Browsing by Subject "Octapeptide repeat insertion"

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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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    Longitudinal Clinical, Neuropsychological, and Neuroimaging Characterization of a Kindred with a 12-Octapeptide Repeat Insertion in PRNP: The Next Generation
    (Taylor & Francis, 2020-08) Townley, Ryan A.; Polsinelli, Angelina J.; Fields, Julie A.; Machulda, Mary M.; Jones, David T.; Graff-Radford, Jonathan; Kantarci, Kejal M.; Lowe, Val J.; Rademakers, Rosa V.; Baker, Matt C.; Kumar, Neeraj; Boeve, Bradley F.; Neurology, School of Medicine
    Background: Highly penetrant inherited mutations in the prion protein gene (PRNP) offer a window to study the pathobiology of prion disorders. Method: Clinical, neuropsychological, and neuroimaging characterization of a kindred. Results: Three of four mutation carriers have progressed to a frontotemporal dementia phenotype. Declines in neuropsychological function coincided with changes in FDG-PET at the identified onset of cognitive impairment. Conclusions and relevance: Gene silencing treatments are on the horizon and when they become available, early detection will be crucial. Longitudinal studies involving familial mutation kindreds can offer important insights into the initial neuropsychological and neuroimaging changes necessary for early detection.