Review: A review on classical and atypical scrapie in caprine: Prion protein gene polymorphisms and their role in the disease

Abstract

Scrapie is a naturally occurring transmissible spongiform encephalopathy in sheep and goat. It has been known for~250 years and is characterised by the accumulation of an abnormal isoform of a host-encoded prion protein that leads to progressive neurodegeneration and death. Scrapie is recognised in two forms, classical and atypical scrapie. The susceptibility to both types of scrapie is influenced by polymorphisms of the prion protein gene (PRNP). Sheep susceptibility or resistance to classical scrapie is strongly regulated by the polymorphisms at codons 136, 154 and 171 of the PRNP. The genetic role in atypical scrapie in sheep has been defined by polymorphisms at codons 141, 154 and 171, which are associated with different degrees of risk in the occurrence of the ovine disease. Progress has been achieved in the prevention of scrapie in sheep due to efficient genetic breeding programmes based on eradication and control of the disease. In Europe, the success of these programmes has been verified by applying eradication and genetic selection plans. In general terms, the ovine selection plans aim to eliminate and reduce the susceptible allele and to enrich the resistant allele ARR. During outbreaks all susceptible animals are slaughtered, only ARR/ARR resistant rams and sheep and semi-resistant females are preserved. In the occurrence of scrapie positive goats a complete cull of the flock (stamping out) is performed with great economic loss and severe risk of extinction for the endangered breeds. The ability to select scrapie-resistant animals allows to define new breeding strategies aimed to boost genetic progress while reducing costs during scrapie outbreaks. Allelic variants of PRNP can be protective for caprine scrapie, and the knowledge of their distribution in goats has become very important. Over the past few years, the integration of genetic information on goat populations could be used to make selection decisions, commonly referred to as genetic selection. The objective of this review was to summarise the main findings of polymorphisms of the caprine prion protein (PrP) gene and to discuss the possible application of goat breeding schemes integrating genetic selection, with their relative advantages and limitations.

The evaluation of 23-bp and 12-bp insertion/deletion within the PRNP gene and their effects on growth traits in healthy Chinese native cattle breeds

“…The prion protein (PrP) which is encoded by prion protein gene (PRNP) plays an important role in the transmissible spongiform encephalopathies which include the bovine spongiform encephalopathy (BSE) (Zhu et al 2011;Zhao et al 2015), caprine (Curcio et al 2016) and ovine scrapie (Dassanayake et al 2013;Li et al 2017). The characteristic of TSE is the accumulation of PrP sc (pathological protease-resistant isoform), which is generated as a result of post-translational modification and changed in the stereochemical conformation of host-encoded, cellular prion proteins (PrP c ) (Prusiner 1998).…”

No polymorphisms in the coding region of the prion-like protein gene in Thoroughbred racehorses

“…Prion diseases are rare, but they are lethal neurodegenerative disorders that include Creutzfeldt-Jakob disease (CJD) in humans, scrapie in sheep and goats, bovine spongiform encephalopathy (BSE) in cattle, and chronic wasting disease (CWD) in deer (Prusiner, 1998;Williams, 2005;Goldmann, 2008;Jeong and Kim, 2014;Curcio et al, 2016). Although there is a wide spectrum of hosts involved in prion diseases, there have been no reports of prion diseases occurring in horses to date.…”

Clinical and laboratory features of 14 young Chinese probable sCJD patients

“…1 About 85% of all CJD cases are sporadic (sporadic CJD, sCJD), 10-15% cases are inherited (genetic CJD, gCJD) and less than 1% is infectious (iatrogenic CJD, iCJD). [2][3][4] The majority of sCJD patients develop clinical symptoms at middle-aged and old-aged period, with the incident peak at the age group of 60-69 year-old worldwide. 4,5 Young sCJD patients under 40 year-old are extremely rare.…”