain cells – developed from skin stem cells – that range in size from a poppy seed to a small pea. Their organization, structure, and electrical signaling mimic some aspects of brain tissue.

Familial forms of prion disease are inherited in an autosomal dominant pattern, which means one copy of the altered PRNP gene in each cell is sufficient to cause the disorder. In most cases, an affected person inherits the altered gene from one affected parent. In some people, familial forms of prion disease are caused by a new mutation in the gene that occurs during the formation of a parent's reproductive cells (eggs or sperm) or in early embryonic development. Although such people do not have an affected parent, they can pass the genetic change to their children.

The sporadic, acquired, and iatrogenic forms of prion disease, including kuru and variant Creutzfeldt-Jakob disease, are not inherited.

Prion diseases are a group of rare, fatal brain diseases that affect animals and humans. They are caused by normally harmless proteins that become abnormal and form clumps in the brain. One form, called variant CJD (vCJD), is associated with eating meat from cattle infected with bovine spongiform encephalopathy, commonly known as “mad cow” disease.

People may have vCJD for years before symptoms—such as depression, hallucinations, moving difficulties, and dementia—appear. These “silent” carriers have small amounts of prions in their bloodstreams and can transmit the disease to others via blood transfusions. The only current method to diagnose vCJD is to perform a biopsy or a postmortem analysis of brain tissue. Thus, a noninvasive test to detect prions in blood is a medical priority.

Two research groups recently developed blood tests to detect prions. The results appeared in a pair of papers published on December 21, 2016, in Science Translational Medicine. One of the groups, led by Dr. Claudio Soto of the University of Texas Health Science Center at Houston, was funded in part by NIH’s National Institute of Allergy and Infectious Diseases (NIAID), National Institute of Neurological Disorders and Stroke (NINDS), and National Center for Advancing Translational Sciences (NCATS).

Prions are scarce in the bloodstream and difficult to measure. Both teams developed methods to amplify the prions in blood samples using a technique called protein misfolding cyclic amplification (PMCA). PMCA relies on the characteristic nature of prions to cause certain healthy proteins to clump abnormally and convert into prions.

Soto’s group first combined healthy proteins with known concentrations of infectious vCJD prions. They intermittently agitated these mixtures with sound waves. The agitation helped break the prions into smaller chunks. This increased the number of prions that could then convert healthy proteins into prions. Using this method, the scientists were able to detect more than a billion-fold dilution of prions using an anti-prion antibody.

The scientists next tested whether the technique could be used to detect prions in blood samples from 14 people with vCJD and 153 controls. The controls included healthy people as well as people with different neurological or neurodegenerative disorders, including sporadic CJD, the most common form of CJD. The assay flagged all the vCJD samples correctly.

In the second paper, a French research group described a similar approach testing a blinded panel of blood samples. That team identified 18 vCJD patients in a group of 256 samples.

“Our findings, which need to be confirmed in further studies, suggest that our method of detection could be useful for the noninvasive diagnosis of this disease in pre-symptomatic individuals,” Soto says. Early diagnosis would allow potential therapies to be tested before substantial brain damage occurred. This technique would also allow blood contaminated with prions to be detected and removed from the blood supply.

Both teams are now working to validate their methods using larger samples sizes.

―by Anita Ramanathan

Prions are abnormal forms of natural proteins. The misshapen proteins collect in brain tissue and cause cells to die, leaving sponge-like holes in the brain. Prion diseases include “mad cow” disease in cattle and Creutzfeldt-Jakob disease (CJD) in people. People can get CJD by eating infected beef, but most cases develop spontaneously. This rare disease, which affects about one in a million people, is untreatable and fatal.

CJD is hard to diagnose because taking a biopsy of the brain is impractical. Previously, Dr. Byron Caughey’s group at NIH’s National Institute of Allergy and Infectious Diseases (NIAID), with collaborators at Nagasaki University, developed a sensitive method to test brain and spinal cord fluid for the presence of prions. The technique, called real-time quaking-induced conversion (RT-QuIC), is already used in clinical settings to diagnose CJD.

Recently, Caughey and colleagues at NIAID, the University of California at San Diego, and UC San Francisco set out to use RT-QuIC to measure the distribution and levels of prions in the eye. Two other NIH components, the National Institute of Neurological Disorders and Stroke (NINDS) and the National Institute on Aging (NIA), also funded the study. Results were published on November 20, 2018, in mBio.

The investigators recruited 11 people with CJD along with six patients with other fatal diseases to serve as controls. All donated their eyes for postmortem analysis. The research team used RT-QuIC to measure prion levels in eight regions of the eye, including the retina, cornea, lens, fluid, muscle, and nerve. They found evidence for prions throughout the eyes of all 11 deceased patients but not in the six controls.

Finding prions in the eye suggests that this easily accessible tissue may be an avenue for early CJD diagnosis. It also raises questions about whether prions could be transmitted to a healthy person through clinical eye procedures if instruments or transplanted tissues have been contaminated. The findings add evidence to previous reports of disease transmission caused by prion-contaminated corneal transplants from undiagnosed CJD patients.

“By testing various components of the eye with the RT-QuIC assay, we found that prions can collect throughout the eye—including the fluid inside the eye,” Caughey says. “Our findings suggest that we may be able to develop methods of detecting prions in eye components even before symptoms develop, which may help prevent unwitting transmission of prions to others through contaminated medical instruments or through donor tissue.”

The researchers continue to assess accessible eye components or fluids that might be used for diagnostic tests. They also plan to use RT-QuIC to evaluate the eyes of patients with various brain disorders to look for the presence of other abnormal proteins, such as those involved in Parkinson’s and Alzheimer’s disease.

Treatment of prion disease in people would be greatly facilitated by early disease diagnosis. RML scientists have developed a rapid and ultra-sensitive diagnostic test for prions called the Real Time-Quaking Induced Conversion (RT-QuIC) assay. This assay uses cell-free prion protein conversion reactions to amplify otherwise undetectable levels of prions to the point where they can be easily detected. It is being used at multiple facilities throughout the world to diagnose CJD. RML scientists also are working to adapt the RT-QuIC assay to detect the proteins that cause Alzheimer’s disease, Parkinson’s disease, dementia with Lewy bodies, and other neurological diseases involving misshapen proteins.

There are no known ways to cure prion diseases but RML scientists are working to develop treatments. Using both cell-free and cell-based assays, NIAID researchers have tested thousands of compounds and identified hundreds of molecules that inhibit the formation of the abnormal form of prion protein. Further testing of the most potent of these inhibitors has revealed several that can prolong the lives of rodents if treatments begin soon after infection.

New research at RML has shown that synthetic compounds called antisense oligonucleotides (ASOs) can be targeted to stop production of normal prion protein without adverse side effects. In one study, RML scientists and colleagues found that ASOs significantly delayed the onset of prion disease in mice by preventing the production of normal prion protein. Work in this area is proceeding with NIAID scientists collaborating with other groups on human studies looking for simple routes to inject ASOs and to determine dosage and treatment schedules.

RML researchers also have identified antibodies and short synthetic protein molecules (fragments of prion protein) that can block the conversion of normal prion protein to the abnormal form. If successful, these investigations will lead to safe and effective methods to prevent prion infections as well as therapies that work in either the pre-symptomatic or symptomatic phases of disease.​

NIAID researchers at RML have discovered that a chemical called hypochlorous acid, which is used to kill bacteria and viruses, also can kill prions. Hypochlorous acid is not toxic to humans and may therefore be useful in hospitals as a disinfectant for prions.

These disorders are very rare. Although the exact prevalence of prion disease is unknown, studies suggest that this group of conditions affects about one person per million worldwide each year. Approximately 350 new cases are reported annually in the United States.