This specificity is further corroborated by GFAP mRNA expression pattern, which mirrors the one of SERPINA3. Indeed, GFAP is a well-known marker of astrogliosis, which is a hallmark of prion diseases: the fact that we find both GFAP and SERPINA3 -either mRNA and protein- strongly up-regulated in the brain tissue of patients with prion disease, reinforce the hypothesis of a strong correlation between prions and SERPINA3 and support our proposal of using SERPINA3 as a potential additional biomarker for human prion diseases. The gene discussed is GFAP; the disease is prion disease.