Table 1 Abbreviations used throughout

PrP^Sc

The abnormal, disease-associated form (generically termed the scrapie isoform, irrespective of the disease and species in which it occurs) which is characterised by increased β-pleated sheet content, decreased solubility and increased protease-resistance compared with PrP^C as a result of refolding of the protein and self-aggregation.

PrP^C

Normal form of the prion protein as expressed in the central nervous system and other tissues.

PrP^res

Protease resistant core of PrP^Sc detected by western blotting following treatment with 50 μg/ml PK.

~8 kDa PrP^res fragment

Low molecular mass PrP^res fragment of ~8 kDa detected by western blotting following treatment with 50 μg/ml PK in brain tissue from patients with VPSPr and some patients with GSS.

senPrP^Sc

The component of PrP^Sc that is poorly resistant to protease treatment (i.e. >2.5 μg/ml PK)

CDI

Conformation dependent immunoassay

GSS

Gerstmann-Sträussler-Scheinker syndrome

GSS (~8 kDa PrP^res)

GSS case associated with a low molecular mass fragment of PrP^res of approximately ~8 kDa when analysed by western blotting following proteinase K digestion.

GSS (type 1 PrP^res)

GSS case characterised by the presence of 20-30 kDa type 1 PrP^res fragments in brain when analysed by western blotting following proteinase K digestion.