Creutzfeldt-Jakob Disease: Could it Be Genetic?

When CJD strikes, it’s time for genetic counseling
Medical illustration of damaged brain

Peek inside a brain afflicted with Creutzfeldt-Jakob Disease (CJD) and you’ll see a sponge-like appearance due to damaged brain tissue caused by the disease. Though rare, the disease causes dementia-like symptoms that progress very quickly with little time for treatment.

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Experts say when the genetic form of CJD occurs in a family, family members should seek genetic counseling and consider being tested to see if they carry the mutated gene.

Rare and often misdiagnosed

“CJD is commonly misdiagnosed,” says neuropsychiatrist Brian Appleby, MD, who specializes in CJD and other related conditions known as prion diseases. “It’s often diagnosed as another neuro-degenerative illness like Alzheimer’s or Parkinson’s disease, a tumor-related condition, or a psychiatric disorder.”

At first, CJD can cause symptoms similar to those caused by Alzheimer’s disease and other dementias. But CJD is quite different in how it progresses rapidly and the inclusion of other associated symptoms, including:

  • Jerky limbs (e.g., myoclonus)
  • Uncoordinated gait
  • Clumsy hands
  • Problems perceiving things visually

Fast onset, rapid decline

The average survival time is four to six months from the time people notice initial symptoms. Also, there’s no known cause for CJD in most patients. But in 10 to 15 percent of cases, the disease is genetic, caused by a mutation to what’s known as the prion protein gene, or PRNP.

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About 300-400 cases of prion disease are diagnosed in the United States each year. It’s rare enough that many doctors miss the signs, delaying diagnosis of an already rapidly progressing disease.

Tough to diagnose

Making the right diagnosis is made more difficult by the fact that there’s no definitive test for CJD outside of examining the brain tissue itself underneath a microscope (e.g., biopsy or autopsy). Doctors can use brain MRIs, EEGs and spinal fluid tests to narrow down a diagnosis, but results that point to CJD can also be markers for other conditions.

The only way to be sure of a CJD diagnosis is through autopsy after the patient’s death. Genetic testing can be done at the time of the autopsy or by a blood test when the patient is still living.

Family connections

After a genetic CJD diagnosis, the patient’s family members can participate in genetic counseling and get a blood test to determine whether they have inherited the mutated PRNP gene.

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“If you have a gene mutation and you live long enough, there is a high likelihood that you will get the illness with most mutations,” says Dr. Appleby. Genetic CJD typically strikes in mid-life, between ages 40 and 70.

There are currently no recommended or approved treatments for CJD, regardless of whether its cause is genetic.

“After diagnosis, we can offer palliative care working closely with hospice,” says Dr. Appleby. We also offer symptomatic treatment, education to the family and healthcare providers, and referral to patient advocacy organizations such as the CJD Foundation

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