PRNP and scrapie: Multiple PRNP polymorphisms have been reported in goats.1, 2 Experimental scrapie inoculation studies revealed that PRNP polymorphisms at codons 146, 154, 211, and 222 can provide resistance or a prolonged incubation period.3, 4, 5 A recent study identified the association between a polymorphism at codon 127 (G127S) and reduced probability of developing clinical signs of scrapie in goats with PrPSc detectable in the brain.6 In that study, the length of the incubation period (time from infection to clinical signs) was not known.