A fixed brain seeded amplification assay to complement neuropathological prion disease diagnosis

Area of Science:

• Neuropathology
• Neurodegenerative Diseases
• Molecular Biology

Background:

• Prion diseases involve misfolding of cellular prion protein into pathogenic prions.
• Definitive diagnosis relies on neuropathology, but some subtypes lack distinct features.
• Current prion seeding assays improve diagnosis but have limitations with rare prion disease subtypes.

Purpose of the Study:

• To develop a formalin-fixed, paraffin-embedded tissue-based prion seeding assay.
• To create a complementary diagnostic tool for prion diseases, especially uncommon subtypes.
• To enhance premortem diagnostic accuracy for prion diseases.

Main Methods:

• Optimized processing of fixed brain tissue blocks.
• Stepwise deparaffinization and homogenization of fixed tissue.
• Adapted cerebrospinal fluid (CSF) prion seeding assay using recombinant hamster prion protein substrate.

Main Results:

• Demonstrated utility of the assay in confirming prion seeding in fixed brain tissue.
• Successfully diagnosed previously misdiagnosed cases of prion protein gene mutation carriers.
• Highlighted the critical role of precise tissue sampling for assay specificity.

Conclusions:

• The developed assay serves as a valuable complementary tool for prion disease diagnosis.
• This method enhances diagnostic capabilities for rare and challenging prion disease subtypes.
• Careful tissue handling is essential for maintaining the diagnostic integrity of prion seeding assays.