Besides, a major influence of the PrPc expression levels has been demonstrated in transgenic mice over-expressing (i) mutated human prion protein linked to Gerstmann–Sträussler-Scheinker syndrome [37], [38] or (ii) a prion protein with a nine-octapeptide insertion associated with a human familial prion disease [39], [40]. The gene discussed is PRNP; the disease is inherited prion disease.