NINDS Transmissible Spongiform Encephalopathies Information Page: NINDS
Article title: NINDS Transmissible Spongiform Encephalopathies Information Page: NINDS
Main condition: Transmissible Spongiform Encephalopathies
Conditions: Transmissible Spongiform Encephalopathies
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. It is a rare type of dementia that affects about one in every one million people each year. Other human TSEs include kuru, fatal familial insomnia (FFI), and Gerstmann-Straussler-Scheinker disease (GSS). Kuru was identified in people of an isolated tribe in Papua New Guinea and has now almost disappeared. FFI and GSS are extremely rare hereditary diseases, found in just a few families around the world. A new type of CJD, called variant CJD (vCJD), was first described in 1996 and has been found in Great Britain and several other European countries. The initial symptoms of vCJD are different from those of classic CJD and the disorder typically occurs in younger patients. 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; and 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 (prion is 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. The harmless and infectious forms of the prion protein are nearly identical, but the infectious form takes on a different folded shape from the normal protein.
Human TSEs can occur three ways: sporadically; as hereditary diseases; or through transmission from infected individuals. 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. 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. 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, and/or an unsteady gait. Patients 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.
Is there any
treatment?
TSEs tend to progress rapidly and usually culminate in
death over the course of a few months to a few years.
What is the
prognosis?
There is currently no treatment that can halt
progression of any of the TSEs. Treatment is aimed at alleviating symptoms
and making the patient as comfortable as possible. A clinical trial of a
potential therapy for CJD is expected to begin soon at the University of
California at San Francisco.
What research is being
done?
The NINDS conducts and supports research on TSEs. This
research is aimed at determining how abnormal prion proteins lead to
disease, at finding better tests for diagnosing CJD and other disorders,
and ultimately at finding ways to treat TSEs.
Creutzfeldt-Jakob (CJD) Foundation Inc.
P.O. Box 611625
No. Miami, FL 33261-1625
crjakob@aol.com
http://cjdfoundation.org/
Tel:
954-704-0519 305-891-7579
Fax: 305-893-9050/954-436-7591 305-893-9050
Centers for Disease Control and Prevention (CDCP)
1600
Clifton Road, N.E.
Atlanta, GA 30333
inquiry@cdc.gov
http://www.cdc.gov/
Tel: 800-311-3435
Food and Drug Administration (FDA)
5600 Fishers Lane
CDER-HFD-210
Rockville, MD 20857
http://www.fda.gov/
Tel: 301-827-4573
888-INFO-FDA (463-6332)
National Organization for Rare Disorders (NORD)
P.O. Box 8923
(100 Route 37)
New Fairfield, CT 06812-8923
orphan@rarediseases.org
http://www.rarediseases.org/
Tel:
203-746-6518 800-999-NORD (6673)
Fax: 203-746-6481
Related NINDS Publications and Information
Creutzfeldt-Jakob Disease (CJD) information sheet
compiled by the National Institute of Neurological Disorders and Stroke
(NINDS).
Creutzfeldt-Jakob Disease (CJD) fact sheet
compiled by the National Institute of Neurological Disorders and Stroke
(NINDS).
Información de
La Enfermedad de Creutzfeldt-Jakob/Spanish-language fact sheet on
Creutzfeldt-Jakob disease compiled by the National Institute of
Neurological Disorders and Stroke (NINDS).
Creutzfeldt-Jakob disease information for
healthcare workers and morticians, compiled by the National Institute of
Neurological Disorders and Stroke (NINDS).
Congressional testimony on
transmissible spongiform encephalopathies (TSEs), April 4, 2001.
Kuru information sheet
compiled by the National Institute of Neurological Disorders and Stroke
(NINDS).
This fact sheet is in the public domain. You may copy it.Provided
by:
The National Institute of Neurological Disorders and Stroke
National Institutes of Health
Bethesda, MD
20892
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