These peptides also encompass the major part of the putative transmembrane form of PrP (CtmPrP) that is thought to be important in prion disease pathogenesis as transgenic mice overexpressing such PrP molecules develop neurological disease, and the accumulation of PrPres is followed closely by an increase in CtmPrP [10,11]. This evidence concerns the gene PRNP and prion disease.