Learn About Prion Disease - A Dangerous Form Of Neurodegenerative Disease

Learn About Prion Disease - A Dangerous Form Of Neurodegenerative Disease

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1. Definition Of Prion Disease

Prion disease is a rare brain disease that develops in adults, characterized by rapid and fatal degeneration of the central nervous system. These diseases are characterized by dementia and are accompanied by various neurological signs. When the first symptoms appear, these diseases progress rapidly, without remission until death. They are caused by the accumulation in the brain of a normally expressed but malformed protein - the prion protein - leading to the formation of aggregates that are harmful to neurons.

Prion Images – Browse 1,006 Stock Photos, Vectors, and Video | Adobe Stock

There are about 30 mutations to the genetic forms of prion diseases.

There are three main prion diseases in humans:
* Creutzfeldt-Jakob disease (CJD) is infectious or genetic in origin or occurs naturally without exposure to the protein.
* Fatal familial insomnia (FFI) is caused by a genetic mutation of a protein.
* Gerstmann-Straüssler-Scheinker syndrome (GSS) is a genetic disorder associated with mutations in the PNRP gene.

Causes of prion disease
The origin of this disease can be due to the following three causes: in most cases there is no specific cause, in some rare cases it is due to genetics. And some others can be transmitted in a special way: consumption of infected beef (about 200 cases reported worldwide), surgical intervention performed with contaminated instruments , contaminated blood transfusion (3 cases in the world).
Additionally, an abnormal prion protein from an individual with prion disease, regardless of its origin, is infectious and could cause disease in a healthy person.

2. Characteristics Of The 3 Main Types Of Human Prion Diseases

Creutzfeldt-Jakob disease (CJD) often begins with nonspecific disturbances, such as symptoms of depression or anxiety, followed by memory disorders. This dementia syndrome gradually comes with other symptoms such as myoclonus (muscle spasms), balance or vision disorders, tremors, epilepsy... CJD is the only human disease that can be related to: a genetic cause (prion protein gene mutation, usually the E200K mutation), an infectious cause (CJD secondary to contamination).

What Is The Incidence Of Sporadic Creutzfeldt-Jakob Disease, 53% OFF

Creutzfeldt-Jakob disease accounts for 85% of diagnoses among prion diseases.

In this case, the disease usually appears after age 60 and progresses over a period of 6 months. When the disease is genetic or infectious in origin, symptoms are often earlier and progress more slowly.

Fatal familial insomnia (FFI) is a brain disease of genetic origin, linked to a mutation (D178N, linked to codon 129 encoding methionine) that increases the likelihood of structural changes in the brain. human prion protein. The disease is characterized by sleep disorders that progress to severe insomnia, are resistant to any treatment, and are associated with autonomic dysfunction. Gradually, movement disorders and memory loss appear. The consequences of the disease are fatal after 6 to 30 months.
​Gerstmann-Straüssler-Scheinker syndrome (GSS) is also caused by a specific mutation in the gene encoding the prion protein. In its most common form, the disease usually begins around age 40, with disorders of balance and coordination. It then progresses over several years to dementia, with increasingly severe neurological disorders.

3. Prion, A Protein With Special Abilities

Prion protein (PrPC) is a protein found in many animals, including humans, and is expressed by most cells in the body (nerve cells). neurons, glial cells, enterocytes, epithelium, endothelium).
This protein is usually synthesized in a three-dimensional and well-defined, helical form: this natural cell form (symbolized as PrPC) allows it to carry out a physiological role, which varies depending on the individual. according to the type of cell in which it is found... For example, in neurons, it will participate in synaptic activity, adhesion and cell signaling.

Types of Prion Disease - CJD Foundation

PrPSc is the main cause of prion diseases.

But the protein can fold into an unusual structure called a scrapie (PrPSc), in the form of a b-sheet: this structure facilitates its aggregation and making it poorly soluble and very persistent.
PrPSc is the main causative agent of prion diseases: thanks to its particularly novel properties, it is, to date, the only infectious agent that does not contain nucleic acids, unlike conventional infectious agents such as viruses , bacteria and parasites. When PrPSc proteins come into contact with a normal protein, they impart a conformational abnormality, from which PrPScs accumulate and become harmful to the functioning of nerve cells. Infectious proteins also have the ability to spread from cell to cell and form extracellular deposits of various shapes, such as amyloid plaques.
Symptoms associated with different prion diseases will vary according to the strain of prion protein involved and its characteristics (structure, incubation period, distribution of damage at the central nervous system level), Specificity and transmission identical to normal proteins have become abnormal.

4. Disease Diagnosis Methods

Prion diseases, these are very serious diseases that have no treatment, progress very quickly and cause death. Some methods of diagnosing the disease include:

* Lumbar puncture: this test looks for indirect signs of the disease in the cerebrospinal fluid, specifically the 14-3-3 protein, which is released by cells diseased nerves.
* Electroencephalography (EEG): helps identify relatively specific brain activity disorders.
* MRI: helps highlight specific abnormalities in brain areas (basal gray nucleus, cerebral cortex).

Today, there is no specific treatment for prion disease. Medications may be prescribed to reduce or limit various symptoms of the disease.