What are other Names for this Condition? (Also known as/Synonyms)

• Acquired Creutzfeldt-Jakob Disease (Variant)
• New Variant Creutzfeldt-Jakob Disease (nvCJD)
• Variant Prion Disease

What is Variant Creutzfeldt-Jakob Disease? (Definition/Background Information)

• Variant Creutzfeldt-Jakob Disease (vCJD) is a rare, acquired form of CJD. CJD is a progressive degenerative disease of the brain that occurs following infection with certain protein types, called prions
• New Variant (or Variant) Creutzfeldt-Jakob Disease (nvCJD or vCJD) is due to the consumption of contaminated beef from cattle affected by a similar disease, called bovine spongiform encephalopathy (BSE) or mad cow disease
• Prions are infectious pathogens, but are very different from other pathogens, such as bacteria, viruses, and fungi. They are unusual, because they lack both DNA and RNA molecules. Instead, prions are normal cellular proteins that take on an abnormal configuration
• Prions are able to multiply by converting similar normal proteins in the brain into infectious abnormal forms, ultimately leading to the destruction of brain tissue. As a result, individuals with CJD develop dementia, involuntary muscle jerks (myoclonus), loss of motor coordination, and psychiatric symptoms
• There is no cure for vCJD; the treatment provided is often symptomatic. The prognosis of Creutzfeldt-Jakob Disease is usually poor
• The onset of Variant Creutzfeldt-Jakob Disease occurs at a much younger age than other forms of CJD. The average age of onset is around 25 years for vCJD; while for the other forms, typically the onset is around age 65
• Currently, there is research being done and a link between Variant Creutzfeldt-Jakob Disease and a specific amino acid combination, at one location on the gene that codes for prion proteins, has been discovered

Creutzfeldt-Jakob Disease is also known as subacute or transmissible spongiform encephalopathy. Several types of CJD exist. All types involve an abnormal form of a naturally-occurring protein in the central nervous system.

• Sporadic Creutzfeldt-Jakob Disease (sCJD) is the most common form of the disorder and accounts for approximately 85% of all cases
• Familial Creutzfeldt-Jakob Disease (fCJD) is an inherited form caused by genetic mutations on chromosome 20
• Iatrogenic Creutzfeldt-Jakob Disease (iCJD) is an unintended consequence of medical therapy

Who gets Variant Creutzfeldt-Jakob Disease? (Age and Sex Distribution)

• Creutzfeldt-Jakob Disease is found worldwide with an incidence of approximately 1 case per 1,000,000 people; Variant CJD accounts for about 1% of these cases
• Variant Creutzfeldt-Jakob Disease can affect individuals of any age, but most individuals are 50-75 years old
• New Variant or Variant Creutzfeldt-Jakob Disease caused by exposure to BSE prions develops more frequently in teenagers and younger adults with the average age being 25 years old
• Both males and females are equally affected by vCJD
• vCJD can affect individuals of any racial, ethnic, or geographical background

Most cases of vCJD have occurred in Europe thus far, but there is concern that new cases may appear worldwide in the future. This is because there is very limited information on how frequently contaminated beef enters the food chain for human consumption; a symptom-free period following transmission, may last for many years.

What are the Risk Factors for Variant Creutzfeldt-Jakob Disease? (Predisposing Factors)

The only known risk factor for Variant Creutzfeldt-Jakob Disease is exposure to infectious prions, particularly from contaminated beef. However, the rate of transmission is thought to be very low and it is difficult to detect when beef is infected with bovine spongiform encephalopathy.

The following genetic link to Variant CJD has been identified: 

• At a specific position in the prion-coding gene, similarities have been identified that are associated with many individuals who have been diagnosed with vCJD
• At this specific location on the gene, called codon 129, individuals can have one of two possible genetic variations which identify a specific amino acid for the body to produce methionine (M) or valine (V)
• Most individuals worldwide have one of two combinations of these amino acids at this location, either methionine-methionine (MM) or methionine-valine (MV), which are usually about equally common. History has shown that individuals who have the MV combination are less likely to develop Variant Creutzfeldt-Jakob Disease than individuals with MM or more rarely VV
• In an ongoing study carried out post-mortem on individuals with vCJD, it has been identified that all individuals with definitive cases of Variant Creutzfeldt-Jakob Disease have had the MM amino acid combination at codon 129 on the prion gene
• It is important to note that all forms of Creutzfeldt-Jakob Disease are not contagious via air or casual contact. Having close interactions with or living with and individual who has CJD does not increase one’s risk for developing CJD
• However, contact with spinal cord fluid or brain tissue from an infected individual can result in the development of Creutzfeldt-Jakob Disease

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Variant Creutzfeldt-Jakob Disease? (Etiology)

• Creutzfeldt-Jakob Disease can be caused by transmission of prions from the consumption of contaminated beef
• The abnormally formed prions ingested from the beef first invade the lymphatic system of the individual. The prions then move from the nerves in the abdominal area to the brain and spinal cord
• The period during which the mutated form of the prion protein is acting in the brain and body without signs or symptoms is called the incubation period. The length of this phase depends on genetic factors
• The abnormal prion proteins are able to recruit more mutated forms of the protein in the brain and convert normal prion proteins into the misshapen form. Accumulation of these abnormally shaped prion proteins in the brain are what cause CJD and the associated dementia symptoms
• The abnormal form of prion proteins are not able to be broken down by enzymes, like the normal type. The standard function of normal prion proteins in the brain is relatively unclear, but it is believed that they play a role in the transmission of signals between brain cells  

What are the Signs and Symptoms of Variant Creutzfeldt-Jakob Disease?

The signs and symptoms of Variant Creutzfeldt-Jakob Disease may include:

• Some individuals may initially experience fatigue, sleep disturbances, hallucinations, weight loss, headaches, and pain
• The initial symptoms in most individuals are mainly cognitive and include memory loss, confusion, and impaired judgment
• Some have vision, speech, or gait disturbances
• Other possible symptoms include rigidity, uncontrollable limb movements, poor coordination, and seizures
• Sudden, loud noises or bright light may trigger myoclonus (involuntary twitching of muscles). This may also occur during sleep
• Depression and sensory disturbances are common in vCJD
• In all cases, the symptoms progress to profound dementia

How is Variant Creutzfeldt-Jakob Disease Diagnosed?

A diagnosis of Variant Creutzfeldt-Jakob Disease is difficult and may not be made until an autopsy is carried out. The indications and criteria for diagnosing vCJD may involve:

• Complete medical history evaluation to help rule out the potential of other forms of CJD and a thorough physical examination; a positive family history may help diagnose CJD in a minority of cases
• Symptoms of dementia, myoclonus, and an abnormal EEG differ from the typical peaks seen in common or sporadic CJD
• At the onset of the disease, psychiatric symptoms are observed along with persistent painful sensory complications
• Brain MRI may be helpful in diagnosing vCJD
• CJD may be confirmed by brain tissue biopsy and assays that detect abnormal prion proteins. If a biopsy is negative, the diagnosis of CJD may not be ruled out, because prion proteins may be absent from a small tissue sample. In such cases, a final diagnosis cannot be made until autopsy

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Variant Creutzfeldt-Jakob Disease?

The complications of Variant Creutzfeldt-Jakob Disease may include:

• Development of pneumonia during the later stages of the disease which is often fatal
• Severe dementia may cause significant stress and social issues for the individual with Creutzfeldt-Jakob Disease, as well as on their caretakers

How is Variant Creutzfeldt-Jakob Disease Treated?

There are currently no effective treatments available for Variant Creutzfeldt-Jakob Disease.

• Quinacrine has shown to slow the rate of decline in some patients
• The affected individuals receive supportive care and may be given medications to control myoclonus and pain, if present
• Treatments in development for CJD include the use of antibodies against prions and several drugs with potential therapeutic efficacy

How can Variant Creutzfeldt-Jakob Disease be Prevented?

Variant Creutzfeldt-Jakob Disease is difficult to prevent, but the best way to avoid developing vCJD is to avoid the possibility of consuming contaminated beef. 

• This can be also minimized by avoiding travel to areas where bovine spongiform encephalopathy or mad cow disease is prevalent
• On the other hand, certain forms of Creutzfeldt-Jakob Disease may be transmitted to others while not exercising due care when handling infected brain tissue
• For example, prions may be transmitted to healthcare workers through accidental needle sticks or stab wounds
• It is very important to sterilize by autoclave, any equipment that has had contact with brain tissue from patients with CJD

What is the Prognosis for Variant Creutzfeldt-Jakob Disease? (Outcomes/Resolutions)

• There is a highly variable incubation period in Creutzfeldt-Jakob Disease, following the transmission of prions. Symptoms have been observed in as few as 1-2 years, or after as many as 30 years, especially in the case of nvCJD
• Individuals diagnosed with CJD may live 3 months to 5 years following onset of symptoms. However with CJD, in a majority of cases, death usually results in less than 1 year
• 5-10% of the patients survive more than 2 years.  Patients with fCJD tend to live longer than those with sCJD

Additional and Relevant Useful Information for Variant Creutzfeldt-Jakob Disease:

There are voluntary organizations and support groups that provide counsel, help, and understanding to the individuals and families affected by Creutzfeldt-Jakob Disease.