Frequency of genotypes in the PrP prion protein gene locus in the Polish sheep population.

Scrapie is an invariably fatal transmissible neurodegenerative disease of sheep, goats and moufflons, characterised by ataxia, lower body weight and changes in behaviour. The aim of this study was to determine the genotype distribution at codons 136, 154 and 171 of the PrP locus in sheep bred in Poland. The genotypes of 801 sheep representing 10 different breeds and crossbreds were analysed using real-time PCR allele discrimination method. The combination of point mutations of the three codons (136, 154 and 171) created twelve different genotypes in the PrP locus classified into five categories of risk. The highest frequency for the ARR/ARR genotype was characteristic of the Pogórze and Berrichon du Cher breeds (72.22% and 63:25%, respectively). In the Romanov breed (1.52%) and in crossbred sheep (2.61%) the VRQ/VRQ genotype was observed.