Creutzfeldt-Jakob Disease (CJD) is a rare form of progressive dementia characterized by degeneration and loss of nerve cells leading to the production of microscopic holes in the brain.

How does Creutzfeldt-Jakob Disease affect the person?

CJD usually has rapid onset and decline. Early symptoms may include lapses in memory, mood swings similar to depression, lack of interest and social withdrawal. The person may become unsteady on his/her feet. Later symptoms may include blurred vision, sudden jerking movements and rigidity in the limbs. The person may experience slurred speech and have difficulty swallowing. Eventually, movement and speech are lost.

Who gets Creutzfeldt-Jakob Disease?

Both men and women can be affected by CJD. The usual age of onset is 45-75 years. In Canada, all cases of CJD are reported to the National CJD Surveillance Unit in Ottawa, which has been gathering information on the disease since 1997.

What are the types of Creutzfeldt-Jakob Disease?

There are four forms of the disease:

•  Sporadic CJD
  
  "Sporadic" means occurring here and there in the general population. There are no obvious risk factors. Sporadic CJD is the most common form, 85-90 per cent of all cases. The cause of transmission is unknown. The incidence of sporadic CJD in Canada is around one per million, or 30 new cases every year.¹
  
  
•  Familial CJD.
  "Familial" means occurring in families; some families have a mutation in the prion protein gene (PrP gene). Familial CJD accounts for 15 per cent of all cases of CJD.It has an early onset, around age 52. Other mutations of the PrP gene have been identified and are associated with two, rare brain diseases which resemble familial CJD. These are Gertsmann-Straussler-Scheiner disease (GSS) and fatal familial insomnia (FFI). GSS usually starts with unsteadiness in walking and progresses to dementia. The main symptom of FFI is a progressive and untreatable form of insomnia.

•  Transmissible CJD.
  This form (also known as "iatrogenic CJD") is caused by direct contact with infected tissue from someone with the disease. This form is the rarest, 1 per cent of all cases. Transmission of CJD has occurred from certain medical procedures such as brain operations performed with instruments which were previously used on someone with CJD, corneal transplants, and grafts of dura mater, the membrane that covers the brain and is used in various kinds of surgery. CJD has also been transmitted by human growth hormone prepared from human pituitary glands. Today the growth hormone is made synthetically, greatly reducing the risk of this type of CJD. Presently, researchers are unsure of the role of blood transfusions in the transmission of the disease, but the consensus is that it represents a theoretical risk.
  
  
•  Variant CJD.
  

  "Variant" CJD is linked to eating contaminated beef products. Variant CJD was first diagnosed in the United Kingdom in 1996. It is believed to be caused by exposure to contaminated meat from cattle suffering from Bovine Spongiform Encephalopathy (BSE or "Mad Cow" disease). The age of onset has been in the range of 12 to 74 years of age.

How is Creutzfeldt-Jakob Disease transmitted?

CJD is unique because it can be inherited or transmitted. The infectious agent is believed to be an abnormal form of the prion protein (PrP). However, CJD is not infectious in the usual way -- like colds or flu, or by skin contact. It is transmitted only through contact with, or dietary exposure to, CJD brain matter. There are no special risks in caring for a person with CJD. The agent has been compared to a "slow virus" because there is a long incubation period (1-30 years) before signs of the disease appear. Once symptoms are visible, decline is usually rapid. Depending upon the type of CJD, the length of the illness is usually a year but can range from months to several years after onset.

Is there a treatment for Creutzfeldt-Jakob Disease?

Currently, there is no way to slow the progression of the disease. Some medications can help relieve jerking movements and unsteadiness.

For more information:

•  Creutzfeldt-Jakob Disease. Alzheimer Canada
•  BSE Fact Sheet. Canadian Food Inspection Agency
•  Bovine Spongiform Encephalopathy. World Health Organization
•  Creutzfeldt-Jacob Disease. General Health Encyclopedia
•  Creutzfeldt-Jakob disease. Mayo Clinic
•  Creutzfeldt-Jakob Disease. Memory & Aging Center, University of California, San Francisco
•  CJD: a matter of life and death. Time Europe
•  CJD Directory. Alzheimer's Outreach
•  Creutzfeldt-Jakob. CRIS
•  Creutzfeldt-Jakob Disease. Medical Encyclopedia. Medlineplus Health Information
•  Creutzfeldt-Jakob Disease Foundation
•  CJD Support Network
•  Creutzfeldt-Jakob Disease Surveillance System. Health Canada
•  Creutzfeldt-Jakob Disease Surveillance Unit (UK)
•  CJD Voice
•  CJD Watch includes information in English, French, Spanish, Swedish
•  Extended European Collaborative Study Group of CJD (NEUROCJD)
•  NINDS Creutzfeldt-Jakob Disease Information Page. National Institute of Neurological Disorders and Stroke
•  Official Mad Cow Disease Home Page. Sperling Biomedical Foundation
•  Variant Creutzfeldt-Jakob Disease. World Health Organization
•  What is Creutzfeldt-Jacob Disease? Alzheimer's Society (UK)

(1) Canadian Statistics and Incidence of CJD Cases: www.phac-aspc.gc.ca/hcai-iamss/cjdss-ssmcj/stats_ehtml#canada.

The contents of this document are provided for information purposes only, and do not represent advice, an endorsement or a recommendation, with respect to any product, service or enterprise, and/or the claims and properties thereof, by the Alzheimer Society of Canada. The Information Sheet is not intended to replace clinical diagnosis by a health professional.

Source: May 2005 - Research- Related Dementia - Creutzfeldt-Jakob Disease - Alzheimer Society of Canada.