Prion diseases: causes, biological mechanisms, symptoms, diagnosis and treatment

Prion diseases are a group of rare diseases that lead to fatal degeneration of the central nervous system, caused by pathological aggregation of the prion protein. Between 100 and 150 cases are diagnosed every year in France. Creutzfeldt-Jakob disease (CJD) is the most common form of prion disease in humans, accounting for 85% of diagnosed cases. There are currently no treatments for these diseases.
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THE CAUSES AND BIOLOGICAL MECHANISMS OF PRION DISEASES

Prion diseases are neurodegenerative diseases in which a malformed protein, the prion protein, accumulates in neurons and leads to their death. The characteristic feature of prion protein pathologies is that they alter the conformation of surrounding prion proteins. They then spread from one neuron to another.

 

SYMPTOMS AND DIAGNOSIS OF PRION DISEASES

Prion diseases such as Creutzfeldt-Jakob disease are characterised by dementia associated with various neurological disorders such as impaired vision, movement or balance. There are three forms of Creutzfeldt-Jakob disease (CJD): sporadic, in which the origin is unknown; hereditary, due to a mutation in the prion protein gene; and acquired, such as the variant form of CJD linked to the ingestion of bovine by-products contaminated with an abnormal prion protein.

Creutzfeldt-Jakob disease can only be formally diagnosed once the patient has died, by examining characteristic brain lesions. It can therefore only be made on the basis of the patient’s clinical signs. In the case of genetic forms, blood samples can be taken to search for mutations.

 

TREATMENTS FOR PRION DISEASES

There are no treatments for prion diseases. Symptomatic treatments may be offered. Medical, psychological and social care is essential.

 

Last updated May 2024.