- Sporadic
- Sporadic CJD
- Sporadic fatal insomnia
- VPSPr
- Inherited
- Genetic CJD
- GSS
- Fatal familial insomnia
- Acquired
- Iatrogenic CJD
- Variant CJD
- Kuru
- In animals
- BSE in cattle
- Chronic wasting disease
- Scrapie in sheep
If you have been given a name for an illness and want to know what it is, find it in the list below and start there. If you have not been given a name yet, what are prion diseases is the gentler place to begin.
Pages on each disease
How do the forms differ?
They differ in how the first misfolded prion protein came to be there.
In sporadic forms it happens for reasons that are not understood. Sporadic CJD is around 85 in every 100 reported CJD cases and is the one most people are referring to when they say CJD without any other word.
In genetic forms a person has inherited a change in PRNP, the gene that carries the instructions for prion protein. Depending on which change it is, the illness is given a different name: familial or genetic CJD, fatal familial insomnia, or Gerstmann-Straussler-Scheinker disease. Inherited forms are about 5 to 15 in every 100 cases, and around 10 to 15 in every 100 by some counts. Genetics explains what a gene in a family means and who to talk to about it.
In acquired forms prions came from outside the body. Variant CJD is linked to eating beef from cattle with BSE. Iatrogenic CJD followed contact with prions during medical care, through tissue grafts, instruments or growth hormone made from human tissue before the mid 1980s. Kuru was passed on through funeral practices in one population in Papua New Guinea and has effectively ended.
Two rarer conditions, sporadic fatal insomnia and variably protease-sensitive prionopathy, sit in the same group.
How rare are they?
Classic CJD causes about 1 to 2 deaths per million people a year worldwide, which is about 500 to 600 cases a year in the United States. Most cases are in older adults, with an average age in the late 60s, and cases under 30 are very unusual.
Does the name change what happens next?
It changes some things. The tests a doctor orders, whether a genetic counsellor is involved, and what the family is told about inheritance all depend on which form it is. The care and support around the illness are much the same across the group, and care and support covers that.
Diagnosis and tests explains how doctors tell these illnesses apart, and Understand and Care is the way back to the rest of this section.
Which form someone has, and what that means for them or for relatives, is a question for the treating neurologist, and for a genetic counsellor where a gene is involved.
Explore
- Prion diseases in animalsPrion diseases also affect animals such as sheep, cattle and deer. A short introduction, with links to pages on each.
- What causes prion disease?Why prion disease happens: the three main causes in plain language, and what is and is not known about risk.
- Creutzfeldt-Jakob disease (CJD)What Creutzfeldt-Jakob disease is, the forms it takes, the symptoms it causes, how it is diagnosed and what care and research exist.
- Fatal familial insomnia (FFI)Fatal familial insomnia in plain words: what it is, the gene change behind it, how it usually begins, how it is found and who to ask about your family.
- Genetic prion diseaseGenetic prion disease explained plainly: what the gene change is, what it means for a family, and who to talk to before anything else.
- Gerstmann-Straussler-Scheinker disease (GSS)Gerstmann-Straussler-Scheinker disease in plain words: an inherited prion disease that usually starts with unsteadiness, runs slowly, and is confirmed by a gene test.
- The history of prion diseaseHow prion disease came to be understood: kuru in Papua New Guinea, the link with scrapie, the BSE years, and the discovery that a protein can carry disease.
- How common is prion disease?How common prion disease is: about 1 to 2 people in a million each year, how that breaks down by type, and why the numbers are hard to pin down exactly.
- Iatrogenic CJDIatrogenic CJD in plain words: the medical treatments that carried prions decades ago, why those routes are closed, and what current operations do not carry.
- KuruKuru in plain words: the prion disease of the Fore people of Papua New Guinea, how it spread, how it ended, and what it taught everyone else.
- Prion disease myths and factsCommon beliefs about CJD and prion disease, checked against what health authorities actually say, in plain words.
- How prion disease progressesHow prion disease usually progresses: the early changes, the middle stage, the last weeks, and the support that can be in place at each point.
- Rapidly progressive dementia and CJDWhy CJD is investigated when dementia comes on quickly, what else can cause it, and why the tests for treatable conditions are done first.
- Sporadic CJDSporadic CJD is the most common human prion disease. Plain answers on what it is, who it affects, how it is found and what care can help.
- Symptoms of prion diseaseThe symptoms of prion disease in plain words, how they usually change over time, and which of them can be treated or eased.
- Variant CJDVariant CJD in plain words: how it is linked to BSE in cattle, how rare it has become, what it looks like and who to ask.
- Variably protease-sensitive prionopathy (VPSPr)Variably protease-sensitive prionopathy in plain words: a very rare prion disease recognised in 2008, how it differs from CJD, and what is known about it.
- What are prion diseases?Prion diseases are rare brain conditions that begin when prion protein folds into the wrong shape. Plain answers on the types and who to ask.
- What is a prion?A prion is a protein folded into the wrong shape. A plain explanation of how it differs from a germ, and who to ask about your own situation.