Prion Diseases: Understanding the Deadliest Neurodegenerative Disorders

Prion diseases (transmissible spongiform encephalopathies) are rare, fatal neurodegenerative disorders caused by misfolded prion proteins (PrP^Sc) that template conversion of normal cellular prion protein (PrP^C), leading to neuronal loss, spongiform change, and gliosis.

Human Prion Diseases

• Creutzfeldt-Jakob disease (CJD): Sporadic (85%), genetic (10–15%), acquired (<1%). Rapid dementia, myoclonus, ataxia; death usually within months.
• Variant CJD (vCJD): Linked to BSE-contaminated beef. Younger onset, psychiatric symptoms prominent.
• Gerstmann-Sträussler-Scheinker (GSS): Genetic, ataxia-predominant, longer course.
• Fatal Familial Insomnia (FFI): Genetic, severe insomnia, autonomic dysfunction, thalamic degeneration.
• Kuru: Historically from ritualistic cannibalism; now virtually extinct.

Transmission & Resistance

Prions resist standard sterilization (heat, radiation, formalin). Iatrogenic transmission occurred via contaminated neurosurgical instruments, dura mater grafts, cadaveric growth hormone, and corneal transplants. Blood transfusion transmission documented for vCJD.

Diagnosis & Management

Diagnosis relies on clinical syndrome, MRI (cortical ribboning, basal ganglia hyperintensity), EEG (periodic sharp waves in sCJD), CSF RT-QuIC (highly sensitive/specific), and genetic testing. No disease-modifying treatment exists. Care is palliative: symptom control, advance directives, infection control precautions.

Key Takeaway

Prion diseases are uniformly fatal, untreatable, and pose unique infection-control challenges due to prion resistance.