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Creutzfeld-Jakob Disease (CJD)

Creutzfeld-Jakob Disease (CJD) is a rare form of dementia that is caused by proteins called prions that have become abnormal.  These proteins damage the brain tissue of affected people, which leads to a rapid decline in mental function.  CJD cannot be spread by casual or sexual contact with a person who has the disease.  Examples of casual contact include coughing, sneezing, hugging, kissing, shaking hands, or having contact with an environment in which the affected person has been.

There are two types of CJD - classic CJD and varient CJD.  There are three subtypes of classic CJD:

  • Sporadic:  cases occurring with no known cause.  Ninety percent of CJD cases in Canada have been sporadic, and there have been no obvious factors identified that increase the risk of getting this subtype.  It is typically found in people over the age of 50.
  • Familial or Genetic:  caused by an abnormal gene passed down in families.  Seven percent of all Canadian cases have been familial.
  • Iatrogenic:  CJD that has been passed on through certain medical procedures, particularly human pituitary hormone therapy, human dura mater grafts, and corneal grafts.  This subtype very rarely occurs in Canada - less than three percent of cases have been iatrogenic.

Variant CJD (vCJD) is primarily caused by eating beef contaminated with abnormal prion proteins.  This form of CJD is typically found in people in their late twenties, and its effects on the brain are very different from the effects observed from classic CJD.  In cattle, this illness is commonly known as Mad Cow Disease.  The majority of human cases worldwide have been identified in the United Kingdom.  Only one case has been identified in Canada, and it was determined that this case was exposed while living in the UK.

More information on both classic and variant CJD can be found on the websites below.

http://www.phac-aspc.gc.ca/hcai-iamss/cjd-mcj/cjd-eng
http://www.alzheimer.ca/english/disease/dementias-creutzfeldt


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