Wednesday, September 9, 2009

Co-existence of scrapie prion protein types 1 and 2 in sporadic Creutzfeldt-Jakob disease: its effect on the phenotype and prion-type characteristics

Co-existence of scrapie prion protein types 1 and 2 in sporadic Creutzfeldt-Jakob disease: its effect on the phenotype and prion-type characteristics.

by: Ignazio Cali, Rudolph Castellani, Amer Alshekhlee, Yvonne Cohen, Janis Blevins, Jue Yuan, Jan P. Langeveld, Piero Parchi, Jiri G. Safar, Wen-Quan Q. Zou, Pierluigi Gambetti Brain : a journal of neurology (4 September 2009)


Five phenotypically distinct subtypes have been identified in sporadic Creutzfeldt-Jakob disease (sCJD), based on the methionine/valine polymorphic genotype of codon 129 of the prion protein (PrP) gene and the presence of either one of the two protease K-resistant scrapie prion protein (PrP(Sc)) types identified as 1 and 2. The infrequent co-existence of both PrP(Sc) types in the same case has been known for a long time. Recently, it has been reported, using type-specific antibodies, that the PrP(Sc) type 1 is present in all cases of sCJD carrying PrP(Sc) type 2. The consistent co-occurrence of both PrP(Sc) types complicates the diagnosis and the current classification of sCJD, and has implications for the pathogenesis of naturally occurring prion diseases. In the present study, we investigated the prevalence of PrP(Sc) types 1 and 2 co-occurrence, along with its effects on the disease phenotype and PrP(Sc) strain characteristics, comparatively analysing 34 cases of sCJD, all methionine homozygous at codon 129 of the PrP gene (sCJDMM). To minimize overestimating the prevalence of the sCJDMM cases carrying PrP(Sc) types 1 and 2 (sCJDMM1-2), we used proteinase K concentrations designed to hydrolyse all fragments resulting from an incomplete digestion, while preserving the protease-resistant PrP(Sc) core. Furthermore, we used several antibodies to maximize the detection of both PrP(Sc) types. Our data show that sCJDMM cases associated exclusively with either PrP(Sc) type 1 (sCJDMM1) or PrP(Sc) type 2 (sCJDMM2) do exist; we estimate that they account for approximately 56% and 5% of all the sCJDMM cases, respectively; while in 39% of the cases, both PrP(Sc) types 1 and 2 are present together (sCJDMM1-2) either mixed in the same anatomical region or separate in different regions. Clinically, sCJDMM1-2 had an average disease duration intermediate between the other two sCJDMM subtypes. The histopathology was also intermediate, except for the cerebellum where it resembled that of sCJDMM1. These features, along with the PrP immunostaining pattern, offer a diagnostic clue. We also observed a correlation between the disease duration and the prevalence of PrP(Sc) type 2 and sCJDMM2 phenotypes. The use of different antibodies and of the conformational stability immunoassay indicated that the co-existence of types 1 and 2 in the same anatomical region may confer special conformational characteristics to PrP(Sc) types 1 and 2. All of these findings indicate that sCJDMM1-2 should be considered as a separate entity at this time.

> sCJDMM1-2 should be considered as a separate entity at this time.

Thank you very much !

Saturday, June 13, 2009

Monitoring the occurrence of emerging forms of Creutzfeldt-Jakob disease in the United States 2003 revisited 2009

Tuesday, August 11, 2009

Characteristics of Established and Proposed Sporadic Creutzfeldt-Jakob Disease Variants

Brian S. Appleby, MD; Kristin K. Appleby, MD; Barbara J. Crain, MD, PhD; Chiadi U. Onyike, MD, MHS; Mitchell T. Wallin, MD, MPH; Peter V. Rabins, MD, MPH

Background: The classic Creutzfeldt-Jakob disease (CJD), Heidenhain, and Oppenheimer-Brownell variants are sporadic CJD (sCJD) phenotypes frequently described in the literature, but many cases present with neuropsychiatric symptoms, suggesting that there may be additional sCJD phenotypes.

Objective: To characterize clinical, diagnostic, and molecular features of 5 sCJD variants.

Design: Retrospective analysis.

Setting: The Johns Hopkins and Veterans Administration health care systems.

Participants: Eighty-eight patients with definite or probable sCJD.

Main Outcome Measures: Differences in age at onset, illness progression, diagnostic test results, and molecular subtype.

Results: The age at onset differed among sCJD variants (P=.03); the affective variant had the youngest mean age at onset (59.7 years). Survival time (P.001) and the time to clinical presentation (P=.003) differed among groups. Patients with the classic CJD phenotype had the shortest median survival time from symptom onset (66 days) and those who met criteria for the affective sCJD variant had the longest (421 days) and presented to clinicians significantly later (median time from onset to presentation, 92 days; P=.004). Cerebrospinal fluid analyses were positive for 14-3-3 protein in all of the affective variants, regardless of illness duration. Periodic sharp-wave complexes were not detected on any of the electroencephalography tracings in the Oppenheimer-Brownell group; basal ganglia hyperintensity was not detected on brain magnetic resonance imaging in this group either. All of the Heidenhain variants were of the methionine/ methionine type 1 molecular subtype.

Conclusions: The classic CJD phenotype and the Heidenhain, Oppenheimer-Brownell, cognitive, and affective sCJD variants differ by age at disease onset, survival time, and diagnostic test results. Characteristics of these 5 phenotypes are provided to facilitate further clinicopathologic investigation that may lead to more reliable and timely diagnoses of sCJD.

Arch Neurol. 2009;66(2):208-215



snip...see full text ;

Sunday, September 6, 2009



MORE BRAINS NOT TESTED PROPERLY, key brain parts missing. ...


Monday, July 27, 2009