Creutzfeldt-Jakob disease (Mad cow disease)

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Risk factors

By Mayo Clinic staff

Most cases of Creutzfeldt-Jakob disease occur for unknown reasons and no risk factors can be identified. However, a few factors seem to be associated with different kinds of CJD.

  • Age. Sporadic CJD tends to develop later in life, usually around the age of 60. Onset of familial CJD occurs only slightly earlier. On the other hand, vCJD has affected people at a much younger age, usually in their late 20s. This suggests that older adults may not be as susceptible to vCJD as children and young adults are.
  • Genetics. People with familial CJD have a genetic mutation that causes the disease. The disease is inherited in an autosomal dominant fashion, which means you only need to inherit one copy of the mutated gene, from either parent, to develop the disease. If you have the mutation, the chance of passing it on to your children is 50 percent.

    Genetic analysis in people with iatrogenic and variant CJD suggest that inheriting identical copies of certain variants of the prion gene may predispose a person to developing CJD if exposed to contaminated tissue.

  • Exposure to contaminated tissue. People who've received human growth hormone derived from human pituitary glands or who've had dura mater grafts may be at risk of iatrogenic CJD.

    The risk of contracting vCJD from eating contaminated beef is difficult to determine. In general, if countries are effectively implementing public health measures, the risk is very low. For example, in the United Kingdom the current estimated risk of acquiring vCJD from beef and beef products appears to be about one case per 10 billion servings. The risk from beef in other high-incidence countries is estimated to be very low, as well.

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July 31, 2008

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