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Molecular Pathophysiological Mechanisms in Huntington's Disease. Biomedicines 2022; 10:biomedicines10061432. [PMID: 35740453 PMCID: PMC9219859 DOI: 10.3390/biomedicines10061432] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/12/2022] [Accepted: 06/14/2022] [Indexed: 12/11/2022] Open
Abstract
Huntington’s disease is an inherited neurodegenerative disease described 150 years ago by George Huntington. The genetic defect was identified in 1993 to be an expanded CAG repeat on exon 1 of the huntingtin gene located on chromosome 4. In the following almost 30 years, a considerable amount of research, using mainly animal models or in vitro experiments, has tried to unravel the complex molecular cascades through which the transcription of the mutant protein leads to neuronal loss, especially in the medium spiny neurons of the striatum, and identified excitotoxicity, transcriptional dysregulation, mitochondrial dysfunction, oxidative stress, impaired proteostasis, altered axonal trafficking and reduced availability of trophic factors to be crucial contributors. This review discusses the pathogenic cascades described in the literature through which mutant huntingtin leads to neuronal demise. However, due to the ubiquitous presence of huntingtin, astrocytes are also dysfunctional, and neuroinflammation may additionally contribute to Huntington’s disease pathology. The quest for therapies to delay the onset and reduce the rate of Huntington’s disease progression is ongoing, but is based on findings from basic research.
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Pigazzini ML, Lawrenz M, Margineanu A, Kaminski Schierle GS, Kirstein J. An Expanded Polyproline Domain Maintains Mutant Huntingtin Soluble in vivo and During Aging. Front Mol Neurosci 2021; 14:721749. [PMID: 34720872 PMCID: PMC8554126 DOI: 10.3389/fnmol.2021.721749] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 08/30/2021] [Indexed: 02/02/2023] Open
Abstract
Huntington's disease is a dominantly inherited neurodegenerative disorder caused by the expansion of a CAG repeat, encoding for the amino acid glutamine (Q), present in the first exon of the protein huntingtin. Over the threshold of Q39 HTT exon 1 (HTTEx1) tends to misfold and aggregate into large intracellular structures, but whether these end-stage aggregates or their on-pathway intermediates are responsible for cytotoxicity is still debated. HTTEx1 can be separated into three domains: an N-terminal 17 amino acid region, the polyglutamine (polyQ) expansion and a C-terminal proline rich domain (PRD). Alongside the expanded polyQ, these flanking domains influence the aggregation propensity of HTTEx1: with the N17 initiating and promoting aggregation, and the PRD modulating it. In this study we focus on the first 11 amino acids of the PRD, a stretch of pure prolines, which are an evolutionary recent addition to the expanding polyQ region. We hypothesize that this proline region is expanding alongside the polyQ to counteract its ability to misfold and cause toxicity, and that expanding this proline region would be overall beneficial. We generated HTTEx1 mutants lacking both flanking domains singularly, missing the first 11 prolines of the PRD, or with this stretch of prolines expanded. We then followed their aggregation landscape in vitro with a battery of biochemical assays, and in vivo in novel models of C. elegans expressing the HTTEx1 mutants pan-neuronally. Employing fluorescence lifetime imaging we could observe the aggregation propensity of all HTTEx1 mutants during aging and correlate this with toxicity via various phenotypic assays. We found that the presence of an expanded proline stretch is beneficial in maintaining HTTEx1 soluble over time, regardless of polyQ length. However, the expanded prolines were only advantageous in promoting the survival and fitness of an organism carrying a pathogenic stretch of Q48 but were extremely deleterious to the nematode expressing a physiological stretch of Q23. Our results reveal the unique importance of the prolines which have and still are evolving alongside expanding glutamines to promote the function of HTTEx1 and avoid pathology.
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Affiliation(s)
- Maria Lucia Pigazzini
- Department of Molecular Physiology and Cell Biology, Leibniz Research Institute for Molecular Pharmacology in the Forschungsverbund Berlin e.V. (FMP), Berlin, Germany
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Mandy Lawrenz
- Department of Molecular Physiology and Cell Biology, Leibniz Research Institute for Molecular Pharmacology in the Forschungsverbund Berlin e.V. (FMP), Berlin, Germany
| | - Anca Margineanu
- Advanced Light Microscopy, Max-Delbrück Centrum for Molecular Medicine (MDC), Berlin, Germany
| | - Gabriele S. Kaminski Schierle
- Molecular Neuroscience Group, Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, United Kingdom
| | - Janine Kirstein
- Department of Molecular Physiology and Cell Biology, Leibniz Research Institute for Molecular Pharmacology in the Forschungsverbund Berlin e.V. (FMP), Berlin, Germany
- Department of Cell Biology, University of Bremen, Bremen, Germany
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Vuono R, Kouli A, Legault EM, Chagnon L, Allinson KS, La Spada A, Biunno I, Barker RA, Drouin‐Ouellet J. Association Between Toll-Like Receptor 4 (TLR4) and Triggering Receptor Expressed on Myeloid Cells 2 (TREM2) Genetic Variants and Clinical Progression of Huntington's Disease. Mov Disord 2020; 35:401-408. [PMID: 31724242 PMCID: PMC7154663 DOI: 10.1002/mds.27911] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 07/31/2019] [Accepted: 09/09/2019] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Although Huntington's disease (HD) is caused by a single dominant gene, it is clear that there are genetic modifiers that may influence the age of onset and disease progression. OBJECTIVES We sought to investigate whether new inflammation-related genetic variants may contribute to the onset and progression of HD. METHODS We first used postmortem brain material from patients at different stages of HD to look at the protein expression of toll-like receptor 4 (TLR4) and triggering receptor expressed on myeloid cells 2 (TREM2). We then genotyped the TREM2 R47H gene variant and 3 TLR4 single nucleotide polymorphisms in a large cohort of HD patients from the European Huntington's Disease Network REGISTRY. RESULTS We found an increase in the number of cells expressing TREM2 and TLR4 in postmortem brain samples from patients dying with HD. We also found that the TREM2 R47H gene variant was associated with changes in cognitive decline in the large cohort of HD patients, whereas 2 of 3 TLR4 single nucleotide polymorphisms assessed were associated with changes in motor progression in this same group. CONCLUSIONS These findings identify TREM2 and TLR4 as potential genetic modifiers for HD and suggest that inflammation influences disease progression in this condition. © 2019 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Romina Vuono
- John van Geest Centre for Brain Repair & Department of Neurology, Department of Clinical NeurosciencesUniversity of CambridgeCambridgeUnited Kingdom
- Medway School of PharmacyUniversity of Kent at MedwayKentUnited Kingdom
| | - Antonina Kouli
- John van Geest Centre for Brain Repair & Department of Neurology, Department of Clinical NeurosciencesUniversity of CambridgeCambridgeUnited Kingdom
| | | | | | - Kieren S. Allinson
- Department of PathologyCambridge University Hospitals NHS (National Health Service) Foundation TrustCambridgeUnited Kingdom
| | | | | | - Ida Biunno
- Institute for Genetic and Biomedical Research ‐ CNRMilanoItaly
| | - Roger A. Barker
- John van Geest Centre for Brain Repair & Department of Neurology, Department of Clinical NeurosciencesUniversity of CambridgeCambridgeUnited Kingdom
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Chen Z, Sequeiros J, Tang B, Jiang H. Genetic modifiers of age-at-onset in polyglutamine diseases. Ageing Res Rev 2018; 48:99-108. [PMID: 30355507 DOI: 10.1016/j.arr.2018.10.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 08/03/2018] [Accepted: 10/17/2018] [Indexed: 11/25/2022]
Abstract
Polyglutamine (polyQ) diseases are a group of clinically and genetically heterogeneous neurodegenerative diseases. Expansion size correlates with age-at-onset (AO) and severity, and shows a critical threshold for each polyQ disease. Although an expanded CAG tract is sufficient to trigger disease, not all variation in AO is explained by (CAG)n length, which suggests the contribution of other modifying factors. Methods used to identify genetic modifiers in polyQ diseases have progressed from candidate genes to unbiased genome-wide searches. Inconsistency of results from candidate-genes studies are partly explained by sample size, study design and variable population frequency of "polymorphisms"; a genome-wide search may help elucidating more precise disease mechanisms underlying specific interaction networks. We review known genetic modifiers for polyQ diseases, and discuss developing strategies to find modulation, from common variants to networks disclosing small cumulative effects of key genes and modifying pathways. This may lead to a better understanding of genotype-phenotype correlation and the proposal of new potential targets for therapeutical interventions.
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Garcia TP, Marder K, Wang Y. Statistical modeling of Huntington disease onset. HANDBOOK OF CLINICAL NEUROLOGY 2018; 144:47-61. [PMID: 28947125 DOI: 10.1016/b978-0-12-801893-4.00004-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Huntington disease (HD) is caused by a CAG trinucleotide expansion in the huntingtin gene. We now have the power to predict age-at-onset from subject-specific features like motor and neuroimaging measures. In clinical trials, properly modeling onset age is important, because it improves power calculations and directs clinicians to recruit subjects with certain features. The history of modeling onset, from simple linear and logistic regression to advanced survival models, is discussed. We highlight their advantages and disadvantages, emphasizing the methodological challenges when genetic mutation status is unavailable. We also discuss the potential bias and higher variability incurred from the uncertainty associated with subjective definitions for onset. Methods to adjust for the uncertainty in survival models are still in their infancy, but would be beneficial for HD and neurodegenerative diseases with long prodromal periods like Alzheimer's and Parkinson's disease.
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Affiliation(s)
- Tanya P Garcia
- Department of Epidemiology and Biostatistics, Texas A&M Health Science Center, College Station, TX, United States.
| | - Karen Marder
- Departments of Neurology and Psychiatry, Sergievsky Center and Taub Institute, Columbia University Medical Center, New York, NY, United States
| | - Yuanjia Wang
- Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, NY, United States
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Risk factors for the onset and progression of Huntington disease. Neurotoxicology 2017; 61:79-99. [PMID: 28111121 DOI: 10.1016/j.neuro.2017.01.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 01/11/2017] [Indexed: 01/10/2023]
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder characterized by chorea, behavioural and psychiatric manifestations, and dementia, caused by a CAG triplet repeat expansion in the huntingtin gene. Systematic review of the literature was conducted to determine the risk factors for the onset and progression of HD. Multiple databases were searched, using terms specific to Huntington disease and to studies of aetiology, risk, prevention and genetics, limited to studies on human subjects published in English or French between 1950 and 2010. Two reviewers independently screened the abstracts and identified potentially relevant articles for full-text review using predetermined inclusion criteria. Three major categories of risk factors for onset of HD were identified: CAG repeat length in the huntingtin gene, CAG instability, and genetic modifiers. Of these, CAG repeat length in the huntingtin gene is the most important risk factor. For the progression of HD: genetic, demographic, past medical/clinical and environmental risk factors have been studied. Of these factors, genetic factors appear to play the most important role in the progression of HD. Among the potential risk factors, CAG repeat length in the mutant allele was found to be a relatively consistent and significant risk factor for the progression of HD, especially in motor, cognitive, and other neurological symptom deterioration. In addition, there were many consistent results in the literature indicating that a higher number of CAG repeats was associated with shorter survival, faster institutionalization, and earlier percutaneous endoscopic gastrostomy.
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Kay C, Hayden MR, Leavitt BR. Epidemiology of Huntington disease. HANDBOOK OF CLINICAL NEUROLOGY 2017; 144:31-46. [DOI: 10.1016/b978-0-12-801893-4.00003-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Arning L. The search for modifier genes in Huntington disease – Multifactorial aspects of a monogenic disorder. Mol Cell Probes 2016; 30:404-409. [DOI: 10.1016/j.mcp.2016.06.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 06/29/2016] [Accepted: 06/29/2016] [Indexed: 11/24/2022]
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Sun YM, Zhang YB, Wu ZY. Huntington's Disease: Relationship Between Phenotype and Genotype. Mol Neurobiol 2016; 54:342-348. [PMID: 26742514 DOI: 10.1007/s12035-015-9662-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 12/17/2015] [Indexed: 12/19/2022]
Abstract
Huntington's disease (HD) is an autosomal dominant inherited neurodegenerative disease with the typical manifestations of involuntary movements, psychiatric and behavior disorders, and cognitive impairment. It is caused by the dynamic mutation in CAG triplet repeat number in exon 1 of huntingtin (HTT) gene. The symptoms of HD especially the age at onset are related to the genetic characteristics, both the CAG triplet repeat and the modified factors. Here, we reviewed the recent advancement on the genotype-phenotype relationship of HD, mainly focus on the characteristics of different expanded CAG repeat number, genetic modifiers, and CCG repeat number in the 3' end of CAG triplet repeat and their effects on the phenotype. We also reviewed the special forms of HD (juvenile HD, atypical onset HD, and homozygous HD) and their phenotype-genotype correlations. The review will aid clinicians to predict the onset age and disease course of HD, give the genetic counseling, and accelerate research into the HD mechanism.
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Affiliation(s)
- Yi-Min Sun
- Department of Neurology and Institute of Neurology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Yan-Bin Zhang
- 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.,Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou, 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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Vital M, Bidegain E, Raggio V, Esperon P. Molecular characterization of genes modifying the age at onset in Huntington's disease in Uruguayan patients. Int J Neurosci 2015; 126:510-513. [DOI: 10.3109/00207454.2015.1036422] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Lauterbach EC. Neuroprotective effects of psychotropic drugs in Huntington's disease. Int J Mol Sci 2013; 14:22558-603. [PMID: 24248060 PMCID: PMC3856079 DOI: 10.3390/ijms141122558] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 10/16/2013] [Accepted: 10/16/2013] [Indexed: 02/06/2023] Open
Abstract
Psychotropics (antipsychotics, mood stabilizers, antidepressants, anxiolytics, etc.) are commonly prescribed to treat Huntington’s disease (HD). In HD preclinical models, while no psychotropic has convincingly affected huntingtin gene, HD modifying gene, or huntingtin protein expression, psychotropic neuroprotective effects include upregulated huntingtin autophagy (lithium), histone acetylation (lithium, valproate, lamotrigine), miR-222 (lithium-plus-valproate), mitochondrial protection (haloperidol, trifluoperazine, imipramine, desipramine, nortriptyline, maprotiline, trazodone, sertraline, venlafaxine, melatonin), neurogenesis (lithium, valproate, fluoxetine, sertraline), and BDNF (lithium, valproate, sertraline) and downregulated AP-1 DNA binding (lithium), p53 (lithium), huntingtin aggregation (antipsychotics, lithium), and apoptosis (trifluoperazine, loxapine, lithium, desipramine, nortriptyline, maprotiline, cyproheptadine, melatonin). In HD live mouse models, delayed disease onset (nortriptyline, melatonin), striatal preservation (haloperidol, tetrabenazine, lithium, sertraline), memory preservation (imipramine, trazodone, fluoxetine, sertraline, venlafaxine), motor improvement (tetrabenazine, lithium, valproate, imipramine, nortriptyline, trazodone, sertraline, venlafaxine), and extended survival (lithium, valproate, sertraline, melatonin) have been documented. Upregulated CREB binding protein (CBP; valproate, dextromethorphan) and downregulated histone deacetylase (HDAC; valproate) await demonstration in HD models. Most preclinical findings await replication and their limitations are reviewed. The most promising findings involve replicated striatal neuroprotection and phenotypic disease modification in transgenic mice for tetrabenazine and for sertraline. Clinical data consist of an uncontrolled lithium case series (n = 3) suggesting non-progression and a primarily negative double-blind, placebo-controlled clinical trial of lamotrigine.
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Affiliation(s)
- Edward C Lauterbach
- Department of Psychiatry and Behavioral Sciences, Mercer University School of Medicine, 655 First Street, Macon, GA 31201, USA.
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Vittori A, Orth M, Roos RAC, Outeiro TF, Giorgini F, Hollox EJ. β-Defensin Genomic Copy Number Does Not Influence the Age of Onset in Huntington's Disease. J Huntingtons Dis 2013; 2:107-124. [PMID: 24587836 DOI: 10.3233/jhd-130047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by the abnormal expansion of a CAG triplet repeat tract in the huntingtin gene. While the length of this CAG expansion is the major determinant of the age of onset (AO), other genetic factors have also been shown to play a modulatory role. Recent evidence suggests that neuroinflammation is a pivotal factor in the pathogenesis of HD, and that targeting this process may have important therapeutic ramifications. The human β-defensin 2 (hBD2) - encoded by DEFB4 - is an antimicrobial peptide that exhibits inducible expression in astrocytes during inflammation and is an important regulator of innate and adaptive immune response. Therefore, DEFB4 may contribute to the neuroinflammatory processes observed in HD. OBJECTIVE In this study we tested the hypothesis that copy number variation (CNV) of the β-defensin region, including DEFB4, modifies the AO in HD. METHODS AND RESULTS We genotyped β-defensin CNV in 490 HD individuals using the paralogue ratio test and found no association between β-defensin CNV and onset of HD. CONCLUSIONS We conclude that it is unlikely that DEFB4 plays a role in HD pathogenesis.
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Affiliation(s)
- Angelica Vittori
- Department of Genetics, University of Leicester, Leicester, UK ; Cell and Molecular Neuroscience Unit, Instituto de Medicina Molecular, Lisboa, Portugal
| | - Michael Orth
- Department of Neurology, University of Ulm, Ulm, Germany
| | - Raymund A C Roos
- Leiden University Medical Center, Department of Neurology, The Netherlands
| | - Tiago F Outeiro
- Cell and Molecular Neuroscience Unit, Instituto de Medicina Molecular, Lisboa, Portugal ; Faculdade de Medicina da Universidade de Lisboa, Instituto de Fisiologia, Lisboa, Portugal ; University Medical Center Göttingen, Department of NeuroDegeneration and Restorative Research, Göttingen, Germany
| | | | - Edward J Hollox
- Department of Genetics, University of Leicester, Leicester, UK
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Zhang Y, Friedlander RM. Using non-coding small RNAs to develop therapies for Huntington's disease. Gene Ther 2012; 18:1139-49. [PMID: 22158031 DOI: 10.1038/gt.2011.170] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Huntington's disease (HD) is caused by an expansion of CAG triplets at the 5' end of the HD gene, which encodes a pathologically elongated polyglutamine stretch near the N-terminus of huntingtin. HD is an incurable autosomal-dominant neurodegenerative disease characterized by movement disorder, as well as emotional distress and dementia. The newly discovered roles of the non-coding small RNAs in specific degradation or translational suppression of the targeted mRNAs suggest a potential therapeutic approach of post-transcriptional gene silencing that targets the underlying disease etiology rather than the downstream pathological consequences. From pre-clinical trials in different HD animal models to cells from HD patients, small RNA interference has been applied to 'allele-non-specifically or allele-specifically' silence the mutant HD transgene or endogenous mutant HD allele. Silencing the mutant HD transgene significantly inhibits neurodegeneration, improves motor control, and extends survival of HD mice. With future improvement of mutant allele selectivity (preserving the expression of the neuroprotective wild-type allele), target specificity, efficacy and safety, as well as optimization of delivery methods, small non-coding RNA-based therapeutic applications will be a promising approach to treat HD.
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Affiliation(s)
- Y Zhang
- Department of Neurological Surgery, UPMC Presbyterian Hospital, University of Pittsburgh Medical Center, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
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Abstract
Huntington’s disease (HD) is caused by the expansion of a CAG repeat within exon 1 of the huntingtin (HTT) gene. Although the variation in age at onset is partly explained by the lengths of the expanded repeat, the unexplained variation is heritable, emphasizing the role of the so-called genetic background on disease expression. Identification of modifier genes can confirm intracellular pathways already suspected to be involved in pathophysiological processes related to HD pathogenesis, but it may also point to completely new pathways and processes that have not yet been considered. Most importantly, confirmed modifier genes provide new targets for the development of therapies. Up to now, a wide range of susceptible HD modifier genes related to different biochemical pathways has been examined. On the basis of the published literature in this field, this review provides an overview of HD modifiers and integrates them into selected pathophysiology aspects.
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Affiliation(s)
| | - Jörg T Epplen
- Department of Human Genetics, Ruhr-University Bochum, Universitätsstr., 150, 44801 Bochum, Germany
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Zhang BR, Tian J, Yan YP, Yin XZ, Zhao GH, Wu ZY, Gu WH, Xia K, Tang BS. CCG polymorphisms in the huntingtin gene have no effect on the pathogenesis of patients with Huntington's disease in mainland Chinese families. J Neurol Sci 2011; 312:92-6. [PMID: 21875723 DOI: 10.1016/j.jns.2011.08.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 08/04/2011] [Accepted: 08/08/2011] [Indexed: 10/17/2022]
Abstract
Huntington's disease (HD) is caused by the abnormal expansion of CAG repeats in the huntingtin gene (HTT). The adjacent proline-rich region, which also has a CCG polymorphism among people of different races, may also affect the pathogenesis of HD. To study the effect of this polymorphism on patients with HD in mainland China, 53 HD mutant alleles were examined. The results showed that 54.72% of the HD mutant alleles had 10-repeat alleles, and the remaining 45.28% had 7-repeat alleles. Moreover, comparison of the clinical features between the two groups revealed no significant difference. We also investigated its effect on the aggregates in vitro. No significant difference was detected when the morphology and size of the aggregates with the two polymorphisms was compared in cells. Given these findings, it was quite reasonable to suppose that the CCG polymorphism may not influence the pathogenesis of patients with HD in mainland China.
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Affiliation(s)
- Bao-rong Zhang
- Department of Neurology, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310009, China.
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Metzger S, Saukko M, Van Che H, Tong L, Puder Y, Riess O, Nguyen HP. Age at onset in Huntington's disease is modified by the autophagy pathway: implication of the V471A polymorphism in Atg7. Hum Genet 2010; 128:453-9. [PMID: 20697744 DOI: 10.1007/s00439-010-0873-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Accepted: 07/31/2010] [Indexed: 10/19/2022]
Abstract
Huntington's disease (HD) is caused by an expansion of a polyglutamine repeat of more than 35 units in the huntingtin protein. The expanded repeat length is inversely correlated with the age at onset (AAO); however, additional genetic factors apart from the expanded CAG repeat length can modify the course and the AAO in HD. Aberrations in macroautophagy have been observed in Huntington, Alzheimer, Parkinson, motor neuron and prion diseases. Therefore, we hypothesized that polymorphisms in autophagy-related (Atg) genes might contribute to the variation in the AAO. We initially tested eight single nucleotide polymorphisms in five Atg genes (Atg3, Atg5, Atg7, Atg16L1 and Beclin-1) for their frequency of ≥1%. Subsequently, we investigated the polymorphisms Atg7 V471A and Atg16L1 T281A for a disease-modifying effect in more than 900 European HD patients (including 2 populations consisting of 346 German patients and 327 patients of Italian descent). One polymorphism in the Atg7 gene that substitutes alanine for valine (V471A) showed a significant effect on the AAO (P=0.0050) and was associated with an earlier disease onset of 4 years. Our results further support the important pathophysiological role of autophagy in HD.
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Affiliation(s)
- Silke Metzger
- Department of Medical Genetics, University of Tuebingen, Calwerstr. 7, 72076, Tübingen, Germany
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Zuccato C, Valenza M, Cattaneo E. Molecular Mechanisms and Potential Therapeutical Targets in Huntington's Disease. Physiol Rev 2010; 90:905-81. [DOI: 10.1152/physrev.00041.2009] [Citation(s) in RCA: 626] [Impact Index Per Article: 44.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by a CAG repeat expansion in the gene encoding for huntingtin protein. A lot has been learned about this disease since its first description in 1872 and the identification of its causative gene and mutation in 1993. We now know that the disease is characterized by several molecular and cellular abnormalities whose precise timing and relative roles in pathogenesis have yet to be understood. HD is triggered by the mutant protein, and both gain-of-function (of the mutant protein) and loss-of-function (of the normal protein) mechanisms are involved. Here we review the data that describe the emergence of the ancient huntingtin gene and of the polyglutamine trait during the last 800 million years of evolution. We focus on the known functions of wild-type huntingtin that are fundamental for the survival and functioning of the brain neurons that predominantly degenerate in HD. We summarize data indicating how the loss of these beneficial activities reduces the ability of these neurons to survive. We also review the different mechanisms by which the mutation in huntingtin causes toxicity. This may arise both from cell-autonomous processes and dysfunction of neuronal circuitries. We then focus on novel therapeutical targets and pathways and on the attractive option to counteract HD at its primary source, i.e., by blocking the production of the mutant protein. Strategies and technologies used to screen for candidate HD biomarkers and their potential application are presented. Furthermore, we discuss the opportunities offered by intracerebral cell transplantation and the likely need for these multiple routes into therapies to converge at some point as, ideally, one would wish to stop the disease process and, at the same time, possibly replace the damaged neurons.
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Affiliation(s)
- Chiara Zuccato
- Department of Pharmacological Sciences and Centre for Stem Cell Research, Università degli Studi di Milano, Milan, Italy
| | - Marta Valenza
- Department of Pharmacological Sciences and Centre for Stem Cell Research, Università degli Studi di Milano, Milan, Italy
| | - Elena Cattaneo
- Department of Pharmacological Sciences and Centre for Stem Cell Research, Università degli Studi di Milano, Milan, Italy
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Langbehn DR, Hayden M, Paulsen JS. CAG-repeat length and the age of onset in Huntington disease (HD): a review and validation study of statistical approaches. Am J Med Genet B Neuropsychiatr Genet 2010; 153B:397-408. [PMID: 19548255 PMCID: PMC3048807 DOI: 10.1002/ajmg.b.30992] [Citation(s) in RCA: 242] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CAG-repeat length in the gene for HD is inversely correlated with age of onset (AOO). A number of statistical models elucidating the relationship between CAG length and AOO have recently been published. In the present article, we review the published formulae, summarize essential differences in participant sources, statistical methodologies, and predictive results. We argue that unrepresentative sampling and failure to use appropriate survival analysis methodology may have substantially biased much of the literature. We also explain why the survival analysis perspective is necessary if any such model is to undergo prospective validation. We use prospective diagnostic data from the PREDICT-HD longitudinal study of CAG-expanded participants to test conditional predictions derived from two survival models of AOO of HD. A prior model of the relationship of CAG and AOO originally published by Langbehn et al. yields reasonably accurate predictions, while a similar model by Gutierrez and MacDonald substantially overestimates diagnosis risk for all but the highest risk participants in this sample. The Langbehn et al. model appears accurate enough to have substantial utility in various research contexts. We also emphasize remaining caveats, many of which are relevant for any direct application to genetic counseling.
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Affiliation(s)
- Douglas R. Langbehn
- Department of Psychiatry, Carver College of Medicine, and Biostatistics (secondary), University of Iowa, Iowa City, Iowa, USA, Department of Biostatistics (secondary), School of Public Health, University of Iowa, Iowa City, Iowa, USA
| | - Michael Hayden
- Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jane S. Paulsen
- Department of Psychiatry, Carver College of Medicine, and Biostatistics (secondary), University of Iowa, Iowa City, Iowa, USA
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20
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Zhang Y, Engelman J, Friedlander RM. Allele-specific silencing of mutant Huntington's disease gene. J Neurochem 2009; 108:82-90. [PMID: 19094060 DOI: 10.1111/j.1471-4159.2008.05734.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Huntington's disease (HD) is an autosomal-dominant neurodegenerative disorder caused by a poly-glutamine expansion in huntingtin, the protein encoded by the HD gene. PolyQ-expanded huntingtin is toxic to neurons, especially the medium spiny neurons of the striatum. At the same time, wild-type huntingtin has important - indeed essential - protective functions. Any effective molecular therapy must preserve the expression of wild-type huntingtin, while silencing the mutant allele. We hypothesized that an appropriate siRNA molecule would display the requisite specificity and efficacy. As RNA interference is incapable of distinguishing among alleles with varying numbers of CAG (glutamine) codons, another strategy is needed. We used HD fibroblasts in which the pathogenic mutation is linked to a polymorphic site: the Delta2642 deletion of one of four tandem GAG triplets. We silenced expression of the harmful Delta2642-marked polyQ-expanded huntingtin without compromising synthesis of its wild-type counterpart. Following this success in HD fibroblasts, we obtained similar results with neuroblastoma cells expressing both wild-type and mutant HD genes. As opposed to the effect of depleting wild-type huntingtin, specifically silencing the mutant species actually lowered caspase-3 activation and protected HD cells under stress conditions. These findings have therapeutic implications not only for HD, but also for other autosomal dominant diseases. This approach has great promise: it may lead to personalized genetic therapy, a holy grail in contemporary medicine.
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Affiliation(s)
- Yu Zhang
- Neuroapoptosis Laboratory, Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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21
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Nørremølle A, Budtz-Jørgensen E, Fenger K, Nielsen JE, Sørensen SA, Hasholt L. 4p16.3 haplotype modifying age at onset of Huntington disease. Clin Genet 2009; 75:244-50. [DOI: 10.1111/j.1399-0004.2008.01136.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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22
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Andresen JM, Gayán J, Cherny SS, Brocklebank D, Alkorta-Aranburu G, Addis EA, Cardon LR, Housman DE, Wexler NS. Replication of twelve association studies for Huntington's disease residual age of onset in large Venezuelan kindreds. J Med Genet 2007; 44:44-50. [PMID: 17018562 PMCID: PMC2597910 DOI: 10.1136/jmg.2006.045153] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2006] [Revised: 08/26/2006] [Accepted: 09/01/2006] [Indexed: 12/29/2022]
Abstract
BACKGROUND The major determinant of age of onset in Huntington's disease is the length of the causative triplet CAG repeat. Significant variance remains, however, in residual age of onset even after repeat length is factored out. Many genetic polymorphisms have previously shown evidence of association with age of onset of Huntington's disease in several different populations. OBJECTIVE To replicate these genetic association tests in 443 affected people from a large set of kindreds from Venezuela. METHODS Previously tested polymorphisms were analysed in the HD gene itself (HD), the GluR6 kainate glutamate receptor (GRIK2), apolipoprotein E (APOE), the transcriptional coactivator CA150 (TCERG1), the ubiquitin carboxy-terminal hydrolase L1 (UCHL1), p53 (TP53), caspase-activated DNase (DFFB), and the NR2A and NR2B glutamate receptor subunits (GRIN2A, GRIN2B). RESULTS The GRIN2A single-nucleotide polymorphism explains a small but considerable amount of additional variance in residual age of onset in our sample. The TCERG1 microsatellite shows a trend towards association but does not reach statistical significance, perhaps because of the uninformative nature of the polymorphism caused by extreme allele frequencies. We did not replicate the genetic association of any of the other genes. CONCLUSIONS GRIN2A and TCERG1 may show true association with residual age of onset for Huntington's disease. The most surprising negative result is for the GRIK2 (TAA)(n) polymorphism, which has previously shown association with age of onset in four independent populations with Huntington's disease. The lack of association in the Venezuelan kindreds may be due to the extremely low frequency of the key (TAA)(16) allele in this population.
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Affiliation(s)
- J M Andresen
- Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
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23
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Pattison LR, Kotter MR, Fraga D, Bonelli RM. Apoptotic cascades as possible targets for inhibiting cell death in Huntington's disease. J Neurol 2006; 253:1137-42. [PMID: 16998646 DOI: 10.1007/s00415-006-0198-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2005] [Accepted: 02/20/2006] [Indexed: 12/31/2022]
Abstract
Huntington's disease (HD) is a devastating autosomal dominant disorder characterized by progressive motor and neuropsychological symptoms. Evidence implicating the apoptotic cascades as a possible cause for the neurodegeneration seen in HD has directed researchers toward investigating therapeutic treatments targeting caspases and other proapoptotic factors. Cellular and murine models, which have demonstrated that caspase-mediated cleavage could be the cause for the neurodegeneration seen in HD, have evoked more research investigating the possible inhibition of apoptosis in HD. In particular, minocycline, a tetracycline-derived antibiotic that has been shown to increase survival in transgenic mouse models of HD, exhibits a neuroprotective feature in HD and demonstrates an anti-inflammatory as well as an anti-microbial effect by inhibiting microglial activation known to cause apoptosis.
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Affiliation(s)
- Lindsay R Pattison
- Department of Biochemistry and Molecular Biology, The College of Wooster, 1189 Beall Avenue, Wooster, OH 44691, USA
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24
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Panegyres PK, Beilby J, Bulsara M, Toufexis K, Wong C. A Study of Potential Interactive Genetic Factors in Huntington’s Disease. Eur Neurol 2006; 55:189-92. [PMID: 16772714 DOI: 10.1159/000093867] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2006] [Accepted: 03/24/2006] [Indexed: 11/19/2022]
Abstract
AIM To assess the role of genetic factors, other than the CAG repeat length, on the development of Huntington's disease (HD) in an isolated Caucasian population in the south-west of Western Australia. METHODS 114 patients with symptomatic HD according to the Unified HD Rating Scale research criteria were examined along with 51 control patients. The length of the CAG repeat sequence in the IT15 gene and the adjacent CCG and Delta2642 polymorphisms were determined by polymerase chain reaction along with common genotypes of the angiotensin-converting enzyme (ACE) and apolipoprotein E (APOE) genes. RESULTS The CAG expansion was associated with age of onset and the development of neurological dysfunction. We found no effect of the expanded CCG allele on age of onset, neurological dysfunction or the size of the CAG expansion. We observed a twofold increase in the Delta2642 polymorphism and the risk of developing symptomatic HD which was not significant (OR 2.06; 95% CI 0.60-7.07). The presence of an APOE epsilon4 allele was associated with an increased risk of HD which was not significant either (OR 1.04-1.73; 95% CI 0.10-10.68). ACE genotypes showed no association with risk factors for the disease. CONCLUSION In our study of a geographically isolated Caucasian HD population in the south-west of Western Australia we have not observed that the expanded CCG allele, the Delta2642 polymorphism, the APOE epsilon4 allele and ACE genotypes are associated with an increased risk for the development of symptomatic HD.
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Affiliation(s)
- Peter K Panegyres
- Neurosciences Unit, Department of Health, University of Western Australia, Perth, Australia.
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25
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Costa MDC, Magalhães P, Guimarães L, Maciel P, Sequeiros J, Sousa A. The CAG repeat at the Huntington disease gene in the Portuguese population: insights into its dynamics and to the origin of the mutation. J Hum Genet 2005; 51:189-195. [PMID: 16372132 DOI: 10.1007/s10038-005-0343-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2005] [Accepted: 11/03/2005] [Indexed: 11/29/2022]
Abstract
Huntington disease (HD) is caused by an expansion of a CAG repeat. This repeat is a dynamic mutation that tends to undergo intergenerational instability. We report the analysis of the CAG repeat in a large population sample (2,000 chromosomes) covering all regions of Portugal, and a haplotype study of (CAG)n and (CCG)n repeats in 140 HD Portuguese families. Intermediate class 2 alleles represented 3.0% of the population; and two expanded alleles (36 and 40 repeats, 0.11%) were found. There was no evidence for geographical clustering of the intermediate or expanded alleles. The Portuguese families showed three different HD founder haplotypes associated with 7-, 9- or 10-CCG repeats, suggesting the possibility of different origins for the HD mutation among this population. The haplotype carrying the 7-CCG repeat was the most frequent, both in normal and in expanded alleles. In general, we propose that three mechanisms, occurring at different times, may lead to the evolution from normal CAGs to full expansion: first, a mutation bias towards larger alleles; then, a stepwise process that could explain the CAG distributions observed in the more recent haplotypes; and, finally, a pool of intermediate (class 2) alleles more prone to give rise to expanded HD alleles.
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Affiliation(s)
- Maria do Carmo Costa
- School of Health Sciences, Life and Health Sciences Research Institute (ICVS), University of Minho, Braga, Portugal
| | - Paula Magalhães
- Institute for Molecular and Cell Biology, UnIGENe, Porto, Portugal
| | | | - Patrícia Maciel
- School of Health Sciences, Life and Health Sciences Research Institute (ICVS), University of Minho, Braga, Portugal
| | - Jorge Sequeiros
- Institute for Molecular and Cell Biology, UnIGENe, Porto, Portugal
- Department of Populations Studies, ICBAS, University of Porto, 4099-003, Porto, Portugal
| | - Alda Sousa
- Institute for Molecular and Cell Biology, UnIGENe, Porto, Portugal.
- Department of Populations Studies, ICBAS, University of Porto, 4099-003, Porto, Portugal.
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26
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Sposìto R, Pasquali L, Galluzzi F, Rocchi A, Solìto B, Soragna D, Tupler R, Siciliano G. Facioscapulohumeral Muscular Dystrophy Type 1A in Northwestern Tuscany: A Molecular Genetics-based Epidemiological and Genotype–Phenotype Study. ACTA ACUST UNITED AC 2005; 9:30-6. [PMID: 15857184 DOI: 10.1089/gte.2005.9.30] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Facioscapulohumeral muscular dystrophy type 1A (FSHD1A) is an autosomal dominant inherited disorder characterized by early involvement of facial and scapular muscles with eventual spreading to pelvic and lower limb muscles. A high degree of clinical variability with respect to age at onset, severity, and pattern of muscle involvement, both between and within families, is present. For this reason, diagnosis of FSHD1A can be sometimes difficult and molecular diagnosis is then necessary. A clinical and molecular genetic-based epidemiological investigation has been carried out in the territory of northwestern Tuscany in central Italy to calculate the prevalence rate of FSHD1A as of March, 2004. The molecular diagnosis has been based on the detection of large deletions of variable size of kpnI repeat units on chromosome 4q35. Results have been compared to those of a previous study conducted in the same area in 1981 (in the premolecular diagnosis era). The minimum prevalence rate was 4.60 x 10(-5) inhabitants, a value four times higher compared to our previous study. No significant correlation between fragment size and clinical severity has been observed. This study confirms in an Italian population a prevalence rate of FSHD1A similar to that observed in other populations. Furthermore, it underlines the usefulness of routine adoption of the genetic testing in confirming clinical suspicion of FSHD1A as well as in correctly diagnosing atypical and otherwise misclassified cases.
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Affiliation(s)
- R Sposìto
- Department of Neuroscience, University of Pisa, 56126 Pisa, Italy
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27
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Wang CK, Wu YR, Hwu WL, Chen CM, Ro LS, Chen ST, Gwinn-Hardy K, Yang CC, Wu RM, Chen TF, Wang HC, Chao MC, Chiu MJ, Lu CJ, Lee-Chen GJ. DNA haplotype analysis of CAG repeat in Taiwanese Huntington's disease patients. Eur Neurol 2004; 52:96-100. [PMID: 15273431 DOI: 10.1159/000079938] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2003] [Accepted: 05/25/2004] [Indexed: 11/19/2022]
Abstract
We studied the expanded CAG repeat and adjacent CCG repeat in 53 Huntington's disease (HD) patients and 172 unrelated normal subjects matched to the patients for ethnic origin. The range of the CAG repeat varied from 38 to 109 in the HD patients and from 10 to 29 in the control group. A significant negative correlation was found between the age at onset and the CAG expansion, with no significant influence of the adjacent CCG repeat on the age at onset by multiple regression analysis. Allelic association using CCG repeat and 2 flanking dinucleotide repeat markers within 150 kb of the HD gene revealed linkage disequilibrium for 2 of 3 markers. Haplotype analysis of 24 HD families using these markers identified 3 major haplotypes underlying 87.5% of HD chromosomes. The data suggested frequent haplotypes in the Taiwanese population on which one or more mutational events leading to the disease occurred.
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Affiliation(s)
- C K Wang
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan, ROC
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Langbehn DR, Brinkman RR, Falush D, Paulsen JS, Hayden MR. A new model for prediction of the age of onset and penetrance for Huntington's disease based on CAG length. Clin Genet 2004; 65:267-77. [PMID: 15025718 DOI: 10.1111/j.1399-0004.2004.00241.x] [Citation(s) in RCA: 563] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by an unstable CAG repeat. For patients at risk, participating in predictive testing and learning of having CAG expansion, a major unanswered question shifts from "Will I get HD?" to "When will it manifest?" Using the largest cohort of HD patients analyzed to date (2913 individuals from 40 centers worldwide), we developed a parametric survival model based on CAG repeat length to predict the probability of neurological disease onset (based on motor neurological symptoms rather than psychiatric onset) at different ages for individual patients. We provide estimated probabilities of onset associated with CAG repeats between 36 and 56 for individuals of any age with narrow confidence intervals. For example, our model predicts a 91% chance that a 40-year-old individual with 42 repeats will have onset by the age of 65, with a 95% confidence interval from 90 to 93%. This model also defines the variability in HD onset that is not attributable to CAG length and provides information concerning CAG-related penetrance rates.
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Affiliation(s)
- D R Langbehn
- Department of Psychiatry, University of Iowa College of Medicine, Iowa City, IA, USA
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29
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Petersén A, Brundin P. Huntington's disease: the mystery unfolds? INTERNATIONAL REVIEW OF NEUROBIOLOGY 2003; 53:315-39. [PMID: 12512345 DOI: 10.1016/s0074-7742(02)53012-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Asa Petersén
- Section for Neuronal Survival, Wallenberg Neuroscience Center, Department of Physiological Sciences, Lund University, Lund, Sweden
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Georgiou-Karistianis N, Smith E, Bradshaw JL, Chua P, Lloyd J, Churchyard A, Chiu E. Future directions in research with presymptomatic individuals carrying the gene for Huntington's disease. Brain Res Bull 2003; 59:331-8. [PMID: 12507683 DOI: 10.1016/s0361-9230(02)00877-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Presymptomatic individuals carrying the gene for Huntington's disease (HD) provide researchers with a unique opportunity of learning more about the neuropathophysiology, symptom onset, behavioural functioning, and mediating factors of this fatal disease. In this review, we attempt to demonstrate that research over the last 8 years, since the isolation of the gene, has remained at large controversial. Although we are aware of some of the factors that can influence age at onset and disease progression, we are still unable to determine exactly when an individual will develop HD symptoms, and how fast these symptoms will progress. In an era rapidly advancing with respect to therapeutic intervention that could forestall the onset and progression of HD, systematic research with improved inclusion criteria is paramount. A greater understanding of the time course of the disease would be beneficial not only in monitoring the effectiveness of future treatments, but also in determining the most appropriate time to administer them. Finally, we present various ethical considerations, as well as put forward various recommendations that could assist in better diagnosing preclinical deficits in presymptomatic individuals.
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31
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Nazé P, Vuillaume I, Destée A, Pasquier F, Sablonnière B. Mutation analysis and association studies of the ubiquitin carboxy-terminal hydrolase L1 gene in Huntington's disease. Neurosci Lett 2002; 328:1-4. [PMID: 12123845 DOI: 10.1016/s0304-3940(02)00231-8] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Huntington's disease (HD) is attributed to a triplet CAG repeat mutation, and about 70% of the variance in age-at-onset can be explained by the size of the repeat expansion. Among potential candidates as modifier genes, we investigated the role of ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) gene. We examined the association of HD with the I93M mutation and S18Y polymorphism in 138 HD patients and 136 control subjects, but we did not identify the I93M mutation. The S18Y polymorphism was present in 17% of HD patients. Of the variance in the age-at-onset that was not accounted for by the CAG repeat, 13% could be attributed to S18Y polymorphism. We sequenced the entire coding region of the UCH-L1 gene in seven HD patients with unexplained older or younger onset age. The S18Y polymorphism was found in three out of the four patients presenting with a later age-at-onset. We conclude that the UCH-L1 gene may be a genetic factor that influences the variability in age-at-onset of HD.
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Affiliation(s)
- Peggy Nazé
- Laboratoire de Biochimie et de Biologie Moléculaire, Unité Fonctionnelle de Neurobiologie, Hôpital R. Salengro, Centre Hospitalier Régional et Universitaire de Lille, 59037 Lille Cedex, France
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Maat-Kievit A, Losekoot M, Zwinderman K, Vegter-van der Vlis M, Belfroid R, Lopez F, Van Ommen GJ, Breuning M, Roos R. Predictability of age at onset in Huntington disease in the Dutch population. Medicine (Baltimore) 2002; 81:251-9. [PMID: 12169880 DOI: 10.1097/00005792-200207000-00001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Affiliation(s)
- Anneke Maat-Kievit
- Centre for Human and Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands.
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Squitieri F, Cannella M, Giallonardo P, Maglione V, Mariotti C, Hayden MR. Onset and pre-onset studies to define the Huntington's disease natural history. Brain Res Bull 2001; 56:233-8. [PMID: 11719256 DOI: 10.1016/s0361-9230(01)00648-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Huntington's disease's (HD) clinical history has not been defined yet. However, many aspects of the most confusing clinical stages, i.e., the first and last disease phases, including the symptom progression and the disease duration, have been better approached after discovery of the responsible gene. The existence of accurate genetic tests, available for affected and pre-symptomatic subjects (i.e., mutation carriers) and the possibility to study transgenic in vivo models, are actually helping us to understand some of the aspects of HD clinical presentation. HD may present with motor symptoms other than chorea, the psychiatric manifestations may represent part of the clinical picture and cognitive deterioration may occur very early in the disease and depend on early cortical involvement. Pre-onset studies are of crucial importance in understanding the temporal sequence of the clinical events. This is also very important for future therapeutic strategies in those diseases initiating late in the life, such as HD.
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Affiliation(s)
- F Squitieri
- Neurogenetics Unit, Neurological Institute IRCCS "Neuromed", (IS), Pozzilli, Italy.
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34
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Abstract
A milestone in Huntington's disease (HD) research is represented by the identification of the causative gene. With the genetics at hand, a series of transgenic cellular and animal models has been developed, which has greatly contributed to understanding of HD. All these models are described in this review, and are compared to each other, along with the information they have generated. Although the mechanism by which progressive loss of striatal neurons occurs in HD remains uncertain, hypotheses on mutant huntingtin toxicity involve impaired vescicular trafficking, transcriptional dysregulation, and/or activation of apoptotic pathways. The development of inducible HD mice has shown that neurodegeneration in HD may be at least partially blocked. Although traditionally considered a "gain-of-function" disease, the recent finding that normal huntingtin has an important role in neuronal survival suggests that loss of function of the normal protein might contribute to HD as well, also discloseing new perspectives on the therapeutical approach to the pathology.
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Affiliation(s)
- S Sipione
- Department of Pharmacological Sciences, University of Milano, Center of Excellence on Neurodegenerative Diseases, Italy
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Squitieri F, Berardelli A, Nargi E, Castellotti B, Mariotti C, Cannella M, Lavitrano ML, de Grazia U, Gellera C, Ruggieri S. Atypical movement disorders in the early stages of Huntington's disease: clinical and genetic analysis. Clin Genet 2000; 58:50-6. [PMID: 10945661 DOI: 10.1034/j.1399-0004.2000.580108.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Huntington's disease (HD) is notably difficult to diagnose in the early stages. One reason is that the early clinical manifestations of HD vary widely and sometimes have an atypical onset. In this paper we primarily sought information on affected patients who initially presented with movement disorders other than chorea. We also investigated atypical motor presentations in relation to triplet CAG expansions. After reviewing the clinical records of two neurological centres, we identified patients with a final, documented diagnosis of HD and selected for study 205 patients according to their onset of motor manifestations. CAG repeats were analysed. Of the 205 patients studied, 15 had atypical motor symptoms at onset. In this group we identified three types of initial clinical manifestations other than chorea: parkinsonism, ataxia and dystonia. We conclude that HD patients may have different motor manifestations at the initiation of the illness. Patients with atypical movement disorders in the early stages have larger CAG expansions and an earlier age at onset than HD patients with typical onset chorea.
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Affiliation(s)
- F Squitieri
- Neurological Institute I.N.M. I.R.C.C.S. Neuromed, Pozzilli (IS), Italy.
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Abstract
We review recent advances regarding the pathogenesis of Huntington's disease (HD). This genetic neurodegenerative disorder is caused by an expanded CAG repeat in a gene coding for a protein, with unknown function, called huntingtin. There is selective death of striatal and cortical neurons. Both in patients and a transgenic mouse model of the disease, neuronal intranuclear inclusions, immunoreactive for huntingtin and ubiquitin, develop. Huntingtin interacts with the proteins GAPDH, HAP-1, HIP1, HIP2, and calmodulin, and a mutant huntingtin is specifically cleaved by the proapoptotic enzyme caspase 3. The pathogenetic mechanism is not known, but it is presumed that there is a toxic gain of function of the mutant huntingtin. Circumstantial evidence suggests that excitotoxicity, oxidative stress, impaired energy metabolism, and apoptosis play a role.
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Affiliation(s)
- A Petersén
- Department of Physiological Sciences, Wallenberg Neuroscience Center, Sölvegatan 17, Lund, 222 52, Sweden
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