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Bhatt V, Tiwari AK. Sirtuins, a key regulator of ageing and age-related neurodegenerative diseases. Int J Neurosci 2023; 133:1167-1192. [PMID: 35549800 DOI: 10.1080/00207454.2022.2057849] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 03/15/2022] [Indexed: 10/18/2022]
Abstract
Sirtuins are Nicotinamide Adenine Dinucleotide (NAD+) dependent class ІΙΙ histone deacetylases enzymes (HDACs) present from lower to higher organisms such as bacteria (Sulfolobus solfataricus L. major), yeasts (Saccharomyces cerevisiae), nematodes (Caenorhabditis elegans), fruit flies (Drosophila melanogaster), humans (Homo sapiens sapiens), even in plants such as rice (Oryza sativa), thale cress (Arabidopsis thaliana), vine (Vitis vinifera L.) tomato (Solanum lycopersicum). Sirtuins play an important role in the regulation of various vital cellular functions during metabolism and ageing. It also plays a neuroprotective role by modulating several biological pathways such as apoptosis, DNA repair, protein aggregation, and inflammatory processes associated with ageing and neurodegenerative diseases. In this review, we have presented an updated Sirtuins and its role in ageing and age-related neurodegenerative diseases (NDDs). Further, this review also describes the therapeutic potential of Sirtuins and the use of Sirtuins inhibitor/activator for altering the NDDs disease pathology.
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Affiliation(s)
- Vidhi Bhatt
- Department of Biological Sciences & Biotechnology, Institute of Advanced Research, Koba, Gandhinagar, Gujarat, India
| | - Anand Krishna Tiwari
- Department of Biological Sciences & Biotechnology, Institute of Advanced Research, Koba, Gandhinagar, Gujarat, India
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2
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Fan C, Chen K, Wang Y, Ball EV, Stenson PD, Mort M, Bacolla A, Kehrer-Sawatzki H, Tainer JA, Cooper DN, Zhao H. Profiling human pathogenic repeat expansion regions by synergistic and multi-level impacts on molecular connections. Hum Genet 2023; 142:245-274. [PMID: 36344696 PMCID: PMC10290229 DOI: 10.1007/s00439-022-02500-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 10/24/2022] [Indexed: 11/09/2022]
Abstract
Whilst DNA repeat expansions cause numerous heritable human disorders, their origins and underlying pathological mechanisms are often unclear. We collated a dataset comprising 224 human repeat expansions encompassing 203 different genes, and performed a systematic analysis with respect to key topological features at the DNA, RNA and protein levels. Comparison with controls without known pathogenicity and genomic regions lacking repeats, allowed the construction of the first tool to discriminate repeat regions harboring pathogenic repeat expansions (DPREx). At the DNA level, pathogenic repeat expansions exhibited stronger signals for DNA regulatory factors (e.g. H3K4me3, transcription factor-binding sites) in exons, promoters, 5'UTRs and 5'genes but were not significantly different from controls in introns, 3'UTRs and 3'genes. Additionally, pathogenic repeat expansions were also found to be enriched in non-B DNA structures. At the RNA level, pathogenic repeat expansions were characterized by lower free energy for forming RNA secondary structure and were closer to splice sites in introns, exons, promoters and 5'genes than controls. At the protein level, pathogenic repeat expansions exhibited a preference to form coil rather than other types of secondary structure, and tended to encode surface-located protein domains. Guided by these features, DPREx ( http://biomed.nscc-gz.cn/zhaolab/geneprediction/# ) achieved an Area Under the Curve (AUC) value of 0.88 in a test on an independent dataset. Pathogenic repeat expansions are thus located such that they exert a synergistic influence on the gene expression pathway involving inter-molecular connections at the DNA, RNA and protein levels.
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Affiliation(s)
- Cong Fan
- Department of Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yan Jiang West Road, Guangzhou, 500001, People's Republic of China
| | - Ken Chen
- School of Computer Science and Engineering, Sun Yat-Sen University, Guangzhou, 500001, China
| | - Yukai Wang
- School of Life Science, Sun Yat-Sen University, Guangzhou, 500001, China
| | - Edward V Ball
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
| | - Peter D Stenson
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
| | - Matthew Mort
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
| | - Albino Bacolla
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, 6767 Bertner Avenue, Houston, TX, 77030, USA
| | | | - John A Tainer
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, 6767 Bertner Avenue, Houston, TX, 77030, USA
| | - David N Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
| | - Huiying Zhao
- Department of Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yan Jiang West Road, Guangzhou, 500001, People's Republic of China.
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Jih KY, Lai KL, Lin KP, Liao YC, Lee YC. Reduced-penetrance Huntington's disease-causing alleles with 39 CAG trinucleotide repeats could be a genetic factor of amyotrophic lateral sclerosis. J Chin Med Assoc 2023; 86:47-51. [PMID: 36599142 DOI: 10.1097/jcma.0000000000000837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Expanded HTT alleles with 40 or more CAG repeats were recently found to be a rare cause of frontotemporal dementia and amyotrophic lateral sclerosis (ALS) spectrum diseases. The aim of this study was to investigate the role of HTT repeat expansions in a Taiwanese cohort with ALS. METHODS We analyzed the numbers of CAG repeats in exon 1 of HTT in a cohort of 410 Taiwanese patients with ALS and 1514 control individuals by utilizing polymerase chain reaction and amplicon fragment length analysis. RESULTS Only one of the 410 ALS patients carried a reduced-penetrance HD-causing allele with 39 CAG repeats, and none had an expanded HTT CAG repeats ≥40. The patient presented with rapidly progressive bulbar-onset ALS with disease onset at the age of 64 years. He had neither chorea nor cognitive impairment. He had a family history of chorea, but no other family member manifested with ALS. None of the 1514 control individuals carried an HTT expanded allele with CAG repeats larger than 37 repeats. CONCLUSION The HTT allele with 39 CAG repeats could be a genetic factor linked to ALS susceptibility.
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Affiliation(s)
- Kang-Yang Jih
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Department of Physiology, National Yang Ming Chiao Tung University School of Medicine, Taipei, Taiwan, ROC
- Department of Neurology, National Yang Ming Chiao Tung University School of Medicine, Taipei, Taiwan, ROC
| | - Kuan-Lin Lai
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Department of Neurology, National Yang Ming Chiao Tung University School of Medicine, Taipei, Taiwan, ROC
- Brain Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
| | - Kon-Ping Lin
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Department of Neurology, National Yang Ming Chiao Tung University School of Medicine, Taipei, Taiwan, ROC
| | - Yi-Chu Liao
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Department of Neurology, National Yang Ming Chiao Tung University School of Medicine, Taipei, Taiwan, ROC
- Brain Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
| | - Yi-Chung Lee
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Department of Neurology, National Yang Ming Chiao Tung University School of Medicine, Taipei, Taiwan, ROC
- Brain Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
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4
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Tabrizi SJ, Schobel S, Gantman EC, Mansbach A, Borowsky B, Konstantinova P, Mestre TA, Panagoulias J, Ross CA, Zauderer M, Mullin AP, Romero K, Sivakumaran S, Turner EC, Long JD, Sampaio C. A biological classification of Huntington's disease: the Integrated Staging System. Lancet Neurol 2022; 21:632-644. [PMID: 35716693 DOI: 10.1016/s1474-4422(22)00120-x] [Citation(s) in RCA: 65] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 02/11/2022] [Accepted: 03/11/2022] [Indexed: 12/24/2022]
Abstract
The current research paradigm for Huntington's disease is based on participants with overt clinical phenotypes and does not address its pathophysiology nor the biomarker changes that can precede by decades the functional decline. We have generated a new research framework to standardise clinical research and enable interventional studies earlier in the disease course. The Huntington's Disease Integrated Staging System (HD-ISS) comprises a biological research definition and evidence-based staging centred on biological, clinical, and functional assessments. We used a formal consensus method that involved representatives from academia, industry, and non-profit organisations. The HD-ISS characterises individuals for research purposes from birth, starting at Stage 0 (ie, individuals with the Huntington's disease genetic mutation without any detectable pathological change) by using a genetic definition of Huntington's disease. Huntington's disease progression is then marked by measurable indicators of underlying pathophysiology (Stage 1), a detectable clinical phenotype (Stage 2), and then decline in function (Stage 3). Individuals can be precisely classified into stages based on thresholds of stage-specific landmark assessments. We also demonstrated the internal validity of this system. The adoption of the HD-ISS could facilitate the design of clinical trials targeting populations before clinical motor diagnosis and enable data standardisation across ongoing and future studies.
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Affiliation(s)
- Sarah J Tabrizi
- UCL Huntington's Disease Centre, Department of Neurodegenerative Diseases, UCL Queen Square Institute of Neurology, UK Dementia Research Institute, University College London, UK.
| | - Scott Schobel
- Product Development Neuroscience, F Hoffmann-La Roche, Basel, Switzerland
| | | | | | | | | | - Tiago A Mestre
- Parkinson's Disease and Movement Disorders Centre, Division of Neurology, Department of Medicine, The Ottawa Hospital Research Institute, University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada
| | | | - Christopher A Ross
- Division of Neurobiology, Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Departments of Neurology, Neuroscience, and Pharmacology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | | | - Klaus Romero
- Critical Path Institute, Tucson, Arizona 85718, USA
| | | | | | - Jeffrey D Long
- Department of Psychiatry, Department of Biostatistics, University of Iowa, Iowa City, IA, USA
| | - Cristina Sampaio
- CHDI Management/CHDI Foundation, Princeton, NJ, USA; Clinical Pharmacology Laboratory, Faculdade de Medicina de Lisboa, University of Lisbon, Lisbon, Portugal.
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McDonnell EI, Wang Y, Goldman J, Marder K. Age of Onset of Huntington's Disease in Carriers of Reduced Penetrance Alleles. Mov Disord 2021; 36:2958-2961. [PMID: 34536046 DOI: 10.1002/mds.28789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 08/04/2021] [Accepted: 08/23/2021] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Age of manifest Huntington's disease (HD) onset correlates with number of CAG repeats in the huntingtin gene. Little is known about onset with 36 to 39 repeats, the "reduced penetrance" (RP) range. OBJECTIVES We provide allele-specific estimates of HD penetrance (diagnostic confidence level of 4) for RP allele carriers. METHODS We analyzed 431 pre-manifest RP allele carriers from Enroll-HD, the largest prospective observational HD study. Cumulative penetrance (CP) was estimated from Kaplan-Meier curves. RESULTS No one with 36 repeats (n = 25) phenoconverted. CP for 38 repeats (n = 120) was 32% (95% confidence interval [CI] 0%-55%) and 51% (CI, 10%-73%) by ages 70 and 75, respectively, and 68% (CI, 46%-81%) and 81% (CI, 58%-92%) by ages 70 and 75 for 39 repeats (n = 253). CP was not estimable at those ages for 37 repeats (n = 33). CONCLUSIONS Differences by RP-range repeat length did not reach significance with a 3-year median follow-up duration among censored individuals. © 2021 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Erin I McDonnell
- Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, New York, USA
| | - Yuanjia Wang
- Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, New York, USA.,Department of Psychiatry, Columbia University Medical Center, New York, New York, USA
| | - Jill Goldman
- The Taub Institute for Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, New York, USA
| | - Karen Marder
- Department of Psychiatry, Columbia University Medical Center, New York, New York, USA.,The Taub Institute for Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, New York, USA.,Gertrude H. Sergievsky Center, Columbia University Medical Center, New York, New York, USA.,Department of Neurology, Columbia University Medical Center, New York, New York, USA
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Frequency of the loss of CAA interruption in the HTT CAG tract and implications for Huntington disease in the reduced penetrance range. Genet Med 2020; 22:2108-2113. [PMID: 32741964 PMCID: PMC7708297 DOI: 10.1038/s41436-020-0917-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/17/2020] [Accepted: 07/17/2020] [Indexed: 11/27/2022] Open
Abstract
Purpose In some Huntington disease (HD) patients, the “loss of interruption” (LOI) variant eliminates an interrupting codon in the HTT CAG-repeat tract, which causes earlier age of onset (AOO). The magnitude of this effect is uncertain, since previous studies included few LOI carriers, and the variant also causes CAG size misestimation. We developed a rapid LOI detection screen, enabling unbiased frequency estimation among manifest HD patients. Additionally, we combined published data with clinical data from newly identified patients to accurately characterize the LOI’s effect on AOO. Methods We developed a LOI detection polymerase chain reaction (PCR) assay, and screened patients to estimate the frequency of the LOI variant and its effect on AOO. Results Mean onset for LOI carriers (n = 49) is 20.4 years earlier than expected based on diagnosed CAG size. After correcting for CAG size underestimation, the variant is still associated with onset 9.5 years earlier. The LOI is present in 1.02% of symptomatic HD patients, and in 32.2% of symptomatic reduced penetrance (RP) range patients (36–39 CAGs). Conclusion The LOI causes significantly earlier onset, greater than expected by CAG length, particularly in persons with 36–39 CAG repeats. Detection of this variant has implications for HD families, especially for those in the RP range.
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Franklin GL, Meira AT, Camargo CHF, Teive HAG. Comment on: “Investigation of intermediate CAG alleles of the HTT in the general population of Rio de Janeiro, Brazil, in comparison with a sample of Huntington disease‐affected families.”. Mol Genet Genomic Med 2020; 8:e1243. [PMID: 32253809 PMCID: PMC7284025 DOI: 10.1002/mgg3.1243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 03/20/2020] [Indexed: 11/08/2022] Open
Affiliation(s)
- Gustavo L. Franklin
- Movement Disorders Unit Neurology Service Internal Medicine Department Federal University of Paraná Curitiba Paraná Brazil
| | - Alex T. Meira
- Movement Disorders Unit Neurology Service Internal Medicine Department Federal University of Paraná Curitiba Paraná Brazil
| | - Carlos H. F. Camargo
- Movement Disorders Unit Neurology Service Internal Medicine Department Federal University of Paraná Curitiba Paraná Brazil
| | - Hélio A. G. Teive
- Movement Disorders Unit Neurology Service Internal Medicine Department Federal University of Paraná Curitiba Paraná Brazil
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Ramond F, Quadrio I, Le Vavasseur L, Chaumet H, Boyer F, Bost M, Ollagnon-Roman E. Predictive testing for Huntington disease over 24 years: Evolution of the profile of the participants and analysis of symptoms. Mol Genet Genomic Med 2019; 7:e00881. [PMID: 31436908 PMCID: PMC6785454 DOI: 10.1002/mgg3.881] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 06/28/2019] [Accepted: 07/01/2019] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Huntington disease (HD) is a devastating neurodegenerative autosomal dominant genetic condition. Predictive testing (PT) is available through a defined protocol for at-risk individuals. We analyzed the over-24-years evolution of practices regarding PT for HD in a single center. METHODS We gathered data from the files of all individuals seeking PT for HD in Lyon, France, from 1994 to 2017. RESULTS 448 out of 567 participants had exploitable data. Age at consultation dichotomized over 24 years toward an eightfold increase in individuals aged >55 (2/94 vs. 30/183; 2% to 16%; p < .0001) and twice as many individuals aged 18-20 (3/94 vs. 12/183; 3%-7%; p < .05). Motives for testing remained stable. The rate of withdrawal doubled over 24 years (9/94 vs. 38/183; 9%-21%; p < .02). Independently of the time period, less withdrawal was observed for married, accompanied, at 50% risk, and symptomatic individuals, and in those able to explicit the motives for testing or taking the test to inform their children. We also assessed the consistency between the presence of subtle symptoms compatible with HD found before the test by the team's neurologist, and the positivity of the molecular test. The concordance was 100% (17/17) for associated motor and cognitive signs, 87% (27/31) for isolated motor signs, and 70% (7/10) for isolated cognitive signs. Furthermore, 91% (20/22) of individuals who requested testing because they thought they had symptoms, were indeed found carriers. CONCLUSION This over-24 years study underlines an increasing withdrawal from protocol and a dichotomization of participants' age. We also show a strong concordance between symptoms perceived by the neurologist or by the patient, and the subsequent positivity of the predictive molecular test.
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Affiliation(s)
- Francis Ramond
- Service de neurogénétique et médecine prédictive, GH Nord-Hôpital de la Croix Rousse, Hospices civils de Lyon, Lyon, France.,Service de Génétique, CHU-Hôpital Nord, Saint-Etienne, France
| | - Isabelle Quadrio
- Unité des Pathologies Neurogénétiques Héréditaires - Service de biochimie et biologie moléculaire Grand Est, CBPE, Hospices Civils de Lyon, Lyon, France.,BIORAN Team, CNRS UMR 5292, INSERM U1028, Lyon Neuroscience Research Center, Lyon 1 University, Bron, France
| | - Laurence Le Vavasseur
- Service de neurogénétique et médecine prédictive, GH Nord-Hôpital de la Croix Rousse, Hospices civils de Lyon, Lyon, France
| | - Hélène Chaumet
- Service de neurogénétique et médecine prédictive, GH Nord-Hôpital de la Croix Rousse, Hospices civils de Lyon, Lyon, France
| | - Fabrice Boyer
- Service de neurogénétique et médecine prédictive, GH Nord-Hôpital de la Croix Rousse, Hospices civils de Lyon, Lyon, France
| | - Muriel Bost
- Unité des Pathologies Neurogénétiques Héréditaires - Service de biochimie et biologie moléculaire Grand Est, CBPE, Hospices Civils de Lyon, Lyon, France
| | - Elisabeth Ollagnon-Roman
- Service de neurogénétique et médecine prédictive, GH Nord-Hôpital de la Croix Rousse, Hospices civils de Lyon, Lyon, France
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Abstract
Huntington's disease (HD) is a dominantly inherited neurodegenerative disease that results in motor, cognitive and psychiatric dysfunction. It is caused by a polyglutamine repeat expansion mutation in the widely expressed HTT protein. The clinical manifestations of HD have been largely attributed to the neurodegeneration of specific neuronal cell types in the brain. However, it has become clear that other cell types, including astrocytes, play important roles in the pathogenesis of HD. The mutant HTT (mHTT) protein is present in neuronal and non-neuronal cell types throughout the nervous system. Studies designed to understand the contribution of mHTT expression in non-neuronal cell types to HD pathogenesis has lagged considerably behind those focused on neurons. However, the role of astrocytes in HD has received more attention over the last 5-10 years. In this chapter we present an overview of HD and our current understanding of astrocytic involvement in this disease. We describe the neuropathological features of HD and provide evidence of morphological and molecular changes in mHTT expressing astrocytes. We review data from animal models and HD patients that implicate mHTT expressing astrocytes to the progression of HD.
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Affiliation(s)
- Michelle Gray
- Department of Neurology and Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, 1720 2nd Ave S, CIRC 425B, Birmingham, AL 35294, USA.
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Chheda P, Chanekar M, Salunkhe Y, Dama T, Pais A, Pande S, Bendre R, Shah N. A Study of Triplet-Primed PCR for Identification of CAG Repeat Expansion in the HTT Gene in a Cohort of 503 Indian Cases with Huntington's Disease Symptoms. Mol Diagn Ther 2018; 22:353-359. [PMID: 29619771 DOI: 10.1007/s40291-018-0327-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Huntington's disease (HD) is an autosomal-dominant neurodegenerative disorder with an average age at onset of 40 years. It is a polyglutamine (polyQ) disorder that is caused by an increase in the number of CAG repeats in the huntingtin (HTT) gene. Genetic tests that accurately determine the number of CAG repeats are performed for confirmation of diagnosis, predictive testing of persons at genetic risk for inheriting HD, and prenatal testing. The aim of our study was to evaluate efficacy of triplet-primed polymerase chain reaction (TP-PCR) for routine diagnosis of HD in suspected cases from India. METHODS We evaluated a combination of CAG flanking PCR and triplet-primed PCR for estimation of CAG repeats in 503 cases with clinical suspicion of HD. RESULTS There were 250 cases (49.7%) that showed the presence of expanded alleles, with 241 (47.9%) being fully penetrant alleles and nine (1.8%) in the reduced penetrance category. There were seven juvenile cases with an age of onset of < 20 years, with the longest allele comprising 106 CAG repeats found in an 8-year-old male patient. The results demonstrated an inverse (R = - 0.67) relationship between CAG length and age at clinical onset. CONCLUSION Our study on pan-Indian cases is one of the largest studies reported so far in India and focuses on the most accurate and comprehensive molecular diagnostic evaluation of HD.
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Affiliation(s)
- Pratiksha Chheda
- Department of Molecular Pathology, Metropolis Healthcare Ltd, Commercial Building A, Unit No. 409 to 416, 4th Floor, Kohinoor City, Near Kohinoor Mall, Kirol Road, Kurla-W, Mumbai, 400 070, India.
| | - Milind Chanekar
- Department of Molecular Pathology, Metropolis Healthcare Ltd, Commercial Building A, Unit No. 409 to 416, 4th Floor, Kohinoor City, Near Kohinoor Mall, Kirol Road, Kurla-W, Mumbai, 400 070, India
| | - Yogita Salunkhe
- Department of Molecular Pathology, Metropolis Healthcare Ltd, Commercial Building A, Unit No. 409 to 416, 4th Floor, Kohinoor City, Near Kohinoor Mall, Kirol Road, Kurla-W, Mumbai, 400 070, India
| | - Tavisha Dama
- Department of Molecular Pathology, Metropolis Healthcare Ltd, Commercial Building A, Unit No. 409 to 416, 4th Floor, Kohinoor City, Near Kohinoor Mall, Kirol Road, Kurla-W, Mumbai, 400 070, India
| | - Anurita Pais
- Genetics Department, Metropolis Healthcare Ltd, Mumbai, 400 070, India
| | - Shailesh Pande
- Genetics Department, Metropolis Healthcare Ltd, Mumbai, 400 070, India
| | - Rajesh Bendre
- Department of Molecular Pathology, Metropolis Healthcare Ltd, Commercial Building A, Unit No. 409 to 416, 4th Floor, Kohinoor City, Near Kohinoor Mall, Kirol Road, Kurla-W, Mumbai, 400 070, India
| | - Nilesh Shah
- Department of Molecular Pathology, Metropolis Healthcare Ltd, Commercial Building A, Unit No. 409 to 416, 4th Floor, Kohinoor City, Near Kohinoor Mall, Kirol Road, Kurla-W, Mumbai, 400 070, India
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Murphy OC, O’Toole O, Hand CK, Ryan AM. Chorea-Acanthocytosis and the Huntington Disease Allele in an Irish Family. Tremor Other Hyperkinet Mov (N Y) 2018; 8:604. [PMID: 30622839 PMCID: PMC6315059 DOI: 10.7916/d8r22j6m] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 10/03/2018] [Indexed: 12/26/2022] Open
Affiliation(s)
- Olwen C. Murphy
- Department of Neurology, National Neuroscience Centre, Cork University Hospital, Cork, IE
- Department of Neurology, Mercy University Hospital, Cork, IE
| | - Orna O’Toole
- Department of Neurology, Mercy University Hospital, Cork, IE
| | | | - Aisling M. Ryan
- Department of Neurology, National Neuroscience Centre, Cork University Hospital, Cork, IE
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12
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Golas MM. Human cellular models of medium spiny neuron development and Huntington disease. Life Sci 2018; 209:179-196. [PMID: 30031060 DOI: 10.1016/j.lfs.2018.07.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 06/22/2018] [Accepted: 07/17/2018] [Indexed: 12/24/2022]
Abstract
The loss of gamma-aminobutyric acid (GABA)-ergic medium spiny neurons (MSNs) in the striatum is the hallmark of Huntington disease (HD), an incurable neurodegenerative disorder characterized by progressive motor, psychiatric, and cognitive symptoms. Transplantation of MSNs or their precursors represents a promising treatment strategy for HD. In initial clinical trials in which HD patients received fetal neurografts directly into the striatum without a pretransplant cell-differentiation step, some patients exhibited temporary benefits. Meanwhile, major challenges related to graft overgrowth, insufficient survival of grafted cells, and limited availability of donated fetal tissue remain. Thus, the development of approaches that allow modeling of MSN differentiation and HD development in cell culture platforms may improve our understanding of HD and translate, ultimately, into HD treatment options. Here, recent advances in the in vitro differentiation of MSNs derived from fetal neural stem cells/progenitor cells (NSCs/NPCs), embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), and induced NSCs (iNSCs) as well as advances in direct transdifferentiation are reviewed. Progress in non-allele specific and allele specific gene editing of HTT is presented as well. Cell characterization approaches involving phenotyping as well as in vitro and in vivo functional assays are also discussed.
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Affiliation(s)
- Monika M Golas
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Alle 3, Building 1233, DK-8000 Aarhus C, Denmark; Department of Human Genetics, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
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Youssov K, Bachoud-Lévi AC. Malattia di Huntington: aspetti diagnostici attuali e applicazioni pratiche. Neurologia 2018. [DOI: 10.1016/s1634-7072(18)89403-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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14
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Espinoza FA, Turner JA, Vergara VM, Miller RL, Mennigen E, Liu J, Misiura MB, Ciarochi J, Johnson HJ, Long JD, Bockholt HJ, Magnotta VA, Paulsen JS, Calhoun VD. Whole-Brain Connectivity in a Large Study of Huntington's Disease Gene Mutation Carriers and Healthy Controls. Brain Connect 2018; 8:166-178. [PMID: 29291624 DOI: 10.1089/brain.2017.0538] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Huntington's disease (HD) is an inherited brain disorder characterized by progressive motor, cognitive, and behavioral dysfunctions. It is caused by abnormally large trinucleotide cytosine-adenine-guanine (CAG) repeat expansions on exon 1 of the Huntingtin gene. CAG repeat length (CAG-RL) inversely correlates with an earlier age of onset. Region-based studies have shown that HD gene mutation carrier (HDgmc) individuals (CAG-RL ≥36) present functional connectivity alterations in subcortical (SC) and default mode networks. In this analysis, we expand on previous HD studies by investigating associations between CAG-RL and connectivity in the whole brain, as well as between CAG-dependent connectivity and motor and cognitive performances. We used group-independent component analysis on resting-state functional magnetic resonance imaging scans of 261 individuals (183 HDgmc and 78 healthy controls) from the PREDICT-HD study, to obtain whole-brain resting state networks (RSNs). Regression analysis was applied within and between RSNs connectivity (functional network connectivity [FNC]) to identify CAG-RL associations. Connectivity within the putamen RSN is negatively correlated with CAG-RL. The FNC between putamen and insula decreases with increasing CAG-RL, and also shows significant associations with motor and cognitive measures. The FNC between calcarine and middle frontal gyri increased with CAG-RL. In contrast, FNC in other visual (VIS) networks declined with increasing CAG-RL. In addition to observed effects in SC areas known to be related to HD, our study identifies a strong presence of alterations in VIS regions less commonly observed in previous reports and provides a step forward in understanding FNC dysfunction in HDgmc.
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Affiliation(s)
- Flor A Espinoza
- 1 Department of Translational Neuroscience, The Mind Research Network , Albuquerque, New Mexico
| | - Jessica A Turner
- 2 Departments of Psychology and Neuroscience, Georgia State University , Atlanta, Georgia
| | - Victor M Vergara
- 1 Department of Translational Neuroscience, The Mind Research Network , Albuquerque, New Mexico
| | - Robyn L Miller
- 1 Department of Translational Neuroscience, The Mind Research Network , Albuquerque, New Mexico
| | - Eva Mennigen
- 1 Department of Translational Neuroscience, The Mind Research Network , Albuquerque, New Mexico
| | - Jingyu Liu
- 1 Department of Translational Neuroscience, The Mind Research Network , Albuquerque, New Mexico
| | - Maria B Misiura
- 2 Departments of Psychology and Neuroscience, Georgia State University , Atlanta, Georgia
| | - Jennifer Ciarochi
- 2 Departments of Psychology and Neuroscience, Georgia State University , Atlanta, Georgia
| | - Hans J Johnson
- 3 Department of Psychiatry, Neurology, Psychological and Brain Sciences, University of Iowa , Iowa City, Iowa
| | - Jeffrey D Long
- 3 Department of Psychiatry, Neurology, Psychological and Brain Sciences, University of Iowa , Iowa City, Iowa.,4 Department of Biostatistics, University of Iowa , Iowa City, Iowa
| | - Henry J Bockholt
- 1 Department of Translational Neuroscience, The Mind Research Network , Albuquerque, New Mexico .,3 Department of Psychiatry, Neurology, Psychological and Brain Sciences, University of Iowa , Iowa City, Iowa
| | | | - Jane S Paulsen
- 3 Department of Psychiatry, Neurology, Psychological and Brain Sciences, University of Iowa , Iowa City, Iowa
| | - Vince D Calhoun
- 1 Department of Translational Neuroscience, The Mind Research Network , Albuquerque, New Mexico .,6 Department of Electrical and Computer Engineering, University of New Mexico , Albuquerque, New Mexico
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15
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Downing NR, Lourens S, De Soriano I, Long JD, Paulsen JS. Phenotype Characterization of HD Intermediate Alleles in PREDICT-HD. J Huntingtons Dis 2017; 5:357-368. [PMID: 27983559 DOI: 10.3233/jhd-160185] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Huntington disease (HD) is a neurodegenerative disease caused by a CAG repeat expansion on chromosome 4. Pathology is associated with CAG repeat length. Prior studies examining people in the intermediate allele (IA) range found subtle differences in motor, cognitive, and behavioral domains compared to controls. OBJECTIVE The purpose of this study was to examine baseline and longitudinal differences in motor, cognitive, behavioral, functional, and imaging outcomes between persons with CAG repeats in three ranges: normal (≤26), intermediate (27-35), and reduced penetrance (36-39). METHODS We examined longitudinal data from 389 participants in three allele groups: 280 normal controls (NC), 21 intermediate allele [IA], and 88 reduced penetrance [RP]. We used linear mixed models to identify differences in baseline and longitudinal outcomes between groups. Three models were tested: 1) no baseline or longitudinal differences; 2) baseline differences but no longitudinal differences; and 3) baseline and longitudinal differences. RESULTS Model 1 was the best fitting model for most outcome variables. Models 2 and 3 were best fitting for some of the variables. We found baseline and longitudinal trends of declining performance across increasing CAG repeat length groups, but no significant differences between the NC and IA groups. CONCLUSION We did not find evidence to support differences in the IA group compared to the NC group. These findings are limited by a small IA sample size.
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Affiliation(s)
| | - Spencer Lourens
- Department of Biostatistics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Isabella De Soriano
- Department of Psychiatry, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Jeffrey D Long
- Department of Psychiatry, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.,Department of Biostatistics, College of Public Health, The University of Iowa, Iowa City, IA, USA
| | - Jane S Paulsen
- Department of Psychiatry, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.,Department of Neurology, Carver College of Medicine, The University of Iowa, Iowa City, IA, USA.,Department of Psychological and Brain Sciences, The University of Iowa, Iowa City, IA, USA
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16
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Gilling M, Budtz-Jørgensen E, Boonen SE, Lildballe D, Bojesen A, Hertz JM, Sørensen SA. The Danish HD Registry-a nationwide family registry of HD families in Denmark. Clin Genet 2017; 92:338-341. [PMID: 28155235 DOI: 10.1111/cge.12984] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 01/15/2017] [Accepted: 01/20/2017] [Indexed: 11/30/2022]
Abstract
The Danish Huntington's Disease Registry (DHR) is a nationwide family registry comprising 14 245 individuals from 445 Huntington's disease (HD) families of which the largest family includes 845 individuals in 8 generations. 1136 DNA and/or blood samples and 18 fibroblast cultures are stored in a local biobank. The birthplace of the oldest HD carrier in each of the 261 families of Danish origin was unevenly distributed across Denmark with a high number of families in the middle part of the peninsula Jutland and in Copenhagen, the capital. The prevalence of HD in Denmark was calculated to be 5-8:100 000. 1451 individuals in the DHR had the size of the HTT CAG repeat determined of which 975 had 36 CAG repeats or more (mean ± SD: 43,5 ± 4,8). Two unrelated individuals were compound heterozygous for alleles ≥36 CAGs, and 60 individuals from 34 independent families carried an intermediate allele.
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Affiliation(s)
- M Gilling
- Department of Neurogenetics, Institute of Cellular and Molecular Medicine, The Panum Institute, University of Copenhagen, Copenhagen, Denmark.,The European Huntington's Disease Network, University of Ulm, Ulm, Germany
| | - E Budtz-Jørgensen
- Department of Biostatistics, Institute of Public Health, University of Copenhagen, Copenhagen, Denmark
| | - S E Boonen
- Department of Clinical Genetics, Aarhus University Hospital, Aarhus, Denmark.,Unit of Clinical Genetics, Department of Paediatrics, Zealand University Hospital, Roskilde, Denmark
| | - D Lildballe
- Department of Clinical Genetics, Aarhus University Hospital, Aarhus, Denmark
| | - A Bojesen
- Department of Clinical Genetics, Vejle Hospital, Vejle, Denmark
| | - J M Hertz
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark
| | - S A Sørensen
- Department of Neurogenetics, Institute of Cellular and Molecular Medicine, The Panum Institute, University of Copenhagen, Copenhagen, Denmark
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17
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Lokhande S, Patra BN, Ray A. A link between chromatin condensation mechanisms and Huntington's disease: connecting the dots. MOLECULAR BIOSYSTEMS 2016; 12:3515-3529. [PMID: 27714015 DOI: 10.1039/c6mb00598e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Huntington's disease is a rare neurodegenerative disorder whose complex pathophysiology exhibits system-wide changes in the body, with striking and debilitating clinical features targeting the central nervous system. Among the various molecular functions affected in this disease, mitochondrial dysfunction and transcriptional dysregulation are some of the most studied aspects of this disease. However, there is evidence of the involvement of a mutant Huntingtin protein in the processes of DNA damage, chromosome condensation and DNA repair. This review attempts to briefly recapitulate the clinical features, model systems used to study the disease, major molecular processes affected, and, more importantly, examines recent evidence for the involvement of the mutant Huntingtin protein in the processes regulating chromosome condensation, leading to DNA damage response and neuronal death.
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Affiliation(s)
- Sonali Lokhande
- Keck Graduate Institute of Applied Life Sciences, Claremont, CA 91711, USA.
| | - Biranchi N Patra
- Keck Graduate Institute of Applied Life Sciences, Claremont, CA 91711, USA.
| | - Animesh Ray
- Keck Graduate Institute of Applied Life Sciences, Claremont, CA 91711, USA.
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18
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Kay C, Collins JA, Miedzybrodzka Z, Madore SJ, Gordon ES, Gerry N, Davidson M, Slama RA, Hayden MR. Huntington disease reduced penetrance alleles occur at high frequency in the general population. Neurology 2016; 87:282-8. [PMID: 27335115 DOI: 10.1212/wnl.0000000000002858] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 03/16/2016] [Indexed: 01/29/2023] Open
Abstract
OBJECTIVE To directly estimate the frequency and penetrance of CAG repeat alleles associated with Huntington disease (HD) in the general population. METHODS CAG repeat length was evaluated in 7,315 individuals from 3 population-based cohorts from British Columbia, the United States, and Scotland. The frequency of ≥36 CAG alleles was assessed out of a total of 14,630 alleles. The general population frequency of reduced penetrance alleles (36-39 CAG) was compared to the prevalence of patients with HD with genetically confirmed 36-39 CAG from a multisource clinical ascertainment in British Columbia, Canada. The penetrance of 36-38 CAG repeat alleles for HD was estimated for individuals ≥65 years of age and compared against previously reported clinical penetrance estimates. RESULTS A total of 18 of 7,315 individuals had ≥36 CAG, revealing that approximately 1 in 400 individuals from the general population have an expanded CAG repeat associated with HD (0.246%). Individuals with CAG 36-37 genotypes are the most common (36, 0.096%; 37, 0.082%; 38, 0.027%; 39, 0.000%; ≥40, 0.041%). General population CAG 36-38 penetrance rates are lower than penetrance rates extrapolated from clinical cohorts. CONCLUSION HD alleles with a CAG repeat length of 36-38 occur at high frequency in the general population. The infrequent diagnosis of HD at this CAG length is likely due to low penetrance. Another important contributing factor may be reduced ascertainment of HD in those of older age.
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Affiliation(s)
- Chris Kay
- From the Centre for Molecular Medicine and Therapeutics (C.K., J.A.C., R.A.S., M.R.H.), University of British Columbia, Canada; Medical Genetics Group (Z.M., M.D.), School of Medicine and Dentistry, University of Aberdeen, UK; and Molecular Biology Group (S.J.M., E.S.G., N.G.), Coriell Institute for Medical Research, Camden, NJ
| | - Jennifer A Collins
- From the Centre for Molecular Medicine and Therapeutics (C.K., J.A.C., R.A.S., M.R.H.), University of British Columbia, Canada; Medical Genetics Group (Z.M., M.D.), School of Medicine and Dentistry, University of Aberdeen, UK; and Molecular Biology Group (S.J.M., E.S.G., N.G.), Coriell Institute for Medical Research, Camden, NJ
| | - Zosia Miedzybrodzka
- From the Centre for Molecular Medicine and Therapeutics (C.K., J.A.C., R.A.S., M.R.H.), University of British Columbia, Canada; Medical Genetics Group (Z.M., M.D.), School of Medicine and Dentistry, University of Aberdeen, UK; and Molecular Biology Group (S.J.M., E.S.G., N.G.), Coriell Institute for Medical Research, Camden, NJ
| | - Steven J Madore
- From the Centre for Molecular Medicine and Therapeutics (C.K., J.A.C., R.A.S., M.R.H.), University of British Columbia, Canada; Medical Genetics Group (Z.M., M.D.), School of Medicine and Dentistry, University of Aberdeen, UK; and Molecular Biology Group (S.J.M., E.S.G., N.G.), Coriell Institute for Medical Research, Camden, NJ
| | - Erynn S Gordon
- From the Centre for Molecular Medicine and Therapeutics (C.K., J.A.C., R.A.S., M.R.H.), University of British Columbia, Canada; Medical Genetics Group (Z.M., M.D.), School of Medicine and Dentistry, University of Aberdeen, UK; and Molecular Biology Group (S.J.M., E.S.G., N.G.), Coriell Institute for Medical Research, Camden, NJ
| | - Norman Gerry
- From the Centre for Molecular Medicine and Therapeutics (C.K., J.A.C., R.A.S., M.R.H.), University of British Columbia, Canada; Medical Genetics Group (Z.M., M.D.), School of Medicine and Dentistry, University of Aberdeen, UK; and Molecular Biology Group (S.J.M., E.S.G., N.G.), Coriell Institute for Medical Research, Camden, NJ
| | - Mark Davidson
- From the Centre for Molecular Medicine and Therapeutics (C.K., J.A.C., R.A.S., M.R.H.), University of British Columbia, Canada; Medical Genetics Group (Z.M., M.D.), School of Medicine and Dentistry, University of Aberdeen, UK; and Molecular Biology Group (S.J.M., E.S.G., N.G.), Coriell Institute for Medical Research, Camden, NJ
| | - Ramy A Slama
- From the Centre for Molecular Medicine and Therapeutics (C.K., J.A.C., R.A.S., M.R.H.), University of British Columbia, Canada; Medical Genetics Group (Z.M., M.D.), School of Medicine and Dentistry, University of Aberdeen, UK; and Molecular Biology Group (S.J.M., E.S.G., N.G.), Coriell Institute for Medical Research, Camden, NJ
| | - Michael R Hayden
- From the Centre for Molecular Medicine and Therapeutics (C.K., J.A.C., R.A.S., M.R.H.), University of British Columbia, Canada; Medical Genetics Group (Z.M., M.D.), School of Medicine and Dentistry, University of Aberdeen, UK; and Molecular Biology Group (S.J.M., E.S.G., N.G.), Coriell Institute for Medical Research, Camden, NJ.
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19
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Baake V, Hart EP, Bos R, Roos RAC. Participants at the Leiden Site of the REGISTRY Study: A Demographic Approach. J Huntingtons Dis 2016; 5:83-90. [PMID: 27003663 DOI: 10.3233/jhd-150157] [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: 11/15/2022]
Abstract
BACKGROUND REGISTRY is the largest European observational study of Huntington's disease (HD). The Leiden University Medical Center (LUMC) in The Netherlands is the largest recruiting site. OBJECTIVE The aim of this paper is to give an overview of the baseline characteristics of all Leiden participants from the start of the study in 2005 until the close of REGISTRY at the LUMC in September 2014. METHODS The Leiden cohort is described in two different ways: CAG repeat length and presence of motor signs. RESULTS Division into groups based on prolonged CAG length revealed that the cohort consists of 4 intermediate - (27-35 CAG), 22 reduced penetrance - (36-39 CAG), 465 full penetrance - (>39 CAG) and 60 control participants (<27 CAG). The second way of dividing the participants based on present or absent of motor signs, showed that 170 pre-motormanifest - and 317 motormanifest participants were enrolled. CONCLUSION The Leiden REGISTRY cohort at baseline is mainly characterized by full penetrance gene expansion carriers who have been clinically diagnosed with HD but who remain relatively functionally independent. For the majority of these participants, disease onset was based on motor signs followed by psychiatric and cognitive signs.
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Affiliation(s)
- Verena Baake
- Leiden University Medical Center, Department of Neurology, Leiden, The Netherlands
| | - Ellen P Hart
- Center for Human Drug Research, Leiden, The Netherlands
| | - Reineke Bos
- Leiden University Medical Center, Department of Neurology, Leiden, The Netherlands
| | - Raymund A C Roos
- Leiden University Medical Center, Department of Neurology, Leiden, The Netherlands
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20
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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: 31] [Impact Index Per Article: 3.9] [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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21
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The role of the immune system in triplet repeat expansion diseases. Mediators Inflamm 2015; 2015:873860. [PMID: 25873774 PMCID: PMC4385693 DOI: 10.1155/2015/873860] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 10/06/2014] [Accepted: 10/07/2014] [Indexed: 11/17/2022] Open
Abstract
Trinucleotide repeat expansion disorders (TREDs) are a group of dominantly inherited neurological diseases caused by the expansion of unstable repeats in specific regions of the associated genes. Expansion of CAG repeat tracts in translated regions of the respective genes results in polyglutamine- (polyQ-) rich proteins that form intracellular aggregates that affect numerous cellular activities. Recent evidence suggests the involvement of an RNA toxicity component in polyQ expansion disorders, thus increasing the complexity of the pathogenic processes. Neurodegeneration, accompanied by reactive gliosis and astrocytosis is the common feature of most TREDs, which may suggest involvement of inflammation in pathogenesis. Indeed, a number of immune response markers have been observed in the blood and CNS of patients and mouse models, and the activation of these markers was even observed in the premanifest stage of the disease. Although inflammation is not an initiating factor of TREDs, growing evidence indicates that inflammatory responses involving astrocytes, microglia, and the peripheral immune system may contribute to disease progression. Herein, we review the involvement of the immune system in the pathogenesis of triplet repeat expansion diseases, with particular emphasis on polyglutamine disorders. We also present various therapeutic approaches targeting the dysregulated inflammation pathways in these diseases.
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22
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Myers KA, Warman Chardon J, Huang L, Boycott KM. Deletion ofAFG3L2associated with spinocerebellar ataxia type 28 in the context of multiple genomic anomalies. Am J Med Genet A 2014; 164A:3209-12. [DOI: 10.1002/ajmg.a.36771] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2013] [Accepted: 08/20/2014] [Indexed: 11/10/2022]
Affiliation(s)
- Kenneth A. Myers
- Division of Neurology; Department of Pediatrics; Alberta Children's Hospital; University of Calgary; Calgary Alberta Canada
| | - Jodi Warman Chardon
- Department of Genetics; Children's Hospital of Eastern Ontario; University of Ottawa; Ottawa Ontario Canada
| | - Lijia Huang
- Department of Genetics; Children's Hospital of Eastern Ontario; University of Ottawa; Ottawa Ontario Canada
| | - Kym M. Boycott
- Department of Genetics; Children's Hospital of Eastern Ontario; University of Ottawa; Ottawa Ontario Canada
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23
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Abstract
Exclusively neuron-centric approaches to neuropathological mechanisms have not resulted in major new breakthroughs in the prevention and therapy of neurodegenerative diseases. In the present paper, we review the role of glia in neurodegeneration in an attempt to identify novel targets that could be used to develop much-needed strategies for the containment and cure of neurodegenerative disorders. We discuss this in the context of glial roles in the homoeostasis and defence of the brain. We consider the mounting evidence supporting a change away from the perception of reactive glial responses merely as secondary detrimental processes that exacerbate the course of neurological disorders, in favour of an emerging contemporary view of glial pathological responses as complex and multistaged defensive processes that also have the potential for dysfunction.
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24
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De Wert G, Dondorp W, Shenfield F, Devroey P, Tarlatzis B, Barri P, Diedrich K, Provoost V, Pennings G. ESHRE task force on ethics and Law22: preimplantation genetic diagnosis. Hum Reprod 2014; 29:1610-7. [PMID: 24927929 DOI: 10.1093/humrep/deu132] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This Task Force document discusses some relatively unexplored ethical issues involved in preimplantation genetic diagnosis (PGD). The document starts from the wide consensus that PGD is ethically acceptable if aimed at helping at-risk couples to avoid having a child with a serious disorder. However, if understood as a limit to acceptable indications for PGD, this 'medical model' may turn out too restrictive. The document discusses a range of possible requests for PGD that for different reasons fall outwith the accepted model and argues that instead of rejecting those requests out of hand, they need to be independently assessed in the light of ethical criteria. Whereas, for instance, there is no good reason for rejecting PGD in order to avoid health problems in a third generation (where the second generation would be healthy but faced with burdensome reproductive choices if wanting to have children), using PGD to make sure that one's child will have the same disorder or handicap as its parents, is ethically unacceptable.
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Affiliation(s)
- G De Wert
- Department of Health, Ethics & Society, Research Institutes CAPHRI and GROW, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands
| | - W Dondorp
- Department of Health, Ethics & Society, Research Institutes CAPHRI and GROW, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands
| | - F Shenfield
- Reproductive Medicine Unit, Obstetric Hospital, 2nd Floor, University College Hospital Huntley Street, London WC1 6AU, UK
| | - P Devroey
- Centre for Reproductive Medicine, UZ Brussel, Brussels, Belgium
| | - B Tarlatzis
- Infertility and IVF Center, Department of OB/GYN Medical School, Aristotle University of Thessaloniki, Greece
| | - P Barri
- Servei de Medicina de la Reproducció, Departament d'Obstetricia, Universitari Dexeus, Ginecologia i Reproducció, Barcelona, Spain
| | - K Diedrich
- Department of Obstetrics and Gynaecology, University of Luebeck, Ratzeburger Allee 160, D-23538 Luebeck, Germany
| | - V Provoost
- Department of Philosophy, University of Ghent, Blandijnberg 2, Gent 9000, Belgium
| | - G Pennings
- Department of Philosophy, University of Ghent, Blandijnberg 2, Gent 9000, Belgium
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25
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Kargieman L, Herrera E, Baez S, García AM, Dottori M, Gelormini C, Manes F, Gershanik O, Ibáñez A. Motor-Language Coupling in Huntington's Disease Families. Front Aging Neurosci 2014; 6:122. [PMID: 24971062 PMCID: PMC4054328 DOI: 10.3389/fnagi.2014.00122] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 05/27/2014] [Indexed: 11/24/2022] Open
Abstract
Traditionally, Huntington’s disease (HD) has been known as a movement disorder, characterized by motor, psychiatric, and cognitive impairments. Recent studies have shown that motor and action–language processes are neurally associated. The cognitive mechanisms underlying this interaction have been investigated through the action compatibility effect (ACE) paradigm, which induces a contextual coupling of ongoing motor actions and verbal processing. The present study is the first to use the ACE paradigm to evaluate action–word processing in HD patients (HDP) and their families. Specifically, we tested three groups: HDP, healthy first-degree relatives (HDR), and non-relative healthy controls. The results showed that ACE was abolished in HDP as well as HDR, but not in controls. Furthermore, we found that the processing deficits were primarily linguistic, given that they did not correlate executive function measurements. Our overall results underscore the role of cortico-basal ganglia circuits in action–word processing and indicate that the ACE task is a sensitive and robust early biomarker of HD and familial vulnerability.
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Affiliation(s)
- Lucila Kargieman
- Laboratory of Experimental Psychology and Neuroscience (LPEN), Institute of Cognitive Neurology (INECO), Favaloro University , Buenos Aires , Argentina ; National Scientific and Technical Research Council (CONICET) , Buenos Aires , Argentina ; UDP-INECO Foundation Core on Neuroscience (UIFCoN), Diego Portales University , Santiago , Chile
| | - Eduar Herrera
- Laboratory of Experimental Psychology and Neuroscience (LPEN), Institute of Cognitive Neurology (INECO), Favaloro University , Buenos Aires , Argentina ; National Scientific and Technical Research Council (CONICET) , Buenos Aires , Argentina ; Universidad Autónoma del Caribe , Barranquilla , Colombia
| | - Sandra Baez
- Laboratory of Experimental Psychology and Neuroscience (LPEN), Institute of Cognitive Neurology (INECO), Favaloro University , Buenos Aires , Argentina ; National Scientific and Technical Research Council (CONICET) , Buenos Aires , Argentina ; UDP-INECO Foundation Core on Neuroscience (UIFCoN), Diego Portales University , Santiago , Chile
| | - Adolfo M García
- Laboratory of Experimental Psychology and Neuroscience (LPEN), Institute of Cognitive Neurology (INECO), Favaloro University , Buenos Aires , Argentina ; National Scientific and Technical Research Council (CONICET) , Buenos Aires , Argentina ; UDP-INECO Foundation Core on Neuroscience (UIFCoN), Diego Portales University , Santiago , Chile ; School of Languages, National University of Córdoba (UNC) , Córdoba , Argentina
| | - Martin Dottori
- Laboratory of Experimental Psychology and Neuroscience (LPEN), Institute of Cognitive Neurology (INECO), Favaloro University , Buenos Aires , Argentina
| | - Carlos Gelormini
- Laboratory of Experimental Psychology and Neuroscience (LPEN), Institute of Cognitive Neurology (INECO), Favaloro University , Buenos Aires , Argentina
| | - Facundo Manes
- Laboratory of Experimental Psychology and Neuroscience (LPEN), Institute of Cognitive Neurology (INECO), Favaloro University , Buenos Aires , Argentina ; National Scientific and Technical Research Council (CONICET) , Buenos Aires , Argentina ; Australian Research Council (ARC) Centre of Excellence in Cognition and its Disorders , Sydney, NSW , Australia
| | - Oscar Gershanik
- Laboratory of Experimental Psychology and Neuroscience (LPEN), Institute of Cognitive Neurology (INECO), Favaloro University , Buenos Aires , Argentina ; National Scientific and Technical Research Council (CONICET) , Buenos Aires , Argentina
| | - Agustín Ibáñez
- Laboratory of Experimental Psychology and Neuroscience (LPEN), Institute of Cognitive Neurology (INECO), Favaloro University , Buenos Aires , Argentina ; National Scientific and Technical Research Council (CONICET) , Buenos Aires , Argentina ; UDP-INECO Foundation Core on Neuroscience (UIFCoN), Diego Portales University , Santiago , Chile ; Universidad Autónoma del Caribe , Barranquilla , Colombia
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Cooper DN, Krawczak M, Polychronakos C, Tyler-Smith C, Kehrer-Sawatzki H. Where genotype is not predictive of phenotype: towards an understanding of the molecular basis of reduced penetrance in human inherited disease. Hum Genet 2013; 132:1077-130. [PMID: 23820649 PMCID: PMC3778950 DOI: 10.1007/s00439-013-1331-2] [Citation(s) in RCA: 407] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 06/15/2013] [Indexed: 02/06/2023]
Abstract
Some individuals with a particular disease-causing mutation or genotype fail to express most if not all features of the disease in question, a phenomenon that is known as 'reduced (or incomplete) penetrance'. Reduced penetrance is not uncommon; indeed, there are many known examples of 'disease-causing mutations' that fail to cause disease in at least a proportion of the individuals who carry them. Reduced penetrance may therefore explain not only why genetic diseases are occasionally transmitted through unaffected parents, but also why healthy individuals can harbour quite large numbers of potentially disadvantageous variants in their genomes without suffering any obvious ill effects. Reduced penetrance can be a function of the specific mutation(s) involved or of allele dosage. It may also result from differential allelic expression, copy number variation or the modulating influence of additional genetic variants in cis or in trans. The penetrance of some pathogenic genotypes is known to be age- and/or sex-dependent. Variable penetrance may also reflect the action of unlinked modifier genes, epigenetic changes or environmental factors. At least in some cases, complete penetrance appears to require the presence of one or more genetic variants at other loci. In this review, we summarize the evidence for reduced penetrance being a widespread phenomenon in human genetics and explore some of the molecular mechanisms that may help to explain this enigmatic characteristic of human inherited disease.
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Affiliation(s)
- David N. Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN UK
| | - Michael Krawczak
- Institute of Medical Informatics and Statistics, Christian-Albrechts University, 24105 Kiel, Germany
| | | | - Chris Tyler-Smith
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA UK
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Moscovitch-Lopatin M, Goodman RE, Eberly S, Ritch JJ, Rosas HD, Matson S, Matson W, Oakes D, Young AB, Shoulson I, Hersch SM. HTRF analysis of soluble huntingtin in PHAROS PBMCs. Neurology 2013; 81:1134-40. [PMID: 23966247 DOI: 10.1212/wnl.0b013e3182a55ede] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
OBJECTIVE We measured the levels of mutant huntingtin (mtHtt) and total huntingtin (tHtt) in blood leukocytes from Prospective Huntington At-Risk Observational Study (PHAROS) subjects at 50% risk of carrying the Huntington disease mutation using a homogeneous time-resolved fluorescence (HTRF) assay to assess its potential as a biomarker. METHODS Peripheral blood mononuclear cells from consenting PHAROS subjects were analyzed by HTRF using antibodies that simultaneously measured mtHtt and tHtt. mtHtt levels were normalized to tHtt, double-stranded DNA, or protein and analyzed according to cytosine-adenine-guanine repeat length (CAGn), demographics, predicted time to clinical onset or known time since clinical onset, and available clinical measures. RESULTS From 363 assayed samples, 342 met quality control standards. Levels of mtHtt and mt/tHtt were higher in 114 subjects with expanded CAG repeats (CAG ≥ 37) compared with 228 subjects with nonexpanded CAG repeats (CAG <37) (p < 0.0001). Analysis of relationships to predicted time to onset or to phenoconversion suggested that the HTRF signal could mark changes during the Huntington disease prodrome or after clinical onset. CONCLUSIONS The HTRF assay can effectively measure mtHtt in multicenter sample sets and may be useful in trials of therapies targeting huntingtin.
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Affiliation(s)
- Miriam Moscovitch-Lopatin
- From the Massachusetts General Hospital (M.M.-L., R.E.G., J.J.R., H.D.R., S.M., A.B.Y., S.M.H.), MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Charlestown, MA; University of Rochester Medical Center (S.E., D.O.), Department of Biostatistics and Computational Biology, Rochester, NY; Veterans Administration Hospital (W.M.), Bedford, MA; and Program for Regulatory Science & Medicine (I.S.), Georgetown University, Washington, DC
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Losekoot M, van Belzen MJ, Seneca S, Bauer P, Stenhouse SAR, Barton DE. EMQN/CMGS best practice guidelines for the molecular genetic testing of Huntington disease. Eur J Hum Genet 2013; 21:480-6. [PMID: 22990145 PMCID: PMC3641377 DOI: 10.1038/ejhg.2012.200] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Huntington disease (HD) is caused by the expansion of an unstable polymorphic trinucleotide (CAG)n repeat in exon 1 of the HTT gene, which translates into an extended polyglutamine tract in the protein. Laboratory diagnosis of HD involves estimation of the number of CAG repeats. Molecular genetic testing for HD is offered in a wide range of laboratories both within and outside the European community. In order to measure the quality and raise the standard of molecular genetic testing in these laboratories, the European Molecular Genetics Quality Network has organized a yearly external quality assessment (EQA) scheme for molecular genetic testing of HD for over 10 years. EQA compares a laboratory's output with a fixed standard both for genotyping and reporting of the results to the referring physicians. In general, the standard of genotyping is very high but the clarity of interpretation and reporting of the test result varies more widely. This emphasizes the need for best practice guidelines for this disorder. We have therefore developed these best practice guidelines for genetic testing for HD to assist in testing and reporting of results. The analytical methods and the potential pitfalls of molecular genetic testing are highlighted and the implications of the different test outcomes for the consultand and his or her family members are discussed.
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Affiliation(s)
- Monique Losekoot
- Department of Clinical Genetics, Laboratory for Diagnostic Genome Analysis, Leiden University Medical Centre, Leiden, The Netherlands.
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Killoran A, Biglan KM, Jankovic J, Eberly S, Kayson E, Oakes D, Young AB, Shoulson I. Characterization of the Huntington intermediate CAG repeat expansion phenotype in PHAROS. Neurology 2013; 80:2022-7. [PMID: 23624566 DOI: 10.1212/wnl.0b013e318294b304] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVES We aimed to describe the clinical phenotype conferred by the intermediate-length huntingtin allele CAG repeat expansion in a population-based study. METHODS The Prospective Huntington At Risk Observational Study (PHAROS) enrolled adults at risk for Huntington disease (HD). They were assessed approximately every 9 months with the Unified Huntington's Disease Rating Scale (UHDRS) by investigators unaware of participants' gene status. UHDRS scores were compared according to the Huntingtin gene CAG repeat number: expanded >36, intermediate 27-35, and nonexpanded controls <26. RESULTS Fifty (5.1%) of the 983 participants had an intermediate allele (IA). They were similar to controls on UHDRS motor, cognitive, and functional measures, but significantly worse behaviorally on apathy and suicidal ideation. On 5 of the 9 other behavioral items and on total behavior, the IA group's scores were worse than those of controls and expanded participants, who themselves scored significantly worse than controls on 6 behavioral measures. Retention rates at 4 years were 48% for the IA group compared to 58% and 60% for the expanded and control groups. CONCLUSIONS In a cohort at risk for HD, the IA was associated with significant behavioral abnormalities but normal motor and cognition. This behavioral phenotype may represent a prodromal stage of HD, with the potential for subsequent clinical manifestations, or be part of a distinct phenotype conferred by pathology independent of the CAG expansion length.
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de Die-Smulders CEM, de Wert GMWR, Liebaers I, Tibben A, Evers-Kiebooms G. Reproductive options for prospective parents in families with Huntington's disease: clinical, psychological and ethical reflections. Hum Reprod Update 2013; 19:304-15. [PMID: 23377865 DOI: 10.1093/humupd/dms058] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Huntington's disease (HD) is an autosomal dominant neurodegenerative late onset disorder. This review of reproductive options aims to increase reproductive confidence and to prevent suffering in relation to family planning around HD and possibly other late onset neurodegenerative disorders. METHODS Selected relevant literature and own views and experiences as clinical geneticists, psychologists and ethicists have been used. RESULTS Possible options, with emphasis on prenatal diagnosis (PD) and preimplantation genetic diagnosis (PGD) to prevent the transmission of HD to the next generation, are described and discussed. They are formally presented in a decision tree, taking into account the presence or absence of a fully penetrant allele (FPA), a reduced penetrant allele (RPA) or an intermediate allele (IA). A table compares invasive and non-invasive PD and PGD. From a psychological perspective, the complex process of counselling and decision-making regarding reproductive options is discussed. Special attention is paid to the decision to avoid the transmission of the mutation and to the confrontation and coping of a mutation-free child growing up with a parent developing disease symptoms. From an ethical point of view, reflections on both PD and PGD are brought forward taking into account the difference between FPA, RPA and IA, direct testing or exclusion testing and taking into account the welfare of the child in the context of medically assisted reproduction. CONCLUSION Recommendations and suggestions for good clinical practice in the reproductive care for HD families are formulated.
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Affiliation(s)
- C E M de Die-Smulders
- Department of Clinical Genetics, Maastricht University Medical Centre, Joseph Bechlaan 113, Maastricht, The Netherlands.
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Kaplan A, Stockwell BR. Therapeutic approaches to preventing cell death in Huntington disease. Prog Neurobiol 2012; 99:262-80. [PMID: 22967354 PMCID: PMC3505265 DOI: 10.1016/j.pneurobio.2012.08.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 07/20/2012] [Accepted: 08/17/2012] [Indexed: 12/01/2022]
Abstract
Neurodegenerative diseases affect the lives of millions of patients and their families. Due to the complexity of these diseases and our limited understanding of their pathogenesis, the design of therapeutic agents that can effectively treat these diseases has been challenging. Huntington disease (HD) is one of several neurological disorders with few therapeutic options. HD, like numerous other neurodegenerative diseases, involves extensive neuronal cell loss. One potential strategy to combat HD and other neurodegenerative disorders is to intervene in the execution of neuronal cell death. Inhibiting neuronal cell death pathways may slow the development of neurodegeneration. However, discovering small molecule inhibitors of neuronal cell death remains a significant challenge. Here, we review candidate therapeutic targets controlling cell death mechanisms that have been the focus of research in HD, as well as an emerging strategy that has been applied to developing small molecule inhibitors-fragment-based drug discovery (FBDD). FBDD has been successfully used in both industry and academia to identify selective and potent small molecule inhibitors, with a focus on challenging proteins that are not amenable to traditional high-throughput screening approaches. FBDD has been used to generate potent leads, pre-clinical candidates, and has led to the development of an FDA approved drug. This approach can be valuable for identifying modulators of cell-death-regulating proteins; such compounds may prove to be the key to halting the progression of HD and other neurodegenerative disorders.
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Affiliation(s)
- Anna Kaplan
- Department of Biological Sciences, Columbia University, Northwest Corner Building, MC4846, 550 West 120 Street, New York, NY 10027, USA
| | - Brent R. Stockwell
- Howard Hughes Medical Institute, Columbia University, Northwest Corner Building, MC4846, 550 West 120 Street, New York, NY 10027, USA
- Department of Chemistry, Columbia University, Northwest Corner Building, MC4846, 550 West 120 Street, New York, NY 10027, USA
- Department of Biological Sciences, Columbia University, Northwest Corner Building, MC4846, 550 West 120 Street, New York, NY 10027, USA
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Squitieri F, Jankovic J. Huntington's disease: how intermediate are intermediate repeat lengths? Mov Disord 2012; 27:1714-7. [PMID: 23008174 DOI: 10.1002/mds.25172] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 07/31/2012] [Accepted: 08/03/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Huntington's disease (HD) is a devastating heredoneurodegenerative disorder associated with a wide variety of neurological and psychiatric symptoms caused by an expanded CAG repeat in the HTT gene. The expansion mutation in HTT is dominantly transmitted and codes for a protein named huntingtin (htt). HYPOTHESIS One hypothesis, according to a multistep mechanism, is that the intergenerational transmission of the normal repeat size causes small, progressive CAG stretch elongations in the general population from one generation to another, until a critical pathological CAG repeat threshold is reached. Mutations may originate in the offspring from paternally transmitted CAG repeats, falling within an intermediate alleles (IA) range of 27 to 35 in repeat length. CONCLUSIONS There has been emerging evidence that some individuals with IAs might develop an HD phenotype. This presents a challenge for genetic counseling, because these individuals are often reassured that they are "disease free." However, there are many unanswered questions related to the role of IAs in the development of the HD phenotype and in the pathogenesis of HD.
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Characterization of a large group of individuals with huntington disease and their relatives enrolled in the COHORT study. PLoS One 2012; 7:e29522. [PMID: 22359536 PMCID: PMC3281013 DOI: 10.1371/journal.pone.0029522] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Accepted: 11/29/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Careful characterization of the phenotype and genotype of Huntington disease (HD) can foster better understanding of the condition. METHODS We conducted a cohort study in the United States, Canada, and Australia of members of families affected by HD. We collected demographic and clinical data, conducted the Unified Huntington's Disease Rating Scale and Mini-Mental State Examination, and determined Huntingtin trinucleotide CAG repeat length. We report primarily on cross-sectional baseline data from this recently completed prospective, longitudinal, observational study. RESULTS As of December 31, 2009, 2,318 individuals enrolled; of these, 1,985 (85.6%) were classified into six analysis groups. Three groups had expanded CAG alleles (36 repeats or more): individuals with clinically diagnosed HD [n = 930], and clinically unaffected first-degree relatives who had previously pursued [n = 248] or not pursued [n = 112] predictive DNA testing. Three groups lacked expanded alleles: first-degree relatives who had previously pursued [n = 41] or not pursued [n = 224] genetic testing, and spouses and caregivers [n = 430]. Baseline mean performance differed across groups in all motor, behavioral, cognitive, and functional measures (p<0.001). Clinically unaffected individuals with expanded alleles weighed less (76.0 vs. 79.6 kg; p = 0.01) and had lower cognitive scores (28.5 vs. 29.1 on the Mini Mental State Examination; p = 0.008) than individuals without expanded alleles. The frequency of "high normal" repeat lengths (27 to 35) was 2.5% and repeat lengths associated with reduced penetrance (36 to 39) was 2.7%. CONCLUSION Baseline analysis of COHORT study participants revealed differences that emerge prior to clinical diagnosis. Longitudinal investigation of this cohort will further characterize the natural history of HD and genetic and biological modifiers. TRIAL REGISTRATION Clinicaltrials.gov NCT00313495.
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Manley G, Lane H, Carlsson A, Ahlborg B, Mårtensson Å, Nilsson MB, Simpson SA, Rae D. Guideline for oral healthcare of adults with Huntington’s disease. Neurodegener Dis Manag 2012. [DOI: 10.2217/nmt.11.68] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
SUMMARY These guidelines present an overall strategy for oral healthcare based on the principles of achieving a disease-free, pain-free and safe mouth. The standards of care referred to in the document seek to provide guidelines for the care and treatment that is no less a standard provided for an individual that does not have this condition. Such care and treatment will take into account the health and safety of each individual within the context of their condition. Particular emphasis is placed on dental professionals working within a multidisciplinary team, focusing on prevention of oral disease and providing treatment appropriate to the various stages of the progression of this condition. It is intended that by providing and subsequently promoting these guidelines, it will focus the dental professions work on this condition and the implementation of good care for people with Huntington’s disease.
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Affiliation(s)
| | - Helen Lane
- The Royal Hospital for Neurodisability, London, UK
| | | | | | | | | | - Sheila A Simpson
- Department of Clinical Genetics, NHS Grampian, Aberdeen, Scotland, UK
- University of Aberdeen, Aberdeen, AB25 2ZA Scotland, UK
| | - Daniela Rae
- Department of Clinical Genetics, NHS Grampian, Aberdeen, Scotland, UK
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Brotherton A, Campos L, Rowell A, Zoia V, Simpson SA, Rae D. Nutritional management of individuals with Huntington’s disease: nutritional guidelines. Neurodegener Dis Manag 2012. [DOI: 10.2217/nmt.11.69] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
SUMMARY The delivery of good nutritional care is a fundamental element of the management of individuals with Huntington’s disease and all patients with Huntington’s disease will, at some time, need dietary intervention because of the sequela of the disease; yet there are no European nutritional guidelines. The European Huntington’s Disease Network Standards of Care Dietitians Group has brought together expert dietitians from across Europe to produce nutritional guidelines to improve the nutritional management of individuals with Huntington’s disease. The guidelines were developed to promote optimal nutritional screening, assessment and management of individuals throughout all stages of the disease, with the aim of improving the standard of nutritional care delivered. Literature was systematically searched in an attempt to ensure that the recommendations are based on sound evidence and where evidence is lacking, specific guidance is based on consensus expert dietetic opinion. The provision of nutritional care varies widely between countries. Implementation of these nutritional guidelines across Europe should improve the quality of nutritional care delivered to individuals with Huntington’s disease.
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Affiliation(s)
| | - Lillian Campos
- Lancashire Teaching Hospital NHS Foundation Trust, Preston, Lancashire, UK
- Lancashire Care MH Foundation Trust, Lancashire, UK
| | | | | | - Sheila A Simpson
- Department of Clinical Genetics, NHS Grampian, Aberdeen, Scotland, UK
- University of Aberdeen, Aberdeen, AB25 2ZA Scotland, UK
| | - Daniela Rae
- Department of Clinical Genetics, NHS Grampian, Aberdeen, Scotland, UK
- University of Aberdeen, Aberdeen, AB25 2ZA Scotland, UK
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Hamilton A, Heemskerk AW, Loucas M, Twiston-Davies R, Matheson KY, Simpson SA, Rae D. Oral feeding in Huntington’s disease: a guideline document for speech and language therapists. Neurodegener Dis Manag 2012. [DOI: 10.2217/nmt.11.77] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
SUMMARY Speech and language therapy has an important role in the management of Huntington’s disease (HD). Swallowing difficulties affect most individuals with HD. Throughout the disease process these difficulties require management with timely and effective therapeutic intervention. Currently there are no European guidelines for the assessment and management of swallowing impairments in HD. The European Huntington’s Disease Network (EHDN) Standards of Care Speech and Language Therapy Working Group has brought together expert speech and language therapists from across Europe to produce guidelines to improve the management of swallowing disorders for individuals with Huntington’s disease. The guidelines were developed with the aim of promoting timely and appropriate assessment of the swallowing process and focused management throughout all stages of the disease. Literature was systematically searched in an attempt to ensure that the recommendations are based on sound evidence. Where evidence was lacking, specific guidance is based on expert consensus. The provision of care varies widely between countries in Europe and the implementation of those guidelines should improve the quality of care delivered to individuals with HD.
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Affiliation(s)
- Alison Hamilton
- Department of Speech and Language Therapy, Aberdeen Royal Infirmary, Aberdeen, Scotland, UK
| | - Anne-Wil Heemskerk
- Department of Neurology, Leiden University Medical Centre, Leiden, The Netherlands
- Department of Speech & Language Therapy, Huntington Centre, Topaz, Overduin, Katwijk, The Netherlands
| | - Melissa Loucas
- National Hospital for Neurology & Neurosurgery, UCLH NHS Foundation Trust, London, UK
| | - Rita Twiston-Davies
- Department of Speech & Language Therapy, Royal Hospital for Neuro-disability, Putney, London, UK
| | - Kirsty Y Matheson
- Department of Clinical Genetics, NHS Grampian, Aberdeen, Scotland, UK
| | - Sheila A Simpson
- Department of Clinical Genetics, NHS Grampian, Aberdeen, Scotland, UK
- University of Aberdeen, Aberdeen, AB25 2ZA Scotland, UK
| | - Daniela Rae
- Department of Clinical Genetics, NHS Grampian, Aberdeen, Scotland, UK
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Quarrell OW, Handley O, O'Donovan K, Dumoulin C, Ramos-Arroyo M, Biunno I, Bauer P, Kline M, Landwehrmeyer GB. Discrepancies in reporting the CAG repeat lengths for Huntington's disease. Eur J Hum Genet 2012; 20:20-6. [PMID: 21811303 PMCID: PMC3234505 DOI: 10.1038/ejhg.2011.136] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Revised: 04/26/2011] [Accepted: 06/13/2011] [Indexed: 11/09/2022] Open
Abstract
Huntington's disease results from a CAG repeat expansion within the Huntingtin gene; this is measured routinely in diagnostic laboratories. The European Huntington's Disease Network REGISTRY project centrally measures CAG repeat lengths on fresh samples; these were compared with the original results from 121 laboratories across 15 countries. We report on 1326 duplicate results; a discrepancy in reporting the upper allele occurred in 51% of cases, this reduced to 13.3% and 9.7% when we applied acceptable measurement errors proposed by the American College of Medical Genetics and the Draft European Best Practice Guidelines, respectively. Duplicate results were available for 1250 lower alleles; discrepancies occurred in 40% of cases. Clinically significant discrepancies occurred in 4.0% of cases with a potential unexplained misdiagnosis rate of 0.3%. There was considerable variation in the discrepancy rate among 10 of the countries participating in this study. Out of 1326 samples, 348 were re-analysed by an accredited diagnostic laboratory, based in Germany, with concordance rates of 93% and 94% for the upper and lower alleles, respectively. This became 100% if the acceptable measurement errors were applied. The central laboratory correctly reported allele sizes for six standard reference samples, blind to the known result. Our study differs from external quality assessment (EQA) schemes in that these are duplicate results obtained from a large sample of patients across the whole diagnostic range. We strongly recommend that laboratories state an error rate for their measurement on the report, participate in EQA schemes and use reference materials regularly to adjust their own internal standards.
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Affiliation(s)
- Oliver W Quarrell
- Department of Clinical Genetics, Sheffield Children's Hospital, Sheffield, UK.
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Ha AD, Jankovic J. Exploring the correlates of intermediate CAG repeats in Huntington disease. Postgrad Med 2011; 123:116-21. [PMID: 21904093 DOI: 10.3810/pgm.2011.09.2466] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVE To explore the clinical phenotype in individuals with huntingtin gene CAG repeat lengths between 27 and 35, a range that is termed "intermediate" and below one traditionally considered diagnostic of Huntington disease (HD). BACKGROUND The Prospective Huntington Disease At-Risk Observational Study (PHAROS) found that patients with intermediate CAG lengths overlapped with those diagnosed as HD (≥ 37 CAG repeats) on the Unified Huntington's Disease Rating Scale (UHDRS) behavioral measures. Furthermore, several patients with intermediate CAG repeats demonstrating clinical (and pathological) evidence of HD have been reported. METHODS We reviewed all cases with intermediate CAG repeats who have presented to our clinic, as well as those reported in the literature. RESULTS We describe 4 patients with intermediate repeats evaluated at our center whose clinical features were highly suggestive of HD. Investigations for HD phenocopies were negative. Anticipation was demonstrated in 1 case with supportive neuropathological evidence of HD. Additionally, we describe the clinical features of 5 other patients reported in the literature. CONCLUSION Individuals with huntingtin gene CAG repeats in the intermediate (27-35) range should be considered at risk for the development of HD, particularly if they have a family history of HD, whether they exhibit clinical features of the disease.
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Affiliation(s)
- Ainhi D Ha
- Parkinson's Disease Center and Movement Disorders Clinic, Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
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Mason RP, Giorgini F. Modeling Huntington disease in yeast: perspectives and future directions. Prion 2011. [PMID: 22052350 DOI: 10.4161/pri.5.4.18005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Yeast have been extensively used to model aspects of protein folding diseases, yielding novel mechanistic insights and identifying promising candidate therapeutic targets. In particular, the neurodegenerative disorder Huntington disease (HD), which is caused by the abnormal expansion of a polyglutamine tract in the huntingtin (htt) protein, has been widely studied in yeast. This work has led to the identification of several promising therapeutic targets and compounds that have been validated in mammalian cells, Drosophila and rodent models of HD. Here we discuss the development of yeast models of mutant htt toxicity and misfolding, as well as the mechanistic insights gleaned from this simple model. The role of yeast prions in the toxicity/misfolding of mutant htt is also highlighted. Furthermore, we provide an overview of the application of HD yeast models in both genetic and chemical screens, and the fruitful results obtained from these approaches. Finally, we discuss the future of yeast in neurodegenerative research, in the context of HD and other diseases.
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Affiliation(s)
- Robert P Mason
- Department of Genetics, University of Leicester, Leicester, UK
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Mason RP, Giorgini F. Modeling Huntington disease in yeast: perspectives and future directions. Prion 2011; 5:269-76. [PMID: 22052350 DOI: 10.4161/pri.18005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Yeast have been extensively used to model aspects of protein folding diseases, yielding novel mechanistic insights and identifying promising candidate therapeutic targets. In particular, the neurodegenerative disorder Huntington disease (HD), which is caused by the abnormal expansion of a polyglutamine tract in the huntingtin (htt) protein, has been widely studied in yeast. This work has led to the identification of several promising therapeutic targets and compounds that have been validated in mammalian cells, Drosophila and rodent models of HD. Here we discuss the development of yeast models of mutant htt toxicity and misfolding, as well as the mechanistic insights gleaned from this simple model. The role of yeast prions in the toxicity/misfolding of mutant htt is also highlighted. Furthermore, we provide an overview of the application of HD yeast models in both genetic and chemical screens, and the fruitful results obtained from these approaches. Finally, we discuss the future of yeast in neurodegenerative research, in the context of HD and other diseases.
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Affiliation(s)
- Robert P Mason
- Department of Genetics, University of Leicester, Leicester, UK
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Jacobsen JC, Gregory GC, Woda JM, Thompson MN, Coser KR, Murthy V, Kohane IS, Gusella JF, Seong IS, MacDonald ME, Shioda T, Lee JM. HD CAG-correlated gene expression changes support a simple dominant gain of function. Hum Mol Genet 2011; 20:2846-60. [PMID: 21536587 DOI: 10.1093/hmg/ddr195] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Huntington's disease is initiated by the expression of a CAG repeat-encoded polyglutamine region in full-length huntingtin, with dominant effects that vary continuously with CAG size. The mechanism could involve a simple gain of function or a more complex gain of function coupled to a loss of function (e.g. dominant negative-graded loss of function). To distinguish these alternatives, we compared genome-wide gene expression changes correlated with CAG size across an allelic series of heterozygous CAG knock-in mouse embryonic stem (ES) cell lines (Hdh(Q20/7), Hdh(Q50/7), Hdh(Q91/7), Hdh(Q111/7)), to genes differentially expressed between Hdh(ex4/5/ex4/5) huntingtin null and wild-type (Hdh(Q7/7)) parental ES cells. The set of 73 genes whose expression varied continuously with CAG length had minimal overlap with the 754-member huntingtin-null gene set but the two were not completely unconnected. Rather, the 172 CAG length-correlated pathways and 238 huntingtin-null significant pathways clustered into 13 shared categories at the network level. A closer examination of the energy metabolism and the lipid/sterol/lipoprotein metabolism categories revealed that CAG length-correlated genes and huntingtin-null-altered genes either were different members of the same pathways or were in unique, but interconnected pathways. Thus, varying the polyglutamine size in full-length huntingtin produced gene expression changes that were distinct from, but related to, the effects of lack of huntingtin. These findings support a simple gain-of-function mechanism acting through a property of the full-length huntingtin protein and point to CAG-correlative approaches to discover its effects. Moreover, for therapeutic strategies based on huntingtin suppression, our data highlight processes that may be more sensitive to the disease trigger than to decreased huntingtin levels.
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Affiliation(s)
- Jessie C Jacobsen
- Center for Human Genetic Research, Massachusetts General Hospital, 185 Cambridge Street, Boston, MA 02114, USA
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Bradley CK, Scott HA, Chami O, Peura TT, Dumevska B, Schmidt U, Stojanov T. Derivation of Huntington's Disease-Affected Human Embryonic Stem Cell Lines. Stem Cells Dev 2011; 20:495-502. [DOI: 10.1089/scd.2010.0120] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
| | | | - Omar Chami
- Sydney IVF Stem Cells, Sydney, Australia
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Morrison PJ, Harding-Lester S, Bradley A. Uptake of Huntington disease predictive testing in a complete population. Clin Genet 2010; 80:281-6. [PMID: 20880124 DOI: 10.1111/j.1399-0004.2010.01538.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Using the Northern Ireland Huntington disease (HD) register, the number of prospectively recorded predictive tests was analysed over a 20-year period. Two hundred and twelve patients completed predictive testing. Ninety-two (43%) received mutation-positive results and 119 (56%) mutation negative. There was one intermediate allele result. There was no significant gender difference. One hundred and eighty affected cases confirmed by molecular genetic testing were alive on 1 January 2001. The uptake of predictive testing in the entire HD 50% at-risk population in 2001 was calculated by three methods giving a range of 12.3-14.6%. Uptake after 20 years was estimated to be 14.7%. The minimum prevalence of affected HD cases was calculated as 10.6/100,000 in 2001. The total uptake of predictive testing was calculated and it suggests that a substantial number of at-risk patients do not come forward for testing until symptomatic. Pre-symptomatic testing for this late-onset condition with no present treatment, and limited management options, still presents challenges for families.
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Affiliation(s)
- P J Morrison
- Regional Medical Genetics Centre, Belfast City Hospital, Belfast, UK.
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Nahhas F, Garbern J, Feely S, Feldman GL. An intergenerational contraction of a fully penetrant Huntington disease allele to a reduced penetrance allele: interpretation of results and significance for risk assessment and genetic counseling. Am J Med Genet A 2009; 149A:732-6. [PMID: 19267413 DOI: 10.1002/ajmg.a.32720] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We report on a healthy 50-year-old woman who sought predictive testing due to a family history of Huntington disease (HD). Her 73-year-old mother had recently been confirmed to carry an HD allele of 42 CAG repeats, and started to show symptoms of HD at age 68. Clinically diagnosed HD is present in the maternal grandfather, maternal uncle, and three maternal cousins. Molecular analysis of the HD CAG repeat region identified an allele with 38 CAG repeats in the consultand, giving evidence of allele size contraction from the maternal 42 CAG repeat allele. Mitotic stability of the CAG repeat was demonstrated in DNA from a skin sample with the same allele size (38). In addition to sex of the parent and size of the repeat, recent data analysis of intergenerational stability of the CAG repeat size suggest a gender effect of the offspring on the likelihood of allele contraction or expansion. Discussion of these results with this patient presented challenges in providing appropriate risk assessment for developing the disease herself as well as the future risk to her offspring.
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Affiliation(s)
- Fatimah Nahhas
- Detroit Medical Center University Laboratories, Molecular Genetics Diagnostic Laboratory, Detroit, Michigan 48210, USA.
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Harris MK, Shneyder N, Borazanci A, Korniychuk E, Kelley RE, Minagar A. Movement disorders. Med Clin North Am 2009; 93:371-88, viii. [PMID: 19272514 DOI: 10.1016/j.mcna.2008.09.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Abnormal involuntary movements are major features of a large group of neurologic disorders, some of which are neurodegenerative and pose a significant diagnostic and treatment challenge to treating physicians. This article presents a concise review of clinical features, pathogenesis, epidemiology, and management of seven of the most common movement disorders encountered in a primary care clinic routinely. The disorders discussed are Parkinson disease, essential tremor, restless legs syndrome, Huntington disease, drug-induced movement disorder, Wilson disease, and Tourette syndrome.
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Affiliation(s)
- Meghan K Harris
- Department of Neurology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
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Herishanu YO, Parvari R, Pollack Y, Shelef I, Marom B, Martino T, Cannella M, Squitieri F. Huntington disease in subjects from an Israeli Karaite community carrying alleles of intermediate and expanded CAG repeats in the HTT gene: Huntington disease or phenocopy? J Neurol Sci 2009; 277:143-6. [DOI: 10.1016/j.jns.2008.11.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2008] [Revised: 10/01/2008] [Accepted: 11/10/2008] [Indexed: 11/29/2022]
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Rosas HD, Salat DH, Lee SY, Zaleta AK, Hevelone N, Hersch SM. Complexity and heterogeneity: what drives the ever-changing brain in Huntington's disease? Ann N Y Acad Sci 2009; 1147:196-205. [PMID: 19076442 DOI: 10.1196/annals.1427.034] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Significant advances are being made in our understanding of basic pathophyiological and biochemical mechanisms that cause Huntington's disease (HD). There is increasing reason to believe that pathologic alterations occur in the brain for years before symptoms manifest. The "classic" hallmark of neuropathology in HD is selective neurodegeneration in which vulnerable populations of neurons degenerate while less vulnerable populations are spared. While the earliest and most striking neuropathologic changes have been found in the neostriatum, neuronal loss has been identified in many other regions of the brain. We report topologically selective, early, and progressive changes in the cortex, striatum, extrastriatal brain structures, and white matter throughout the spectrum of disease. Our growing understanding of HD underscores the reality that points to the complexity of HD. A single, well-defined, genetic mutation causes a cascade of events whose final result is an aggregate insult of the homeostatic process. We explore possible explanations for the selective vulnerability of the brain in HD. The ultimate goal in HD is to develop disease-modifying therapies that will prevent the onset of clinical symptoms in those individuals who are at risk and slow the progression of symptoms in those individuals already affected with symptoms. Understanding changes in brain morphometry and their relationship to clinical symptoms may provide important and new insights into basic pathophysiological mechanisms at play in the disease.
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Affiliation(s)
- H Diana Rosas
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
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Bernhardt C, Schwan AM, Kraus P, Epplen JT, Kunstmann E. Decreasing uptake of predictive testing for Huntington's disease in a German centre: 12 years' experience (1993-2004). Eur J Hum Genet 2008; 17:295-300. [PMID: 18781186 DOI: 10.1038/ejhg.2008.164] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
In this retrospective study, we examined changes in decision-making for and against the predictive genetic test for Huntington's disease including 478 persons at risk who had undergone genetic counselling in one centre in Germany between 1993 and 2004. At the outset of the counselling procedure the majority of subjects (71%) wanted to make use of the test, yet the actual demand of the predictive test result declined from 67 to 38% over the years. In addition, the time interval between counselling session and blood withdrawal was reduced, as determined by the counselees: in 2000-2004 the majority of persons at risk made the appointment for blood withdrawal after the shortest possible time span. Demographic factors of the cohort remained comparatively stable in the investigated time period. An association was evident between the ratio of test usage and the counselling person. These and other possible factors influencing the time flow of predictive DNA testing are discussed. Further studies are necessary to investigate whether changes of test demand rates are a general phenomenon.
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Abstract
Huntington's disease (HD) is a devastating autosomal dominant neurodegenerative disease caused by a CAG trinucleotide repeat expansion encoding an abnormally long polyglutamine tract in the huntingtin protein. Much has been learnt since the mutation was identified in 1993. We review the functions of wild-type huntingtin. Mutant huntingtin may cause toxicity via a range of different mechanisms. The primary consequence of the mutation is to confer a toxic gain of function on the mutant protein and this may be modified by certain normal activities that are impaired by the mutation. It is likely that the toxicity of mutant huntingtin is revealed after a series of cleavage events leading to the production of N-terminal huntingtin fragment(s) containing the expanded polyglutamine tract. Although aggregation of the mutant protein is a hallmark of the disease, the role of aggregation is complex and the arguments for protective roles of inclusions are discussed. Mutant huntingtin may mediate some of its toxicity in the nucleus by perturbing specific transcriptional pathways. HD may also inhibit mitochondrial function and proteasome activity. Importantly, not all of the effects of mutant huntingtin may be cell-autonomous, and it is possible that abnormalities in neighbouring neurons and glia may also have an impact on connected cells. It is likely that there is still much to learn about mutant huntingtin toxicity, and important insights have already come and may still come from chemical and genetic screens. Importantly, basic biological studies in HD have led to numerous potential therapeutic strategies.
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