The Generative Brain

Skin punch biopsy RT-QuIC

RT-QuIC on a skin punch biopsy detects prion seeding with about 89 percent sensitivity in one 71-sample series; sensitivity varies by strain and sampling site and a multisite study found it more accurate than CSF. It is investigational and offered by few laboratories.

Key facts

  • 89 percent sensitivity and 100 percent specificity in 71 biopsies from 35 CJD patients; activity varies by strain (higher in V2 types).
  • Combining two or three skin sites outperformed CSF alone; all sites at three dilutions reached 95.0 percent sensitivity (96 of 101).
  • Limits: Strain-dependent sensitivity; not yet shown to predict onset in healthy carriers.
  • What it asks of the person: Skin punch biopsy (less invasive than lumbar puncture).
  • A skin punch biopsy study (71 samples from 35 patients) confirmed skin prion RT-QuIC has about 89 percent sensitivity for CJD, higher in sporadic subtypes with more peripheral PrPSc.
  • Samples in the multisite approach were taken from the distal leg, distal thigh and posterior cervical (C7) region, and the review states multisite skin RT-QuIC was significantly more accurate than CSF for prion disease diagnosis in the study it cites.
  • The review notes skin biopsy is more accessible than brain PET or CSF sampling and is being extended to tau and alpha-synuclein seed assays.
  • A 2022 review frames peripheral-tissue RT-QuIC as a route to earlier and even preclinical diagnosis in people at genetic risk, who will likely be the main population in future trials.

Timeline

  1. 2020Skin punch biopsy RT-QuIC series published.
  2. 2022Review of RT-QuIC in human prion disease published.
  3. 2025Review of skin biopsy for protein misfolding diseases published.
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