PRNP and scrapie: These correspond to occurrence in supposedly scrapie-resistant ovine Prnp genotypes [53,54], protease resistant PrP of an unusually short type (~12 kDa) [52], and immunohistochemical detection of PrPSc deposition in the cerebellar cortex yet no obvious deposition in the medulla oblongata, which is the primary and earliest site of detection in classical scrapie.