PRNP and fatal familial insomnia: Genetic types of the disease in humans are familial CJD (fCJD), fatal familial insomnia (FFI), prion protein cerebral angiopathy (PrP CAA) and Gerstmann–Sträussler–Scheinker syndrome (GSS), while sporadic types include sporadic CJD (sCJD), sporadic fatal insomnia and variably protease-sensitive prionopathy (VPSPr) [3], the most recently identified prionopathy [4].