Alternative Names
Inherited Human Transmissible Spongiform Encephalopathies; Prion-associated disorders; Prion-Induced Disorders; Prion Protein Diseases; Transmissible Dementias; Transmissible Spongiform Encephalopathie; TSEs
Symptoms & Characteristics
Prion diseases belong to group of progressive conditions that affect the nervous system in humans and animals. In people, prion diseases impair brain function, causing memory changes, personality changes, a decline in intellectual function (dementia), and problems with movement that worsen over time. The signs and symptoms of these conditions typically begin in adulthood, and these disorders lead to death within a few months to several years.
Familial prion diseases of humans include classic Creutzfeldt-Jakob disease (CJD), Gerstmann-Sträussler-Scheinker syndrome (GSS), and fatal insomnia (FI). These conditions form a spectrum of diseases with overlapping signs and symptoms.
Treatment
The management and treatment of prion diseases depend on the specific symptoms. Early diagnosis, routine surveillance and treatment may help to manage some of the symptoms and sometimes prevent related problems.
How Common Is It?
Prion diseases are very rare. They affect about one person per million worldwide each year. Approximately 300 cases occur annually in the United States.
Genetics & Inheritance
Most cases of prion disease are sporadic, which means they occur in people without any known risk factors or gene mutations.
Rarely, prion diseases can be transmitted by accidental exposure to prion-contaminated tissues during a medical procedure. This type of prion disease is called iatrogenic. One type of prion disease in humans, variant Creutzfeldt-Jakob disease (vCJD), is acquired by eating beef products obtained 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 tribe in Papua New Guinea. The disorder was transmitted when tribe members ate the tissue of affected people during cannibalistic funeral rituals.
The sporadic, iatrogenic, and acquired forms of prion disease, including kuru and variant Creutzfeldt-Jakob disease, are not inherited.
Only a small percentage of prion disease cases run in families. Familial forms of prion disease are caused by inherited mutations in the PRNP gene.
Familial forms of prion disease are inherited in an autosomal dominant pattern, which means one copy of the altered 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 PRNP gene. Although such people most likely do not have an affected parent, they can pass the genetic change to their children.
Genetic Testing
Clinical genetic testing for the familial forms of prion disease may be available through an in person genetic consultation for people who are considered at risk. Use our find a genetic professional directory to locate a trained genetic professional in your area.
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