Prion disease has its own vocabulary. This page gives a short definition of each main term and links to the full entry. Terms are listed in the order they are usually met, starting with the protein itself.
What do the basic terms mean?
Prion. A misfolded protein that can make normal copies of the same protein misfold too. Prions cause prion diseases, including Creutzfeldt-Jakob disease (CJD).
PrP. The prion protein. Every person makes normal PrP. Prion disease begins when it misfolds and builds up in the brain.
PRNP. The gene that holds the instructions for making PrP. A change in this gene causes genetic prion disease.
What do the genetic terms mean?
Penetrance. The share of people carrying a gene change who go on to develop the condition. It varies between changes and between families, and a genetic counsellor can explain it.
Codon 129. A position in the PRNP gene where people carry one of two variants, methionine or valine. It can influence how prion disease appears.
What do the test terms mean?
RT-QuIC. Real-time quaking-induced conversion. A laboratory test that detects misfolded prion protein in a sample such as spinal fluid by amplifying it.
PMCA. Protein misfolding cyclic amplification. A laboratory method that also amplifies misfolded prion protein, used in research and in studies of blood and urine.
Details of these and other tests are on Tests and assays.
What do the research terms mean?
Surrogate endpoint. A measurement used in a trial in place of a direct measure of how a person feels or how long they live. Regulators decide whether a given measurement is accepted.
Antisense oligonucleotide. A short strand of genetic material designed to lower the amount of a protein by acting on its messenger RNA. Some prion therapies in trials use this approach. See Therapies in development.
How are the forms of CJD described?
Sporadic CJD is the most common form and has no known cause. Genetic or familial forms are linked to a PRNP change and include familial CJD, fatal familial insomnia and Gerstmann-Straussler-Scheinker disease. Acquired forms include iatrogenic CJD, spread through certain medical procedures, and variant CJD, linked to beef contaminated with bovine spongiform encephalopathy (BSE).
Where can I read more?
Organizations lists the groups that work on these topics, and Funding programs lists who pays for research. The Atlas home has the other sections.