title: Prion disease with a 144 base pair insertion: unusual cerebellar prion protein immunoreactivity.
abstract: Sporadic, acquired, and genetic human prion diseases are characterized neuropathologically by distinct deposition patterns of the abnormal, disease-associated form of the prion protein (PrP(sc)). In addition to mutations in the prion protein gene (PRNP), PrP(sc) immunostaining patterns correlate with molecular phenotypes of prion diseases defined by the PRNP polymorphism at codon 129 and with protease-resistant PrP classified by Western blotting. Some point or insertional PRNP mutations share similar clinical and neuropathological phenotypes, whereas others show great variability even within the same family. Here we report a patient who presented clinically as sporadic Creutzfeldt-Jakob disease (CJD). Histologically moderate spongiform change was seen in cerebral and cerebellar cortical areas. Neuronal loss was restricted mainly to the occipital cortex and the basal ganglia. Surprisingly, numerous eosinophilic globular structures were noted in the molecular layer and the parahippocampal gyrus. These globules showed intense PrP immunopositivity using anti-PrP antibodies against different epitopes. They were stained with PAS but lacked congophilia and birefringence in polarized light. Ultrastructurally, globules were composed of 21-nm-thick intermingled filaments without dense core. Genetic analysis revealed a PRNP 144 base pair insertion. Our case reinforces the importance of molecular genetic diagnosis, especially in those patients who lack a family history of prion disease and show unusual neuropathological changes. It also widens the phenotypic spectrum of prion diseases. The phenotypic variability within the same mutation suggests further, yet uncharacterized, genetic or epigenetic influence on phenotype in these diseases.
authors.affiliation: Institute of Neurology, Medical University of Vienna, Austria.
authors.forename: Ellen
authors.initials: E
authors.lastname: Gelpi
authors.forename: Gabor G
authors.initials: GG
authors.lastname: Kovacs
authors.forename: Thomas
authors.initials: T
authors.lastname: Ströbel
authors.forename: Oskar
authors.initials: O
authors.lastname: Koperek
authors.forename: Till
authors.initials: T
authors.lastname: Voigtländer
authors.forename: Pawel P
authors.initials: PP
authors.lastname: Liberski
authors.forename: Herbert
authors.initials: H
authors.lastname: Budka
mesh_terms: D000368:Aged; D020029:Base Pairing; D015153:Blotting, Western; D002540:Cerebral Cortex / Q000737:chemistry* / Q000473:pathology; D003062:Codon / Q000235:genetics; D004247:DNA / Q000032:analysis / Q000235:genetics*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D009154:Mutation; D020534:Parahippocampal Gyrus / Q000737:chemistry / Q000473:pathology; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D018620:PrPSc Proteins / Q000032:analysis; D017096:Prion Diseases / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology; D011328:Prions / Q000032:analysis* / Q000235:genetics* / Q000276:immunology
chemical_list: D003062:Codon; D018620:PrPSc Proteins; D011328:Prions; D004247:DNA