Tau filament structures identical with those in sporadic AD cases have also been found in other tauopathies including PART, posterior cortical atrophy (PCA), familial British dementia (FBD) and familial Danish dementia (FDD) and in prion diseases including PrP cerebral amyloid angiopathy (PrP-CAA) and Gerstmann-Sträussler-Scheinker disease (GSS) [127, 265, 266]. The gene discussed is PRNP; the disease is posterior cortical atrophy.