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Solís-Añez E, Salles PA, Rojas N, Benavides O, Chaná-Cuevas P. Huntington's Disease in Chile: Epidemiological and Genetic Aspects. Neuroepidemiology 2023; 57:176-184. [PMID: 37121230 DOI: 10.1159/000528961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 12/20/2022] [Indexed: 05/02/2023] Open
Abstract
INTRODUCTION Huntington's disease (HD) is a neurodegenerative, autosomal dominant disabling condition due to an expansion of the CAG trinucleotide in the HTT gene. Motor, psychiatric, and cognitive disorders characterize it. Chilean reports on HD in the era of molecular diagnosis were wanted. METHODS This is a retrospective analysis of a prospective cohort of patients with HD seen at the Center for Movement Disorders (CETRAM) in Chile between 2013 and 2019. Sociodemographic, genotype, and neuropsychiatric features were investigated. RESULTS One hundred three probands with HD were identified. The majority (63.1%) were born in the metropolitan region, followed by the VIII and V regions with 8.73% and 7.76%, respectively. When pedigrees were analyzed, ninety unrelated families encompassing 1,007 individuals were identified; among relatives, other 35 manifested HD, and 106 died of HD. Besides, five hundred seventy-nine individuals were at genetic risk. The minimum estimated prevalence of HD in Chile in 2019 was 0.72 × 100,000 inhabitants. The mean CAG repeats (CAGR) of 47.2 ± 10.74 for the expanded allele and 17.93 ± 2.05 for the normal allele. The mean age of onset was 41.39 ± 13.47 years. Juvenile cases represented 7.8% of this cohort, and 4.9% had a late onset. There was a negative correlation between the age of onset and the CAGR of the expanded allele (r =-0.84 p < 0.0001). Besides, 79.6% had a family history of HD. CONCLUSIONS This is the first report characterizing genetics, motor, and neuropsychiatric features in patients with HD in Chile. The mean length of CAGR expansion of the abnormal allele was similar to previous reports in North America (i.e., Mexico and Canada) and higher than that reported in the neighboring country of Argentina. According to previous estimations, the minimal prevalence of HD in Chile may be lower than expected.
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Affiliation(s)
| | - Philippe A Salles
- Center for Movement Disorders CETRAM, University of Santiago de Chile, Santiago, Chile,
| | - Natalia Rojas
- Center for Movement Disorders CETRAM, University of Santiago de Chile, Santiago, Chile
| | - Olga Benavides
- Neurology Department, Dr. Eloisa Díaz La Florida Metropolitan Hospital, Santiago, Chile
| | - Pedro Chaná-Cuevas
- Center for Movement Disorders CETRAM, University of Santiago de Chile, Santiago, Chile
- Faculty of Medical Sciences, University of Santiago de Chile, Santiago, Chile
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Apolinário TA, Rodrigues DC, Lemos MB, Antão Paiva CL, Agostinho LA. Distribution of the HTT Gene A1 and A2 Haplotypes Worldwide: A Systematic Review. Clin Med Res 2020; 18:145-152. [PMID: 32878904 PMCID: PMC7735449 DOI: 10.3121/cmr.2020.1523] [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: 08/13/2019] [Revised: 02/15/2020] [Accepted: 08/04/2020] [Indexed: 11/18/2022]
Abstract
BACKGROUND Huntington's disease (HD)(MIM:143100) is an severe autosomal dominant neurodegenerative disease caused by the dynamic expansion of CAG trinucleotides (> 35) in the HTT gene [Genomic Coordinates- (GRCh38):4:3,074,680-3,243,959]. OBJECTIVES The aim of this systematic review was to investigate the reported associations between the frequencies of the A1 and A2 haplotypes in HD-affected and non-affected populations from different countries on different continents, in order to demonstrate the overall profile of these haplotypes worldwide, pointing towards the most frequent haplotypes that could be useful for HTT mutant-specific allele silencing in different populations. METHODS Publications in MEDLINE (PubMed) and Embase from the last 10 years (PROSPERO CRD42018115282) were assessed. RESULTS A total of 20 articles from 113 were selected for evaluation in their entirety, and eight were eligible for this study. CONCLUSION Regardless of the size of the CAG tract, the articles included in this review demonstrate that populations with high HD prevalence present higher frequencies of the A1 or A2 haplotypes than populations exhibiting low HD prevalence, even when similar average CAG numbers are noted. Based on the presented articles, we suggest that the haplotypic profile is more closely related to the ancestral origin than to the size of the CAG tract. The identification of populations presenting a higher frequency of high-risk genotypes can contribute to more accurate genetic counseling, in addition to providing knowledge on HD epidemiology. According to the continued progress in the development of specific genetic silencing therapies by different research groups and pharmaceutical companies, such as haplotype targeting strategies for allele-specific HTT suppression, we conclude that the definition of haplotypes in phase with CAG expansions will contribute to the design of gene-silencing drugs specific for different populations worldwide.
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Affiliation(s)
- Thays Andrade Apolinário
- Graduate Program in Neurology, Universidade Federal do Estado do Rio de Janeiro (UNIRIO), Rio de Janeiro, RJ, Brazil
| | - Dionatan Costa Rodrigues
- Graduate Program in Neurology, Universidade Federal do Estado do Rio de Janeiro (UNIRIO), Rio de Janeiro, RJ, Brazil
| | - Mayra Braga Lemos
- Department of Genetics and Molecular Biology, Instituto Bimédico, UNIRIO, RJ, Brazil
| | - Carmen Lúcia Antão Paiva
- Graduate Program in Neurology, Universidade Federal do Estado do Rio de Janeiro (UNIRIO), Rio de Janeiro, RJ, Brazil
- Department of Genetics and Molecular Biology, Instituto Bimédico, UNIRIO, RJ, Brazil
- Graduate Program in Molecular and Cell Biology, UNIRIO, RJ, Brazil
| | - Luciana Andrade Agostinho
- Graduate Program in Neurology, Universidade Federal do Estado do Rio de Janeiro (UNIRIO), Rio de Janeiro, RJ, Brazil
- University Center UNIFAMINAS - UNIFAMINAS, Muriaé, MG, Brazil
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3
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Apolinário TA, da Silva IDS, Agostinho LDA, Paiva CLA. Investigation of intermediate CAG alleles of the HTT in the general population of Rio de Janeiro, Brazil, in comparison with a sample of Huntington disease-affected families. Mol Genet Genomic Med 2020; 8:e1181. [PMID: 32067426 PMCID: PMC7196456 DOI: 10.1002/mgg3.1181] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 01/14/2020] [Accepted: 01/30/2020] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Huntington disease (HD) (MIM: 143100) is a severe autosomal dominant neurodegenerative disease caused by the expansion of CAG trinucleotides (>35) in the HTT. OBJECTIVE To investigate the frequency of intermediate CAG alleles (IAs) in individuals residing in Rio de Janeiro city with no familial history of HD (general population, GP) in comparison with a sample of individuals from families presenting with HD who were previously investigated by our group (affected sample, AS). RESULTS The frequency of normal CAG alleles was 96.2%, while that of IAs was 3.6%, and that of reduced penetrance alleles was 0.2% in the GP (n = 470 chromosomes); 7.2% (17/235 individuals) of the GP presented an IA in heterozygosis with a normal allele. There was no statistically significant difference between the frequencies of the IAs in the GP and in the AS (p = .9). The most frequent haplotype per normal allele was (CAG)17-(CCG)7 (101/461) and per IA was (CAG)27-(CCG)7 (6/17) in the GP. These haplotypes were also the most frequent in the normal and IA chromosomes of the AS, respectively. CONCLUSION The genetic profiles of the IAs obtained from GP and AS were rather similar. It is important to investigate the frequencies of the IAs because expansions arise from a step-by-step mechanism in which, during intergenerational transmission, large normal alleles can generate IAs, which are then responsible for generating de novo HD mutations. The genetic investigation of IAs in the GP was also important because it was focused on the population of Rio de Janeiro, an understudied group. CCG7 was the most frequent CCG allele in linkage disequilibrium with normal, intermediate, and expanded CAG alleles, similar to the Western Europe population. However, a more robust investigation, in conjunction with haplogroup determination (A, B, or C), will be required to elucidate the ancestral origin of the HTT mutations in Brazilians.
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Affiliation(s)
- Thays A. Apolinário
- Programa de Pós‐Graduação em NeurologiaUniversidade Federal do Estado do Rio de Janeiro (UNIRIO)Rio de JaneiroRJBrazil
| | - Iane dos Santos da Silva
- Programa de Pós‐Graduação em Biologia Molecular e CelularUniversidade Federal do Estado do Rio de Janeiro (UNIRIO)Rio de JaneiroRJBrazil
| | - Luciana de Andrade Agostinho
- Programa de Pós‐Graduação em NeurologiaUniversidade Federal do Estado do Rio de Janeiro (UNIRIO)Rio de JaneiroRJBrazil
- Centro Universitário FAMINAS – UNIFAMINASMuriaéMGBrazil
- Fundação Cristiano Varella‐Hospital do CâncerMuriaéMGBrazil
| | - Carmen L. A. Paiva
- Programa de Pós‐Graduação em NeurologiaUniversidade Federal do Estado do Rio de Janeiro (UNIRIO)Rio de JaneiroRJBrazil
- Programa de Pós‐Graduação em Biologia Molecular e CelularUniversidade Federal do Estado do Rio de Janeiro (UNIRIO)Rio de JaneiroRJBrazil
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Véliz-Otani D, Inca-Martinez M, Bampi GB, Ortega O, Jardim LB, Saraiva-Pereira ML, Mazzetti P, Cornejo-Olivas M. ATXN10 Microsatellite Distribution in a Peruvian Amerindian Population. THE CEREBELLUM 2019; 18:841-848. [DOI: 10.1007/s12311-019-01057-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Costa IPD, Almeida BC, Sequeiros J, Amorim A, Martins S. A Pipeline to Assess Disease-Associated Haplotypes in Repeat Expansion Disorders: The Example of MJD/SCA3 Locus. Front Genet 2019; 10:38. [PMID: 30804982 PMCID: PMC6370646 DOI: 10.3389/fgene.2019.00038] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 01/18/2019] [Indexed: 12/13/2022] Open
Abstract
At least 40 human diseases are associated with repeat expansions; yet, the mutational origin and instability mechanisms remain unknown for most of them. Previously, genetic epidemiology and predisposing backgrounds for the instability of some expanding loci have been studied in different populations through the analysis of diversity flanking the respective pathogenic repeats. Here, we aimed at developing a pipeline to assess disease-associated haplotypes at oligonucleotide repeat loci, combining analysis of single nucleotide polymorphisms (SNPs) and short tandem repeats (STRs). Machado-Joseph disease (MJD/SCA3), the most frequent dominant ataxia worldwide, was used as an example of a detailed procedure. Thus, to identify genetic backgrounds that segregate with expanded/mutated alleles in MJD, we selected a set of 26 SNPs and 7 STRs flanking the causative CAG repeat. Key criteria and steps for this selection are described, and included (1) haplotype blocks minimizing the occurrence of recombination (for SNPs); and (2) match scores to increase potential for polymorphic information content of repetitive sequences found in Tandem Repeats Finder (for STRs). To directly assess SNP haplotypes in phase with MJD expansions, we optimized a strategy with preferential amplification of normal over expanded alleles, in addition to SNP allele-specific amplifications; this allowed the identification of disease-associated SNP haplotypes, even when only the proband is available in a given family. To infer STR haplotypes, we optimized a multiplex PCR, including 7 STRs plus the MJD_CAG repeat, followed by analysis of segregation or the use of the PHASE software. This protocol is a ready-to-use tool to assess MJD haplotypes in different populations. The pipeline designed can be used to assess disease-associated haplotypes in other repeat-expansion diseases. This should be of great utility to study (1) genetic epidemiology (population-of-origin, age and spreading routes of mutations) and (2) mechanisms responsible for de novo expansions, in these neurological diseases; (3) to detect predisposing haplotypes and (4) phenotype modifiers; (5) to help solving cases of apparent homoallelism (two same-size normal alleles) in diagnosis; and (6) to identify the best targets for the development of allele-specific therapies in ethnically diverse patient populations.
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Affiliation(s)
- Inês P. D. Costa
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IPATIMUP – Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal
| | - Beatriz C. Almeida
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IPATIMUP – Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal
- Faculdade de Ciências da Universidade do Porto, Porto, Portugal
| | - Jorge Sequeiros
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IBMC – Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- ICBAS – Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - António Amorim
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IPATIMUP – Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal
- Faculdade de Ciências da Universidade do Porto, Porto, Portugal
| | - Sandra Martins
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IPATIMUP – Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal
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Morton AJ, Skillings EA, Wood NI, Zheng Z. Antagonistic pleiotropy in mice carrying a CAG repeat expansion in the range causing Huntington's disease. Sci Rep 2019; 9:37. [PMID: 30631090 PMCID: PMC6328633 DOI: 10.1038/s41598-018-37102-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 11/28/2018] [Indexed: 02/06/2023] Open
Abstract
Antagonist pleiotropy, where a gene exerts a beneficial effect at early stages and a deleterious effect later on in an animal’s life, may explain the evolutionary persistence of devastating genetic diseases such as Huntington’s disease (HD). To date, however, there is little direct experimental evidence to support this theory. Here, we studied a transgenic mouse carrying the HD mutation with a repeat of 50 CAGs (R6/2_50) that is within the pathological range of repeats causing adult-onset disease in humans. R6/2_50 mice develop characteristic HD brain aggregate pathology, with aggregates appearing predominantly in the striatum and cortex. However, they show few signs of disease in their lifetime. On the contrary, R6/2_50 mice appear to benefit from carrying the mutation. They have extended lifespans compared to wildtype (WT) mice, and male mice show enhanced fecundity. Furthermore, R6/2_50 mice outperform WT mice on the rotarod and show equal or better performance in the two choice discrimination task than WT mice. This novel mouse line provides direct experimental evidence that, although the HD mutation causes a fatal neurodegenerative disorder, there may be premorbid benefits of carrying the mutation.
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Affiliation(s)
- A J Morton
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, United Kingdom.
| | - E A Skillings
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, United Kingdom
| | - N I Wood
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, United Kingdom
| | - Z Zheng
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, United Kingdom
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7
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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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8
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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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9
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Ramos EM, Gillis T, Mysore JS, Lee JM, Alonso I, Gusella JF, Smoller JW, Sklar P, MacDonald ME, Perlis RH. Prevalence of Huntington's disease gene CAG trinucleotide repeat alleles in patients with bipolar disorder. Bipolar Disord 2015; 17:403-8. [PMID: 25726852 PMCID: PMC9980711 DOI: 10.1111/bdi.12289] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 11/05/2014] [Indexed: 01/04/2023]
Abstract
OBJECTIVES Huntington's disease is a neurodegenerative disorder characterized by motor, cognitive, and psychiatric symptoms that are caused by huntingtin gene (HTT) CAG trinucleotide repeat alleles of 36 or more units. A greater than expected prevalence of incompletely penetrant HTT CAG repeat alleles observed among individuals diagnosed with major depressive disorder raises the possibility that another mood disorder, bipolar disorder, could likewise be associated with Huntington's disease. METHODS We assessed the distribution of HTT CAG repeat alleles in a cohort of individuals with bipolar disorder. HTT CAG allele sizes from 2,229 Caucasian individuals diagnosed with DSM-IV bipolar disorder were compared to allele sizes in 1,828 control individuals from multiple cohorts. RESULTS We found that HTT CAG repeat alleles > 35 units were observed in only one of 4,458 chromosomes from individuals with bipolar disorder, compared to three of 3,656 chromosomes from control subjects. CONCLUSIONS These findings do not support an association between bipolar disorder and Huntington's disease.
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Affiliation(s)
- Eliana Marisa Ramos
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA, USA,UnIGENe, IBMC – Institute for Molecular and Cell Biology, University of Porto, Porto, Portugal
| | - Tammy Gillis
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA, USA
| | - Jayalakshmi S Mysore
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA, USA
| | - Jong-Min Lee
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA, USA
| | - Isabel Alonso
- UnIGENe, IBMC – Institute for Molecular and Cell Biology, University of Porto, Porto, Portugal
| | - James F Gusella
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA, USA
| | - Jordan W Smoller
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA, USA
| | - Pamela Sklar
- Division of Psychiatric Genomics, Department of Psychiatry, Mount Sinai School of Medicine, New York, NY, USA
| | - Marcy E MacDonald
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA, USA
| | - Roy H Perlis
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA, USA
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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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11
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Vázquez-Mojena Y, Laguna-Salvia L, Laffita-Mesa JM, González-Zaldívar Y, Almaguer-Mederos LE, Rodríguez-Labrada R, Almaguer-Gotay D, Zayas-Feria P, Velázquez-Pérez L. Genetic features of Huntington disease in Cuban population: Implications for phenotype, epidemiology and predictive testing. J Neurol Sci 2013; 335:101-4. [DOI: 10.1016/j.jns.2013.08.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 08/22/2013] [Accepted: 08/26/2013] [Indexed: 10/26/2022]
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12
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Baine FK, Kay C, Ketelaar ME, Collins JA, Semaka A, Doty CN, Krause A, Greenberg LJ, Hayden MR. Huntington disease in the South African population occurs on diverse and ethnically distinct genetic haplotypes. Eur J Hum Genet 2013; 21:1120-7. [PMID: 23463025 DOI: 10.1038/ejhg.2013.2] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 12/12/2012] [Accepted: 12/28/2012] [Indexed: 11/09/2022] Open
Abstract
Huntington disease (HD) is a neurodegenerative disorder resulting from the expansion of a CAG trinucleotide repeat in the huntingtin (HTT) gene. Worldwide prevalence varies geographically with the highest figures reported in populations of European ancestry. HD in South Africa has been reported in Caucasian, black and mixed subpopulations, with similar estimated prevalence in the Caucasian and mixed groups and a lower estimate in the black subpopulation. Recent studies have associated specific HTT haplotypes with HD in distinct populations. Expanded HD alleles in Europe occur predominantly on haplogroup A (specifically high-risk variants A1/A2), whereas in East Asian populations, HD alleles are associated with haplogroup C. Whether specific HTT haplotypes associate with HD in black Africans and how these compare with haplotypes found in European and East Asian populations remains unknown. The current study genotyped the HTT region in unaffected individuals and HD patients from each of the South African subpopulations, and haplotypes were constructed. CAG repeat sizes were determined and phased to haplotype. Results indicate that HD alleles from Caucasian and mixed patients are predominantly associated with haplogroup A, signifying a similar European origin for HD. However, in black patients, HD occurs predominantly on haplogroup B, suggesting several distinct origins of the mutation in South Africa. The absence of high-risk variants (A1/A2) in the black subpopulation may also explain the reported low prevalence of HD. Identification of haplotypes associated with HD-expanded alleles is particularly relevant to the development of population-specific therapeutic targets for selective suppression of the expanded HTT transcript.
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Affiliation(s)
- Fiona K Baine
- 1] Division of Human Genetics, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa [2] Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
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Gatto E, Parisi V, Persi G, Converso DP, Etcheverry JL, Varela V, Alba L, Fretchel G. Clinical and genetic characteristics in patients with Huntington’s Disease from Argentina. Parkinsonism Relat Disord 2012; 18:166-9. [DOI: 10.1016/j.parkreldis.2011.09.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 09/09/2011] [Accepted: 09/15/2011] [Indexed: 02/01/2023]
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HTT haplotypes contribute to differences in Huntington disease prevalence between Europe and East Asia. Eur J Hum Genet 2011; 19:561-6. [PMID: 21248742 DOI: 10.1038/ejhg.2010.229] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Huntington disease (HD) results from CAG expansion in the huntingtin (HTT) gene. Although HD occurs worldwide, there are large geographic differences in its prevalence. The prevalence in populations derived from Europe is 10-100 times greater than in East Asia. The European general population chromosomes can be grouped into three major haplogroups (group of similar haplotypes): A, B and C. The majority of HD chromosomes in Europe are found on haplogroup A. However, in the East-Asian populations of China and Japan, we find the majority of HD chromosomes are associated with haplogroup C. The highest risk HD haplotypes (A1 and A2), are absent from the general and HD populations of China and Japan, and therefore provide an explanation for why HD prevalence is low in East Asia. Interestingly, both East-Asian and European populations share a similar low level of HD on haplogroup C. Our data are consistent with the hypothesis that different HTT haplotypes have different mutation rates, and geographic differences in HTT haplotypes explain the difference in HD prevalence. Further, the bias for expansion on haplogroup C in the East-Asian population cannot be explained by a higher average CAG size, as haplogroup C has a lower average CAG size in the general East-Asian population compared with other haplogroups. This finding suggests that CAG-tract size is not the only factor important for CAG instability. Instead, the expansion bias may be because of genetic cis-elements within the haplotype that influence CAG instability in HTT, possibly through different mutational mechanisms for the different haplogroups.
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Johnson CD, Davidson BL. Huntington's disease: progress toward effective disease-modifying treatments and a cure. Hum Mol Genet 2010; 19:R98-R102. [PMID: 20421366 DOI: 10.1093/hmg/ddq148] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Huntington's disease (HD) is caused by a dominant mutation in HTT, the HD gene. This discovery opens possibilities for treatment based on silencing of the disease-causing allele or with compounds that reduce the production of disease-causing mRNA and/or protein. Although additional developments are needed related to the delivery of gene silencing and discovery and development of drugs that reduce disease-causing gene products, these treatments are predicted to be effective since they act by reducing the source of toxicity. The identification of therapies that act by blocking toxicity is conceptually more complicated, as this requires an accurate understanding of the cellular location and the specific molecular dysfunctions that cause the phenotypes of HD, which is not yet available. Though challenges remain, significant progress has been made. Effective disease-modifying treatments will soon be tested and may lead to disease-altering therapies.
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