Creutzfeldt-Jakob Disease (CJD) is a rare neurodegenerative brain disease in humans. CJD is the most common human form of a group of diseases that affects humans and animals known as transmissible spongiform encephalopathies (TSE) or prion diseases. While CJD most commonly occurs without known explanation it is unique in that it can also be genetic and is transmissible. CJD is invariably fatal with no known disease-modifying treatment or cure. About 40 to 50 people die every year of CJD in Australia.
The three forms of CJD:
1. Sporadic CJD (sCJD) is a rapidly progressive disease that has no known cause but is believed to be the result of a spontaneous conformational change in the native or normal form of the prion protein. It occurs at random in about 1 to 2 people per million of the population per year and accounts for 85%–90% of all cases of prion disease.
2. Genetic Prion disease accounts for approximately 10-15% of cases and occurs due to a mutation in a gene called the prion protein gene (PRNP) that encodes the normal form of the prion protein. Mutations in PRNP can lead to familial Creutzfeldt-Jakob disease (fCJD), Gerstmann-Sträussler-Scheinker syndrome (GSS) and fatal familial insomnia (FFI). Approximately one in 50,000 people have a pathogenic PRNP mutation.
3. Acquired prion disease is very rare and includes;
Iatrogenic or medically acquired CJD which is associated with transmission via medical treatments and surgical procedures. In the mid-1970s it became evident that CJD could be transmitted from one person to another through invasive medical procedures including corneal transplants or contaminated surgical instruments. In the 1980s it was recognised that explanted material, such as extracted human pituitary hormones for fertility and short stature, dura mater grafts accidentally contaminated with prion protein, could also transmit this disease to recipients.
Kuru which is a historical prion disease that affected the Fore people of the Eastern Highlands of Papua New Guinea. Kuru was instrumental in establishing that CJD is transmissible. In the 1960’s it was realised that Kuru was transmitted through ritualistic endocannibalism. This practice was outlawed in the late 1950s with the incidence of Kuru gradually declining thereafter and is now essentially eradicated.
Variant CJD (vCJD) was first reported in 1996 following the first death of an affected individual in 1994 in the UK. Globally, there have been 232 cases, mainly in the UK, with the vast majority occurring as a result of the consumption of contaminated meat products from bovine spongiform encephalopathy (BSE) affected cattle. vCJD can also be transmitted through blood and blood products. Variant CJD is usually clinically quite different from sporadic CJD as described below. Deposits of the abnormal, misfolded form of the prion protein are often found in peripheral lympho-reticular tissues such the spleen, lymph nodes and tonsils and hence pose extra risks of transmission that do not occur with sporadic CJD.
Variant CJD is often incorrectly referred to as ‘Mad Cow Disease’ by the media.
BSE has NOT been found in Australian livestock and to date there have been no reported cases of vCJD in Australia.
CJD: The accumulation of misfolded prion protein causes neuronal dysfunction and the hallmark vacuolation (sponge-like or spongiform) changes in the brain (gray matter). Patients typically present with rapidly progressive dementia and gross motor impairment (such as unsteady gait), culminating in death on average within 4-6 months. Symptoms characteristically include cognitive decline, behavioural changes, impaired balance, lack of coordination, muscle jerking (myoclonus), weakness and spasticity. Patients are usually 50–70 years old but illness onset can be in adolescence or as late as the ninth decade.
Characteristic diagnostic test findings are: generalised period complexes on an EEG, T2 hyperintensity in the caudate/putamen and/or multiple cerebral cortical regions on brain MRI, elevated 14-3-3 and tau proteins in CSF and ability to amplify abnormal misfolded prion protein (“seeding activity”) using protein amplification techniques such as the real-time quaking-induced conformation (RT-QuIC) assay.
Variant CJD (vCJD) typically manifests a longer duration of illness (median ~14 months) and presents with psychiatric and sensory symptoms; it usually affects a much younger age group (median age at death 28 years).
Currently, there is no disease-modifying therapy or cure for any form of prion disease, including CJD. Treatment is symptomatic and supportive.
CJD is always fatal and is unfortunately distinctive because of its typically rapid clinical progression. The duration of illness can vary but approximately 80% of patients die within a year of symptom onset with a small number of patients surviving for more than two years.
FURTHER INFORMATION AND SUPPORT
Further information may be obtained from Health Departments in each Australian State.
Australian National CJD Registry (ANCJDR)
CJD Support Group Network (CJDSGN)
National CJD Infection Control guidelines
Better Health Channel
Creutzfeldt-Jakob disease International Surveillance Network
CJD International Support Alliance
Reviewed January 2020 by Professor Steven Collins, Director, ANCJDR, Dept of Medicine (RMH) and Florey Institute, The University of Melbourne, https://findanexpert.unimelb.edu.au/profile/13853-steven-collins
DISCLAIMER: The information provided is designed to support, not replace, the relationship that exists between a patient / site visitor and his / her existing health care professionals.