PrP genotype in Sarda breed sheep and its relevance to scrapie

Several PrP gene polymorphisms modulate sheep scrapie susceptibility. Recently, an increase of scrapie outbreaks has been reported in Italy. A vaccine containing sheep brain homogenate was used in most of the outbreaks. We investigated PrP gene polymorphisms in scrapie-affected and clinically healthy Sarda breed sheep from a flock exposed to the aforementioned vaccine, and in affected Sarda sheep from unexposed flocks. All affected animals were (Gln/Gln)(171) homozygous. Moreover, we observed no variation for Ala(136) and a new polymorphism (Lys to Asn) at codon 176. Our findings confirm the correlation between scrapie and (Gln/Gln)(171) in breeds with no variation for Ala(136).