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Rudenskaya GE, Konovalov FA, Illarioshkin SN, Shchagina OA. [Gerstmann-Sträussler disease: a familial case with common PRNP mutation and atypical features]. Zh Nevrol Psikhiatr Im S S Korsakova 2023; 123:138-143. [PMID: 36843471 DOI: 10.17116/jnevro2023123021138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
Gerstmann-Sträussler disease (GSD) is a very rare autosomal dominant late-onset neurodegenerative disorder related to prion protein gene PRNP. Mutation p.Pro102Leu produces about 80% of cases, which are often named GSD-102. DNA testing provides exact diagnosis. In the presented Russian family there were 3 patients: a female index case, age 32 years, her brother, age 37 years (age of onset in both is 27 years) and their deceased father (onset in 35 years, death in 44 years). GSD was not suspected until whole exome sequencing in the female detected PRNP mutation p.Pro102Leu confirmed in her and in the brother by Sanger sequencing. Atypical features of the case are: early onset in siblings, absence of mental and behavioral problems in the female and in the father and mild disturbances in the brother; epilepsy in the brother; atypical onset with transient signs in the brother. Other intrafamilial differences are prevailing spastic paraparesis in the female in contrast to predominant ataxia in the brother and dysarthria absence in the female. The case illustrates GSD-102 variability, complicating clinical diagnostics.
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Affiliation(s)
| | - F A Konovalov
- Genomed Ltd, Moscow, Russia.,Laboratory of Clinical Bioinformatics, Moscow, Russia
| | | | - O A Shchagina
- Research Centre for Medical Genetics, Moscow, Russia
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2
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Goldman JS, Vallabh SM. Genetic counseling for prion disease: Updates and best practices. Genet Med 2022; 24:1993-2003. [PMID: 35819418 DOI: 10.1016/j.gim.2022.06.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 06/13/2022] [Accepted: 06/15/2022] [Indexed: 10/17/2022] Open
Abstract
Prion disease is a rare, fatal, and often rapidly progressive neurodegenerative disease. Ten to fifteen percent of cases are caused by autosomal dominant gain-of-function variants in the prion protein gene, PRNP. Rarity and phenotypic variability complicate diagnosis, often obscuring family history and leaving families unprepared for the genetic implications of an index case. Several recent developments inspire this update in best practices for prion disease genetic counseling. A new prion-detection assay has transformed symptomatic diagnosis. Meanwhile, penetrance, age of onset, and duration of illness have been systematically characterized across PRNP variants in a global cohort. Clinically, the traditional genotype-phenotype correlation has weakened over time, and the term genetic prion disease may now better serve providers than the historical subtypes Creutzfeldt-Jakob disease, fatal familial insomnia, and Gerstmann-Sträussler-Scheinker disease. Finally, in the age of genetically targeted therapies, clinical trials for prion disease are being envisaged, and healthy at-risk individuals may be best positioned to benefit. Such individuals need to be able to access clinical services for genetic counseling and testing. Thus, this update on the genetics of prion disease and best practices for genetic counseling for this disease aims to provide the information needed to expand genetic counseling services.
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Affiliation(s)
| | - Sonia M Vallabh
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA; Henry and Allison McCance Center for Brain Health, Massachusetts General Hospital, Boston, MA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA; Prion Alliance, Cambridge, MA.
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3
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Asante EA, Linehan JM, Tomlinson A, Jakubcova T, Hamdan S, Grimshaw A, Smidak M, Jeelani A, Nihat A, Mead S, Brandner S, Wadsworth JDF, Collinge J. Spontaneous generation of prions and transmissible PrP amyloid in a humanised transgenic mouse model of A117V GSS. PLoS Biol 2020; 18:e3000725. [PMID: 32516343 PMCID: PMC7282622 DOI: 10.1371/journal.pbio.3000725] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 05/06/2020] [Indexed: 12/02/2022] Open
Abstract
Inherited prion diseases are caused by autosomal dominant coding mutations in the human prion protein (PrP) gene (PRNP) and account for about 15% of human prion disease cases worldwide. The proposed mechanism is that the mutation predisposes to conformational change in the expressed protein, leading to the generation of disease-related multichain PrP assemblies that propagate by seeded protein misfolding. Despite considerable experimental support for this hypothesis, to-date spontaneous formation of disease-relevant, transmissible PrP assemblies in transgenic models expressing only mutant human PrP has not been demonstrated. Here, we report findings from transgenic mice that express human PrP 117V on a mouse PrP null background (117VV Tg30 mice), which model the PRNP A117V mutation causing inherited prion disease (IPD) including Gerstmann-Sträussler-Scheinker (GSS) disease phenotypes in humans. By studying brain samples from uninoculated groups of mice, we discovered that some mice (≥475 days old) spontaneously generated abnormal PrP assemblies, which after inoculation into further groups of 117VV Tg30 mice, produced a molecular and neuropathological phenotype congruent with that seen after transmission of brain isolates from IPD A117V patients to the same mice. To the best of our knowledge, the 117VV Tg30 mouse line is the first transgenic model expressing only mutant human PrP to show spontaneous generation of transmissible PrP assemblies that directly mirror those generated in an inherited prion disease in humans. Transgenic mice expressing the human prion protein containing a mutation linked to the inherited prion disease Gerstmann-Sträussler-Scheinker disease develop spontaneous neuropathology. This represents the first human prion protein transgenic model to show spontaneous generation of transmissible prion assemblies that directly mirror those generated in humans.
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Affiliation(s)
- Emmanuel A. Asante
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, London, United Kingdom
- * E-mail: (EAA); (JDFW); (JC)
| | | | - Andrew Tomlinson
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, London, United Kingdom
| | - Tatiana Jakubcova
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, London, United Kingdom
| | - Shyma Hamdan
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, London, United Kingdom
| | - Andrew Grimshaw
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, London, United Kingdom
| | - Michelle Smidak
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, London, United Kingdom
| | - Asif Jeelani
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, London, United Kingdom
| | - Akin Nihat
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, London, United Kingdom
| | - Simon Mead
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, London, United Kingdom
| | - Sebastian Brandner
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, London, United Kingdom
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology and Division of Neuropathology, the National Hospital For Neurology and Neurosurgery, University College London NHS Foundation Trust, Queen Square, London United Kingdom
| | - Jonathan D. F. Wadsworth
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, London, United Kingdom
- * E-mail: (EAA); (JDFW); (JC)
| | - John Collinge
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, London, United Kingdom
- * E-mail: (EAA); (JDFW); (JC)
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4
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Mitrová E, Záková-Slivarichová D, Stelzer M, Belay G, Janáková A, Koscová S. Genetic Creutzfeldt-Jakob disease affected monozygotic twins: Analysis of survival time, age at death and possible exogenous risk factors. J Clin Neurosci 2019; 66:191-195. [PMID: 31097381 DOI: 10.1016/j.jocn.2019.04.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 02/20/2019] [Accepted: 04/12/2019] [Indexed: 11/19/2022]
Abstract
Three monozygotic twin pairs with the Creutzfeldt-Jakob diseases-specific mutation E200K are described. All three have been concordant for genetic CJDE200K and discordant for the age at death and the duration of the disease. Twin pairs have been compared with genetically non - identical sibling pairs also concordant for genetic CJDE200K and discordant for the age at death. The difference of the mean age at death in compared subgroups was not significant. Detailed analysis of twin pairs revealed considerable differences in the duration and quality of chronic stress, induced by the analysed exogenous factors. The stress was evidently of higher intensity in two of the three earlier affected twins. Clear correlation between the age at death and medical history of twins was not observed. The discordance of twins with genetic CJDE200K in the age at death and the striking correlation with the discordant intensity of analysed exogenous influence, draw attention to described potential risk factors (mainly to chronic social, economic and emotional stress) and support their role in accelerating the clinical onset of genetic CJDE200K.
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Affiliation(s)
- Eva Mitrová
- Department of Prion Diseases, Slovak Medical University, Limbová 14, Bratislava, Slovakia.
| | | | - Martin Stelzer
- Department of Prion Diseases, Slovak Medical University, Limbová 14, Bratislava, Slovakia
| | - Girma Belay
- Department of Prion Diseases, Slovak Medical University, Limbová 14, Bratislava, Slovakia
| | - Alzbeta Janáková
- Department of Prion Diseases, Slovak Medical University, Limbová 14, Bratislava, Slovakia
| | - Silvia Koscová
- Department of Prion Diseases, Slovak Medical University, Limbová 14, Bratislava, Slovakia
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Honda H, Sasaki K, Takashima H, Mori D, Koyama S, Suzuki SO, Iwaki T. Different Complicated Brain Pathologies in Monozygotic Twins With Gerstmann-Sträussler-Scheinker Disease. J Neuropathol Exp Neurol 2017; 76:854-863. [PMID: 28922846 DOI: 10.1093/jnen/nlx068] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Gerstmann-Sträussler-Scheinker disease (GSS) is an autosomal, dominantly inherited prion disease. In this study, we present different complicated brain pathologies determined postmortem of monozygotic GSS twin sisters. Case 1 showed cerebellar ataxia at the age of 58 years, and died at 66 years. Case 2 became symptomatic at the age of 75 years, and died at 79 years. There was a 17-year difference in the age of onset between the twins. Postmortem examination revealed numerous prion protein (PrP) plaques in the brains of both cases. The spongiform change and brain atrophy in case 1 were more severe compared with those in case 2. Western-blot analysis identified proteinase-resistant PrP (PrPres) at the molecular weight of 21-30 kDa and 8 kDa in the twins. Gel filtration revealed that PrPres was mainly composed of PrP oligomer. PrPres signal patterns were similar between the twins. Additionally, case 1 showed α-synucleinopathy and case 2 showed Alzheimer disease pathology. These different proteinopathies were involved in the amyloid plaque formations of both cases. The degree of GSS pathology was mainly related to disease duration. The amyloid plaque formations could be decorated by concomitant neuropathological changes such as α-synucleinopathy and tauopathy.
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Affiliation(s)
- Hiroyuki Honda
- Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, Higashi-Ku, Fukuoka, Japan; Department of Neurology, Saga-Ken Medical Centre Koseikan, Saga, Japan; Department of Pathology, Saga-Ken Medical Centre Koseikan, Saga, Japan
| | - Kensuke Sasaki
- Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, Higashi-Ku, Fukuoka, Japan; Department of Neurology, Saga-Ken Medical Centre Koseikan, Saga, Japan; Department of Pathology, Saga-Ken Medical Centre Koseikan, Saga, Japan
| | - Hiroshi Takashima
- Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, Higashi-Ku, Fukuoka, Japan; Department of Neurology, Saga-Ken Medical Centre Koseikan, Saga, Japan; Department of Pathology, Saga-Ken Medical Centre Koseikan, Saga, Japan
| | - Daisuke Mori
- Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, Higashi-Ku, Fukuoka, Japan; Department of Neurology, Saga-Ken Medical Centre Koseikan, Saga, Japan; Department of Pathology, Saga-Ken Medical Centre Koseikan, Saga, Japan
| | - Sachiko Koyama
- Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, Higashi-Ku, Fukuoka, Japan; Department of Neurology, Saga-Ken Medical Centre Koseikan, Saga, Japan; Department of Pathology, Saga-Ken Medical Centre Koseikan, Saga, Japan
| | - Satoshi O Suzuki
- Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, Higashi-Ku, Fukuoka, Japan; Department of Neurology, Saga-Ken Medical Centre Koseikan, Saga, Japan; Department of Pathology, Saga-Ken Medical Centre Koseikan, Saga, Japan
| | - Toru Iwaki
- Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, Higashi-Ku, Fukuoka, Japan; Department of Neurology, Saga-Ken Medical Centre Koseikan, Saga, Japan; Department of Pathology, Saga-Ken Medical Centre Koseikan, Saga, Japan
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Elezgarai SR, Fernández-Borges N, Eraña H, Sevillano AM, Charco JM, Harrathi C, Saá P, Gil D, Kong Q, Requena JR, Andréoletti O, Castilla J. Generation of a new infectious recombinant prion: a model to understand Gerstmann-Sträussler-Scheinker syndrome. Sci Rep 2017; 7:9584. [PMID: 28851967 PMCID: PMC5575253 DOI: 10.1038/s41598-017-09489-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 07/10/2017] [Indexed: 12/15/2022] Open
Abstract
Human transmissible spongiform encephalopathies (TSEs) or prion diseases are a group of fatal neurodegenerative disorders that include Kuru, Creutzfeldt-Jakob disease, Gerstmann-Sträussler-Scheinker syndrome (GSS), and fatal familial insomnia. GSS is a genetically determined TSE caused by a range of mutations within the prion protein (PrP) gene. Several animal models, based on the expression of PrPs carrying mutations analogous to human heritable prion diseases, support that mutations might predispose PrP to spontaneously misfold. An adapted Protein Misfolding Cyclic Amplification methodology based on the use of human recombinant PrP (recPMCA) generated different self-propagating misfolded proteins spontaneously. These were characterized biochemically and structurally, and the one partially sharing some of the GSS PrPSc molecular features was inoculated into different animal models showing high infectivity. This constitutes an infectious recombinant prion which could be an invaluable model for understanding GSS. Moreover, this study proves the possibility to generate recombinant versions of other human prion diseases that could provide a further understanding on the molecular features of these devastating disorders.
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Affiliation(s)
- Saioa R Elezgarai
- CIC bioGUNE, Parque tecnológico de Bizkaia, Derio, 48160, Bizkaia, Spain
| | | | - Hasier Eraña
- CIC bioGUNE, Parque tecnológico de Bizkaia, Derio, 48160, Bizkaia, Spain
| | - Alejandro M Sevillano
- CIMUS Biomedical Research Institute, University of Santiago de Compostela-IDIS, Santiago de Compostela, Spain
| | - Jorge M Charco
- CIC bioGUNE, Parque tecnológico de Bizkaia, Derio, 48160, Bizkaia, Spain
| | - Chafik Harrathi
- CIC bioGUNE, Parque tecnológico de Bizkaia, Derio, 48160, Bizkaia, Spain
| | - Paula Saá
- American Red Cross, Gaithersburg, MD, USA
| | - David Gil
- CIC bioGUNE, Parque tecnológico de Bizkaia, Derio, 48160, Bizkaia, Spain
| | - Qingzhong Kong
- Department of Pathology, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Jesús R Requena
- CIMUS Biomedical Research Institute, University of Santiago de Compostela-IDIS, Santiago de Compostela, Spain
| | - Olivier Andréoletti
- Ecole Nationale du Veterinaire, Service de Pathologie du Bétail, Toulouse, 31076, France
| | - Joaquín Castilla
- CIC bioGUNE, Parque tecnológico de Bizkaia, Derio, 48160, Bizkaia, Spain. .,IKERBASQUE, Basque Foundation for Science, Bilbao, 48011, Bizkaia, Spain.
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7
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Li HF, Liu ZJ, Dong HL, Xie JJ, Zhao SY, Ni W, Dong Y, Wu ZY. Clinical features of Chinese patients with Gerstmann-Sträussler-Scheinker identified by targeted next-generation sequencing. Neurobiol Aging 2016; 49:216.e1-216.e5. [PMID: 28340953 DOI: 10.1016/j.neurobiolaging.2016.09.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 09/04/2016] [Accepted: 09/25/2016] [Indexed: 12/11/2022]
Abstract
Gerstmann-Sträussler-Scheinker (GSS) is an autosomal dominant neurodegenerative disease due to mutations within prion protein (PRNP) gene. Clinically, it is not easy to distinguish GSS from spinocerebellar ataxia (SCA), especially in the early stage of disease. We aimed to identify genetic mutations in 8 Chinese pedigrees with dominant ataxia but excluded dynamic mutations of SCA genes. Targeted next-generation sequencing was performed in the 8 probands. A customized panel was designed to capture 24 known causative genes, including 15 autosomal dominant SCA genes and 9 dementia-related genes. A 2-year follow-up was performed in these patients who harbored mutation. Of the 8 probands, 5 were identified to harbor the p.P102L mutation within PRNP. All these 5 cases had progressive ataxia with age at onset ranging from 48 to 52 years (49.5 ± 4.51). Remarkable phenotypic heterogeneity was observed in them. Cognitive decline was found in 4/5 probands. The average duration from initial symptoms to cognitive decline is 32.5 months, ranging from 22 to 48 months. In this study, we presented the detailed clinical features of 5 GSS pedigrees with PRNP p.P102L mutation. The variable phenotypes among these GSS patients indicated other genetic or environmental factors might be involved in the phenotypic heterogeneity of GSS. Our findings also support the proposal that screening of PRNP mutations should be performed for the patients with dominant ataxia if dynamic mutations of SCA genes were excluded.
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Affiliation(s)
- Hong-Fu Li
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and the Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhi-Jun Liu
- Department of Neurology, Huashan Hospital, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Hai-Lin Dong
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and the Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, China
| | - Juan-Juan Xie
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and the Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, China
| | - Shao-Yun Zhao
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and the Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, China
| | - Wang Ni
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and the Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, China
| | - Yi Dong
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and the Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhi-Ying Wu
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and the Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, China.
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Xiromerisiou G, Houlden H, Sailer A, Silveira-Moriyama L, Hardy J, Lees AJ. Identical twins with Leucine rich repeat kinase type 2 mutations discordant for Parkinson's disease. Mov Disord 2012; 27:1323. [PMID: 22488887 PMCID: PMC3664414 DOI: 10.1002/mds.24924] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Revised: 12/22/2011] [Accepted: 01/02/2012] [Indexed: 11/16/2022] Open
Affiliation(s)
| | | | | | | | | | - Andrew J Lees
- *Correspondence to: Andrew J. Lees, UCL, IoN, Reta Lila Weston Institute of Neurological Studies, 1 Wakefield Street, London WC1N 1PJ, UK;
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9
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Stevens JC, Fisher EMC, Mead S. How does the genetic assassin select its neuronal target? Mamm Genome 2011; 22:139-47. [PMID: 21373885 DOI: 10.1007/s00335-011-9319-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Accepted: 01/23/2011] [Indexed: 12/12/2022]
Abstract
Through many different routes of analysis, including human familial studies and animal models, we are identifying an increasing number of genes that are causative for human neurodegenerative disease and are now in a position for many such disorders to dissect the molecular pathology that gives rise to neuronal death. Yet a paradox remains: The majority of the genes identified cause neurodegeneration in specific neuronal subtypes, but the genes themselves are ubiquitously expressed. Furthermore, the different mutations in the same gene may cause quite different types of neurodegeneration. Something in our understanding of neurodegenerative disease is clearly missing, and we refer to this as the phenomenon of "neuronal targeting." Here we discuss possible explanations for neuronal targeting, why specific neuronal subtypes are vulnerable to specific mutations in ubiquitously expressed genes.
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Affiliation(s)
- James C Stevens
- Department of Neurodegenerative Disease, University College London, Queen Square, London, WC1N 3BG, UK
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10
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Iyegbe CO, Abiola OO, Towlson C, Powell JF, Whatley SA. Evidence for varied aetiologies regulating the transmission of prion disease: implications for understanding the heritable basis of prion incubation times. PLoS One 2010; 5:e14186. [PMID: 21152031 PMCID: PMC2996284 DOI: 10.1371/journal.pone.0014186] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Accepted: 08/12/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Transmissible Spongiform Encephalopathies (TSEs) are a group of progressive fatal neurodegenerative disorders, triggered by abnormal folding of the endogenous prion protein molecule. The encoding gene is a major biological factor influencing the length of the asymptomatic period after infection. It remains unclear the extent to which the variation between quantitative trait loci (QTLs) reported in mouse models is due to methodological differences between approaches or genuine differences between traits. With this in mind, our approach to identifying genetic factors has sought to extend the linkage mapping approach traditionally applied, to a series of additional traits, while minimising methodological variability between them. Our approach allows estimations of heritability to be derived, as well as predictions to be made about possible existence of genetic overlap between the various traits. METHODOLOGY/PRINCIPAL FINDINGS Our data indicate a surprising degree of heritability (up to 60%). Correlations between traits are also identified. A series of QTLs on chromosomes 1, 2, 3, 4, 6, 11 and 18 accompany our heritability estimates. However, only a locus on chromosome 11 has a general effect across all 4 models explored. CONCLUSIONS/SIGNIFICANCE We have achieved some success in detecting novel and pre-existing QTLs associated with incubation time. However, aside from the general effects described, the model-specific nature of the broader host genetic architecture has also been brought into clearer focus. This suggests that genetic overlap can only partially account for the general heritability of incubation time when factors, such as the nature of the TSE agent and the route of administration are considered. This point is highly relevant to vCJD (a potential threat to public health) where the route of primary importance is oral, while the QTLs being sought derive exclusively from studies of the ic route. Our results highlight the limitations of a single-model approach to QTL-mapping of TSEs.
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Affiliation(s)
- Conrad O Iyegbe
- Psychosis Centre, Institute of Psychiatry, King's College London, London, United Kingdom.
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11
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Zwijnenburg PJG, Meijers-Heijboer H, Boomsma DI. Identical but not the same: the value of discordant monozygotic twins in genetic research. Am J Med Genet B Neuropsychiatr Genet 2010; 153B:1134-49. [PMID: 20468073 DOI: 10.1002/ajmg.b.31091] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Monozygotic (MZ) twins show remarkable resemblance in many aspects of behavior, health, and disease. Until recently, MZ twins were usually called "genetically identical"; however, evidence for genetic and epigenetic differences within rare MZ twin pairs has accumulated. Here, we summarize the literature on MZ twins discordant for Mendelian inherited disorders and chromosomal abnormalities. A systematic literature search for English articles on discordant MZ twin pairs was performed in Web of Science and PubMed. A total number of 2,016 publications were retrieved and reviewed and 439 reports were retained. Discordant MZ twin pairs are informative in respect to variability of phenotypic expression, pathogenetic mechanisms, epigenetics, and post-zygotic mutagenesis and may serve as a model for research on genetic defects. The analysis of single discordant MZ twin pairs may represent an elegant approach to identify genes in inherited disorders.
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Affiliation(s)
- Petra J G Zwijnenburg
- Department of Clinical Genetics, VU University Medical Center, de Boelelaan 1117, Amsterdam, the Netherlands.
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