Neurodegenerative diseases affect the nerve cells of the body. These conditions result in the damage and death of nerve cells, which leads to movement and/or mental dysfunction. Prion diseases, also called transmissible spongiform encephalopathies, are neurodegenerative conditions characterized by an accumulation of abnormal prion proteins (PrPs).
PrPs are found in normal brain cells. When PrPs fold abnormally, they clump and accumulate in the brain. Abnormal PrPs lead to brain damage that manifests as movement difficulties, behavior changes, and memory problems.
Prion diseases, categorized as infectious diseases, can affect humans and animals. The diseases can be acquired through contaminated meat or medical equipment or inherited as a result of genetic mutations. Some cases of prion disease are sporadic and have no known cause. Although they are rare, prion diseases are considered fatal due to the lack of an effective treatment.
Prion diseases are divided into human and animal subtypes. The most common human prion disease is Creutzfeldt-Jakob disease (CJD). Other human subtypes include variant Gerstmann-Sträussler-Scheinker disease, fatal familial insomnia, and kuru. Animal prion diseases include bovine spongiform encephalopathy, chronic wasting disease, and scrapie.
Symptom onset may take many years, but once symptoms develop, they follow a rapid course. Patients with prion diseases experience physical symptoms such as muscle stiffness, slurred speech, and loss of coordination. Mentally, patients develop dementia accompanied by personality changes and confusion.
Diagnosing prion disease can be difficult. To conclusively confirm the diagnosis, physicians typically examine a biopsy sample from the patient’s brain, often after death. Nevertheless, various tests can facilitate the diagnosis. For example, a lumbar puncture obtains a sample of cerebrospinal fluid (CSF). CSF testing can identify specific biomarkers associated with prion disease. Additionally, brain changes can be seen with magnetic resonance imaging (MRI) tests.
Since there is no cure for prion disease, most patients receive supportive treatment. Physicians may prescribe medications to manage pain and muscle spasms. Unfortunately, the disease progresses into a debilitating condition; patients eventually require assistance with daily activities.
Recent research has demonstrated key points about the development and possible treatment of prion disease. In 2017, the Journal of Immunology published a study that identified complement regulatory protein factor H (fH) as a prion receptor that contributes to the accumulation of abnormal PrP in the brains of infected mice. The study offered insight into the interaction of PrP with the immune system.
Scientists are still working on a treatment for prion disease. A research team at the University of Texas Mitchell Center for Alzheimer’s Disease and Related Brain Disorders published a study proposing a potential therapy for prion disease in 2017. Named anti-prion, the treatment comprises a designed PrP similar in form to the abnormal PrP. The anti-prion competes with the disease-causing PrP, reducing the replication of the disease-causing PrP and overall disease development.
In 2021, researchers at Imperial College London and the University of Zurich conducted a study that detected a critical location on mutant PrP where the abnormal folding process begins. They targeted this spot with antibodies that halted the abnormal folding, providing a potential treatment for prion disease.
