Browsing by Subject "Creutzfeldt-Jakob disease"

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    Characterization of Prion Disease Associated with a Two-Octapeptide Repeat Insertion
    (MDPI, 2021-09-08) Brennecke, Nicholas; Cali, Ignazio; Mok, Tze How; Speedy, Helen; Hosszu, Laszlo L.P.; Stehmann, Christiane; Cracco, Laura; Puoti, Gianfranco; Prior, Thomas W.; Cohen, Mark L.; Collins, Steven J.; Mead, Simon; Appleby, Brian S.; Pathology and Laboratory Medicine, School of Medicine
    Genetic prion disease accounts for 10-15% of prion disease. While insertion of four or more octapeptide repeats are clearly pathogenic, smaller repeat insertions have an unclear pathogenicity. The goal of this case series was to provide an insight into the characteristics of the 2-octapeptide repeat genetic variant and to provide insight into the risk for Creutzfeldt-Jakob disease in asymptomatic carriers. 2-octapeptide repeat insertion prion disease cases were collected from the National Prion Disease Pathology Surveillance Center (US), the National Prion Clinic (UK), and the National Creutzfeldt-Jakob Disease Registry (Australia). Three largescale population genetic databases were queried for the 2-octapeptide repeat insertion allele. Eight cases of 2-octapeptide repeat insertion were identified. The cases were indistinguishable from the sporadic Creutzfeldt-Jakob cases of the same molecular subtype. Western blot characterization of the prion protein in the absence of enzymatic digestion with proteinase K revealed that 2-octapeptide repeat insertion and sporadic Creutzfeldt-Jakob disease have distinct prion protein profiles. Interrogation of large-scale population datasets suggested the variant is of very low penetrance. The 2-octapeptide repeat insertion is at most a low-risk genetic variant. Predictive genetic testing for asymptomatic blood relatives is not likely to be justified given the low risk.
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    Gerstmann-Sträussler-Scheinker disease revisited: accumulation of covalently-linked multimers of internal prion protein fragments
    (Biomed Central, 2019-05-29) Cracco, Laura; Xiao, Xiangzhu; Nemani, Satish K.; Lavrich, Jody; Cali, Ignazio; Ghetti, Bernardino; Notari, Silvio; Surewicz, Witold K.; Gambetti, Pierluigi; Pathology and Laboratory Medicine, School of Medicine
    Despite their phenotypic heterogeneity, most human prion diseases belong to two broadly defined groups: Creutzfeldt-Jakob disease (CJD) and Gerstmann-Sträussler-Scheinker disease (GSS). While the structural characteristics of the disease-related proteinase K-resistant prion protein (resPrPD) associated with the CJD group are fairly well established, many features of GSS-associated resPrPD are unclear. Electrophoretic profiles of resPrPD associated with GSS variants typically show 6-8 kDa bands corresponding to the internal PrP fragments as well as a variable number of higher molecular weight bands, the molecular nature of which has not been investigated. Here we have performed systematic studies of purified resPrPD species extracted from GSS cases with the A117V (GSSA117V) and F198S (GSSF198S) PrP gene mutations. The combined analysis based on epitope mapping, deglycosylation treatment and direct amino acid sequencing by mass spectrometry provided a conclusive evidence that high molecular weight resPrPD species seen in electrophoretic profiles represent covalently-linked multimers of the internal ~ 7 and ~ 8 kDa fragments. This finding reveals a mechanism of resPrPD aggregate formation that has not been previously established in prion diseases.