PRNP and Gerstmann-Straussler-Scheinker syndrome: Forty-two different mutations in the PrP gene (PRNP) were identified to cause a variety of genetic prion diseases, including genetic Creutzfeldt-Jakob disease (CJD), Gerstmann-Sträussler-Scheinker disease, and fatal familial insomnia (2, 4, 6, 10).