Cervid Prion Protein Polymorphisms: Role in Chronic Wasting Disease Pathogenesis

Chronic wasting disease (CWD) is a prion disease found in both free-ranging and farmed cervids. Susceptibility of these animals to CWD is governed by various exogenous and endogenous factors. Past studies have demonstrated that polymorphisms within the prion protein (PrP) sequence itself affect an animal's susceptibility to CWD. PrP polymorphisms can modulate CWD pathogenesis in two ways: the ability of the endogenous prion protein (PrP(R)) to convert into infectious prions (PrPSc) or it can give rise to novel prion strains. In vivo studies in susceptible cervids, complemented by studies in transgenic mice expressing the corresponding cervid PrP sequence, show that each polymorphism has distinct effects on both PrP(R) and PrPSc. It is not entirely clear how these polymorphisms are responsible for these effects, but in vitro studies suggest they play a role in modifying PrP epitopes crucial for PrP(R) to PrPSc conversion and determining PrP(R) stability. PrP polymorphisms are unique to one or two cervid species and most confer a certain degree of reduced susceptibility to CWD. However, to date, there are no reports of polymorphic cervid PrP alleles providing absolute resistance to CWD. Studies on polymorphisms have focused on those found in CWD-endemic areas, with the hope that understanding the role of an animal's genetics in CWD can help to predict, contain, or prevent transmission of CWD.

Automated summary

Chronic wasting disease (CWD) is a prion disease found in both free-ranging and farmed cervids, with susceptibility governed by various factors, including PrP polymorphisms. While most polymorphisms reduce susceptibility to CWD, there have been no reports of cervid PrP alleles providing absolute resistance to CWD. Studies have focused on understanding the role of animal genetics in predicting, containing, or preventing transmission of CWD in endemic areas.