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Huntington's Chorea-a Rare Neurodegenerative Autosomal Dominant Disease: Insight into Molecular Genetics, Prognosis and Diagnosis. Appl Biochem Biotechnol 2021; 193:2634-2648. [PMID: 34235640 DOI: 10.1007/s12010-021-03523-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Accepted: 01/27/2021] [Indexed: 12/24/2022]
Abstract
Huntington's disease is a neurodegenerative autosomal disease results due to expansion of polymorphic CAG repeats in the huntingtin gene. Phosphorylation of the translation initiation factor 4E-BP results in the alteration of the translation control leading to unwanted protein synthesis and neuronal function. Consequences of mutant huntington (mhtt) gene transcription are not well known. Variability of age of onset is an important factor of Huntington's disease separating adult and juvenile types. The factors which are taken into account are-genetic modifiers, maternal protection i.e excessive paternal transmission, superior ageing genes and environmental threshold. A major focus has been given to the molecular pathogenesis which includes-motor disturbance, cognitive disturbance and neuropsychiatric disturbance. The diagnosis part has also been taken care of. This includes genetic testing and both primary and secondary symptoms. The present review also focuses on the genetics and pathology of Huntington's disease.
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Sienes Bailo P, Lahoz R, Sánchez Marín JP, Izquierdo Álvarez S. Incidence of Huntington disease in a northeastern Spanish region: a 13-year retrospective study at tertiary care centre. BMC MEDICAL GENETICS 2020; 21:233. [PMID: 33228555 PMCID: PMC7684714 DOI: 10.1186/s12881-020-01174-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 11/12/2020] [Indexed: 11/15/2022]
Abstract
Background Despite the progress in the knowledge of Huntington disease (HD) in recent years, the epidemiology continues uncertain, so the study of incidence becomes relevant. This is important since various factors (type of population, diagnostic criteria, disease-modifying factors, etc.) make these data highly variable. Therefore, the genetic diagnosis of these patients is important, since it unequivocally allows the detection of new cases. Methods Descriptive retrospective study with 179 individuals. Incidence of HD was calculated from the ratio of number of symptomatic cases newly diagnosed per 100,000 inhabitants per year during the period 2007–2019 in Aragon (Spain). Results 50 (27.9%) incident cases of HD (CAG repeat length ≥ 36) were identified from a total of 179 persons studied. The remaining 129/179 (72.1%) were HD negative (CAG repeat length < 36). 29 (58.0%) females and 21 (42.0%) males were confirmed as HD cases. The overall incidence was 0.648 per 100,000 patient-years. 11/50 positive HD cases (22.0%) were identified by performing a predictive test, without clinical symptoms. The minimum number of CAG repeats found was 9 and the most common CAG length among HD negative individuals was 16. Conclusions Our incidence lied within the range reported for other Caucasian populations. Implementation of new techniques has allowed to determine the exact number of CAG repeats, which is especially important in patients with triplet expansions in an HD intermediate and/or incomplete penetrance allele, both in diagnostic, predictive and prenatal tests. Supplementary Information The online version contains supplementary material available at 10.1186/s12881-020-01174-z.
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Affiliation(s)
- Paula Sienes Bailo
- Departamento de Genética. Servicio de Bioquímica Clínica, Hospital Universitario Miguel Servet. C/ Padre Arrupe, s/n. Consultas Externas. Planta 3ª. 50009, Zaragoza, Spain
| | - Raquel Lahoz
- Departamento de Genética. Servicio de Bioquímica Clínica, Hospital Universitario Miguel Servet. C/ Padre Arrupe, s/n. Consultas Externas. Planta 3ª. 50009, Zaragoza, Spain.
| | - Juan Pelegrín Sánchez Marín
- Departamento de Genética. Servicio de Bioquímica Clínica, Hospital Universitario Miguel Servet. C/ Padre Arrupe, s/n. Consultas Externas. Planta 3ª. 50009, Zaragoza, Spain
| | - Silvia Izquierdo Álvarez
- Departamento de Genética. Servicio de Bioquímica Clínica, Hospital Universitario Miguel Servet. C/ Padre Arrupe, s/n. Consultas Externas. Planta 3ª. 50009, Zaragoza, Spain
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Gilling M, Budtz-Jørgensen E, Boonen SE, Lildballe D, Bojesen A, Hertz JM, Sørensen SA. The Danish HD Registry-a nationwide family registry of HD families in Denmark. Clin Genet 2017; 92:338-341. [PMID: 28155235 DOI: 10.1111/cge.12984] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 01/15/2017] [Accepted: 01/20/2017] [Indexed: 11/30/2022]
Abstract
The Danish Huntington's Disease Registry (DHR) is a nationwide family registry comprising 14 245 individuals from 445 Huntington's disease (HD) families of which the largest family includes 845 individuals in 8 generations. 1136 DNA and/or blood samples and 18 fibroblast cultures are stored in a local biobank. The birthplace of the oldest HD carrier in each of the 261 families of Danish origin was unevenly distributed across Denmark with a high number of families in the middle part of the peninsula Jutland and in Copenhagen, the capital. The prevalence of HD in Denmark was calculated to be 5-8:100 000. 1451 individuals in the DHR had the size of the HTT CAG repeat determined of which 975 had 36 CAG repeats or more (mean ± SD: 43,5 ± 4,8). Two unrelated individuals were compound heterozygous for alleles ≥36 CAGs, and 60 individuals from 34 independent families carried an intermediate allele.
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Affiliation(s)
- M Gilling
- Department of Neurogenetics, Institute of Cellular and Molecular Medicine, The Panum Institute, University of Copenhagen, Copenhagen, Denmark.,The European Huntington's Disease Network, University of Ulm, Ulm, Germany
| | - E Budtz-Jørgensen
- Department of Biostatistics, Institute of Public Health, University of Copenhagen, Copenhagen, Denmark
| | - S E Boonen
- Department of Clinical Genetics, Aarhus University Hospital, Aarhus, Denmark.,Unit of Clinical Genetics, Department of Paediatrics, Zealand University Hospital, Roskilde, Denmark
| | - D Lildballe
- Department of Clinical Genetics, Aarhus University Hospital, Aarhus, Denmark
| | - A Bojesen
- Department of Clinical Genetics, Vejle Hospital, Vejle, Denmark
| | - J M Hertz
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark
| | - S A Sørensen
- Department of Neurogenetics, Institute of Cellular and Molecular Medicine, The Panum Institute, University of Copenhagen, Copenhagen, Denmark
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Risk factors for the onset and progression of Huntington disease. Neurotoxicology 2017; 61:79-99. [PMID: 28111121 DOI: 10.1016/j.neuro.2017.01.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 01/11/2017] [Indexed: 01/10/2023]
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder characterized by chorea, behavioural and psychiatric manifestations, and dementia, caused by a CAG triplet repeat expansion in the huntingtin gene. Systematic review of the literature was conducted to determine the risk factors for the onset and progression of HD. Multiple databases were searched, using terms specific to Huntington disease and to studies of aetiology, risk, prevention and genetics, limited to studies on human subjects published in English or French between 1950 and 2010. Two reviewers independently screened the abstracts and identified potentially relevant articles for full-text review using predetermined inclusion criteria. Three major categories of risk factors for onset of HD were identified: CAG repeat length in the huntingtin gene, CAG instability, and genetic modifiers. Of these, CAG repeat length in the huntingtin gene is the most important risk factor. For the progression of HD: genetic, demographic, past medical/clinical and environmental risk factors have been studied. Of these factors, genetic factors appear to play the most important role in the progression of HD. Among the potential risk factors, CAG repeat length in the mutant allele was found to be a relatively consistent and significant risk factor for the progression of HD, especially in motor, cognitive, and other neurological symptom deterioration. In addition, there were many consistent results in the literature indicating that a higher number of CAG repeats was associated with shorter survival, faster institutionalization, and earlier percutaneous endoscopic gastrostomy.
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Kay C, Hayden MR, Leavitt BR. Epidemiology of Huntington disease. HANDBOOK OF CLINICAL NEUROLOGY 2017; 144:31-46. [DOI: 10.1016/b978-0-12-801893-4.00003-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Agostinho LA, Spitz M, Pereira JS, Paiva CLA. Clinical and genetic investigation of a Brazilian family with Huntington's disease. FUNCTIONAL NEUROLOGY 2016; 31:135-42. [PMID: 27678206 DOI: 10.11138/fneur/2016.31.3.135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The aim of this study was to investigate a Brazilian family carrying full penetrance alleles for Huntington's disease (HD) in order to correlate each member's genetic and clinical features. To this end, the following scales were administered in each patient: the Beck Depression Inventory, the Mini-Mental State Examination (MMSE) and the Unified Huntington's Disease Rating Scale (UHDRS). The patterns of CAG and CCG polymorphic regions in the HTT gene were determined, the disease burden score was calculated, and genotypes were correlated with phenotypes within this family. We suggest that HD duration, the number of years of formal education, and UHDRS status variables can explain 96.6% of the MMSE variability in HD patients. A strong significant correlation was found between the disease burden score and the UHDRS (r = 0.76; p-value = 0.049) and the MMSE (r = -0.90; p-value = 0.006). The correlations between CAG allele size and the three clinical evaluations performed in the HD patients were not statistically significant.
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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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Haplotype analysis of the CAG and CCG repeats in 21 Brazilian families with Huntington's disease. J Hum Genet 2012; 57:796-803. [PMID: 23051704 DOI: 10.1038/jhg.2012.120] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We studied the allelic profile of CAG and CCG repeats in 61 Brazilian individuals in 21 independent families affected by Huntington's disease (HD). Thirteen individuals had two normal alleles for HD, two had one mutable normal allele and no HD phenotype, and forty-six patients carried at least one expanded CAG repeat allele. Forty-five of these individuals had one expanded allele and one individual had one mutable normal allele (27 CAG repeats) and one expanded allele (48 CAG repeats). Eleven of these forty-five subjects had a mutant allele with reduced penetrance, and thirty-four patients had a mutant allele with complete penetrance. Inter- and intragenerational investigations of CAG repeats were also performed. We found a negative correlation between the number of CAG repeats and the age of disease onset (r=-0.84; P<0.001) and no correlation between the number of CCG repeats and the age of disease onset (r=0.06). We found 40 different haplotypes and the analysis showed that (CCG)(10) was linked to a CAG normal allele in 19 haplotypes and to expanded alleles in two haplotypes. We found that (CCG)(7) was linked to expanded CAG repeats in 40 haplotypes (95.24%) and (CCG)(10) was linked to expanded CAG repeats in only two haplotypes (4.76%). Therefore, (CCG)(7) was the most common allele in HD chromosomes in this Brazilian sample. It was also observed that there was a significant association of (CCG)(7) with the expanded CAG alleles (χ(2)=6.97, P=0.0084). Worldwide, the most common CCG alleles have 7 or 10 repeats. In Western Europe, (CCG)(7) is the most frequent allele, similarly to our findings.
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Nopoulos P, Epping EA, Wassink T, Schlaggar BL, Perlmutter J. Correlation of CAG repeat length between the maternal and paternal allele of the Huntingtin gene: evidence for assortative mating. Behav Brain Funct 2011; 7:45. [PMID: 22008211 PMCID: PMC3219594 DOI: 10.1186/1744-9081-7-45] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 10/18/2011] [Indexed: 11/10/2022] Open
Abstract
Triplet repeats contribute to normal variation in behavioral traits and when expanded, cause brain disorders. While Huntington's Disease is known to be caused by a CAG triplet repeat in the gene Huntingtin, the effect of CAG repeats on brain function below disease threshold has not been studied. The current study shows a significant correlation between the CAG repeat length of the maternal and paternal allele in the Huntingtin gene among healthy subjects, suggesting assortative mating.
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Affiliation(s)
- Peg Nopoulos
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.
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Ma M, Yang Y, Shang H, Su D, Zhang H, Ma Y, Liu Y, Tao D, Zhang S. Evidence for a predisposing background for CAG expansion leading to HTT mutation in a Chinese population. J Neurol Sci 2011; 298:57-60. [PMID: 20864123 DOI: 10.1016/j.jns.2010.08.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Revised: 08/17/2010] [Accepted: 08/23/2010] [Indexed: 02/05/2023]
Abstract
OBJECTIVE To investigate the predisposing background for the instability of CAG expansions of the HTT gene in a Chinese population. METHODS Genotyping and haplotyping of CAG and CCG repeats of the HTT gene were carried out in 32 unrelated HD patients and 95 non-HD control individuals of Han origin, using capillary electrophoresis and DNA sequencing. The frequencies of different CCG repeats were compared between mutant and wild-type HTT genes. In controls, the comparison of the mean CAG repeat size was performed among different CCG repeats. RESULTS A total of five alleles of CCG repeats were distinguished, in which four were present in HD chromosomes. In the CCG alleles, (CCG)10 showed a higher frequency in mutant HTT genes relative to wild-type ones, and the highest mean CAG repeat size was observed in the (CCG)10 background. Additionally, a haplotype of (CAG)32-(CCG)10 was found in the control group. CONCLUSION Our findings indicate that HTT mutation is likely of multiple origins in the Chinese population. Among the origins, more new HTT mutations may arise from the (CCG)10 than from other CCG alleles, which suggests that the (CCG)10 allele may represent a predisposing background for CAG expansion in Chinese populations. Therefore, in comparison with Europeans, the significantly lower prevalence of Huntington's disease in Chinese individuals may not be due to the absence of the predisposing background for CAG expansion but instead may partly result from the lower frequency of the predisposing haplotype for CAG instability in the population.
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Affiliation(s)
- Mingyi Ma
- Department of Medical Genetics, West China Hospital and State Key Laboratory of Biotherapy, Sichuan University, Gaopeng street, Keyuan Road 4, Chengdu, Sichuan 610041, China
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Palau F. [Rare diseases, an emergent paradigm in the medicine of the XXI century]. Med Clin (Barc) 2009; 134:161-8. [PMID: 19767033 DOI: 10.1016/j.medcli.2009.06.038] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Accepted: 06/15/2009] [Indexed: 10/20/2022]
Affiliation(s)
- Francesc Palau
- Instituto de Biomedicina de Valencia, Consejo Superior de Investigaciones Científicas (IBV-CSIC), CIBER de Enfermedades Raras (CIBERER), ISCIII, Valencia, España.
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Warby SC, Montpetit A, Hayden AR, Carroll JB, Butland SL, Visscher H, Collins JA, Semaka A, Hudson TJ, Hayden MR. CAG expansion in the Huntington disease gene is associated with a specific and targetable predisposing haplogroup. Am J Hum Genet 2009; 84:351-66. [PMID: 19249009 DOI: 10.1016/j.ajhg.2009.02.003] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Revised: 01/13/2009] [Accepted: 02/03/2009] [Indexed: 12/19/2022] Open
Abstract
Huntington disease (HD) is an autosomal-dominant disorder that results from >or=36 CAG repeats in the HD gene (HTT). Approximately 10% of patients inherit a chromosome that underwent CAG expansion from an unaffected parent with <36 CAG repeats. This study is a comprehensive analysis of genetic diversity in HTT and reveals that HD patients of European origin (n = 65) have a significant enrichment (95%) of a specific set of 22 tagging single nucleotide polymorphisms (SNPs) that constitute a single haplogroup. The disease association of many SNPs is much stronger than any previously reported polymorphism and was confirmed in a replication cohort (n = 203). Importantly, the same haplogroup is also significantly enriched (83%) in individuals with 27-35 CAG repeats (intermediate alleles, n = 66), who are unaffected by the disease, but have increased CAG tract sizes relative to the general population (n = 116). These data support a stepwise model for CAG expansion into the affected range (>or=36 CAG) and identifies specific haplogroup variants in the general population associated with this instability. The specific variants at risk for CAG expansion are not present in the general population in China, Japan, and Nigeria where the prevalence of HD is much lower. The current data argue that cis-elements have a major predisposing influence on CAG instability in HTT. The strong association between specific SNP alleles and CAG expansion also provides an opportunity of personalized therapeutics in HD where the clinical development of only a small number of allele-specific targets may be sufficient to treat up to 88% of the HD patient population.
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Paradisi I, Hernández A, Arias S. Huntington disease mutation in Venezuela: age of onset, haplotype analyses and geographic aggregation. J Hum Genet 2007; 53:127-135. [PMID: 18157708 DOI: 10.1007/s10038-007-0227-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2007] [Accepted: 11/09/2007] [Indexed: 11/29/2022]
Abstract
The aggregation of patients with Huntington's disease (HD) around Lake Maracaibo, Zulia State, Venezuela, is widely recognized, but the epidemiology of HD in the whole country is relatively unstudied. We have examined 279 individuals from 60 unrelated affected families residing in various areas of Venezuela for the presence of CAG repeats and other features associated with HD. The number of expanded repeats in 139 carriers varied from 35 to 112. Based on our examination of 71 symptomatic individuals, we developed a log-transformed regression equation, y= -0.0238x + 2.6616, to enable the prediction of age of onset in asymptomatic carriers. Intragenic haplotypes were constructed with two VNTRs (variable number of tandem repeats) and two SNPs (single nucleotide polymorphisms) in the promoter region as well as CCG repeat and Delta2642 polymorphisms to assess kinship between families. In 43 of 45 tested families, the haplotype on the mutated chromosome was 1;G;C;7;(A). The other haplotypes observed, 1;G;C;7;(B) and 4;G;C;7;(A), were of Peruvian and French origins, respectively. The geographic source of the first affected ancestor was assessed in 54 families from 15 different states. Residents of the states of Miranda, Lara and Táchira, excluding those of Zulia, had a mutated allele prevalence five- to ninefold higher than that of other areas. A low (approx. 1/200,000) prevalence, a wide-spread distribution with aggregation in some states and a likely remote European Caucasoid origin are defining epidemiologic features of HD in Venezuela.
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Affiliation(s)
- Irene Paradisi
- Laboratorio de Genética Humana, Centro de Medicina Experimental, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado 21827, Caracas, 1020A, Venezuela
| | - Alba Hernández
- Laboratorio de Genética Humana, Centro de Medicina Experimental, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado 21827, Caracas, 1020A, Venezuela
| | - Sergio Arias
- Laboratorio de Genética Humana, Centro de Medicina Experimental, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado 21827, Caracas, 1020A, Venezuela.
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Scholefield J, Greenberg J. A common SNP haplotype provides molecular proof of a founder effect of Huntington disease linking two South African populations. Eur J Hum Genet 2007; 15:590-5. [PMID: 17327878 DOI: 10.1038/sj.ejhg.5201796] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
This study involved the detailed investigation of the region surrounding the huntingtin gene in families with a history of Huntington Disease (HD) in South Africa. The primary aim was to investigate the origins of the HD mutation in South Africa by constructing a single-nucleotide polymorphism (SNP) haplotype around the HD gene and to determine how many haplotypes there are in two different South African populations. Haplotypes were created by genotyping six SNPs in a total of 13 HD families--seven Caucasian and six Mixed Ancestry. Of the six Mixed Ancestry families, four shared a common SNP haplotype, which was observed in two Afrikaans-speaking Caucasian HD families thus indicating that a founder effect was present in the South African population. The genotyping of a recently identified highly polymorphic marker close to the HD disease-causing mutation further corroborated the SNP haplotype results. Computational analysis was used to analyze the extent of the common haplotype identified in the study cohort in additional South African HD individuals. The results strongly suggest that the common haplotype extends further into the South African Mixed Ancestry HD population and is predominant in the Mixed Ancestry HD families.
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Affiliation(s)
- Janine Scholefield
- Division of Human Genetics, Faculty of Health Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
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