Thursday, December 23, 2010

Atypical Prion Protein Conformation in Familial Prion Disease with PRNP P105T Mutation

RESEARCH A R T I C L E bpa_439 1..6

Atypical Prion Protein Conformation in Familial Prion Disease with PRNP P105T Mutation

Magdalini Polymenidou1,2,*; Stefan Prokop1,3,*; Hans H. Jung4; Ekkehard Hewer1; David Peretz5,6;

Rita Moos1; Markus Tolnay1,7; Adriano Aguzzi1

4 Department of Neurology, 1 Institute of Neuropathology, University Hospital Zurich and 7 Basel, Switzerland.

5 Novartis Vaccines and Diagnostics, Emeryville, Calif.

2 Current address: Department of Cellular and Molecular Medicine, University of California at San Diego, Calif.

3 Current address: Department of Neuropathology, Charité—Universitätsmedizin Berlin, Germany.

6 Current address: Tethys Bioscience, Emeryville, Calif.


Abstract

Protease-resistant prion protein (PrPSc) is diagnostic of prion disease, yet its detection is

frequently difficult. Here, we describe a patient with a PRNP P105T mutation and typical

familial prion disease. Brain PrPSc was undetectable by conventional Western blotting and

barely detectable after phosphotungstate precipitation, where it displayed an atypical pattern

suggestive of noncanonical conformation. Therefore, we used a novel misfolded protein

assay (MPA) that detects PrP aggregates independently of their protease resistance. The

MPA revealed the presence of aggregated PrP in similar amounts as in typical sporadic

Creutzfeldt-Jakob disease. These findings suggest that measurements of PrP aggregation

with the MPA may be potentially more sensitive than protease-based methodologies.


Keywords

familial prion disease, misfolded protein assay, prion.

Corresponding authors:

Adriano Aguzzi, MD PHD, Institute of

Neuropathology, University Hospital of Zurich,

Schmelzbergstrasse 12, Zurich CH-8091,

Switzerland (E-mail: adriano.aguzzi@usz.ch);

Magdalini Polymenidou, PHD, Department of

Cellular and Molecular Medicine, University of

California, San Diego, 9500 Gilman Drive, La

Jolla, CA 92093-0670, USA (E-mail:

mpolymen@ucsd.edu)

Received 2 June 2010; accepted 2 August

2010.

* These authors contributed equally to this

work.

doi:10.1111/j.1750-3639.2010.00439.x

http://www.pathol.uzh.ch/publications/2010/Polymenidou_BrainPath_2010.pdf



Sunday, November 28, 2010

Variably protease-sensitive prionopathy in a PRNP codon 129 heterozygous UK patient with co-existing tau, a synuclein and AB pathology


http://prionopathy.blogspot.com/2010/11/variably-protease-sensitive-prionopathy.html



http://sporadicffi.blogspot.com/



TSS

Thursday, November 19, 2009

Inherited Creutzfeldt–Jakob disease in a Dutch patient with a novel five octapeptide repeat insertion and unusual cerebellar morphology

J Neurol Neurosurg Psychiatry 2009;80:1386-1389 doi:10.1136/jnnp.2008.169359

Short report

Inherited Creutzfeldt–Jakob disease in a Dutch patient with a novel five octapeptide repeat insertion and unusual cerebellar morphology

C Jansen1, J C van Swieten2, S Capellari3, R Strammiello3, P Parchi3, A J M Rozemuller1 + Author Affiliations

1Dutch Surveillance Centre for Prion Diseases, University Medical Centre Utrecht, Utrecht, The Netherlands 2Department of Neurology, Erasmus University Medical Centre, Rotterdam, The Netherlands 3Dipartimento di Scienze Neurologiche, Università di Bologna, Bologna, Italy Correspondence to Dr C Jansen, Dutch Surveillance Centre for Prion Diseases, University Medical Centre Utrecht, Heidelberglaan 100, PO Box 85500, 3508 GA, Utrecht, The Netherlands; c.jansen@umcutrecht.nl Received 2 December 2008 Revised 22 February 2009 Accepted 5 March 2009 Abstract An atypical case of inherited Creutzfeldt–Jakob disease (CJD) is described in a 35-year-old Dutch woman, homozygous for methionine at codon 129 of the prion protein gene (PRNP). The clinical phenotype was characterised by slowly progressive cognitive decline and parkinsonism. Neuropathological findings consisted of scanty spongiosis and only faint to absent immunohistochemical staining for the abnormal prion protein, PrPSc, with patchy deposits in the cerebellar cortex. Purkinje cells were abnormally located in the molecular layer of the cerebellum. Western blot analysis showed the co-occurrence of PrPSc types 1 and 2 with an unusual distribution. Sequence analysis disclosed a novel 120 bp insertion in the octapeptide repeat region of the PRNP, encoding five additional R2 octapeptide repeats. These features define an unusual neuropathological phenotype and novel genotype, further expanding the spectrum of genotype–phenotype correlations in inherited prion diseases and emphasising the need to carry out pre-mortem PRNP sequencing in all young patients with atypical dementias.

snip...

METHODS Case history The patient presented with forgetfulness and difficulties in writing at the age of 35 years, after the birth of her second child. Her family noted that she had become increasingly absentminded and apathetic. Her clinical history was otherwise unremarkable. Her father had suffered from dementia and parkinsonism from the age of 45 years and died at the age of 55 years. At neurological examination, 2.5 years after the first symptoms, the patient was disoriented in time and place, and exhibited echolalia, perseveration and disturbed visual perception. She had a masked face with vertical gaze palsy, and increased tone of the extremities. Neuropsychological evaluation revealed an intact memory with acalculia, agraphia and apraxia. Brain MRI showed generalised cortical atrophy without evidence of hyperintensity or atrophy of either the caudate nucleus or the basal ganglia (fig 1A). The 14-3-3 test in CSF was negative. An electroencephalogram was not recorded. Genetic analysis revealed no abnormalities in the tau protein gene (MAPT), the Presenilin 1 gene (PSEN1) or the Huntingtin gene. Over the next 3 years, rigidity increased with the appearance of a slight tremor in her right hand, without any beneficial effect on levodopa and amantadin treatment. She increasingly developed dysarthria and swallowing problems, and suffered from anxiety and panic attacks. She was admitted to a nursing home where she died from bronchopneumonia at the age of 42 years, 92 months after the clinical onset of the disease.


snip...


DISCUSSION

Seventeen patients with six different 5-OPRI have been described so far in the literature.6 As in other inherited prion diseases, these disorders show a considerable degree of phenotypic variability, partly accounted for by the codon 129 Met/Val polymorphism. Age at onset in codon 129 heterozygous patients is usually later (58.0 years) than in codon 129 homozygous patients (42.3 years).6 Approximately half of these patients show a disease duration of more than 60 months. Although the clinical and pathological features of 5-OPRI mutations are relatively well known, genotype–phenotype correlation has not been clearly established, warranting the description of further genetic cases.

In this report, we describe a novel insertion mutation in PRNP, consisting of five extra R2 octapeptide repeats (R1-(R2)7- R3-R4). The clinical phenotype in our patient was characterised by slowly progressive cognitive decline, parkinsonism, anxiety and a long disease duration of 92 months. Neuropathological findings included scanty spongiosis and faint synaptic or even absent immunohistochemical staining, except for small patchy deposits in the cerebellar cortex, without the characteristic perpendicular orientation to the meningeal outline, as described in other patients with insertion mutations.8 12 An intriguing finding, although described before in three other patients with a 5-OPRI mutation,13 was the abnormal localisation of Purkinje cells in the molecular layer of the cerebellum. The type of abnormalities, combined with the absence of ataxia and significant cerebellar pathology, strongly suggest this defect as being longstanding and likely related to a developmental defect. Thus although largely speculative, the observation may suggest a role for PrPC in cerebellar neuronal migration or in the elimination of misplaced Purkinje cells during development which likely involve the programmed cell death machinery, as recently suggested.14 Furthermore, in the absence of a specific histopathological picture, the observation of misplacement of Purkinje cells in the molecular layer might be a helpful diagnostic clue prompting the suspicion of inherited prion disease with OPRI mutation.

Another interesting finding was the co-occurrence of PrPSc types 1 and 2 in brain homogenates, as demonstrated by immunoblotting. To our knowledge, this has only been described once before in a patient with one extra octapeptide repeat in PRNP, who showed widespread spongiosis and diffuse synaptic immunoreactivity in all cortical lobes.15 In light of the scanty spongiosis and faint immunohistochemical staining in the brain of our patient, the presence of type 2 protein is a peculiar finding, since in methionine homozygotes (MM) at codon 129, type 2 is usually associated with prominent spongiosis with confluent vacuoles and more consistent coarse and perivacuolar deposits of PrPSc in the cerebral cortex.11 Furthermore, type 2 in MM cases preferentially accumulates in the cerebral cortex11 whereas it was mainly detected in the striatum and cerebellum in the present case. The 5-OPRI mutation in this patient was probably inherited in an autosomal dominant pattern but a positive family history in patients with inherited prion disease is not obligate. In all patients with a clinical history of frontotemporal dementia or atypical dementia and abnormal localisation of Purkinje cells in the molecular layer of the cerebellum, inherited prion disease should always be considered and pre-mortem PRNP sequencing should be carried out.

snip...see full text ;





http://jnnp.bmj.com/content/80/12/1386.abstract




http://sporadicffi.blogspot.com/



TSS

Wednesday, August 12, 2009

Neurobiology of Disease A New Transgenic Mouse Model of GSS Syndrome Caused by the A117V Mutation of PRNP

Neurobiology of Disease A New Transgenic Mouse Model of Gerstmann–Sträussler–Scheinker Syndrome Caused by the A117V Mutation of PRNP

Wenbin Yang,1 Julie Cook,1 Benjamin Rassbach,1 Azucena Lemus,2 Stephen J. DeArmond,2 and James A. Mastrianni1

1Department of Neurology, University of Chicago, Chicago, Illinois 60637, and 2Department of Neuropathology, University of California, San Francisco, San Francisco, California 94143

Correspondence should be addressed to James A. Mastrianni, Department of Neurology, University of Chicago, MC2030, 5841 South Maryland Avenue, Chicago, IL 60637. Email: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000475/!x-usc:mailto:jmastria@uchicago.edu

Gerstmann–Sträussler–Scheinker syndrome (GSS) is a genetic prion disease typified clinically by the development of progressive ataxia and dementia, and histopathologically by the presence of prion protein (PrP) amyloid plaques in the CNS, especially within the cerebellum. Several mutations of the PrP gene (PRNP) are associated with GSS, but only the P102L mutation has been convincingly modeled in transgenic (Tg) mice. To determine whether other mutations carry specific GSS phenotypic information, we constructed Tg mice that express PrP carrying the mouse homolog of the GSS-associated A117V mutation. Tg(A116V) mice express approximately six times the endogenous levels of PrP, develop progressive ataxia by 140 d, and die by 170 d. Compared with a mouse model of transmissible Creutzfeldt–Jakob disease (CJD), the ataxia of Tg(A116V) mice is more prominent, and the course of disease is more protracted, paralleling that observed in human disease. Neuropathology includes mild scattered vacuolation and prominent, mainly cerebellar localized, thioflavin S-positive PrP plaques comprised of full-length PrPA116V. In some mice, more prominent vacuolation or a noncerebellar distribution of PrP plaques was evident, suggesting some variability in phenotype. The biophysical properties of PrP from Tg(A116V) mice and human GSS(A117V) revealed a similarly low fraction of insoluble PrP and a weakly protease-resistant 13 kDa midspan PrP fragment, not observed in CJD. Overall, Tg(A116V) mice recapitulate many clinicopathologic features of GSS(A117V) that are distinct from CJD, supporting PrPA116V to carry specific phenotypic information. The occasional variation in histopathology they exhibit may shed light on a similar observation in human GSS(A117V).

-------------------------------------------------------------------------------- Received June 2, 2009; revised June 30, 2009; accepted July 3, 2009.

Correspondence should be addressed to James A. Mastrianni, Department of Neurology, University of Chicago, MC2030, 5841 South Maryland Avenue, Chicago, IL 60637. Email: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000475/!x-usc:mailto:jmastria@uchicago.edu




http://www.jneurosci.org/cgi/content/abstract/29/32/10072?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=prion&searchid=1&FIRSTINDEX=0&volume=29&issue=32&resourcetype=HWCIT





http://sporadicffi.blogspot.com/

Thursday, May 28, 2009

Cerebrospinal fluid biomarkers in human genetic transmissible spongiform encephalopathies

J Neurol DOI 10.1007/s00415-009-5163-x

Cerebrospinal fluid biomarkers in human genetic transmissible spongiform encephalopathies

Anna Ladogana Æ Pascual Sanchez-Juan Æ Eva Mitrova´ Æ Alison Green Æ Natividad Cuadrado-Corrales Æ Raquel Sa´nchez-Valle Æ Silvia Koscova Æ Adriano Aguzzi Æ Theodoros Sklaviadis Æ Jerzy Kulczycki Æ Joanna Gawinecka Æ Albert Saiz Æ Miguel Calero Æ Cornelia M. van Duijn Æ Maurizio Pocchiari Æ Richard Knight Æ Inga Zerr

Received: 16 December 2008 / Revised: 8 April 2009 / Accepted: 27 April 2009  Springer-Verlag 2009

Abstract The 14-3-3 protein test has been shown to support the clinical diagnosis of sporadic Creutzfeldt-Jakob disease (CJD) when associated with an adequate clinical context, and a high differential potential for the diagnosis of sporadic CJD has been attributed to other cerebrospinal fluid (CSF) proteins such as tau protein, S100b and neuron specific enolase (NSE). So far there has been only limited information available about biochemical markers in genetic transmissible spongiform encephalopathies (gTSE), although they represent 10–15% of human TSEs. In this study, we analyzed CSF of 174 patients with gTSEs for 14-3-3 (n = 166), tau protein (n = 78), S100b (n = 46) and NSE (n = 50). Levels of brain-derived proteins in CSF varied in different forms of gTSE. Biomarkers were found positive in the majority of gCJD (81%) and insert gTSE (69%), while they were negative in most cases of fatal familial insomnia (13%) and Gerstmann-Stra¨ussler- Scheinker syndrome (10%). Disease duration and codon 129 genotype influence the findings in a different way than in sporadic CJD.

snip...

Discussion

Data on brain-derived proteins in the CSF of patients with genetic TSE are limited and conflicting results have been reported, mostly because they are frequently based on single case observations (see Table 4). In these reports, sensitivity of biochemical markers in CSF is reported to be lower than in sporadic CJD and this was explained in terms of prolonged disease duration and relatively slow disease progression. Because of the limited numbers of patients, no detailed analysis on this topic is available.

In this study we provide data on four brain-derived proteins in a cohort of patients with various forms of genetic TSE. We found firm evidence for elevated concentrations of 14-3-3, tau, S100b and NSE in the CSF of patients with genetic CJD, but not in FFI or GSS patients. Of interest, the median concentrations for tau, S100b and NSE were similar to those detected in sporadic CJD in other studies [1, 16, 20]. In our previous study on sporadic CJD, we reported median tau levels in the range of

6,000 pg/ml, which is not significantly different from what we found in gCJD patients [21]. These results are concordant with the observation that some gCJD might present clinical similarities with sporadic CJD [11, 15]. Indeed, these cases are often misclassified as sporadic CJD if family history and genetic testing are not done.

The rate of elevated levels of 14-3-3, tau, NSE and S100b in genetic CJD was comparable to that observed in sporadic CJD [3, 20, 26, 27]. In other forms of gTSE, such as FFI and GSS, these tests were consistently negative. Although levels of tau in FFI and GSS patients were lower than the cut-off levels given for CJD, they were still elevated if compared to non-demented controls [24].

The crude analyses of disease modifying factors of the 14-3-3 test in gCJD revealed that age at onset and PRNP codon 129 genotype influenced sensitivity. 14-3-3 test sensitivity was lower in patients with disease onset before 40 years. These data parallel the results performed on sporadic CJD [20]. However, while in the multivariate analysis age remained as an independent variable in sporadic CJD, in gCJD it did not. Interestingly, in gCJD the PRNP codon 129 genotype influences 14-3-3 sensitivity in a different way with respect to what has been observed in sporadic CJD. Valine homozygous gCJD patients had a lower sensitivity in the 14-3-3 test than heterozygous patients. Though there are too few patients to draw any definite conclusions, a possible explanation might be that the PRNP mutations coupled with the valine alleles (R208H, D178N, E196K) confer low sensitivity to 14-3-3.

The biological significance of brain-derived proteins in the CSF of patients with TSEs remains to be determined. It is generally assumed that the release of 14-3-3, tau and

NSE proteins in the CSF is a consequence of leakage into the CSF following rapid neuronal damage. Recently, a systematic analysis of brain-derived proteins in CSF and neuropathological lesions has shown that the levels of these proteins are the consequence of both the degree of neuronal damage and the localization of the most affected areas [2]. For example NSE levels correlated with damage of subcortical areas (such as the thalamus) and tau protein levels correlated with the degree of spongiform changes in the frontal cortex. Our findings on inverse correlation of tau levels and the number of octapeptide repeats are of interest, since the number of repeats has been correlated to the type of cerebellar PrPSc deposits [28].

In conclusion, the validity of the biomarkers varied among the different forms of gTSEs. Sensitivity of biomarkers was high in those forms, which are clinically more similar to sporadic CJD, such as genetic CJD and insert gTSEs.

Keywords Creutzfeldt-Jakob disease  CSF proteins  14-3-3 protein  Tau

A. Ladogana  M. Pocchiari Department of Cellular Biology and Neurosciences, Instituto Superiore di Sanita, Viale Regina Elena 299, 00161 Rome, Italy e-mail: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000094/!x-usc:mailto:Ladogana@iss.it

M. Pocchiari e-mail: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000094/!x-usc:mailto:Maurizio.pocchiari@iss.it

P. Sanchez-Juan Centro de Investigacion Biomedica en Red sobre Enferemedades neurodegenerativas (CIBERNED) and Institute for Formation and Research of the Fundacion ‘‘Marques de Valdecilla’’ (IFIMAV), Santander, Spain e-mail: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000094/!x-usc:mailto:ifimav.uapoyo@fmdv.org

E. Mitrova´  S. Koscova National Reference Centre for Prion Diseases, Research Base of Slovak Medical University, Limbova´ 14, 833-03 Bratislava, Slovakia e-mail: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000094/!x-usc:mailto:eva.mitrova@szu.sk

S. Koscova e-mail: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000094/!x-usc:mailto:silvia.koscova@szu.sk

A. Green  R. Knight National CJD Surveillance Unit, The University of Edinburgh, EH4-2XU Edinburgh, UK e-mail: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000094/!x-usc:mailto:Alison.Green@ed.ac.uk

N. Cuadrado-Corrales  M. Calero Instituto de Salud Carlos III, Centro Nacional de Microbiologia, Ctra. Majadahonda, 28220 Madrid, Spain e-mail: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000094/!x-usc:mailto:ncuadrado@isciii.es

M. Calero e-mail: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000094/!x-usc:mailto:mcalero@isciii.es

R. Sa´nchez-Valle  A. Saiz Department of Neurology, Hospital Clinic Provincial de Barcelona, Villarroel 170, 08036 Barcelona, Spain e-mail: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000094/!x-usc:mailto:31799rsd@comb.es

A. Saiz e-mail: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000094/!x-usc:mailto:asaiz@clinic.ub.es

A. Aguzzi National Reference Center for Human Prion Diseases (NRPE), Institute of Neuropathology, Schmelzbergstr.12, 8091 Zurich, Switzerland e-mail: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000094/!x-usc:mailto:adriano.aguzzi@usz.ch

T. Sklaviadis Laboratory of Pharmacology, Department of Pharmaceutical Sciences, School of Health Sciences, Aristotle University of Thessaloniki, 54124 Thessaloni´ki, Greece e-mail: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000094/!x-usc:mailto:sklaviad@pharm.auth.gr

J. Kulczycki I-st Neurological Department, Institute of Psychiatry and Neurology, Sobieskiego 9, 02-957 Warsaw, Poland e-mail: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000094/!x-usc:mailto:jkulczycki@data.pl



http://www.springerlink.com/content/w22g7074518hl00w/



Sunday, May 10, 2009

Meeting of the Transmissible Spongiform Encephalopathies Committee On June 12, 2009 (Singeltary submission)



http://tseac.blogspot.com/2009/05/meeting-of-transmissible-spongiform.html




TSS

Monday, December 8, 2008

Genetic risk factors for variant Creutzfeldt—Jakob disease: a genome-wide association study

Articles

The Lancet Neurology, Volume 8, Issue 1, Pages 57 - 66, January 2009


doi:10.1016/S1474-4422(08)70265-5Cite or Link Using DOI

Editors' note: Although millions of people in the UK are thought to have been exposed to the bovine spongiform encephalopathy (BSE) prion, fewer than 200 people have developed variant Creutzfeldt-Jakob disease (vCJD) so far. Polymorphisms at codon 129 of the gene encoding prion protein (PRNP) partially explain why some people have been affected whereas others have not, but other factors that might contribute to susceptibility or incubation time remain to be identified. Using genome-wide association technology, this study has confirmed the association with codon 129 of PRNP and has also identified novel candidate loci. The results could provide a basis for further investigation into whether vCJD is likely to develop in people who have been exposed to the BSE prion but are currently unaffected.

Genetic risk factors for variant Creutzfeldt—Jakob disease: a genome-wide association study

Simon Mead PhD a, Mark Poulter BSc a, James Uphill BSc a, John Beck BSc a, Jerome Whitfield MA a b, Thomas EF Webb MRCP a, Tracy Campbell BSc a, Gary Adamson BSc a, Pelagia Deriziotis MSc a, Sarah J Tabrizi PhD a, Holger Hummerich PhD a, Claudio Verzilli PhD d, Michael P Alpers FRS a c, John C Whittaker PhD d, John Collinge FRS a

Summary Background Human and animal prion diseases are under genetic control, but apart from PRNP (the gene that encodes the prion protein), we understand little about human susceptibility to bovine spongiform encephalopathy (BSE) prions, the causal agent of variant Creutzfeldt—Jakob disease (vCJD). Methods We did a genome-wide association study of the risk of vCJD and tested for replication of our findings in samples from many categories of human prion disease (929 samples) and control samples from the UK and Papua New Guinea (4254 samples), including controls in the UK who were genotyped by the Wellcome Trust Case Control Consortium. We also did follow-up analyses of the genetic control of the clinical phenotype of prion disease and analysed candidate gene expression in a mouse cellular model of prion infection. Findings The PRNP locus was strongly associated with risk across several markers and all categories of prion disease (best single SNP [single nucleotide polymorphism] association in vCJD p=2·5×10-17; best haplotypic association in vCJD p=1×10-24). Although the main contribution to disease risk was conferred by PRNP polymorphic codon 129, another nearby SNP conferred increased risk of vCJD. In addition to PRNP, one technically validated SNP association upstream of RARB (the gene that encodes retinoic acid receptor beta) had nominal genome-wide significance (p=1·9×10-7). A similar association was found in a small sample of patients with iatrogenic CJD (p=0·030) but not in patients with sporadic CJD (sCJD) or kuru. In cultured cells, retinoic acid regulates the expression of the prion protein. We found an association with acquired prion disease, including vCJD (p=5·6×10-5), kuru incubation time (p=0·017), and resistance to kuru (p=2·5×10-4), in a

region upstream of STMN2 (the gene that encodes SCG10). The risk genotype was not associated with sCJD but conferred an earlier age of onset. Furthermore, expression of Stmn2 was reduced 30-fold post-infection in a mouse cellular model of prion disease. Interpretation The polymorphic codon 129 of PRNP was the main genetic risk factor for vCJD; however, additional candidate loci have been identified, which justifies functional analyses of these biological pathways in prion disease. Funding The UK Medical Research Council.



http://www.lancet.com/journals/laneur/article/PIIS1474-4422(08)70265-5/fulltext



sporadic TSE, spontaneous TSE, sporadic FFI, to genetic TSE,



http://sporadicffi.blogspot.com/



REPORT ON CURRENT & FUTURE SURVEILLANCE FOR BOVINE SPONGIFORM ENCEPHALOPATHY



http://madcowtesting.blogspot.com/2008/11/report-on-current-future-surveillance.html



Evaluation of the Human Transmission Risk of an Atypical Bovine Spongiform Encephalopathy Prion Strain

Qingzhong Kong,1* Mengjie Zheng,1 Cristina Casalone,2 Liuting Qing,1 Shenghai Huang,1? Bikram Chakraborty,1 Ping Wang,1 Fusong Chen,1 Ignazio Cali,1 Cristiano Corona,2 Francesca Martucci,2 Barbara Iulini,2 Pierluigi Acutis,2 Lan Wang,1 Jingjing Liang,1 Meiling Wang,1 Xinyi Li,1 Salvatore Monaco,3 Gianluigi Zanusso,3 Wen-Quan Zou,1 Maria Caramelli,2 and Pierluigi Gambetti1* Department of Pathology, Case Western Reserve University, Cleveland, Ohio 44106,1 CEA, Istituto Zooprofilattico Sperimentale, 10154 Torino, Italy,2 Department of Neurological and Visual Sciences, University of Verona, 37134 Verona, Italy3 *Corresponding author. Mailing address: Department of Pathology, Case Western Reserve University, Cleveland, OH 44106. Phone for Pierluigi Gambetti: (216) 368-0586. Fax: (216) 368-2546. E-mail: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000009/!x-usc:mailto:pxg13@case.edu . Phone for Qingzhong Kong: (216) 368-1756. Fax: (216) 368-2546. E-mail: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000009/!x-usc:mailto:qxk2@case.edu ?Present address: Department of Patient Education and Health Information, Cleveland Clinic Foundation, Cleveland, OH 44195. Received November 30, 2007; Accepted January 16, 2008.

Bovine spongiform encephalopathy (BSE), the prion disease in cattle, was widely believed to be caused by only one strain, BSE-C. BSE-C causes the fatal prion disease named new variant Creutzfeldt-Jacob disease in humans. Two atypical BSE strains, bovine amyloidotic spongiform encephalopathy (BASE, also named BSE-L) and BSE-H, have been discovered in several countries since 2004; their transmissibility and phenotypes in humans are unknown. We investigated the infectivity and human phenotype of BASE strains by inoculating transgenic (Tg) mice expressing the human prion protein with brain homogenates from two BASE strain-infected cattle. Sixty percent of the inoculated Tg mice became infected after 20 to 22 months of incubation, a transmission rate higher than those reported for BSE-C. A quarter of BASE strain-infected Tg mice, but none of the Tg mice infected with prions causing a sporadic human prion disease, showed the presence of pathogenic prion protein isoforms in the spleen, indicating that the BASE prion is intrinsically lymphotropic. The pathological prion protein isoforms in BASE strain-infected humanized Tg mouse brains are different from those from the original cattle BASE or sporadic human prion disease. Minimal brain spongiosis and long incubation times are observed for the BASE strain-infected Tg mice. These results suggest that in humans, the BASE strain is a more virulent BSE strain and likely lymphotropic.



http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2268471



Thursday, December 04, 2008 2:37 PM

"we have found that H-BSE can infect humans."

personal communication with Professor Kong. ...TSS



November 25, 2008

Update On Feed Enforcement Activities To Limit The Spread Of BSE



http://madcowfeed.blogspot.com/2008/11/november-2008-update-on-feed.html



"the biochemical signature of PrPres in the BASE-inoculated animal was found to have a higher proteinase K sensitivity of the octa-repeat region. We found the same biochemical signature in three of four human patients with sporadic CJD and an MM type 2 PrP genotype who lived in the same country as the infected bovine."

just another one of those sporadic CJD coincidences i suppose $$$

NOT to forget ;

Thursday, June 05, 2008

Review on the epidemiology and dynamics of BSE epidemics

Vet. Res. (2008) 39:15 www.vetres.org DOI: 10.1051/vetres:2007053 c INRA, EDP Sciences, 2008 Review article

snip...

And last but not least, similarities of PrPres between Htype BSE and human prion diseases like CJD or GSS have been put forward [10], as well as between L-type BSE and CJD [17]. These findings raise questions about the origin and inter species transmission of these prion diseases that were discovered through the BSE active surveillance.

snip...

Cases of atypical BSE have only been found in countries having implemented large active surveillance programs. As of 1st September 2007, 36 cases (16 H, 20 L) have been described all over the world in cattle: Belgium (1 L) [23], Canada (1 H)15, Denmark (1 L)16, France (8 H, 6 L)17, Germany (1 H, 1 L) [13], Italy (3 L)18, Japan (1 L) [71], Netherlands (1 H, 2 L)19, Poland (1 H, 6 L)20, Sweden (1 H)21, United Kingdom (1 H)22, and USA (2 H)23. Another H-type case has been found in a 19 year old miniature zebu in a zoological park in Switzerland [56]. It is noteworthy that atypical cases have been found in countries that did not experience classical BSE so far, like Sweden, or in which only few cases of classical BSE have been found, like Canada or the USA.

And last but not least, similarities of PrPres between Htype BSE and human prion diseases like CJD or GSS have been put forward [10], as well as between L-type BSE and CJD [17]. These findings raise questions about the origin and inter species transmission of these prion diseases that were discovered through the BSE active surveillance.

full text 18 pages ;



http://www.vetres.org/index.php?option=article&access=standard&Itemid=129&url=/articles/vetres/pdf/2008/04/v07232.pdf



please see full text ;



http://bse-atypical.blogspot.com/2008/06/review-on-epidemiology-and-dynamics-of.html



***Atypical forms of BSE have emerged which, although rare, appear to be more virulent than the classical BSE that causes vCJD.***

Progress Report from the National Prion Disease Pathology Surveillance Center

An Update from Stephen M. Sergay, MB, BCh & Pierluigi Gambetti, MD

April 3, 2008



http://www.aan.com/news/?event=read&article_id=4397&page=72.45.45



Sunday, March 16, 2008

MAD COW DISEASE terminology UK c-BSE (typical), atypical BSE H or L, and or Italian L-BASE



http://bse-atypical.blogspot.com/2008/03/mad-cow-disease-terminology-uk-c-bse.html



HUMAN and ANIMAL TSE Classifications i.e. mad cow disease and the UKBSEnvCJD only theory JUNE 2008

snip...

Tissue infectivity and strain typing of the many variants Manuscript of the human and animal TSEs are paramount in all variants of all TSE. There must be a proper classification that will differentiate between all these human TSE in order to do this. With the CDI and other more sensitive testing coming about, I only hope that my proposal will some day be taken seriously. ...

snip...



http://cjdmadcowbaseoct2007.blogspot.com/2008/06/human-and-animal-tse-classifications-ie.html



Friday, December 05, 2008

Detection of Prion Infectivity in Fat Tissues of Scrapie-Infected Mice



http://scrapie-usa.blogspot.com/2008/12/detection-of-prion-infectivity-in-fat.html



Monday, December 08, 2008 vCJD & dental treatment



http://creutzfeldt-jakob-disease.blogspot.com/2008/12/vcjd-dental-treatment.html



TSS

Tuesday, October 28, 2008

A novel PRNP-P105S mutation associated with atypical prion disease and a rare PrPSc conformation

NEUROLOGY 2008;71:1431-1438 © 2008 American Academy of Neurology

A novel PRNP-P105S mutation associated with atypical prion disease and a rare PrPSc conformation

E. Tunnell, MD, R. Wollman, MD, PhD, S. Mallik, BA, C. J. Cortes, BS, S. J. DeArmond, MD, PhD and J. A. Mastrianni, MD, PhD From the Departments of Neurology (E.T., S.M., C.J.C., J.A.M.) and Pathology, Division of Neuropathology (R.W.), The University of Chicago, IL; and the Department of Pathology, Division of Neuropathology (S.J.D.), UCSF, San Francisco, CA.

Address correspondence and reprint requests to Dr. James A. Mastrianni, Department of Neurology, University of Chicago, Pritzker School of Medicine, 5841 So. Maryland Ave., Chicago, IL 60637 jmastria@uchicago.edu

Objective: To define the clinicopathologic, genetic, and pathogenic prion protein (PrPSc) characteristics associated with a novel mutation of the prion protein gene (PRNP).

Methods: The coding segment of PRNP from the proband and family members was sequenced and the brain of the proband was histologically studied. The Western blot profile of the proteinase K (PK) resistant fraction of PrPSc, an approximation of its conformation, or "PrPSc-type," was determined.

Results: We detected a novel mutation at codon 105 of PRNP that results in a serine (S) substitution of proline (P) (P105S), in a young woman who developed progressive aphasia, behavioral changes, dementia, and parkinsonism, lasting 10 years to her death. Histopathologic findings included an intense focus of multicentric PrP-plaques within the hippocampus, punctate plaques scattered throughout the cerebellum, and intense spongiform degeneration focally within the putamen, suggesting a variant of Gerstmann-Sträussler-Scheinker syndrome (GSS). However, PrPSc-typing revealed two PK-resistant PrPSc fragments (21 and 26 kDa), a pattern not previously detected in GSS.

Conclusions: This mutation is the third sequence variation at codon 105 of PRNP. The unusual phenotype and PrPSc-type distinguishes this genetic prion disease from typical Gerstmann-Sträussler-Scheinker syndrome and other codon 105 substitutions, suggesting that, in addition to the loss of proline at this position, the PrPSc conformation and phenotype is dependent on the specific amino acid substitution.

Abbreviations: fCJD = familial Creutzfeldt-Jakob disease; FFI = familial fatal insomnia; FTD = frontotemporal dementia; GSS = Gerstmann-Sträussler-Scheinker syndrome; PK = proteinase K.

--------------------------------------------------------------------------------

Supported by the NIH (NIH R01 NS46037, NIH R01 NS051480); the Brain Research Foundation, Chicago, IL; The John Miko Foundation for Prion Research; and the Pioneer Fund.

Disclosure: The authors report no disclosures.

Received March 18, 2008. Accepted in final form July 16, 2008.

http://www.neurology.org/cgi/content/abstract/71/18/1431?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=prion&searchid=1&FIRSTINDEX=0&volume=71&issue=18&resourcetype=HWCIT


Brain Advance Access published September 1, 2008

Phenotypic heterogeneity and genetic modification of P102L inherited prion disease in an international series

http://sporadicffi.blogspot.com/2008/09/phenotypic-heterogeneity-and-genetic.html


http://sporadicffi.blogspot.com/



HUMAN and ANIMAL TSE Classifications i.e. mad cow disease and the UKBSEnvCJD only theory JUNE 2008

snip...

Tissue infectivity and strain typing of the many variants of the human and animal TSEs are paramount in all variants of all TSE. There must be a proper classification that will differentiate between all these human TSE in order to do this. With the CDI and other more sensitive testing coming about, I only hope that my proposal will some day be taken seriously. ...

snip...

http://cjdmadcowbaseoct2007.blogspot.com/2008/06/human-and-animal-tse-classifications-ie.html




TSS

Wednesday, September 3, 2008

Phenotypic heterogeneity and genetic modification of P102L inherited prion disease in an international series

Brain Advance Access published September 1, 2008

Phenotypic heterogeneity and genetic modification of P102L inherited prion disease in an international series

T. E. F.Webb,1,2 M. Poulter,1 J. Beck,1 J.Uphill,1 G. Adamson,1 T. Campbell,1 J. Linehan,1 C. Powell,1 S. Brandner,1,2 S. Pal,1,2 D. Siddique,1,2 J. D.Wadsworth,1 S. Joiner,1 K. Alner,2 C. Petersen,2 S. Hampson,2 C. Rhymes,2 C. Treacy,2 E. Storey,3 M. D.Geschwind,4 A. H. Nemeth,5 S.Wroe,1,2 J. Collinge1,2 and S. Mead1,2 1MRC Prion Unit and Department of Neurodegenerative Disease,UCL Institute of Neurology, 2National Prion Clinic and National Hospital for Neurology & Neurosurgery, Queen Square, London,WC1N 3BG, 3Department of Medicine (Neuroscience), Monash University, Melbourne, Australia, 4Department of Neurology,University of California, San Francisco (UCSF), San Francisco, CA,USA and 5Department of Clinical Genetics, Churchill Hospital and Weatherall Institute of Molecular Medicine, John Radcliffe Hospital,Oxford,OX3 9DU, UK Correspondence to: Prof. John Collinge, Department of Neurodegenerative Disease and MRC Prion Unit, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, LondonWC1N 3BG, UK E-mail: j.collinge@prion.ucl.ac.uk

The largest kindred with inherited prion disease P102L, historically Gerstmann-Stra«ussler-Scheinker syndrome, originates from central England, with e¤migre¤ s now resident in various parts of the English-speaking world. We have collected data from 84 patients in the large UK kindred and numerous small unrelated pedigrees to investigate phenotypic heterogeneity and modifying factors.This collection represents by far the largest series of P102L patients so far reported.Microsatellite and genealogical analyses of eight separate European kindreds support multiple distinct mutational events at a cytosine-phosphate diester-guanidine dinucleotide mutation hot spot. All of the smaller P102L kindreds were linked to polymorphic human prion protein gene codon 129M andwere not connected by genealogy ormicrosatellite haplotype background to the large kindred or each other. While many present with classical Gerstmann-Stra«ussler-Scheinker syndrome, a slowly progressive cerebellar ataxia with later onset cognitive impairment, there is remarkable heterogeneity. A subset of patients present with prominent cognitive and psychiatric features and some have met diagnostic criteria for sporadic Creutzfeldt-Jakob disease. We show that polymorphic human prion protein gene codon 129 modifies age at onset: the earliest eight clinical onsets were all MM homozygotes and overall age at onset was 7 years earlier for MM compared with MV heterozygotes (P=0.02).Unexpectedly, apolipoprotein E4 carriers have a delayed age of onset by10 years (P=0.02).We found a preponderance of female patients comparedwithmales (54 females versus 30 males,P=0.01), which probably relates to ascertainment bias.However, thesemodifiers had no impact on a semi-quantitative pathological phenotype in 10 autopsied patients.These data allow an appreciation of the range of clinical phenotype, modern imaging andmolecular investigation and should inform genetic counselling of at-risk individuals, with the identification of two genetic modifiers.

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Discussion

The patients presented here constitute by far the largest study of the classical GSS-associated PRNP mutation, P102L. Modern investigation, molecular genetic techniques and advances in pathological examination have allowed us to revisit a historical British pedigree and other smaller kindreds. We find evidence of a mutation hot spot at codon 102, a subgroup presenting with rapid cognitive decline and the significant modification of phenotype by two single nucleotide polymorphisms. The microsatellite haplotyping presented here demonstrates the existence of multiple separate and worldwide P102L kindreds of UK origin, confirmed in most patients by established genealogical links that had not been identified previously. However, the identification of a further six UK P102L kindreds along with two others of European origin suggests that multiple mutational events have occurred in the recent past. This might be supported by the identification of at least one of these patients (6.VIII.1) in an individual without suggestive family history or of known P102L patients living nearby, suggesting that this might represent a novel mutation. Given the identification of IPD patients in otherwise typical sCJD presentations, as well as in patients without a family history of neurodegeneration, novel mutational events may occur more commonly than previously thought. The commonest point mutations associated with IPD occur at cytosine-phosphate diesterguanidine dinucleotide sites hypothesized to be mutation ‘hot spots’ in human DNA (Vollmert et al., 2006). These hot spots are related to the spontaneous demethylation of cytosine to thymidine. Cytosine-phosphate diester-guanidine dinucleotide sites are associated with E200K, D178N and P102L point mutations, which between them account for the bulk of IPD patients worldwide (Dagvadorj et al., 2002; Mead, 2006). An alternative possibility to multiple separate mutational events being responsible for these apparently unconnected P102L IPD kindreds is that these small pedigrees do share a common ancestor with the large pedigree but that this was long enough in the past for linkage to the disease haplotype to have broken down. We estimate a probability of recombination of the 3MB microsatellite haplotype as about 10% per generation (assuming a genetic:physical ratio of 3.7). The unexpected finding that significantly greater numbers of females were identified with P102L IPD and the consequently higher number of individuals having an affected mother rather than father as the parent from whom the mutation was inherited is puzzling. This discrepancy has been reported once previously in this family, albeit with smaller numbers of individuals and without available genetic techniques, allowing the linkage of kindreds not known to share ancestry (Baker et al., 1985). It has also been observed in the large 6-OPRI IPD kindred from the South-East of England (Mead et al., 2006). In the earlier study in P102L, the finding was explained by postulating that affected females had significantly more children than their unaffected siblings and that greater than half these were daughters. Such an explanation is intriguing, though hard to explain. Alternatively, because of possible illegitimacy, we suspected that genealogical research might more readily identify affected mothers than affected fathers. In order to consider the possibility of ascertainment bias, the gender of members of the kindred identified from parish records or census entries, but who have not been identified as having suffered from IPD P102L, were collected. An excess of males in these untraced individuals was indeed identified. When these were added to the presumed affected male and female individuals, an excess of females to males remained (82–68), although this was not significantly different from an expected proportion of 0.5. It seems likely that ascertainment bias is responsible for this gender difference, although the intriguing possibility of a biological explanation remains. While the majority of P102L IPD patients here present with progressive ataxia accompanied by mild or absent cognitive symptoms and signs, a subset present with a predominantly cognitive and or psychiatric onset, with mild or absent cerebellar signs initially. Psychiatric involvement has been severe enough to necessitate antipsychotic medication in four patients (VII.1, VII.8, VIII.4 and 3.VIII.1) and inpatient treatment in two (VII.1 and VII.8). The existence of these distinct phenotypes (cognitive and psychiatric versus cerebellar onset) is supported by the finding of early prominent frontal executive impairment on neuropsychology in these patients not seen in other patients so tested. Neuropsychological assessment is now routine at the National Prion Clinic but in the past this was more usually performed only when clinical evidence of cognitive impairment existed. In addition to these neuropsychological differences, there is a suggestion that the cognitive and Fig. 9 Photograph of original 1871 asylum entry relating to admission and care of III.3 from Fig. 2. His condition is described as hereditary and reference ismade to his relatives’ care in the same institution.He is reported as being ‘scarcely able to move one leg in ront of another’ and his countenance is described as ‘imbecile’. He appears to have had dementia as well as weakness: ‘Can only answer in monosyllables & then incoherently; is much paralysed’. He was treated with daily doses of brandy until he died. ‘Paralysis’ was listed as the cause on the death certificate. Page 12 of 15 Brain (2008) T. E. F.Webb et al. psychiatric presentations have an earlier age at onset and death. Neuropsychology also highlights, however, that most if not all patients have cognitive deficits when psychology is performed, even if the findings are subtle, although selection bias may limit this conclusion. No pathological correlates of these two syndrome types have been identified, although numbers compared are small. Kuru and growth hormone-associated prion disease are notable for their onset with cerebellar symptoms (Collinge, 2001), which prompts speculation that cerebellar onset in P102L might result from the onset of prion replication outside the central nervous system. The range of tissue available did not permit the thorough testing of this hypothesis. The high degree of clinical heterogeneity and the lack of characteristic findings on commonly available clinical neurological investigations make correct diagnosis of P102L IPD challenging. The finding of positive CSF 14-3-3 combined with the albeit unusual occurrence of periodic sharp wave complexes on EEG and an sCJD-like phenotype in some individuals raises the possibility of missed diagnosis. It also supports our clinical practice of advising PRNP analysis routinely in all those presenting with otherwise undiagnosed pre-senile dementing or ataxic illnesses. Peripheral sensory symptoms and muscle weakness appear almost universal during the course of P102L IPD. The demonstration of muscle denervation and axonal sensorimotor neuropathy suggest peripheral neurological pathology is responsible. Experimental mice over-expressing wild-type PrP have shown demyelinating peripheral nerve pathology (Westaway et al., 1994). However, evidence of peripheral neuropathy in P102L IPD was inconsistent and where present was axonal, a form that is not uncommon in the population from unrelated causes. No prion protein (scrapie isoform) positivity could be demonstrated on two muscle biopsies examined here and although an indirect pathological process could still be responsible, peripheral findings in P102L IPD may be incidental, while sensory symptoms could be centrally rather than peripherally driven. Presented for the first time here is the finding that P102L IPD patients with methionine homozygosity at codon 129 present significantly earlier than codon 129 heterozygotes. Earlier age at onset is well recognized in codon 129 homozygotes in other IPD mutations (Collinge et al., 1992; Poulter et al., 1992; Mead et al., 2006), although the association with IPD associated with point mutations rather than OPRIs is less clear (Dlouhy et al., 1992). The less strong effect in P102L with respect to 6-OPRI may explain why this observation has not been made before where smaller numbers of patients have been examined (Hainfellner et al., 1995; Barbanti et al., 1996). There are several possible mechanisms of action of codon 129 genotype on clinical phenotype. It has long been known that the interaction between prion protein, scrapie isoform (PrPSc) and prion protein, normal cellular isoform (PrPc) occurs most efficiently when the proteins have an identical primary structure (Palmer et al., 1991); therefore, prion replication may occur more rapidly and clinical onset earlier in 129MM individuals. As a further complexity, the primary structure of PrP determines the permissible conformations of PrPSc. The extent to which a pathogenic 102L-129M PrP conformer is permitted by wild-type PrPc with 129V or 129M may also be important [see Collinge, 2007 for a recent review (Collinge and Clarke, 2007)]. 102L-129M PrP may be able to adopt several different pathogenic conformations, which may be permissible to a greater or lesser extent by the wild-type protein (Parchi et al., 1998; Hill et al., 2006). The involvement of wild-type protein is known to be a variable phenomenon in P102L and a possible determinant of phenotype (Wadsworth et al., 2006). The identification of the P102L mutation on a methionine allele in all of the patients presented here with adequate haplotype data probably relates simply to the frequency of this allele in the background population. P102L patients existing on a codon 129 valine allele have been reported, apparently occurring in the context of a distinct phenotype with prominent psychiatric features and seizures, different from classical P102L codon 129 methionine patients (Young et al., 1997; Bianca et al., 2003). Such a phenotypic difference could relate to different prion strain propagation originating from the valine allele. Genotype–phenotype correlations presented here, corrected for codon 129, demonstrate an effect of APOE genotype on age at onset, with individuals carrying the E4 allele having a significantly later age at onset than those without. While this evidence appears in contrast to the strong association of E4 with risk of Alzheimer’s disease (Corder et al., 1993) and to published work on the possible impact of APOE polymorphisms in sCJD showing an overrepresentation of the E4 allele in sCJD patients (Amouyel et al., 1994; Van Everbroeck et al., 2001), such findings have not been replicated in all published studies (Nakagawa et al., 1995; Zerr et al., 1996) nor in our own observations (387 sCJD patients versus unaffected controls, unpublished data). Recent reports present a similar result in frontotemporalobar degeneration, with later disease onset in those with the APOE E4 genotype in the context of progranulin mutations (Gass et al., 2006; Beck et al., 2008). APOE may thus have contrasting effects in the context of different neurodegenerative disease types. Most of the P102L IPD patients shared common features on pathological analysis. Spongiform change, astrocytosis and PrP deposition, both as multicentric plaques and synaptic deposits, were seen in the majority. However, the degree of severity of spongiform change and plaque deposition were very variable. This did not seem to correlate with age at onset or duration of illness. Neither did predominantly cerebellar or cognitive clinical presentations seem to correlate with pathological findings. PRNP codon 129MM homozygotes and MV heterozygotes were equally represented in the pathology series but no significant differences were seen between these two groups. However, the small Inherited prion disease P102L Brain (2008) Page 13 of 15 numbers in each subgroup and the age of some of the samples examined (with tissue up to 30 years old) may prevent correlations from being made. A single highly atypical clinical patient showed no significant histological differences from the rest of the series, while an atypical pathological patient has limited clinical data, although what is known about this individual is not obviously different from the other patients examined. These results suggest no clear clinicopathological correlations, but sample size was necessarily small. Immunoblots of proteinase K-digested brain homogenate from P102L patients demonstrate a spectrum of involvement of protease-resistant wild-type PrP in P102L IPD (Wadsworth et al., 2006). Four of the seven P102L IPD patients examined in this study were negative for prion protein (scrapie isoform), which most probably relates to sampling issues and the differing density of PrP deposition in tissue samples both within and between patients. Our large study therefore does not expand the existing data and we were unable to test whether protease-resistant PrP diversity might contribute to clinical heterogeneity. This remains a plausible concept in IPD that requires a large series of fresh frozen brain tissue and molecular analysis of PrP type following partial protease digestion. The need for public health control measures, together with the evident diagnostic challenges that IPD heterogeneity causes, make a strong argument for including PRNP gene analysis in he list of investigations for suspected prion disease of any type and indeed of all undiagnosed familial dementia or cerebellar syndromes. Successful diagnosis allows clinicians to provide more accurate prognostic information to patients, to allow participation in the clinical trials and reduce the risk of iatrogenic transmission of disease. As a consequence of these geographically highly mobile ancestors, and the large number of untraced individuals in the nineteenth century who were clearly at risk of inheriting the P102L mutation, it remains likely that further patients and at-risk individuals exist who have yet to be identified. It is hoped that the data presented here will help to raise awareness of P102L IPD and its associated presentations.

snip...end...TSS

http://brain.oxfordjournals.org/cgi/reprint/awn202v2


please see also ;

http://sporadicffi.blogspot.com/


TSS