PRNP and primary systemic amyloidosis: The prion protein can form amyloid deposits outside of the CNS in the presence of selected mutations of the PRNP gene, leading to PrP systemic amyloidosis (Mead et al., 2013; Matsuzono et al., 2016; Capellari et al., 2018), or in the context of variant Creutzfeldt-Jakob disease (Will et al., 1996; Bruce et al., 2001).