PRNP and familial pityriasis rubra pilaris: These distinct disease-associated PrP assembly states from GSS patients with the P102L PrP mutation transmit different phenotypes to experimental reporter mice resulting in either a lethal transmissible spongiform encephalopathy (associated with transmission of classical PrPSc) or a clinically silent PrP amyloidosis (associated with the transmission of the PrP conformer generating an ~8 kDa, protease-resistant PrP fragment)32,33.