Identification of an allelic variant of the goat PrP gene associated with resistance to scrapie

1 Department of Food Safety and Veterinary Public Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy 2 Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata, Via Manfredonia 20, 71100 Foggia, Italy 3 Department of Comparative Biomedical Sciences, Faculty of Veterinary Medicine, University of Teramo, Piazza Aldo Moro 45, 64100 Teramo, Italy Correspondence Gabriele Vaccari gvaccari{at}iss.it The association between PrP gene variations and scrapie susceptibility was studied in a single herd of Ionica breed goats. The entire herd comprised 100 animals, 11 of which were clinically affected and showed pathological prion protein (PrP Sc ) deposition in both their central nervous system (CNS) and lymphoreticular system (LRS). Among asymptomatic goats, nine harboured PrP Sc in both CNS and LRS, 19 showed PrP Sc only at the LRS level and 61 animals had no PrP Sc deposition. Genetic analysis of the PrP gene coding sequence revealed the presence of several polymorphisms, namely G37V, T110P, H143R, R154H, Q222K and P240S. Silent polymorphisms were also found at codons 42, 138, 219 and 232. The effect of PrP polymorphism on scrapie susceptibility was assessed by comparing the genotype distribution at each locus among animals with different pathogenetic and clinical disease stages. Significant differences in the distribution of genotypes were observed for codons 154 and 222, with polymorphism at codon 154 modulating susceptibility to scrapie and lysine at codon 222 being associated with scrapie resistance. The allelic variant encoding lysine at position 222 could be a valuable candidate to select in the framework of appropriate breeding programmes for scrapie resistance in goats. The GenBank/EMBL/DDBJ accession number for the sequence reported in this paper is DQ013244 [GenBank] .