As previously described, in some (n = 7/13) susceptible genotypes (ARQ/ARQ) [13],[14] and in all (n = 9) investigated heterozygote ARR scrapie incubating ewes, no PrPS was detected in LRS, despite its typical accumulation in CNS [15],[16],[17],[18] (Table 1). This evidence concerns the gene MSMB and scrapie.