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Jackson WS, Bauer S, Kaczmarczyk L, Magadi SS. Selective Vulnerability to Neurodegenerative Disease: Insights from Cell Type-Specific Translatome Studies. BIOLOGY 2024; 13:67. [PMID: 38392286 PMCID: PMC10886597 DOI: 10.3390/biology13020067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/12/2024] [Accepted: 01/17/2024] [Indexed: 02/24/2024]
Abstract
Neurodegenerative diseases (NDs) manifest a wide variety of clinical symptoms depending on the affected brain regions. Gaining insights into why certain regions are resistant while others are susceptible is vital for advancing therapeutic strategies. While gene expression changes offer clues about disease responses across brain regions, the mixture of cell types therein obscures experimental results. In recent years, methods that analyze the transcriptomes of individual cells (e.g., single-cell RNA sequencing or scRNAseq) have been widely used and have provided invaluable insights into specific cell types. Concurrently, transgene-based techniques that dissect cell type-specific translatomes (CSTs) in model systems, like RiboTag and bacTRAP, offer unique advantages but have received less attention. This review juxtaposes the merits and drawbacks of both methodologies, focusing on the use of CSTs in understanding conditions like amyotrophic lateral sclerosis (ALS), Huntington's disease (HD), Alzheimer's disease (AD), and specific prion diseases like fatal familial insomnia (FFI), genetic Creutzfeldt-Jakob disease (gCJD), and acquired prion disease. We conclude by discussing the emerging trends observed across multiple diseases and emerging methods.
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Affiliation(s)
- Walker S Jackson
- Wallenberg Center for Molecular Medicine, Linköping University, 581 85 Linköping, Sweden
- Department of Biomedical and Clinical Sciences, Linköping University, 581 85 Linköping, Sweden
| | - Susanne Bauer
- Wallenberg Center for Molecular Medicine, Linköping University, 581 85 Linköping, Sweden
- Department of Biomedical and Clinical Sciences, Linköping University, 581 85 Linköping, Sweden
| | - Lech Kaczmarczyk
- Wallenberg Center for Molecular Medicine, Linköping University, 581 85 Linköping, Sweden
- Department of Biomedical and Clinical Sciences, Linköping University, 581 85 Linköping, Sweden
| | - Srivathsa S Magadi
- Wallenberg Center for Molecular Medicine, Linköping University, 581 85 Linköping, Sweden
- Department of Biomedical and Clinical Sciences, Linköping University, 581 85 Linköping, Sweden
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2
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Kim R, Seong MW, Oh B, Shin HS, Lee JS, Park S, Jang M, Jeon B, Kim HJ, Lee JY. Analysis of HTT CAG repeat expansion among healthy individuals and patients with chorea in Korea. Parkinsonism Relat Disord 2024; 118:105930. [PMID: 37992538 DOI: 10.1016/j.parkreldis.2023.105930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 11/07/2023] [Accepted: 11/09/2023] [Indexed: 11/24/2023]
Abstract
BACKGROUND Although the epidemiology of Huntington's disease (HD) in Korea differs notably from that in Western countries, the genetic disparities between these regions remain unclear. OBJECTIVE To investigate the characteristics and clinical significance of cytosine-adenine-guanine (CAG) repeat size associated with HD in the Korean population. METHODS We analyzed the CAG repeat lengths of the HTT gene in 941 healthy individuals (1,882 alleles) and 954 patients with chorea (1,908 alleles) from two referral hospitals in Korea. We presented normative CAG repeat length data for the Korean population and computed the reduced penetrance (36-39 CAG) and intermediate allele (27-35 CAG) frequencies in the two groups. Furthermore, we investigated the relationship between intermediate alleles and chorea development using logistic regression models in individuals aged ≥55 years. RESULTS The mean (±standard deviation) CAG repeat length in healthy individuals was 17.5 ± 2.0, with a reduced penetrance allele frequency of 0.05 % (1/1882) and intermediate allele frequency of 0.69 % (13/1882). We identified 213 patients with genetically confirmed HD whose CAG repeat length ranged from 39 to 140, with a mean of 45.2 ± 7.9 in the longer allele. Compared with normal CAG repeat alleles, intermediate CAG repeat alleles were significantly related to a higher risk of developing chorea (age of onset range, 63-84 years) in individuals aged ≥55 years. CONCLUSIONS This study provides insights into the specific characteristics of CAG repeat lengths in the HTT gene in the Korean population. The reduced penetrance and intermediate allele frequencies in the Korean general population seem to be lower than those reported in Western populations. The presence of intermediate alleles may increase the risk of chorea in the Korean elderly population, which requires further large-scale investigations.
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Affiliation(s)
- Ryul Kim
- Department of Neurology, Inha University Hospital, Inha University College of Medicine, Incheon, South Korea
| | - Moon-Woo Seong
- Department of Laboratory Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, South Korea; Cancer Research Institute, Seoul National University College of Medicine, Seoul, South Korea
| | - Bumjo Oh
- Department of Familial Medicine, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul National University College of Medicine, Seoul, South Korea
| | - Ho Seop Shin
- Department of Laboratory Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, South Korea
| | - Jee-Soo Lee
- Department of Laboratory Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, South Korea
| | - Sangmin Park
- Department of Neurology, Daejeon Eulji Medical Center, Eulji University College of Medicine, Daejeon, South Korea
| | - Mihee Jang
- Department of Neurology, JMH Seoul Neurologic Clinic, Seoul, South Korea
| | - Beomseok Jeon
- Department of Neurology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, South Korea
| | - Han-Joon Kim
- Department of Neurology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, South Korea.
| | - Jee-Young Lee
- Department of Neurology, Seoul Metropolitan Government - Seoul National University Boramae Medical Center, Seoul National University College of Medicine, Seoul, South Korea.
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Nikitina M, Bragina E, Nazarenko M, Alifirova V. The role of alleles with an intermediate number of trinucleotide repeats in Parkinson’s disease and other neurodegenerative disorders. Zh Nevrol Psikhiatr Im S S Korsakova 2022; 122:42-50. [DOI: 10.17116/jnevro202212207142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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4
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Stoker TB, Holden ST, Barker RA. Late-onset Huntington's disease associated with CAG repeat lengths of 30 and 31. J Neurol 2021; 268:3916-3919. [PMID: 34142177 DOI: 10.1007/s00415-021-10633-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 05/27/2021] [Accepted: 05/28/2021] [Indexed: 11/24/2022]
Affiliation(s)
- Thomas B Stoker
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, E.D. Adrian Building, Forvie Site, Robinson Way, Cambridge, CB2 0PY, UK.
| | - Simon T Holden
- Department of Clinical Genetics, East Anglian Medical Genetics Service, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - Roger A Barker
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, E.D. Adrian Building, Forvie Site, Robinson Way, Cambridge, CB2 0PY, UK.,Wellcome Medical Research Council Stem Cell Institute, University of Cambridge, Cambridge, UK
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Bessi V, Mazzeo S, Bagnoli S, Giacomucci G, Ingannato A, Ferrari C, Padiglioni S, Franchi V, Sorbi S, Nacmias B. The Effect of CAG Repeats within the Non-Pathological Range in the HTT Gene on Cognitive Functions in Patients with Subjective Cognitive Decline and Mild Cognitive Impairment. Diagnostics (Basel) 2021; 11:1051. [PMID: 34200421 PMCID: PMC8228729 DOI: 10.3390/diagnostics11061051] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 05/27/2021] [Accepted: 06/04/2021] [Indexed: 12/27/2022] Open
Abstract
The Huntingtin gene (HTT) is within a class of genes containing a key region of CAG repeats. When expanded beyond 39 repeats, Huntington disease (HD) develops. Individuals with less than 35 repeats are not associated with HD. Increasing evidence has suggested that CAG repeats play a role in modulating brain development and brain function. However, very few studies have investigated the effect of CAG repeats in the non-pathological range on cognitive performances in non-demented individuals. In this study, we aimed to test how CAG repeats' length influences neuropsychological scores in patients with subjective cognitive decline (SCD) and mild cognitive impairment (MCI). We included 75 patients (46 SCD and 29 MCI). All patients underwent an extensive neuropsychological battery and analysis of HTT alleles to quantify the number of CAG repeats. Results: CAG repeat number was positively correlated with scores of tests assessing for executive function, visual-spatial ability, and memory in SCD patients, while in MCI patients, it was inversely correlated with scores of visual-spatial ability and premorbid intelligence. When we performed a multiple regression analysis, we found that these relationships still remained, also when adjusting for possible confounding factors. Interestingly, logarithmic models better described the associations between CAG repeats and neuropsychological scores. CAG repeats in the HTT gene within the non-pathological range influenced neuropsychological performances depending on global cognitive status. The logarithmic model suggested that the positive effect of CAG repeats in SCD patients decreases as the number of repeats grows.
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Affiliation(s)
- Valentina Bessi
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, 50139 Florence, Italy; (S.M.); (S.B.); (G.G.); (A.I.); (C.F.); (V.F.); (S.S.); (B.N.)
| | - Salvatore Mazzeo
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, 50139 Florence, Italy; (S.M.); (S.B.); (G.G.); (A.I.); (C.F.); (V.F.); (S.S.); (B.N.)
- IRCCS Fondazione Don Carlo Gnocchi, 50143 Florence, Italy
| | - Silvia Bagnoli
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, 50139 Florence, Italy; (S.M.); (S.B.); (G.G.); (A.I.); (C.F.); (V.F.); (S.S.); (B.N.)
| | - Giulia Giacomucci
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, 50139 Florence, Italy; (S.M.); (S.B.); (G.G.); (A.I.); (C.F.); (V.F.); (S.S.); (B.N.)
| | - Assunta Ingannato
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, 50139 Florence, Italy; (S.M.); (S.B.); (G.G.); (A.I.); (C.F.); (V.F.); (S.S.); (B.N.)
| | - Camilla Ferrari
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, 50139 Florence, Italy; (S.M.); (S.B.); (G.G.); (A.I.); (C.F.); (V.F.); (S.S.); (B.N.)
| | - Sonia Padiglioni
- Regional Referral Centre for Relational Criticalities, 50139 Tuscany Region, Italy;
- Unit Clinic of Organizations Careggi University Hospital, 50139 Florence, Italy
| | - Virginia Franchi
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, 50139 Florence, Italy; (S.M.); (S.B.); (G.G.); (A.I.); (C.F.); (V.F.); (S.S.); (B.N.)
| | - Sandro Sorbi
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, 50139 Florence, Italy; (S.M.); (S.B.); (G.G.); (A.I.); (C.F.); (V.F.); (S.S.); (B.N.)
- IRCCS Fondazione Don Carlo Gnocchi, 50143 Florence, Italy
| | - Benedetta Nacmias
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, 50139 Florence, Italy; (S.M.); (S.B.); (G.G.); (A.I.); (C.F.); (V.F.); (S.S.); (B.N.)
- IRCCS Fondazione Don Carlo Gnocchi, 50143 Florence, Italy
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6
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Despotov K, Zádori D, Veres G, Jakab K, Gárdián G, Tóth E, Kincses TZ, Vécsei L, Ajtay A, Bereczki D, Klivényi P. Genetic epidemiological characteristics of a Hungarian subpopulation of patients with Huntington's disease. BMC Neurol 2021; 21:79. [PMID: 33602179 PMCID: PMC7890867 DOI: 10.1186/s12883-021-02089-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 02/02/2021] [Indexed: 11/22/2022] Open
Abstract
Background Recent advances in therapeutic options may prevent deterioration related to Huntington’s disease (HD), even at the pre-symptomatic stage. Be that as it may, a well-characterized patient population is essential for screening and monitoring outcome. Accordingly, the aim of this study was to describe the characteristics of a Hungarian subpopulation of HD patients and mutation carriers diagnosed at the University of Szeged. Methods We conducted a search for International Classification of Diseases (ICD) code G10H0 in the local medical database for the period of 1 January 1998 to 31 December 2018. Results We identified 90 HD cases (male: 45, female: 45) and 34 asymptomatic carriers (male: 15, female: 19). The median age of onset was 45 years (range: 16–79). There were 3 cases of juvenile onset (3.3%), and 7 of late disease onset (7.8%). The median repeat length was 43 (range: 36–70) for the pathological and 19 for the non-pathological alleles (range: 9–35). 17.5% of the pathological alleles were in the decreased penetrance range, while 7% of non-pathological alleles were intermediate. Conclusions The genetic and clinical features of the population examined in the present study were in line with the previous Hungarian study, as well as with international literature. The exceptions were the higher ratio of reduced penetrance and intermediate alleles. Supplementary Information The online version contains supplementary material available at 10.1186/s12883-021-02089-9.
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Affiliation(s)
- Katalin Despotov
- Department of Neurology, University of Szeged, 6 Semmelweis Street, Szeged, 6725, Hungary
| | - Dénes Zádori
- Department of Neurology, University of Szeged, 6 Semmelweis Street, Szeged, 6725, Hungary
| | - Gábor Veres
- Department of Neurology, University of Szeged, 6 Semmelweis Street, Szeged, 6725, Hungary
| | - Katalin Jakab
- Department of Neurology, University of Szeged, 6 Semmelweis Street, Szeged, 6725, Hungary
| | - Gabriella Gárdián
- Department of Neurology, University of Szeged, 6 Semmelweis Street, Szeged, 6725, Hungary
| | - Eszter Tóth
- Department of Neurology, University of Szeged, 6 Semmelweis Street, Szeged, 6725, Hungary
| | - Tamás Zsigmond Kincses
- Department of Neurology, University of Szeged, 6 Semmelweis Street, Szeged, 6725, Hungary
| | - László Vécsei
- Department of Neurology, University of Szeged, 6 Semmelweis Street, Szeged, 6725, Hungary
| | - András Ajtay
- Department of Neurology, Semmelweis University, Budapest, Hungary.,MTA-SE Neuroepidemiological Research Group, Budapest, Hungary
| | - Dániel Bereczki
- Department of Neurology, Semmelweis University, Budapest, Hungary.,MTA-SE Neuroepidemiological Research Group, Budapest, Hungary
| | - Péter Klivényi
- Department of Neurology, University of Szeged, 6 Semmelweis Street, Szeged, 6725, Hungary.
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Zhao X, Kumari D, Miller CJ, Kim GY, Hayward B, Vitalo AG, Pinto RM, Usdin K. Modifiers of Somatic Repeat Instability in Mouse Models of Friedreich Ataxia and the Fragile X-Related Disorders: Implications for the Mechanism of Somatic Expansion in Huntington's Disease. J Huntingtons Dis 2021; 10:149-163. [PMID: 33579860 PMCID: PMC7990428 DOI: 10.3233/jhd-200423] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Huntington's disease (HD) is one of a large group of human disorders that are caused by expanded DNA repeats. These repeat expansion disorders can have repeat units of different size and sequence that can be located in any part of the gene and, while the pathological consequences of the expansion can differ widely, there is evidence to suggest that the underlying mutational mechanism may be similar. In the case of HD, the expanded repeat unit is a CAG trinucleotide located in exon 1 of the huntingtin (HTT) gene, resulting in an expanded polyglutamine tract in the huntingtin protein. Expansion results in neuronal cell death, particularly in the striatum. Emerging evidence suggests that somatic CAG expansion, specifically expansion occurring in the brain during the lifetime of an individual, contributes to an earlier disease onset and increased severity. In this review we will discuss mouse models of two non-CAG repeat expansion diseases, specifically the Fragile X-related disorders (FXDs) and Friedreich ataxia (FRDA). We will compare and contrast these models with mouse and patient-derived cell models of various other repeat expansion disorders and the relevance of these findings for somatic expansion in HD. We will also describe additional genetic factors and pathways that modify somatic expansion in the FXD mouse model for which no comparable data yet exists in HD mice or humans. These additional factors expand the potential druggable space for diseases like HD where somatic expansion is a significant contributor to disease impact.
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Affiliation(s)
- Xiaonan Zhao
- Laboratory of Cell and Molecular Biology, National Institutes of Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Daman Kumari
- Laboratory of Cell and Molecular Biology, National Institutes of Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Carson J Miller
- Laboratory of Cell and Molecular Biology, National Institutes of Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Geum-Yi Kim
- Laboratory of Cell and Molecular Biology, National Institutes of Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Bruce Hayward
- Laboratory of Cell and Molecular Biology, National Institutes of Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Antonia G Vitalo
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA.,Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Ricardo Mouro Pinto
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA.,Department of Neurology, Harvard Medical School, Boston, MA, USA.,Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Karen Usdin
- Laboratory of Cell and Molecular Biology, National Institutes of Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
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8
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Oliveira CR, Mendes Á, Sequeiros J, Sousa L. Management of information within Portuguese families with Huntington disease: a transgenerational process for putting the puzzle together. Eur J Hum Genet 2020; 28:1210-1217. [PMID: 32341469 PMCID: PMC7608350 DOI: 10.1038/s41431-020-0630-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 03/27/2020] [Accepted: 04/07/2020] [Indexed: 11/28/2022] Open
Abstract
Huntington disease (HD) is a rare progressive neurological disease, with no cure, inherited in an autosomal dominant fashion, significantly impacting family relations, health and well-being. So far, no studies have reported how Portuguese families deal with information about HD, from a transgenerational perspective. This qualitative study aims to fill in that gap, and focuses on how families acquire knowledge about HD and management of information within the family and in their social relationships. The study adopted semi-structured interviews with 10 participants from HD families. Interviews were transcribed and analysed thematically. Findings suggested that management of information in the family started with the search for a diagnosis in an affected family member. Diagnosis led to a process of "making sense of HD in the family", which activated a transgenerational process to understand HD in the family context, marked by improved awareness and different ways family members manage it (closedness and openness). These results should be relevant for health-care professionals, bringing further insight into the process of acquiring knowledge about HD, and highlighting the relevance of continued efforts for enhanced pre- and post-test counselling and ongoing support to the HD families.
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Affiliation(s)
- Carla Roma Oliveira
- Department of Education and Psychology, CINTESIS (Centre for Health Technology and Services Research), University of Aveiro, Aveiro, Portugal.
- UnIGENe, IBMC - Institute for Molecular and Cell Biology, i3S - Instituto de Investigação e Inovação em Saúde, University of Porto, Porto, Portugal.
| | - Álvaro Mendes
- UnIGENe and CGPP - Centre for Predictive and Preventive Genetics, IBMC - Institute for Molecular and Cell Biology, i3S - Instituto de Investigação e Inovação em Saúde, University of Porto, Porto, Portugal
| | - Jorge Sequeiros
- UnIGENe and CGPP - Centre for Predictive and Preventive Genetics, IBMC - Institute for Molecular and Cell Biology, i3S - Instituto de Investigação e Inovação em Saúde, Univ. Porto, Portugal; and ICBAS - Instituto de Ciências Biomédicas Abel Salazar, University of Porto, Porto, Portugal
| | - Liliana Sousa
- Department of Education and Psychology, CINTESIS (Centre for Health Technology and Services Research), University of Aveiro, Aveiro, Portugal
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Frequency and distribution of polyQ disease intermediate-length repeat alleles in healthy Italian population. Neurol Sci 2020; 41:1475-1482. [PMID: 31940111 DOI: 10.1007/s10072-019-04233-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 12/30/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND Huntington disease (HD) and spinocerebellar ataxia type 1-2-17 (SCA1-2-17) are adult-onset autosomal dominant diseases, caused by triplet repeat expansions in the HTT, ATXN1, ATXN2, and TBP genes. Alleles with a repeat number just below the pathological threshold are associated with reduced penetrance and meiotic instability and are defined as intermediate alleles (IAs). OBJECTIVES We aimed to determine the frequencies of IAs in healthy Italian subjects and to compare the proportion of the IAs with the prevalence of the respective diseases. METHODS We analyzed the triplet repeat size in HTT, ATXN1, ATXN2, and TBP genes in the DNA samples from 729 consecutive adult healthy Italian subjects. RESULTS IAs associated with reduced penetrance were found in ATXN2 gene (1 subject, 0.1%) and TBP gene (0.82%). IAs at risk for meiotic instability were found in HTT (5.3%) and ATXN2 genes (2.7%). In ATXN1, we found a low percentage of IAs (0.4%). Alleles lacking the common CAT interruption within the CAG sequence were also rare (0.3%). CONCLUSIONS The high frequencies of IAs in HTT and ATXN2 genes suggest a correlation with the prevalence of the diseases in our population and support the hypothesis that IAs could represent a reservoir of new pathological expansions. On the opposite, ATXN1-IA were very rare in respect to the prevalence of SCA1 in our country, and TBP- IA were more frequent than expected, suggesting that other mechanisms could influence the occurrence of novel pathological expansions.
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Turner H, Jackson L. Evidence for penetrance in patients without a family history of disease: a systematic review. Eur J Hum Genet 2020; 28:539-550. [PMID: 31937893 PMCID: PMC7170932 DOI: 10.1038/s41431-019-0556-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 10/08/2019] [Accepted: 11/26/2019] [Indexed: 01/21/2023] Open
Abstract
Family-based penetrance is frequently cited as a major challenge for translating penetrance estimates from familial populations to asymptomatic populations. A systematic review was performed to assess the literature evidencing penetrance estimates in patients without a family history of disease, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework. Initially 1592 papers were identified, which were filtered to a final nine, through application of inclusion and exclusion criteria. Fundamental differences in the identified papers prevented combination of papers using meta-analysis, so thematic analysis to produce a narrative synthesis was performed. Key themes included disease risk modifiers, evidence, study limitations and bias. A methodological appraisal too was used to assess quality of included studies. It is evident from the findings that the evidence base for penetrance estimates in individuals without a family history of disease is limited. Future work is needed to refine design of penetrance studies and the impact of incorrect estimates.
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Affiliation(s)
- Heather Turner
- University of Exeter Medical School, 4.07 RILD, Royal Devon & Exeter Hospital, Barrack Road, Exeter, EX2 5DW, UK
| | - Leigh Jackson
- University of Exeter Medical School, 4.07 RILD, Royal Devon & Exeter Hospital, Barrack Road, Exeter, EX2 5DW, UK.
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11
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Tibben A, Dondorp WJ, de Wert GM, de Die-Smulders CE, Losekoot M, Bijlsma EK. Risk Assessment for Huntington's Disease for (Future) Offspring Requires Offering Preconceptional CAG Analysis to Both Partners. J Huntingtons Dis 2020; 8:71-78. [PMID: 30689590 DOI: 10.3233/jhd-180314] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Amongst the main reasons people at risk for Huntington's disease (HD) have for undergoing predictive genetic testing are planning a family and prevention of passing on an expanded CAG-repeat to future offspring. After having received an unfavourable test result, a couple may consider prenatal testing in the foetus or preimplantation genetic diagnostic testing (PGD) in embryos. Testing of the foetus or embryos is possible by means of direct testing of the expanded repeat. Optimal reliability in testing the foetus or embryos requires the establishment of the origin of the repeats of both parents in the foetus. For PGD the analysis is combined with or sometimes solely based on identification of the at-risk haplotype in the embryo. This policy implies that in the context of direct testing, the healthy partner's CAG repeat lengths in the HD gene are also tested, but with the expectation that the repeat lengths of the partner are within the normal range, with the proviso that the partner's pedigree is free of clinically confirmed HD. However, recent studies have shown that the expanded repeat has been observed more often in the general population than previously estimated. Moreover, we have unexpectedly observed an expanded repeat in the non-HD partner in four cases which had far-reaching consequences. Hence, we propose that in the context of reproductive genetic counselling, prior to a planned pregnancy, and irrespective of the outcome of the predictive test in the HD-partner, the non-HD partner should also be given the option of being tested on the expanded allele. International recommendations for predictive testing for HD should be adjusted.
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Affiliation(s)
- Aad Tibben
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Wybo J Dondorp
- Department of Health, Ethics and Society, Maastricht University, Maastricht, The Netherlands
| | - Guido M de Wert
- Department of Health, Ethics and Society, Maastricht University, Maastricht, The Netherlands
| | | | - Moniek Losekoot
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Emilia K Bijlsma
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
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12
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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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13
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Quarrell OW, Delatycki MB, Clarke AJ, Lahiri N, Craufurd D, Miedzybrodzka Z, MacLeod R, Renwick P, Tomlinson C. Letter in Response to Tibben et al., Risk Assessment for Huntington's Disease for (Future) Offspring Requires Offering Preconceptional CAG Analysis to Both Partners. J Huntingtons Dis 2019; 8:357-359. [PMID: 31282428 DOI: 10.3233/jhd-190360] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Oliver W Quarrell
- Department of Clinical Genetics, Sheffield Children's NHS Trust, OPD II Northern General Hospital, Sheffield, UK
| | - Martin B Delatycki
- Victorian Clinical Genetic Services, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville VIC, Australia
| | - Angus J Clarke
- Institute of Cancer and Genetics, University of Cardiff, Cardiff, UK
| | - Nayana Lahiri
- Clinical Genetics Department, St George's University of London, London, UK and St George's University Hospitals NHS Foundation Trust, London, UK
| | - David Craufurd
- Manchester Centre for Genomic Medicine, Division of Evolution and Genomics Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK. and St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - Zosia Miedzybrodzka
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, UK.,North of Scotland Regional Genetics Service, Aberdeen Royal Infirmary, Aberdeen, UK
| | - Rhona MacLeod
- Manchester Centre for Genomic Medicine, Division of Evolution and Genomics Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK. and St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - Pamela Renwick
- Center for Preimplantation Genetic Diagnosis, Guy's and St Thomas' NHS Foundation Trust, Great Maze Pond, London, UK
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14
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Castilhos RMD, Santos JAD, Augustin MC, Pedroso JL, Barsottini O, Saba R, Ferraz HB, Godeiro Junior C, Vargas FR, Salarini DZ, Furtado GV, Polese-Bonatto M, Rodrigues LP, Sena LS, Saraiva-Pereira ML, Jardim LB. Minimal prevalence of Huntington's disease in the South of Brazil and instability of the expanded CAG tract during intergenerational transmissions. Genet Mol Biol 2019; 42:329-336. [PMID: 31259362 PMCID: PMC6726154 DOI: 10.1590/1678-4685-gmb-2018-0032] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 10/22/2018] [Indexed: 11/22/2022] Open
Abstract
Huntington’s disease (HD) is due to dominant expansions of the CAG repeat of the
HTT gene. Meiotic instability of the (CAG)n
might impact the disorder frequency. We report on HD minimal prevalence in Rio
Grande do Sul (RS) state, Brazil, and on intergenerational instability of the
(CAG)n in HD families. Symptomatic and at-risk subjects from 179
HD families were ascertained between 2013 and 2016. Clinical, molecular and
family history data were obtained. Expanded (CAG)n length differences
between parent and child (delta-expanded-(CAG)n) were calculated.
Effect of parental age on the (CAG)n instability upon transmission
was inferred by correlating delta-expanded-(CAG)n between siblings to
their age differences. HD minimal prevalence in RS state was estimated as
1.85:100,000 inhabitants. Alleles with (CAG)27-35 were found on
21/384 non-disease associated chromosomes (5.5%); among 253 expanded alleles,
four (1.6%) were within reduced penetrance range with (CAG)36-39. In
32 direct transmissions, mean instability was larger among paternal than
maternal transmissions. In direct transmissions and in 51 sibling pairs,
parental age at the time of child birth were not correlated with
delta-expanded-(CAG)n. Briefly, HD prevalence in RS state was
lower than those reported for European populations. Expanded (CAG)n
transmissions were unstable and not associated to parental age.
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Affiliation(s)
- Raphael Machado de Castilhos
- Programa de Pós-graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil.,Rede Neurogenética, Centro de Pesquisa Clínica, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, RS, Brazil.,Instituto Nacional de Genética Médica Populacional (INAGEMP), Porto Alegre, RS, Brazil
| | - José Augusto Dos Santos
- Faculdade de Medicina, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil.,Rede Neurogenética, Centro de Pesquisa Clínica, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, RS, Brazil
| | - Marina Coutinho Augustin
- Faculdade de Medicina, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil.,Rede Neurogenética, Centro de Pesquisa Clínica, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, RS, Brazil
| | - José Luiz Pedroso
- Disciplina de Neurologia Clínica, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Orlando Barsottini
- Disciplina de Neurologia Clínica, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Roberta Saba
- Disciplina de Neurologia Clínica, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Henrique Ballalai Ferraz
- Disciplina de Neurologia Clínica, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Clécio Godeiro Junior
- Departamento de Medicina Integrada, Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN, Brazil
| | - Fernando Regla Vargas
- Hospital Graffrée e Guinle, Universidade Federal do Estado do Rio de Janeiro (UNIRIO), Rio de Janeiro, RJ, Brazil.,Laboratório de Epidemiologia de Malformações Congênitas, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil
| | | | - Gabriel Vasata Furtado
- Programa de Pós-graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil.,Rede Neurogenética, Centro de Pesquisa Clínica, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, RS, Brazil
| | - Marcia Polese-Bonatto
- Programa de Pós-graduação em Bioquímica, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil.,Rede Neurogenética, Centro de Pesquisa Clínica, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, RS, Brazil
| | - Luiza Paulsen Rodrigues
- Programa de Pós-graduação em Biologia Celular e Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil.,Rede Neurogenética, Centro de Pesquisa Clínica, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, RS, Brazil
| | - Lucas Schenatto Sena
- Programa de Pós-graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
| | - Maria Luiza Saraiva-Pereira
- Programa de Pós-graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil.,Programa de Pós-graduação em Bioquímica, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil.,Programa de Pós-graduação em Biologia Celular e Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil.,Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil.,Laboratório de Identificação Genética, Centro de Pesquisa Experimental, Hospital de Clinicas de Porto Alegre (HCPA), Porto Alegre, RS, Brazil.,Serviço de Genética Médica, Hospital de Clinicas de Porto Alegre (HCPA), Porto Alegre, RS, Brazil.,Rede Neurogenética, Centro de Pesquisa Clínica, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, RS, Brazil
| | - Laura Bannach Jardim
- Programa de Pós-graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil.,Departamento de Medicina Interna, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil.,Faculdade de Medicina, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil.,Laboratório de Identificação Genética, Centro de Pesquisa Experimental, Hospital de Clinicas de Porto Alegre (HCPA), Porto Alegre, RS, Brazil.,Serviço de Genética Médica, Hospital de Clinicas de Porto Alegre (HCPA), Porto Alegre, RS, Brazil.,Rede Neurogenética, Centro de Pesquisa Clínica, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, RS, Brazil.,Instituto Nacional de Genética Médica Populacional (INAGEMP), Porto Alegre, RS, Brazil
| | -
- Rede Neurogenética, Centro de Pesquisa Clínica, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, RS, Brazil
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15
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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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16
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Lieberman AP, Shakkottai VG, Albin RL. Polyglutamine Repeats in Neurodegenerative Diseases. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2018; 14:1-27. [PMID: 30089230 DOI: 10.1146/annurev-pathmechdis-012418-012857] [Citation(s) in RCA: 164] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Among the age-dependent protein aggregation disorders, nine neurodegenerative diseases are caused by expansions of CAG repeats encoding polyglutamine (polyQ) tracts. We review the clinical, pathological, and biological features of these inherited disorders. We discuss insights into pathogenesis gleaned from studies of model systems and patients, highlighting work that informs efforts to develop effective therapies. An important conclusion from these analyses is that expanded CAG/polyQ domains are the primary drivers of neurodegeneration, with the biology of carrier proteins influencing disease-specific manifestations. Additionally, it has become apparent that CAG/polyQ repeat expansions produce neurodegeneration via multiple downstream mechanisms, involving both gain- and loss-of-function effects. This conclusion indicates that the likelihood of developing effective therapies targeting single nodes is reduced. The evaluation of treatments for premanifest disease will likely require new investigational approaches. We highlight the opportunities and challenges underlying ongoing work and provide recommendations related to the development of symptomatic and disease-modifying therapies and biomarkers that could inform future research.
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Affiliation(s)
- Andrew P Lieberman
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA;
| | - Vikram G Shakkottai
- Department of Neurology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA; , .,Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
| | - Roger L Albin
- Department of Neurology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA; , .,Neurology Service and the Geriatric Research, Education, and Clinical Center (GRECC), VA Ann Arbor Healthcare System, Ann Arbor, Michigan 48105, USA
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17
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Kay C, Collins JA, Wright GEB, Baine F, Miedzybrodzka Z, Aminkeng F, Semaka AJ, McDonald C, Davidson M, Madore SJ, Gordon ES, Gerry NP, Cornejo-Olivas M, Squitieri F, Tishkoff S, Greenberg JL, Krause A, Hayden MR. The molecular epidemiology of Huntington disease is related to intermediate allele frequency and haplotype in the general population. Am J Med Genet B Neuropsychiatr Genet 2018; 177:346-357. [PMID: 29460498 DOI: 10.1002/ajmg.b.32618] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 12/21/2017] [Indexed: 01/31/2023]
Abstract
Huntington disease (HD) is the most common monogenic neurodegenerative disorder in populations of European ancestry, but occurs at lower prevalence in populations of East Asian or black African descent. New mutations for HD result from CAG repeat expansions of intermediate alleles (IAs), usually of paternal origin. The differing prevalence of HD may be related to the rate of new mutations in a population, but no comparative estimates of IA frequency or the HD new mutation rate are available. In this study, we characterize IA frequency and the CAG repeat distribution in fifteen populations of diverse ethnic origin. We estimate the HD new mutation rate in a series of populations using molecular IA expansion rates. The frequency of IAs was highest in Hispanic Americans and Northern Europeans, and lowest in black Africans and East Asians. The prevalence of HD correlated with the frequency of IAs by population and with the proportion of IAs found on the HD-associated A1 haplotype. The HD new mutation rate was estimated to be highest in populations with the highest frequency of IAs. In European ancestry populations, one in 5,372 individuals from the general population and 7.1% of individuals with an expanded CAG repeat in the HD range are estimated to have a molecular new mutation. Our data suggest that the new mutation rate for HD varies substantially between populations, and that IA frequency and haplotype are closely linked to observed epidemiological differences in the prevalence of HD across major ancestry groups in different countries.
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Affiliation(s)
- Chris Kay
- Centre for Molecular Medicine Therapeutics, University of British Columbia, Vancouver, BC, Canada
| | - Jennifer A Collins
- Centre for Molecular Medicine Therapeutics, University of British Columbia, Vancouver, BC, Canada
| | - Galen E B Wright
- Centre for Molecular Medicine Therapeutics, University of British Columbia, Vancouver, BC, Canada
| | - Fiona Baine
- Division of Human Genetics, Department of Pathology, University of Cape Town, South Africa.,Division of Human Genetics, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Zosia Miedzybrodzka
- Medical Genetics Group, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, UK
| | - Folefac Aminkeng
- Centre for Molecular Medicine Therapeutics, University of British Columbia, Vancouver, BC, Canada.,Translational Laboratory in Genetic Medicine, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Alicia J Semaka
- Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada
| | - Cassandra McDonald
- Centre for Molecular Medicine Therapeutics, University of British Columbia, Vancouver, BC, Canada
| | - Mark Davidson
- Medical Genetics Group, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, UK
| | - Steven J Madore
- Molecular Biology Group, Coriell Institute for Medical Research, Camden, New Jersey
| | - Erynn S Gordon
- Molecular Biology Group, Coriell Institute for Medical Research, Camden, New Jersey
| | - Norman P Gerry
- Molecular Biology Group, Coriell Institute for Medical Research, Camden, New Jersey
| | - Mario Cornejo-Olivas
- Neurogenetics Research Center, Instituto Nacional de Ciencias Neurologicas, Lima, Peru
| | - Ferdinando Squitieri
- IRCCS Casa Sollievo della Sofferenza Hospital, Huntington and Rare Diseases Unit (CSS-Mendel Rome), San Giovanni Rotondo, Italy
| | - Sarah Tishkoff
- Department of Genetics, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Jacquie L Greenberg
- Division of Human Genetics, Department of Pathology, University of Cape Town, South Africa
| | - Amanda Krause
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Michael R Hayden
- Centre for Molecular Medicine Therapeutics, University of British Columbia, Vancouver, BC, Canada
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18
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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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19
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Risk factors for the onset and progression of Huntington disease. Neurotoxicology 2017; 61:79-99. [PMID: 28111121 DOI: 10.1016/j.neuro.2017.01.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 01/11/2017] [Indexed: 01/10/2023]
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder characterized by chorea, behavioural and psychiatric manifestations, and dementia, caused by a CAG triplet repeat expansion in the huntingtin gene. Systematic review of the literature was conducted to determine the risk factors for the onset and progression of HD. Multiple databases were searched, using terms specific to Huntington disease and to studies of aetiology, risk, prevention and genetics, limited to studies on human subjects published in English or French between 1950 and 2010. Two reviewers independently screened the abstracts and identified potentially relevant articles for full-text review using predetermined inclusion criteria. Three major categories of risk factors for onset of HD were identified: CAG repeat length in the huntingtin gene, CAG instability, and genetic modifiers. Of these, CAG repeat length in the huntingtin gene is the most important risk factor. For the progression of HD: genetic, demographic, past medical/clinical and environmental risk factors have been studied. Of these factors, genetic factors appear to play the most important role in the progression of HD. Among the potential risk factors, CAG repeat length in the mutant allele was found to be a relatively consistent and significant risk factor for the progression of HD, especially in motor, cognitive, and other neurological symptom deterioration. In addition, there were many consistent results in the literature indicating that a higher number of CAG repeats was associated with shorter survival, faster institutionalization, and earlier percutaneous endoscopic gastrostomy.
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20
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Nance MA. Genetic counseling and testing for Huntington's disease: A historical review. Am J Med Genet B Neuropsychiatr Genet 2017; 174:75-92. [PMID: 27174011 DOI: 10.1002/ajmg.b.32453] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 04/15/2016] [Indexed: 12/26/2022]
Abstract
This manuscript describes the ways in which genetic counseling has evolved since John Pearson and Sheldon Reed first promoted "a genetic education" in the 1950s as a voluntary, non-directive clinical tool for permitting individual decision making. It reviews how the emergence of Huntington's disease (HD) registries and patient support organizations, genetic testing, and the discovery of a disease-causing CAG repeat expansion changed the contours of genetic counseling for families with HD. It also reviews the guidelines, outcomes, ethical and laboratory challenges, and uptake of predictive, prenatal, and preimplantation testing, and it casts a vision for how clinicians can better make use of genetic counseling to reach a broader pool of families that may be affected by HD and to ensure that genetic counseling is associated with the best levels of care. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Martha A Nance
- Struthers Parkinson's Center, Golden Valley, Minnesota.,Hennepin County Medical Center, Minneapolis, Minnesota
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21
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Kay C, Hayden MR, Leavitt BR. Epidemiology of Huntington disease. HANDBOOK OF CLINICAL NEUROLOGY 2017; 144:31-46. [DOI: 10.1016/b978-0-12-801893-4.00003-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Genetic Contributors to Intergenerational CAG Repeat Instability in Huntington's Disease Knock-In Mice. Genetics 2016; 205:503-516. [PMID: 27913616 PMCID: PMC5289832 DOI: 10.1534/genetics.116.195578] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 11/12/2016] [Indexed: 12/11/2022] Open
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by the expansion of a CAG trinucleotide repeat in exon 1 of the HTT gene. Longer repeat sizes are associated with increased disease penetrance and earlier ages of onset. Intergenerationally unstable transmissions are common in HD families, partly underlying the genetic anticipation seen in this disorder. HD CAG knock-in mouse models also exhibit a propensity for intergenerational repeat size changes. In this work, we examine intergenerational instability of the CAG repeat in over 20,000 transmissions in the largest HD knock-in mouse model breeding datasets reported to date. We confirmed previous observations that parental sex drives the relative ratio of expansions and contractions. The large datasets further allowed us to distinguish effects of paternal CAG repeat length on the magnitude and frequency of expansions and contractions, as well as the identification of large repeat size jumps in the knock-in models. Distinct degrees of intergenerational instability were observed between knock-in mice of six background strains, indicating the occurrence of trans-acting genetic modifiers. We also found that lines harboring a neomycin resistance cassette upstream of Htt showed reduced expansion frequency, indicative of a contributing role for sequences in cis, with the expanded repeat as modifiers of intergenerational instability. These results provide a basis for further understanding of the mechanisms underlying intergenerational repeat instability.
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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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Baig SS, Strong M, Rosser E, Taverner NV, Glew R, Miedzybrodzka Z, Clarke A, Craufurd D, Quarrell OW. 22 Years of predictive testing for Huntington's disease: the experience of the UK Huntington's Prediction Consortium. Eur J Hum Genet 2016; 24:1396-402. [PMID: 27165004 PMCID: PMC5027682 DOI: 10.1038/ejhg.2016.36] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 03/06/2016] [Accepted: 03/29/2016] [Indexed: 11/09/2022] Open
Abstract
Huntington's disease (HD) is a progressive neurodegenerative condition. At-risk individuals have accessed predictive testing via direct mutation testing since 1993. The UK Huntington's Prediction Consortium has collected anonymised data on UK predictive tests, annually, from 1993 to 2014: 9407 predictive tests were performed across 23 UK centres. Where gender was recorded, 4077 participants were male (44.3%) and 5122 were female (55.7%). The median age of participants was 37 years. The most common reason for predictive testing was to reduce uncertainty (70.5%). Of the 8441 predictive tests on individuals at 50% prior risk, 4629 (54.8%) were reported as mutation negative and 3790 (44.9%) were mutation positive, with 22 (0.3%) in the database being uninterpretable. Using a prevalence figure of 12.3 × 10(-5), the cumulative uptake of predictive testing in the 50% at-risk UK population from 1994 to 2014 was estimated at 17.4% (95% CI: 16.9-18.0%). We present the largest study conducted on predictive testing in HD. Our findings indicate that the vast majority of individuals at risk of HD (>80%) have not undergone predictive testing. Future therapies in HD will likely target presymptomatic individuals; therefore, identifying the at-risk population whose gene status is unknown is of significant public health value.
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Affiliation(s)
- Sheharyar S Baig
- Department of Clinical Genetics, Sheffield Children's Hospital, Sheffield, UK
| | - Mark Strong
- School of Health and Related Research, University of Sheffield, Sheffield, UK
| | - Elisabeth Rosser
- Great Ormond Street Hospital for Children, NE Thames Regional Genetics Service, London, UK
| | - Nicola V Taverner
- Institute of Cancer and Genetics, University of Cardiff, Cardiff, UK
| | - Ruth Glew
- MND Care Centre, Morriston Hospital, Swansea, UK
| | - Zosia Miedzybrodzka
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, UK
| | - Angus Clarke
- Institute of Cancer and Genetics, University of Cardiff, Cardiff, UK
| | - David Craufurd
- Faculty of Medical Sciences, Institute of Human Development, University of Manchester, Manchester, UK
- St Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
| | - UK Huntington's Disease Prediction Consortium
- Department of Clinical Genetics, Sheffield Children's Hospital, Sheffield, UK
- School of Health and Related Research, University of Sheffield, Sheffield, UK
- Great Ormond Street Hospital for Children, NE Thames Regional Genetics Service, London, UK
- Institute of Cancer and Genetics, University of Cardiff, Cardiff, UK
- MND Care Centre, Morriston Hospital, Swansea, UK
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, UK
- Faculty of Medical Sciences, Institute of Human Development, University of Manchester, Manchester, UK
- St Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
| | - Oliver W Quarrell
- Department of Clinical Genetics, Sheffield Children's Hospital, Sheffield, UK
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25
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Oosterloo M, Van Belzen MJ, Bijlsma EK, Roos RA. Reply: Late onset Huntington's disease with 29 CAG repeat expansion. J Neurol Sci 2016; 368:343. [DOI: 10.1016/j.jns.2016.07.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 07/11/2016] [Indexed: 11/16/2022]
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26
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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: 53] [Impact Index Per Article: 6.6] [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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27
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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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28
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Sun YM, Zhang YB, Wu ZY. Huntington's Disease: Relationship Between Phenotype and Genotype. Mol Neurobiol 2016; 54:342-348. [PMID: 26742514 DOI: 10.1007/s12035-015-9662-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 12/17/2015] [Indexed: 12/19/2022]
Abstract
Huntington's disease (HD) is an autosomal dominant inherited neurodegenerative disease with the typical manifestations of involuntary movements, psychiatric and behavior disorders, and cognitive impairment. It is caused by the dynamic mutation in CAG triplet repeat number in exon 1 of huntingtin (HTT) gene. The symptoms of HD especially the age at onset are related to the genetic characteristics, both the CAG triplet repeat and the modified factors. Here, we reviewed the recent advancement on the genotype-phenotype relationship of HD, mainly focus on the characteristics of different expanded CAG repeat number, genetic modifiers, and CCG repeat number in the 3' end of CAG triplet repeat and their effects on the phenotype. We also reviewed the special forms of HD (juvenile HD, atypical onset HD, and homozygous HD) and their phenotype-genotype correlations. The review will aid clinicians to predict the onset age and disease course of HD, give the genetic counseling, and accelerate research into the HD mechanism.
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Affiliation(s)
- Yi-Min Sun
- Department of Neurology and Institute of Neurology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Yan-Bin Zhang
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and the Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou, China
| | - Zhi-Ying Wu
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and the Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, China.
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29
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Motor onset and diagnosis in Huntington disease using the diagnostic confidence level. J Neurol 2015; 262:2691-8. [PMID: 26410751 DOI: 10.1007/s00415-015-7900-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 08/21/2015] [Accepted: 09/08/2015] [Indexed: 10/23/2022]
Abstract
Huntington disease (HD) is a neurodegenerative disorder characterized by motor dysfunction, cognitive deterioration, and psychiatric symptoms, with progressive motor impairments being a prominent feature. The primary objectives of this study are to delineate the disease course of motor function in HD, to provide estimates of the onset of motor impairments and motor diagnosis, and to examine the effects of genetic and demographic variables on the progression of motor impairments. Data from an international multisite, longitudinal observational study of 905 prodromal HD participants with cytosine-adenine-guanine (CAG) repeats of at least 36 and with at least two visits during the followup period from 2001 to 2012 was examined for changes in the diagnostic confidence level from the Unified Huntington's Disease Rating Scale. HD progression from unimpaired to impaired motor function, as well as the progression from motor impairment to diagnosis, was associated with the linear effect of age and CAG repeat length. Specifically, for every 1-year increase in age, the risk of transition in diagnostic confidence level increased by 11% (95% CI 7-15%) and for one repeat length increase in CAG, the risk of transition in diagnostic confidence level increased by 47% (95% CI 27-69%). Findings show that CAG repeat length and age increased the likelihood of the first onset of motor impairment as well as the age at diagnosis. Results suggest that more accurate estimates of HD onset age can be obtained by incorporating the current status of diagnostic confidence level into predictive models.
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30
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Castilhos RM, Augustin MC, Santos JA, Perandones C, Saraiva-Pereira ML, Jardim LB. Genetic aspects of Huntington's disease in Latin America. A systematic review. Clin Genet 2015; 89:295-303. [PMID: 26178794 DOI: 10.1111/cge.12641] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 07/07/2015] [Accepted: 07/07/2015] [Indexed: 01/16/2023]
Abstract
We aimed to present a systematic review on Huntington's disease (HD) in Latin America (LA). PubMed and LILACS were searched up to March 2015, reporting confirmed HD cases in LA. Case series, cross-sectional, case-control, and prospective studies were included. From 534 communications, 47 were eligible. Population-based studies were not found; minimal prevalence of 0.5-4/100,000 was estimated for Venezuela and Mexico. Geographical isolates were well characterized in Venezuela and in Peru. CAG repeats at HTT gene varied between 7-33 and 37-112 in normal and expanded alleles, respectively. Intermediate alleles were found in 4-10% of controls. Ages at onset and the expanded CAG repeats correlated with r from - 0.55 to -0.91. While haplotype patterns of Venezuelan and Brazilian chromosomes were similar to those observed in Europeans, haplotypes from Peruvian HD patients did not match the same pattern. The limited number of papers found suggests that HD is poorly diagnosed in LA. Minimal prevalence seemed to be halfway between those of Caucasians and Asians. Range of CAG repeats was similar to those of Europeans. Haplotype studies indicate that majority of HD patients might be of Caucasian descent; an Asian origin for some Peruvian patients was proposed.
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Affiliation(s)
- R M Castilhos
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Instituto Nacional de Genética Médica Populacional (INAGEMP), Porto Alegre, Brazil
| | - M C Augustin
- Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - J A Santos
- Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - C Perandones
- Parkinson's Disease and Movement Disorders Program, Hospital de Clínicas, University of Buenos Aires, Buenos Aires, Argentina
| | - M L Saraiva-Pereira
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Departmento de Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Serviço de Genética Médica, Hospital de Clinicas de Porto Alegre, Porto Alegre, Brazil.,Laboratório de Identificação Humana, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - L B Jardim
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Instituto Nacional de Genética Médica Populacional (INAGEMP), Porto Alegre, Brazil.,Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Serviço de Genética Médica, Hospital de Clinicas de Porto Alegre, Porto Alegre, Brazil.,Laboratório de Identificação Humana, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.,Centro de Pesquisa Clínica, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.,Departamento de Medicina Interna, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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31
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Oosterloo M, Van Belzen MJ, Bijlsma EK, Roos RA. Is There Convincing Evidence that Intermediate Repeats in the HTT Gene Cause Huntington’s Disease? J Huntingtons Dis 2015; 4:141-8. [DOI: 10.3233/jhd-140120] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Mayke Oosterloo
- Department of Neurology, Maastricht University Medical Center, Maastricht, The Netherlands
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
| | - Martine J. Van Belzen
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Emilia K. Bijlsma
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Raymund A.C. Roos
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
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32
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Moran S, Chi T, Prucha MS, Ahn KS, Connor-Stroud F, Jean S, Gould K, Chan AWS. Germline transmission in transgenic Huntington's disease monkeys. Theriogenology 2015; 84:277-85. [PMID: 25917881 DOI: 10.1016/j.theriogenology.2015.03.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 01/15/2015] [Accepted: 03/18/2015] [Indexed: 12/24/2022]
Abstract
Transgenic nonhuman primate models are an increasingly popular model for neurologic and neurodegenerative disease because their brain functions and neural anatomies closely resemble those of humans. Transgenic Huntington's disease monkeys (HD monkeys) developed clinical features similar to those seen in HD patients, making the monkeys suitable for a preclinical study of HD. However, until HD monkey colonies can be readily expanded, their use in preclinical studies will be limited. In the present study, we confirmed germline transmission of the mutant huntingtin (mHTT) transgene in both embryonic stem cells generated from three male HD monkey founders (F0) and in second-generation offspring (F1) produced via artificial insemination by using intrauterine insemination technique. A total of five offspring were produced from 15 females that were inseminated by intrauterine insemination using semen collected from the three HD founders (5 of 15, 33%). Thus far, sperm collected from the HD founder (rHD8) has led to two F1 transgenic HD monkeys with germline transmission rate at 100% (2 of 2). mHTT expression was confirmed by quantitative real-time polymerase chain reaction using skin fibroblasts from the F1 HD monkeys and induced pluripotent stem cells established from one of the F1 HD monkeys (rHD8-2). Here, we report the stable germline transmission and expression of the mHTT transgene in HD monkeys, which suggest possible expansion of HD monkey colonies for preclinical and biomedical research studies.
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Affiliation(s)
- Sean Moran
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, USA; Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, USA
| | - Tim Chi
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, USA; Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, USA
| | - Melinda S Prucha
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, USA; Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, USA
| | - Kwang Sung Ahn
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, USA; Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, USA
| | - Fawn Connor-Stroud
- Division of Animal Resources, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, USA
| | - Sherrie Jean
- Division of Animal Resources, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, USA
| | - Kenneth Gould
- Division of Animal Resources, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, USA
| | - Anthony W S Chan
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, USA; Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, USA.
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33
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Uhlmann WR, Peñaherrera MS, Robinson WP, Milunsky JM, Nicholson JM, Albin RL. Biallelic mutations in huntington disease: A new case with just one affected parent, review of the literature and terminology. Am J Med Genet A 2015; 167A:1152-60. [DOI: 10.1002/ajmg.a.37009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 01/22/2015] [Indexed: 11/12/2022]
Affiliation(s)
- Wendy R. Uhlmann
- Division of Molecular Medicine and Genetics; Department of Internal Medicine; University of Michigan; Ann Arbor Michigan
- Department of Human Genetics; University of Michigan; Ann Arbor Michigan
| | - Maria S. Peñaherrera
- Department of Medical Genetics; University of British Columbia; Vancouver British Columbia
- Child and Family Research Institute; Vancouver British Columbia
| | - Wendy P. Robinson
- Department of Medical Genetics; University of British Columbia; Vancouver British Columbia
- Child and Family Research Institute; Vancouver British Columbia
| | | | - Jane M. Nicholson
- Division of Molecular Medicine and Genetics; Department of Internal Medicine; University of Michigan; Ann Arbor Michigan
- Department of Obstetrics and Gynecology; University of Michigan; Ann Arbor Michigan
| | - Roger L. Albin
- Department of Neurology; University of Michigan; Ann Arbor Michigan
- VA Ann Arbor Healthcare System; Geriatrics Research, Education, and Clinical Center; Ann Arbor Michigan
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34
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Ramos EM, Gillis T, Mysore JS, Lee J, Gögele M, D'Elia Y, Pichler I, Sequeiros J, Pramstaller PP, Gusella JF, MacDonald ME, Alonso I. Haplotype analysis of the 4p16.3 region in Portuguese families with Huntington's disease. Am J Med Genet B Neuropsychiatr Genet 2015; 168B:135-43. [PMID: 25656686 PMCID: PMC5006842 DOI: 10.1002/ajmg.b.32289] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 11/25/2014] [Indexed: 12/12/2022]
Abstract
Huntington's disease (HD) is a neurodegenerative disorder characterized by involuntary choreic movements, cognitive impairment, and behavioral changes, caused by the expansion of an unstable CAG repeat in HTT. We characterized the genetic diversity of the HD mutation by performing an extensive haplotype analysis of ∼1Mb region flanking HTT in over 300 HD families of Portuguese origin. We observed that haplotype A, marked by HTT delta2642, was enriched in HD chromosomes and carried the two largest expansions reported in the Portuguese population. However, the most frequent HD haplotype B carried one of the largest (+12 CAGs) expansions, which resulted in an allele class change to full penetrance. Despite having a normal CAG distribution skewed to the higher end of the range, these two core haplotypes had similar expanded CAG repeat sizes compared to the other major core haplotypes (C and D) and there was no statistical difference in transmitted repeat instability across haplotypes. We observed a diversity of HTT region haplotypes in both normal and expanded chromosomes, representative of more than one ancestral chromosome underlying HD in Portugal, where multiple independent events on distinct chromosome 4 haplotypes have given rise to expansion into the pathogenic range.
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Affiliation(s)
- Eliana Marisa Ramos
- Center for Human Genetic ResearchMassachusetts General HospitalBostonMassachusettsUSA,UnIGENeIBMC–Institute for Molecular and Cell BiologyUniversity of PortoPortoPortugal
| | - Tammy Gillis
- Center for Human Genetic ResearchMassachusetts General HospitalBostonMassachusettsUSA
| | - Jayalakshmi S. Mysore
- Center for Human Genetic ResearchMassachusetts General HospitalBostonMassachusettsUSA
| | - Jong‐Min Lee
- Center for Human Genetic ResearchMassachusetts General HospitalBostonMassachusettsUSA
| | - Martin Gögele
- Center for BiomedicineEuropean Academy of Bozen/Bolzano (EURAC)BolzanoItaly
| | - Yuri D'Elia
- Center for BiomedicineEuropean Academy of Bozen/Bolzano (EURAC)BolzanoItaly
| | - Irene Pichler
- Center for BiomedicineEuropean Academy of Bozen/Bolzano (EURAC)BolzanoItaly
| | - Jorge Sequeiros
- UnIGENeIBMC–Institute for Molecular and Cell BiologyUniversity of PortoPortoPortugal,CGPPIBMC–Institute for Molecular and Cell BiologyUniversity of PortoPortoPortugal,ICBAS–Instituto de Ciências Biomédicas Abel SalazarUniversity of PortoPortoPortugal
| | - Peter P. Pramstaller
- Center for BiomedicineEuropean Academy of Bozen/Bolzano (EURAC)BolzanoItaly,Department of NeurologyCentral HospitalBolzanoItaly,Department of NeurologyUniversity of LübeckLübeckGermany
| | - James F. Gusella
- Center for Human Genetic ResearchMassachusetts General HospitalBostonMassachusettsUSA
| | - Marcy E. MacDonald
- Center for Human Genetic ResearchMassachusetts General HospitalBostonMassachusettsUSA
| | - Isabel Alonso
- UnIGENeIBMC–Institute for Molecular and Cell BiologyUniversity of PortoPortoPortugal,CGPPIBMC–Institute for Molecular and Cell BiologyUniversity of PortoPortoPortugal,ICBAS–Instituto de Ciências Biomédicas Abel SalazarUniversity of PortoPortoPortugal
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Kim HS, Lyoo CH, Lee PH, Kim SJ, Park MY, Ma HI, Lee JH, Song SK, Baik JS, Kim JH, Lee MS. Current Status of Huntington's Disease in Korea: A Nationwide Survey and National Registry Analysis. J Mov Disord 2015; 8:14-20. [PMID: 25614781 PMCID: PMC4298714 DOI: 10.14802/jmd.14038] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 12/19/2014] [Accepted: 12/24/2014] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE Huntington's disease (HD) is a rare neurological disorder, and its current status in Korea is not well investigated. This study aims to determine the prevalence and incidence of HD and to investigate the clinical features of HD patients in Korea. METHODS We estimated the crude prevalence and annual incidence of HD based on the databases of the Rare Diseases Registry (RDR) and the National Health Insurance (NHI). The clinical data of genetically confirmed HD patients was collected from 10 referral hospitals and analyzed. RESULTS The mean calculated annual incidence was 0.06 cases per 100,000 persons, and the mean calculated prevalence was 0.38 based on the NHI database. The estimated crude prevalence based on the RDR was 0.41. Of the sixty-eight HD patients recruited, the mean age of onset was 44.16 ± 14.08 years and chorea was most frequently reported as the initial symptom and chief complaint. The mean CAG repeat number of the expanded allele was 44.7 ± 4.8 and correlated inversely with the age of onset (p < 0.001). About two-thirds of the patients have a positive family history, and HD patients without positive family history showed a delay in onset of initial symptoms, a prolonged interval between initial symptom onset and genetic diagnosis and a delay in the age of genetic diagnosis. CONCLUSIONS To the best of our knowledge, this is the first study to estimate the prevalence and incidence of HD in Korea and the largest HD series in the Asian population. Our analyses might be useful for further studies and large-scale investigations in HD patients.
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Affiliation(s)
- Hyun Sook Kim
- Department of Neurology, CHA Bundang Medical Center, CHA University, Seongnam, Korea
| | - Chul Hyoung Lyoo
- Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Phil Hyu Lee
- Department of Neurology and Brain Research Institute, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Sang Jin Kim
- Department of Neurology, Busan Paik Hospital, Inje University College of Medicine, Busan, Korea
| | - Mee Young Park
- Department of Neurology, Yeungnam University Medical Center, Daegu, Korea
| | - Hyeo-Il Ma
- Department of Neurology, Hallym University Sacred Heart Hospital, Anyang, Korea
| | - Jae Hyeok Lee
- Department of Neurology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Sook Kun Song
- Department of Neurology, Jeju National University Hospital, Jeju, Korea
| | - Jong Sam Baik
- Department of Neurology, Sanggye Paik Hospital, Inje University College of Medicine, Seoul, Korea
| | - Jin Ho Kim
- Department of Neurology, Chosun University School of Medicine, Gwangju, Korea
| | - Myung Sik Lee
- Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
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Jiang H, Sun YM, Hao Y, Yan YP, Chen K, Xin SH, Tang YP, Li XH, Jun T, Chen YY, Liu ZJ, Wang CR, Li H, Pei Z, Shang HF, Zhang BR, Gu WH, Wu ZY, Tang BS, Burgunder JM. Huntingtin gene CAG repeat numbers in Chinese patients with Huntington's disease and controls. Eur J Neurol 2014; 21:637-42. [PMID: 24471773 DOI: 10.1111/ene.12366] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Accepted: 12/17/2013] [Indexed: 02/05/2023]
Affiliation(s)
- H. Jiang
- Department of Neurology; Xiangya Hospital; Central South University; Changsha China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders; State Key Laboratory of Medical Genetics of China; Central South University; Changsha China
| | - Y. M. Sun
- Department of Neurology; Institute of Neurology; Huashan Hospital; Shanghai Medical College; Fudan University; Shanghai China
| | - Y. Hao
- Department of Neurology; China−Japan Friendship Hospital; Beijing China
| | - Y. P. Yan
- Department of Neurology; Second Affiliated Hospital; College of Medicine; Zhejiang University; Hangzhou China
| | - K. Chen
- Department of Neurology; West China Hospital; Sichuan University; Chengdu China
| | - S. H. Xin
- First Affiliated Hospital of Sun Yat-Sen University; Guangzhou China
| | - Y. P. Tang
- Department of Medical Genetics; Tongji Medical College; Huazhong University of Science and Technology; Wuhan China
| | - X. H. Li
- First Affiliated Hospital of Sun Yat-Sen University; Guangzhou China
| | - T. Jun
- Department of Neurology; Second Affiliated Hospital; College of Medicine; Zhejiang University; Hangzhou China
| | - Y. Y. Chen
- Department of Neurology; China−Japan Friendship Hospital; Beijing China
| | - Z. J. Liu
- Department of Neurology; Institute of Neurology; Huashan Hospital; Shanghai Medical College; Fudan University; Shanghai China
| | - C. R. Wang
- Department of Neurology; Xiangya Hospital; Central South University; Changsha China
| | - H. Li
- Department of Medical Genetics; Tongji Medical College; Huazhong University of Science and Technology; Wuhan China
| | - Z. Pei
- First Affiliated Hospital of Sun Yat-Sen University; Guangzhou China
| | - H. F. Shang
- Department of Neurology; West China Hospital; Sichuan University; Chengdu China
| | - B. R. Zhang
- Department of Neurology; Second Affiliated Hospital; College of Medicine; Zhejiang University; Hangzhou China
| | - W. H. Gu
- Department of Neurology; China−Japan Friendship Hospital; Beijing China
| | - Z. Y. Wu
- Department of Neurology; Institute of Neurology; Huashan Hospital; Shanghai Medical College; Fudan University; Shanghai China
| | - B. S. Tang
- Department of Neurology; Xiangya Hospital; Central South University; Changsha China
| | - J.-M. Burgunder
- Department of Neurology; Xiangya Hospital; Central South University; Changsha China
- Department of Neurology; West China Hospital; Sichuan University; Chengdu China
- First Affiliated Hospital of Sun Yat-Sen University; Guangzhou China
- Swiss Huntington's Disease Centre; Department of Neurology; University of Bern; NeuroBu Clinics; Bern Switzerland
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Pulkes T, Papsing C, Wattanapokayakit S, Mahasirimongkol S. CAG-Expansion Haplotype Analysis in a Population with a Low Prevalence of Huntington's Disease. J Clin Neurol 2014; 10:32-6. [PMID: 24465260 PMCID: PMC3896646 DOI: 10.3988/jcn.2014.10.1.32] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 08/07/2013] [Accepted: 08/07/2013] [Indexed: 11/23/2022] Open
Abstract
Background and Purpose The prevalence of Huntington's disease (HD) among East Asians is less than one-tenth of that among Caucasians. Such a low prevalence may be attributable to a lack of carriers of specific predisposing haplogroups associated with the high instability of the Huntingtin gene (HTT). The aim of this study was to evaluate the association between specific HTT haplogroups and the occurrence of HD in a Thai population. Methods CAG-repeat sizes and HTT haplotypes were analyzed in 18 Thai HD patients and 215 control subjects. Twenty-two tagging single-nucleotide polymorphisms (tSNPs) were genotyped. Results Only 18 patients from 15 unrelated families were identified over the last 17 years. Pathological CAG-repeat alleles ranged from 39 to 48 repeats (43.5±3.0, mean±SD), and normal alleles ranged from 9 to 24 repeats (16.49±1.74). Only two of the chromosomes studied comprised intermediate alleles. Unlike the Caucasian data, all but 1 of the 22 tSNPs were not associated with the occurrence of HD. The predisposing haplogroups for Caucasian HD (haplogroups A1 and A2) are very rare in Thai patients (<4%). Both HD and normal chromosomes are commonly haplogroups A5 and C, in contrast to the case for Chinese and Japanese patients, in whom only haplogroup C was common in HD chromosomes. The frequency of CAG-repeat sizes of haplogroup A5 and C were also similarly distributed. Conclusions HD chromosomes of Thai patients may arise randomly from each haplogroup, with a similar mutation rate. This rate is much lower than the CAG expansions from Caucasian HD haplogroups. These data suggest that the different mechanisms underlie CAG expansion in Thai and Caucasian patients.
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Affiliation(s)
- Teeratorn Pulkes
- Department of Neurology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Chutima Papsing
- Department of Neurology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Sukanya Wattanapokayakit
- Department of Medical Sciences, Medical Genetic Section, National Institute of Health, Ministry of Public Health, Nonthaburi, Thailand
| | - Surakameth Mahasirimongkol
- Department of Medical Sciences, Medical Genetic Section, National Institute of Health, Ministry of Public Health, Nonthaburi, Thailand
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Semaka A, Hayden M. Evidence-based genetic counselling implications for Huntington disease intermediate allele predictive test results. Clin Genet 2014; 85:303-11. [DOI: 10.1111/cge.12324] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 11/18/2013] [Accepted: 11/18/2013] [Indexed: 11/29/2022]
Affiliation(s)
- A. Semaka
- Centre for Molecular Medicine and Therapeutics; University of British Columbia; Vancouver British Columbia Canada
| | - M.R. Hayden
- Centre for Molecular Medicine and Therapeutics; University of British Columbia; Vancouver British Columbia Canada
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Semaka A, Kay C, Doty CN, Collins JA, Tam N, Hayden MR. High frequency of intermediate alleles on Huntington disease-associated haplotypes in British Columbia's general population. Am J Med Genet B Neuropsychiatr Genet 2013; 162B:864-71. [PMID: 24038799 DOI: 10.1002/ajmg.b.32193] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 07/11/2013] [Indexed: 11/08/2022]
Abstract
Intermediate alleles (27-35 CAG, IAs) for Huntington disease (HD) usually do not confer the disease phenotype but are prone to CAG repeat instability. Consequently, offspring are at-risk of inheriting an expanded allele in the HD range (≥36 CAG). IAs that expand into a new mutation have been hypothesized to be more susceptible to instability compared to IAs identified on the non-HD side of a family from the general population. Frequency estimates for IAs are limited and have largely been determined using clinical samples of HD or related disorders, which may result in an ascertainment bias. This study aimed to establish the frequency of IAs in a sample of a British Columbia's (B.C.) general population with no known association to HD and examine the haplotype of new mutation and general population IAs. CAG sizing was performed on 1,600 DNA samples from B.C.'s general population. Haplotypes were determined using 22 tagging SNPs across the HTT gene. 5.8% of individuals were found to have an IA, of which 60% were on HD-associated haplotypes. There was no difference in the haplotype distribution of new mutation and general population IAs. These findings suggest that IAs are relatively frequent in the general population and are often found on haplotypes associated with expanded CAG lengths. There is likely no difference in the propensity of new mutation and general population IAs to expand into the disease range given that they are both found on disease-associated haplotypes. These findings have important implications for clinical practice.
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Affiliation(s)
- Alicia Semaka
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, Canada
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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: 417] [Impact Index Per Article: 37.9] [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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Semaka A, Kay C, Doty C, Collins JA, Bijlsma EK, Richards F, Goldberg YP, Hayden MR. CAG size-specific risk estimates for intermediate allele repeat instability in Huntington disease. J Med Genet 2013; 50:696-703. [PMID: 23896435 DOI: 10.1136/jmedgenet-2013-101796] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION New mutations for Huntington disease (HD) occur due to CAG repeat instability of intermediate alleles (IA). IAs have between 27 and 35 CAG repeats, a range just below the disease threshold of 36 repeats. While they usually do not confer the HD phenotype, IAs are prone to paternal germline CAG repeat instability. Consequently, they may expand into the HD range upon transmission to the next generation, producing a new mutation. Quantified risk estimates for IA repeat instability are extremely limited but needed to inform clinical practice. METHODS Using small-pool PCR of sperm DNA from Caucasian men, we examined the frequency and magnitude of CAG repeat instability across the entire range of intermediate CAG sizes. The CAG size-specific risk estimates generated are based on the largest sample size ever examined, including 30 IAs and 18 198 sperm. RESULTS Our findings demonstrate a significant risk of new mutations. While all intermediate CAG sizes demonstrated repeat expansion into the HD range, alleles with 34 and 35 CAG repeats were associated with the highest risk of a new mutation (2.4% and 21.0%, respectively). IAs with ≥33 CAG repeats showed a dramatic increase in the frequency of instability and a switch towards a preponderance of repeat expansions over contractions. CONCLUSIONS These data provide novel insights into the origins of new mutations for HD. The CAG size-specific risk estimates inform clinical practice and provide accurate risk information for persons who receive an IA predictive test result.
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Affiliation(s)
- Alicia Semaka
- Department of Medical Genetics, Centre for Molecular Medicine & Therapeutics, University of British Columbia, Vancouver, British Columbia, Canada
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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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van Rij MC, de Koning Gans PAM, Aalfs CM, Elting M, Ippel PF, Maat-Kievit JA, Vermeer S, Verschuuren-Bemelmans CC, van Belzen MJ, Belfroid RDM, Losekoot M, Geraedts JPM, Roos RAC, Tibben A, de Die-Smulders CEM, Bijlsma EK. Prenatal testing for Huntington's disease in the Netherlands from 1998 to 2008. Clin Genet 2013; 85:78-86. [PMID: 23350614 DOI: 10.1111/cge.12090] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 12/27/2012] [Accepted: 12/31/2012] [Indexed: 11/27/2022]
Abstract
This study aims to give an overview of the number of prenatal tests for Huntington's disease (HD), test results, and pregnancy outcomes in the Netherlands between 1998 and 2008 and to compare them with available data from the period 1987 to 1997. A total of 126 couples underwent prenatal diagnosis (PND) on 216 foetuses: 185 (86%) direct tests and 31 (14%) exclusion tests. In 9% of direct tests the risk for the foetus was 25%. Four at-risk parents (4%) carried intermediate alleles. Ninety-one foetuses had CAG expansions ≥36% or 50% risk haplotypes: 75 (82%) were terminated for HD, 12 (13%) were carried to term; four pregnancies were miscarried, terminated for other reasons or lost to follow-up. Unaffected pregnancies (122 foetuses) resulted in the birth of 112 children. The estimated uptake of PND was 22% of CAG expansion carriers (≥36 repeats) at reproductive age. PND was used by two new subgroups: carriers of intermediate alleles and 50% at-risk persons opting for a direct prenatal test of the foetus. A significant number of HD expansion or 50% risk pregnancies were continued. Speculations were made on causative factors contributing to these continuations. Further research on these couples' motives is needed.
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Affiliation(s)
- M C van Rij
- Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands; Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, the Netherlands
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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: 33] [Impact Index Per Article: 3.0] [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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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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Semaka A, Balneaves LG, Hayden MR. "Grasping the grey": patient understanding and interpretation of an intermediate allele predictive test result for Huntington disease. J Genet Couns 2012; 22:200-17. [PMID: 22903792 DOI: 10.1007/s10897-012-9533-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 07/30/2012] [Indexed: 10/28/2022]
Abstract
Since the discovery of the genetic mutation underlying Huntington disease (HD) and the development of predictive testing, the genetics of HD has generally been described as straightforward; an individual receives either mutation-positive or negative predictive test results. However, in actuality, the genetics of HD is complex and a small proportion of individuals receive an unusual predictive test result called an intermediate allele (IA). Unlike mutation-positive or negative results, IAs confer uncertain clinical implications. While individuals with an IA will usually not develop HD, there remains an unknown risk for their children and future generations to develop the disorder. The purpose of this study was to explore how individuals understood and interpreted their IA result. Interviews were conducted with 29 individuals who received an IA result and 8 medical genetics service providers. Interviews were analyzed using the constant comparative method and the coding procedures of grounded theory. Many participants had difficulty "Grasping the Grey" (i.e. understanding and interpreting their IA results) and their family experience, beliefs, expectations, and genetic counseling influenced the degree of this struggle. The theoretical model developed informs clinical practice regarding IAs, ensuring that this unique subset of patients received appropriate education, support, and counseling.
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Affiliation(s)
- A Semaka
- Department of Medical Genetics, Centre for Molecular Medicine & Therapeutics, University of British Columbia, 950 West 28th Ave, Vancouver, BC V5Z 4H4, Canada.
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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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Ha AD, Beck CA, Jankovic J. Intermediate CAG Repeats in Huntington's Disease: Analysis of COHORT. Tremor Other Hyperkinet Mov (N Y) 2012; 2:tre-02-64-287-4. [PMID: 23440000 PMCID: PMC3569951 DOI: 10.7916/d8ff3r2p] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 10/20/2011] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND There is emerging evidence that clinical and neuro-pathological manifestations of Huntington's disease (HD) may occur in individuals with intermediate length cytosine-adenine-guanine (CAG) repeats (27-35 CAG repeats) in the Huntingtin (HTT) gene. We aim to further define the clinical characteristics of individuals who possess CAG repeat lengths in this range. METHODS Data from the Cooperative Huntington's Observational Research Trial (COHORT) were analyzed. Participants were categorized according to the number of CAG repeats into normal (≤26), intermediate (27-35) and HD (≥36) groups. The motor, cognitive and behavioral scores on the Unified Huntington's Disease Rating Scale (UHDRS) were compared between the intermediate and normal groups. RESULTS Of 1985 individuals affected by HD or with a family history of HD who were genotyped, 50 (2.5%) had their larger CAG repeat in the intermediate range. There were statistically significant differences in scores of some motor, cognitive, and behavioral domains of UHDRS at baseline between normal and intermediate length CAG repeats. Furthermore, a significantly greater number of subjects with CAG repeats in the intermediate range reported at least one suicide attempt compared to the normal group. DISCUSSION Our findings of motor, cognitive and behavioral abnormalities in individuals with intermediate CAG repeats suggest the presence of subtle, but relevant, disease manifestations in patients with intermediate CAG repeats. These results have important implications for the pathogenesis of the disease and genetic counseling.
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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, Texas, United States of America
| | - Christopher A. Beck
- Department of Biostatistics and Computational Biology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Joseph Jankovic
- Parkinson's Disease Center and Movement Disorders Clinic, Department of Neurology, Baylor College of Medicine, Houston, Texas, United States of America
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Klein C. The Wilson films--Huntington's chorea. Mov Disord 2011; 26:2464-6. [PMID: 22170268 DOI: 10.1002/mds.23986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Wilson's Queen Square Case 9 with Huntington's chorea shows a 68-year-old man with mild to moderate generalized chorea, impaired fixation, and probable cognitive decline in keeping with a diagnosis of Huntington's disease (HD). An age of onset in the late sixties and a negative family history suggest a relatively small expanded trinucleotide repeat in the HTT gene in the patient and reduced penetrance of an even shorter repeat allele in one of his parents. A highly sensitive and specific gene test has been offered worldwide for diagnostic testing of HD for almost two decades. This test, obviously unavailable at Wilson's times, became the historic frontrunner for guidelines of symptomatic, presymptomatic, and prenatal testing for an adult-onset neurodegenerative disorder. Regarding treatment of HD, however, we are still awaiting the successful translation of research results into the development of effective cause-directed, neuropreventive and neurorestaurative therapies.
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Affiliation(s)
- Christine Klein
- Section of Clinical and Molecular Neurogenetics, Department of Neurology, University of Luebeck, Luebeck, Germany.
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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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