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Zeng S, Zhou X, He R, Zhao Y, Liu Z, Xu Q, Guo J, Yan X, Li J, Tang B, Sun Q. Association Analysis of Essential Tremor-Associated Genetic Variants in Sporadic Late-Onset Parkinson's Disease. Tremor Other Hyperkinet Mov (N Y) 2024; 14:25. [PMID: 38737298 PMCID: PMC11086585 DOI: 10.5334/tohm.885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 04/25/2024] [Indexed: 05/14/2024] Open
Abstract
Background Parkinson's disease (PD) and Essential tremor (ET) are the two most common tremor diseases with recognized genetic pathogenesis. The overlapping clinical features suggest they may share genetic predispositions. Our previous study systematically investigated the association between rare coding variants in ET-associated genes and early-onset PD (EOPD), and found the suggestive association between teneurin transmembrane protein 4 (TENM4) and EOPD. In the current research, we explored the potential genetic interplay between ET-associated genetic loci/genes and sporadic late-onset PD (LOPD). Methods We performed whole-genome sequencing in the 1962 sporadic LOPD cases and 1279 controls from mainland China. We first used logistic regression analysis to test the top 16 SNPs identified by the ET genome-wide association study for the association between ET and LOPD. Then we applied the optimized sequence kernel association testing to explore the rare variant burden of 33 ET-associated genes in this cohort. Results We did not observe a significant association between the included SNPs with LOPD. We also did not discover a significant burden of rare deleterious variants of ET-associated genes in association with LOPD risk. Conclusion Our results do not support the role of ET-associated genetic loci and variants in LOPD. Highlights 1962 cases and 1279 controls were recruited to study the potential genetic interplay between ET-associated genetic loci/variants and sporadic LOPD.No significant association between the ET-associated SNPs and LOPD were observed.No significant burden of rare deleterious variants of ET-associated gene in LOPD risk were found.
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Affiliation(s)
- Sheng Zeng
- Department of Geriatrics, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan, 410008, China
| | - Xun Zhou
- Department of Geriatric Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Runcheng He
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
| | - Yuwen Zhao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
| | - Zhenhua Liu
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan, 410008, China
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
| | - Qian Xu
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan, 410008, China
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
| | - Jifeng Guo
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan, 410008, China
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
| | - Xinxiang Yan
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan, 410008, China
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
| | - Jinchen Li
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan, 410008, China
- Department of Geriatric Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
| | - Beisha Tang
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan, 410008, China
- Department of Geriatric Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, 410008, China
| | - Qiying Sun
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan, 410008, China
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, 410008, China
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Kim JJ, Vitale D, Otani DV, Lian MM, Heilbron K, Iwaki H, Lake J, Solsberg CW, Leonard H, Makarious MB, Tan EK, Singleton AB, Bandres-Ciga S, Noyce AJ, Blauwendraat C, Nalls MA, Foo JN, Mata I. Multi-ancestry genome-wide association meta-analysis of Parkinson's disease. Nat Genet 2024; 56:27-36. [PMID: 38155330 PMCID: PMC10786718 DOI: 10.1038/s41588-023-01584-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 10/20/2023] [Indexed: 12/30/2023]
Abstract
Although over 90 independent risk variants have been identified for Parkinson's disease using genome-wide association studies, most studies have been performed in just one population at a time. Here we performed a large-scale multi-ancestry meta-analysis of Parkinson's disease with 49,049 cases, 18,785 proxy cases and 2,458,063 controls including individuals of European, East Asian, Latin American and African ancestry. In a meta-analysis, we identified 78 independent genome-wide significant loci, including 12 potentially novel loci (MTF2, PIK3CA, ADD1, SYBU, IRS2, USP8, PIGL, FASN, MYLK2, USP25, EP300 and PPP6R2) and fine-mapped 6 putative causal variants at 6 known PD loci. By combining our results with publicly available eQTL data, we identified 25 putative risk genes in these novel loci whose expression is associated with PD risk. This work lays the groundwork for future efforts aimed at identifying PD loci in non-European populations.
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Affiliation(s)
- Jonggeol Jeffrey Kim
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA.
- Preventive Neurology Unit, Centre for Prevention Diagnosis and Detection, Wolfson Institute of Population Health, Queen Mary University of London, London, UK.
| | - Dan Vitale
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
- Data Tecnica International, Washington, DC, USA
- Center for Alzheimer's and Related Dementias (CARD), National Institute on Aging and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Diego Véliz Otani
- Neurogenetics Research Center, Instituto Nacional de Ciencias Neurológicas, Lima, Peru
- Institute for Genome Sciences, University of Maryland, Baltimore, MD, USA
| | - Michelle Mulan Lian
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore, Singapore
- Genome Institute of Singapore, Agency for Science, Technology and Research, A*STAR, Singapore, Singapore
| | | | - Hirotaka Iwaki
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
- Data Tecnica International, Washington, DC, USA
- Center for Alzheimer's and Related Dementias (CARD), National Institute on Aging and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Julie Lake
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
| | - Caroline Warly Solsberg
- Pharmaceutical Sciences and Pharmacogenomics, UCSF, San Francisco, CA, USA
- Department of Neurology and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
- Memory and Aging Center, UCSF, San Francisco, CA, USA
| | - Hampton Leonard
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
- Data Tecnica International, Washington, DC, USA
- Center for Alzheimer's and Related Dementias (CARD), National Institute on Aging and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Mary B Makarious
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
- UCL Movement Disorders Centre, University College London, London, UK
| | - Eng-King Tan
- Department of Neurology, National Neuroscience Institute, Duke NUS Medical School, Singapore, Singapore
| | - Andrew B Singleton
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
- Center for Alzheimer's and Related Dementias (CARD), National Institute on Aging and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Sara Bandres-Ciga
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
- Center for Alzheimer's and Related Dementias (CARD), National Institute on Aging and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Alastair J Noyce
- Preventive Neurology Unit, Centre for Prevention Diagnosis and Detection, Wolfson Institute of Population Health, Queen Mary University of London, London, UK
| | - Cornelis Blauwendraat
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA.
- Center for Alzheimer's and Related Dementias (CARD), National Institute on Aging and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
| | - Mike A Nalls
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA.
- Data Tecnica International, Washington, DC, USA.
- Center for Alzheimer's and Related Dementias (CARD), National Institute on Aging and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
| | - Jia Nee Foo
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore, Singapore.
- Genome Institute of Singapore, Agency for Science, Technology and Research, A*STAR, Singapore, Singapore.
| | - Ignacio Mata
- Genomic Medicine, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA.
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Jiménez-Jiménez FJ, Alonso-Navarro H, García-Martín E, Álvarez I, Pastor P, Agúndez JAG. Genomic Markers for Essential Tremor. Pharmaceuticals (Basel) 2021; 14:ph14060516. [PMID: 34072005 PMCID: PMC8226734 DOI: 10.3390/ph14060516] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 05/23/2021] [Accepted: 05/24/2021] [Indexed: 12/13/2022] Open
Abstract
There are many reports suggesting an important role of genetic factors in the etiopathogenesis of essential tremor (ET), encouraging continuing the research for possible genetic markers. Linkage studies in families with ET have identified 4 genes/loci for familial ET, although the responsible gene(s) have not been identified. Genome-wide association studies (GWAS) described several variants in LINGO1, SLC1A2, STK32B, PPARGC1A, and CTNNA3, related with ET, but none of them have been confirmed in replication studies. In addition, the case-control association studies performed for candidate variants have not convincingly linked any gene with the risk for ET. Exome studies described the association of several genes with familial ET (FUS, HTRA2, TENM4, SORT1, SCN11A, NOTCH2NLC, NOS3, KCNS2, HAPLN4, USP46, CACNA1G, SLIT3, CCDC183, MMP10, and GPR151), but they were found only in singular families and, again, not found in other families or other populations, suggesting that some can be private polymorphisms. The search for responsible genes for ET is still ongoing.
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Affiliation(s)
- Félix Javier Jiménez-Jiménez
- Section of Neurology, Hospital Universitario del Sureste, E28500 Arganda del Rey, Spain;
- Correspondence: ; Tel.: +34-636-96-83-95; Fax: +34-913-28-07-04
| | | | - Elena García-Martín
- ARADyAL Instituto de Salud Carlos III, University Institute of Molecular Pathology Biomarkers, University of Extremadura, E10071 Caceres, Spain; (E.G.-M.); (J.A.G.A.)
| | - Ignacio Álvarez
- Movement Disorders Unit, Department of Neurology, University Hospital Mútua de Terrassa, Fundació Docencia i Recerça Mútua de Terrassa, E08221 Terrassa, Spain; (I.Á.); (P.P.)
| | - Pau Pastor
- Movement Disorders Unit, Department of Neurology, University Hospital Mútua de Terrassa, Fundació Docencia i Recerça Mútua de Terrassa, E08221 Terrassa, Spain; (I.Á.); (P.P.)
| | - José A. G. Agúndez
- ARADyAL Instituto de Salud Carlos III, University Institute of Molecular Pathology Biomarkers, University of Extremadura, E10071 Caceres, Spain; (E.G.-M.); (J.A.G.A.)
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Siokas V, Aloizou AM, Tsouris Z, Liampas I, Aslanidou P, Dastamani M, Brotis AG, Bogdanos DP, Hadjigeorgiou GM, Dardiotis E. Genetic Risk Factors for Essential Tremor: A Review. Tremor Other Hyperkinet Mov (N Y) 2020; 10:4. [PMID: 32775018 DOI: 10.5334/tohm.67] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Highlights In the current review, we thoroughly reviewed 74 identified articles regarding genes and genetic loci that confer susceptibility to ET. Over 50 genes/genetic loci have been examined for possible association with ET, but consistent results failed to be reported raising the need for collaborative multiethnic studies. Background: Essential tremor (ET) is a common movement disorder, which is mainly characterized by bilateral tremor (postural and/or kinetic) in the upper limbs, with other parts of the body possibly involved. While the pathophysiology of ET is still unclear, there is accumulating evidence indicating that genetic variability may be heavily involved in ET pathogenesis. This review focuses on the role of genetic risk factors in ET susceptibility. Methods: The PubMed database was searched for articles written in English, for studies with humans with ET, controls without ET, and genetic variants. The terms “essential tremor” and “polymorphism” (as free words) were used during search. We also performed meta-analyses for the most examined genetic variants. Results: Seventy four articles concerning LINGO1, LINGO2, LINGO4, SLC1A2, STK32B, PPARGC1A, CTNNA3, DRD3, ALAD, VDR, HMOX1, HMOX2, LRRK1,LRRK2, GBA, SNCA, MAPT, FUS, CYPsIL17A, IL1B, NOS1, ADH1B, TREM2, RIT2, HNMT, MTHFR, PPP2R2B, GSTP1, PON1, GABA receptors and GABA transporter, HS1BP3, ADH2, hSKCa3 and CACNL1A4 genes, and ETM genetic loci were included in the current review. Results from meta-analyses revealed a marginal association for the STK32B rs10937625 and a marginal trend for association (in sensitivity analysis) for the LINGO1 rs9652490, with ET. Discussion: Quite a few variants have been examined for their possible association with ET. LINGO1 rs9652490 and STK32B rs10937625 appear to influence, to some extent, ET susceptibility. However, the conflicting results and the lack of replication for many candidate genes raise the need for collaborative multiethnic studies.
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Abstract
Essential tremor (ET) is a neurological movement disorder characterised by bilateral limb kinetic/postural tremor, with or without tremor in other body parts including head, voice and lower limbs. Since no causative genes for ET have been identified, it is likely that the disorder occurs as a result of complex genetic factors interacting with various cellular and environmental factors that can result in abnormal function of circuitry involving the cerebello-thalamo-cortical pathway. Genetic analyses have uncovered at least 14 loci and 11 genes that are related to ET, as well as various risk or protective genetic factors. Limitations in ET genetic analyses include inconsistent disease definition, small sample size, varied ethnic backgrounds and many other factors that may contribute to paucity of relevant genetic data in ET. Genetic analyses, coupled with functional and animal studies, have led to better insights into possible pathogenic mechanisms underlying ET. These genetic studies may guide the future development of genetic testing and counselling, and specific, pathogenesis-targeted, therapeutic strategies.
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Tarakad A, Jankovic J. Essential Tremor and Parkinson's Disease: Exploring the Relationship. Tremor Other Hyperkinet Mov (N Y) 2019; 8:589. [PMID: 30643667 PMCID: PMC6329774 DOI: 10.7916/d8md0gvr] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 10/04/2018] [Indexed: 12/31/2022] Open
Abstract
Background There is longstanding controversy surrounding the possible link between essential tremor (ET) and Parkinson's disease (PD). Inconsistent and unreliable diagnostic criteria may in part account for some of the difficulties in defining the relationship between these two common movement disorders. Methods References for this systematic review were identified using PubMed with the search terms "essential tremor" AND "Parkinson's disease" with articles published in English between 1960 and September 2018 included. Results In this review we provide evidence that some patients diagnosed with ET have an increased risk of developing PD years or decades after onset of action tremor. There are several still unresolved questions about the link between the two disorders including lack of verifiable diagnostic criteria for the two disorders and marked overlap in phenomenology. Here we review clinical, epidemiologic, imaging, pathologic, and genetic studies that address the ET-PD relationship. Several lines of evidence support the association between ET and PD, including overlapping motor and non-motor features, relatively high prevalence of rapid eye movement sleep behavior disorder (26-43%) in ET patients, increased prevalence of PD in patients with longstanding antecedent ET, increased prevalence of ET in family members of patients with PD, and the presence of Lewy bodies in the brains of some ET patients (15-24%). Discussion There is a substantial body of evidence supporting the association between ET and PD within at least a subset of patients, although the nature and possible pathogenic mechanisms of the relationship are not well understood.
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Affiliation(s)
- Arjun Tarakad
- Parkinson’s Disease Center and Movement Disorders Clinic, Baylor College of Medicine Houston, TX, USA
| | - Joseph Jankovic
- Parkinson’s Disease Center and Movement Disorders Clinic, Baylor College of Medicine Houston, TX, USA
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Abstract
Essential tremor (ET) is one of the most common neurologic disorders, and genetic factors are thought to contribute significantly to disease etiology. There has been a relative lack of progress in understanding the genetic etiology of ET. This could reflect a number of factors, including the presence of substantial phenotypic and genotypic heterogeneity. Thus, a meticulous approach to phenotyping is important for genetic research. A lack of standardized phenotyping across studies and patient centers likely has contributed to the relative lack of success of genomewide association studies in ET. To dissect the genetic architecture of ET, whole-genome sequencing will likely be of value. This will allow specific hypotheses about the mode of inheritance and genetic architecture to be tested. A number of approaches still remain unexplored in ET genetics, including the contribution of copy number variants, uncommon moderate-effect alleles, rare variant large-effect alleles (including Mendelian and complex/polygenic modes of inheritance), de novo and gonadal mosaicism, epigenetic changes, and noncoding variation.
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Affiliation(s)
- Lorraine N Clark
- Department of Pathology and Cell Biology, College of Physicians and Surgeons, and Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, United States
| | - Elan D Louis
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York; and Departments of Neurology and of Chronic Disease Epidemiology and Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, New Haven, CT, United States.
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Hicks JE, Konidari I, Scott BL, Stajich JM, Ashley-Koch AE, Gilbert JR, Scott WK. Linkage of familial essential tremor to chromosome 5q35. Mov Disord 2016; 31:1059-62. [PMID: 26918299 DOI: 10.1002/mds.26582] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 11/17/2015] [Accepted: 11/22/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Essential tremor is a neurological condition characterized by tremor during voluntary movement. To date, 3 loci linked to familial essential tremor have been identified. METHODS We examined 48 essential tremor patients in 5 large essential tremor pedigrees in our data set for genetic linkage using an Affymetrix Axiom array. Linkage analysis was performed using an affecteds-only dominant model in SIMWALK2. To incorporate all genotype information, GERMLINE was used to identify genome segments shared identical-by-descent in pairs of affecteds. Exome sequencing was performed in pedigrees showing evidence of linkage. RESULTS For one family, chromosomes 5 and 18 showed genome-wide significant linkage to essential tremor. Shared segment analysis excluded the 18p11 candidate region and reduced the 5q35 region by 1 megabase. Exome sequencing did not identify a potential causative variant in this region. CONCLUSION A locus on chromosome 5 is linked to essential tremor. Further research is needed to identify a causative variant. © 2016 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- James E Hicks
- John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, Florida, USA.,Dr. John T. Macdonald Foundation Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Ioanna Konidari
- John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, Florida, USA.,Dr. John T. Macdonald Foundation Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Burton L Scott
- Department of Neurology, Duke University Medical Center, Durham, North Carolina, USA
| | - Jeffrey M Stajich
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | | | - John R Gilbert
- John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, Florida, USA.,Dr. John T. Macdonald Foundation Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - William K Scott
- John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, Florida, USA.,Dr. John T. Macdonald Foundation Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, Florida, USA
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Schmouth JF, Dion PA, Rouleau GA. Genetics of essential tremor: From phenotype to genes, insights from both human and mouse studies. Prog Neurobiol 2014; 119-120:1-19. [DOI: 10.1016/j.pneurobio.2014.05.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 04/16/2014] [Accepted: 05/02/2014] [Indexed: 11/30/2022]
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Abstract
Essential tremor (ET) is a common movement disorder but its pathogenesis remains poorly understood. This has limited the development of effective pharmacotherapy. The current therapeutic armamentaria for ET represent the product of careful clinical observation rather than targeted molecular modeling. Here we review their pharmacokinetics, metabolism, dosing, and adverse effect profiles and propose a treatment algorithm. We also discuss the concept of medically refractory tremor, as therapeutic trials should be limited unless invasive therapy is contraindicated or not desired by patients.
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Affiliation(s)
- Peter Hedera
- Department of Neurology, Vanderbilt University, Nashville, TN
| | - František Cibulčík
- Department of Neurology, Slovak Medical University and University Hospital Bratislava, Slovakia
| | - Thomas L Davis
- Department of Neurology, Vanderbilt University, Nashville, TN
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Jiménez-Jiménez FJ, Alonso-Navarro H, García-Martín E, Lorenzo-Betancor O, Pastor P, Agúndez JAG. Update on genetics of essential tremor. Acta Neurol Scand 2013; 128:359-71. [PMID: 23682623 DOI: 10.1111/ane.12148] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2013] [Indexed: 12/25/2022]
Abstract
Despite the research, few advances in the etiopathogenesis on essential tremor (ET) have been made to date. The high frequency of positive family history of ET and the observed high concordance rates in monozygotic compared with dizygotic twins support a major role of genetic factors in the development of ET. In addition, a possible role of environmental factors has been suggested in the etiology of ET (at least in non-familial forms). Although several gene variants in the LINGO1 gene may increase the risk of ET, to date no causative mutated genes have been identified. In this review, we summarize the studies performed on families with tremor, twin studies, linkage studies, case-control association studies, and exome sequencing in familial ET.
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Affiliation(s)
- F. J. Jiménez-Jiménez
- Section of Neurology; Hospital Universitario del Sureste; Arganda del Rey Madrid Spain
| | - H. Alonso-Navarro
- Section of Neurology; Hospital Universitario del Sureste; Arganda del Rey Madrid Spain
| | - E. García-Martín
- Department of Biochemistry and Molecular Biology; University of Extremadura; Cáceres Spain
- AMGenomics; Edificio Tajo, Avda. de la Universidad s/n; Cáceres Spain
| | - O. Lorenzo-Betancor
- Neurogenetics Laboratory; Division of Neurosciences; Center for Applied Medical Research (CIMA); University of Navarra; Pamplona Spain
- Department of Neurology; Clínica Universidad de Navarra; University of Navarra School of Medicine; Pamplona Spain
| | - P. Pastor
- Neurogenetics Laboratory; Division of Neurosciences; Center for Applied Medical Research (CIMA); University of Navarra; Pamplona Spain
- Department of Neurology; Clínica Universidad de Navarra; University of Navarra School of Medicine; Pamplona Spain
- CIBERNED; Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas; Instituto de Salud Carlos III; Madrid Spain
| | - J. A. G. Agúndez
- AMGenomics; Edificio Tajo, Avda. de la Universidad s/n; Cáceres Spain
- Department of Pharmacology; University of Extremadura; Cáceres Spain
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Hedera P, Davis TL, Phibbs FT, Charles PD, LeDoux MS. FUS in familial essential tremor – The search for common causes is still on. Parkinsonism Relat Disord 2013; 19:818-20. [DOI: 10.1016/j.parkreldis.2013.04.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 04/04/2013] [Accepted: 04/08/2013] [Indexed: 11/17/2022]
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Liang H, Song Z, Deng X, Xu H, Zhu A, Zheng W, Zhao Y, Deng H. Genetic analysis of the leucine-rich repeat and lg domain containing Nogo receptor-interacting protein 1 gene in essential tremor. J Mol Neurosci 2013; 51:403-7. [PMID: 23754655 DOI: 10.1007/s12031-013-0029-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2013] [Accepted: 05/03/2013] [Indexed: 12/19/2022]
Abstract
Variants in the leucine-rich repeat and lg domain containing nogo receptor-interacting protein 1 gene (LINGO1) have been identified to be associated with the increased risk of essential tremor (ET), especially among Caucasians. To explore whether the LINGO1 gene plays a role in ET susceptibility, we performed a systematic genetic analysis of the coding region in the LINGO1 gene. Four nucleotide variants have been genotyped, including three known variants (rs2271398, rs2271397, and rs3743481), and a novel G → C transition (ss491228439). Extended analysis showed no significant difference in genotypic and allelic distributions between 151 patients and 301 control subjects for these four variants (all P > 0.05). However, further sex-stratified analysis revealed that the C allele of rs2271397 and ss491228439 contributed the risk of ET in female (P = 0.017, OR = 2.139, 95 % CI 1.135 ~ 4.030 for rs2271397 and P = 0.038, OR = 1.812, 95 % CI 1.027 ~ 3.194 for ss491228439). Haplotype analysis indicated that A465-C474-C714 haplotype was significantly associated with increased risk of ET in female (P = 0.041, OR = 1.800, 95 % CI 1.020 ~ 3.178). Our results indicate that the LINGO1 variants are associated with ET in Chinese Han female patients.
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Affiliation(s)
- Hui Liang
- Center for Experimental Medicine, Third Xiangya Hospital, Central South University, 138 Tongzipo Road, Changsha, Hunan, 410013, People's Republic of China
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Testa CM. Key issues in essential tremor genetics research: Where are we now and how can we move forward? Tremor Other Hyperkinet Mov (N Y) 2013; 3. [PMID: 23450143 PMCID: PMC3582856 DOI: 10.7916/d8q23z0z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 12/04/2012] [Indexed: 01/06/2023]
Abstract
Background Genetics research is an avenue towards understanding essential tremor (ET). Advances have been made in genetic linkage and association: there are three reported ET susceptibility loci, and mixed but growing data on risk associations. However, causal mutations have not been forthcoming. This disappointing lack of progress has opened productive discussions on challenges in ET and specifically ET genetics research, including fundamental assumptions in the field. Methods This article reviews the ET genetics literature, results to date, the open questions in ET genetics and the current challenges in addressing them. Results Several inherent ET features complicate genetic linkage and association studies: high potential phenocopy rates, inaccurate tremor self-reporting, and ET misdiagnoses are examples. Increasing use of direct examination data for subjects, family members, and controls is one current response. Smaller moves towards expanding ET phenotype research concepts into non-tremor features, clinically disputed ET subsets, and testing phenotype features instead of clinical diagnosis against genetic data are gradually occurring. The field has already moved to considering complex trait mechanisms requiring detection of combinations of rare genetic variants. Hypotheses may move further to consider novel mechanisms of inheritance, such as epigenetics. Discussion It is an exciting time in ET genetics as investigators start moving past assumptions underlying both phenotype and genetics experimental contributions, overcoming challenges to collaboration, and engaging the ET community. Multicenter collaborative efforts comprising rich longitudinal prospective phenotype data and neuropathologic analysis combined with the latest in genetics experimental design and technology will be the next wave in the field.
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Affiliation(s)
- Claudia M Testa
- Virginia Commonwealth University, Parkinson's and Movement Disorders Center, Richmond Virginia, USA
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Abstract
Essential tremor (ET) is a prevalent condition manifesting with progressive action tremor. Although ET was traditionally viewed as a sporadic disease, a significant proportion of cases report a positive family history of tremor. Autosomal dominant inheritance can be demonstrated in many families. Previously, genome-wide linkage studies in families mapped three loci for ET, hereditary essential tremor-1 (ETM1), ETM2 and ETM3. However, no causal mutation has been replicated in candidate genes within these loci, including dopamine D3 receptor (DRD3) and HS1-binding protein 3 (HS1BP3). Recently, the first genome-wide association study in ET followed by replication studies conducted in diverse populations identified a significant association between the leucine-rich repeat and Ig domain containing 1 gene (LINGO1) SNP rs9652490 and risk for ET Although further novel variants were indentified in LINGO1 and its paralog LINGO2 that may be associated with risk for ET, the pathogenic mechanisms involved remain elusive. Given the possibility that ET as a complex trait may be influenced by the combined effects of rare variants, novel high-throughput technologies sequencing all exons across the genome (exome sequencing) or the whole genome (genome sequencing) may become crucial in understanding/deciphering the genetic background of ET.
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Abstract
The leucine-rich repeat and Ig domain containing 1 gene (LINGO1), recently considered to be conferred increased risk of essential tremor (ET), has been also implicated in Parkinson disease (PD). As the two common movement disorders have overlapping clinical and pathological features, it has been postulated that the LINGO1 gene may play a role in the pathogenesis of the two diseases. Here, we review published reports of the LINGO1 variants in ET and PD in an attempt to better understand the molecular and pathogenic relationship of LINGO1 to the two disorders.
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Affiliation(s)
- H Deng
- Center for Experimental Medicine, Department of Neurology, the Third Xiangya Hospital, Central South University, Changsha, HN, China.
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Guo Y, Lin H, Gao K, Xu H, Deng X, Zhang Q, Luo Z, Sun S, Deng H. Genetic analysis of IREB2, FAM13A and XRCC5 variants in Chinese Han patients with chronic obstructive pulmonary disease. Biochem Biophys Res Commun 2011; 415:284-7. [DOI: 10.1016/j.bbrc.2011.10.042] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2011] [Accepted: 10/11/2011] [Indexed: 10/16/2022]
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Abstract
PURPOSE OF REVIEW This review summarizes some key findings of the past few years on the genetics of the two common movement disorders Parkinson's disease and essential tremor. RECENT FINDINGS Within the last two years, genome-wide association (GWA) analyses have revealed a number of novel low-risk susceptibility variants for Parkinson's disease, among them HLA-DRB5, BST1, ACMSD, STK39, MCCC1/LAMP3, SYT11, and CCDC62/HIP1R) and have confirmed LINGO1 as risk factor for essential tremor. The identification of copy number variations in the Parkin gene in healthy control individuals suggests no major role of these variations in late onset Parkinson's disease. Drosophila studies on Parkin and Pink1 have uncovered a role in the mitochondrial quality control pathway in the pathogenesis of the disease. LRRK2 has been found to interact with the microRNAs processing protein Argonaut, thereby affecting protein translation. Notably, despite the high familial risk for essential tremor no high-risk gene has been found to date. The possibility of a nonmendelian transmission in some cases is discussed. SUMMARY GWA studies and positional cloning approaches have led to the identification of a number of risk genes for Parkinson's disease, which give novel insights into pathogenic pathways of the disease. In contrast, our knowledge of the genetics of essential tremor is scarce. Except for LINGO1, no other risk gene has so far been identified. New technologies such as next generation high throughput sequencing might help to identify more risk genes.
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Guo Y, Deng X, Zheng W, Xu H, Song Z, Liang H, Lei J, Jiang X, Luo Z, Deng H. HLA rs3129882 variant in Chinese Han patients with late-onset sporadic Parkinson disease. Neurosci Lett 2011; 501:185-7. [PMID: 21791235 DOI: 10.1016/j.neulet.2011.05.245] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2011] [Revised: 05/18/2011] [Accepted: 05/22/2011] [Indexed: 11/16/2022]
Abstract
Recently, the rs3129882 variant in intron 1 of HLA-DRA was found to be associated with late-onset sporadic Parkinson disease (PD) in Americans of European ancestry. To evaluate whether the same variant is related to PD in Chinese population, we investigated late-onset sporadic PD patients of Chinese Han ethanicity in Mainland China. We found significant difference in genotypic and allele distribution between patients and control subjects (χ²)=6.446, p=0.040 for genotypic distribution; χ²=5.762, p=0.016 for allele distribution), suggesting this variant is associated with late-onset sporadic PD in Chinese Han population.
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Affiliation(s)
- Yi Guo
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, China
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Thier S, Lorenz D, Nothnagel M, Stevanin G, Dürr A, Nebel A, Schreiber S, Kuhlenbäumer G, Deuschl G, Klebe S. LINGO1 polymorphisms are associated with essential tremor in Europeans. Mov Disord 2010; 25:717-23. [DOI: 10.1002/mds.22887] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Keeling BH, Vilariño-Güell C, Ross OA, Wszolek ZK, Uitti RJ, Farrer MJ. DRD3 Ser9Gly and HS1BP3 Ala265Gly are not associated with Parkinson disease. Neurosci Lett 2009; 461:74-5. [PMID: 19524641 DOI: 10.1016/j.neulet.2009.05.084] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Revised: 05/12/2009] [Accepted: 05/31/2009] [Indexed: 10/20/2022]
Abstract
Variants in the dopamine receptor D3 (DRD3) and HCLS1 binding protein 3 (HS1BP3) have been nominated as risk factors for essential tremor (ET). Although ET and Parkinson disease (PD) are considered different entities, they have many overlapping clinical and pathological features. We aim to evaluate the role of the Ser9Gly variant in DRD3 and Ala265Gly in HS1BP3 in PD development. To this end, we genotyped these two variants in a PD matched case-control series from the United States. Statistical analysis failed to identify significant differences in the frequency of these variants between the case and control groups; therefore our results do not support a role for these DRD3 and HS1BP3 variants in PD.
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Affiliation(s)
- Brett H Keeling
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
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Abstract
In this report, we identified a large five-generation distinctive kindred with essential tremor (ET) presenting during the teen years and the consequent appearance of idiopathic normal pressure hydrocephalus (iNPH) when elderly (>65 years), in an autosomal dominant fashion. Through clinical and genetic analysis, we defined this kindred as a new essential tremor-idiopathic normal pressure hydrocephalus (ETINPH) disorder. One of the most common neurological disorders, ET comprises uncontrollable tremor, most commonly the upper limbs. Molecular genetic studies in hereditary ET have been initiated, but only with negative results so far. iNPH is an adult-onset hydrocephalus characterized by ventricular enlargement in the absence of significant elevations of intracranial pressure. iNPH patients usually have a triad of clinical symptoms: gait impairment, incontinence, and dementia, which is among the most common medical problems in the older population. The genetic etiology of iNPH is totally unknown. We hypothesize that ET is the consequence of the abnormal function of a specific neuronal gene, and that the same gene causes tremor at an early age eventually leading to the development of iNPH later in life. An understanding of the genetic components of this disorder may offer us significant insights into the molecular pathogenesis of ET, iNPH, and other related neurological conditions. In our genetic analysis of this family, array-based comparative genomic hybridization (aCGH) was carried out, and we could not identify any possible copy number changes of the genomic fragment along the whole-genome in ETINPH patient. Candidate gene linkage analysis was also performed, and we excluded this disorder from several established loci associated with tremor. We conclude that the pedigree reported here is a new autosomal dominant genetic disorder ETINPH. The characterization of the gene that causes ETINPH will certainly enhance our understanding of motor diseases in general.
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Affiliation(s)
- Jun Zhang
- Department of Neurosurgery, University of Mississippi Medical Center, Jackson, Mississippi 39216-4505, USA.
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Blair MA, Ma S, Phibbs F, Fang JY, Cooper MK, Davis TL, Hedera P. Reappraisal of the role of the DRD3 gene in essential tremor. Parkinsonism Relat Disord 2008; 14:471-5. [PMID: 18316228 DOI: 10.1016/j.parkreldis.2007.11.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2007] [Revised: 11/21/2007] [Accepted: 11/25/2007] [Indexed: 10/22/2022]
Abstract
OBJECTIVES Analyze the distribution of polymorphism in the dopamine receptor D3 (DRD3) gene, which was previously reported as a susceptibility risk for essential tremor (ET), in a large cohort of ET. METHODS The role of 312G>A DRD3 polymorphism was analyzed using linkage analysis, association study and transmission disequilibrium test in a group of 433 ET patients, and two unrelated control groups with 121 and 151 individuals. RESULTS Allelic frequencies of glycine and serine forms of the DRD3 gene did not differ between patients and both control groups, and were in Hardy-Weinberg equilibrium. Linkage analysis identified obligatory recombinants in every large pedigree, even in those with relatively high frequency of glycine allele, thus excluding the linkage to this locus. Both alleles were transmitted with an equal likelihood to affected offspring. We also failed to replicate the relationship between glycine homozygosity and an earlier age of onset or more severe tremor course. CONCLUSIONS Our comprehensive genetic analysis in a large ET cohort strongly argues against the role of the DRD3 gene in ET pathogenesis.
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Dogu O, Louis ED, Tamer L, Unal O, Yilmaz A, Kaleagasi H. Elevated blood lead concentrations in essential tremor: a case-control study in Mersin, Turkey. Environ Health Perspect 2007; 115:1564-8. [PMID: 18007985 PMCID: PMC2072853 DOI: 10.1289/ehp.10352] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2007] [Accepted: 08/01/2007] [Indexed: 05/20/2023]
Abstract
BACKGROUND Essential tremor (ET) is one of the most common neurologic disorders. Aside from underlying susceptibility genes, recent studies have also begun to focus on environmental toxic factors. Yet there remains a paucity of information on such factors, making studies of environmental factors important. A recent study in New York City found blood lead concentrations to be elevated in ET cases compared with matched controls. Chronic exposure to lead produces cerebellar damage, and this could predispose individuals to develop ET. OBJECTIVE The aim of this study was to determine whether the elevation in blood lead concentrations observed in a single study in New York was similarly present in ET cases sampled from a completely different geographic region. METHODS Blood lead concentrations were measured in 105 ET cases and 105 controls at Mersin University, Mersin, Turkey. RESULTS The median blood lead concentration was 2.7 microg/dL in ET cases compared with 1.5 microg/dL in controls (p < 0.001). In an unadjusted logistic regression model, blood lead concentration was associated with diagnosis: odds ratio (OR) = 4.01; 95% confidence interval (CI), 2.53-6.37; p < 0.001 (i.e., each 1-microg/dL increase in blood lead concentration was associated with a 4-fold increased odds of ET). This association was more robust when cases were compared with a subsample of controls who did not share the same home environment (OR = 8.13; 95% CI, 3.05-21.65; p < 0.001). In adjusted models, results were similar. CONCLUSIONS These data replicate those of a previous study in New York and demonstrate an association between the environmental toxicant lead and a common neurologic disorder.
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Affiliation(s)
- Okan Dogu
- Department of Neurology, Faculty of Medicine, Mersin University, Mersin, Turkey
| | - Elan D. Louis
- G.H. Sergievsky Center
- Department of Neurology and
- Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, New York, USA
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York, USA
- Address correspondence to E.D. Louis, Unit 198, Neurological Institute, 710 West 168th St., New York, NY 10032 USA. Telephone: (212) 305-9194. Fax: (212) 305-1304. E-mail:
| | - Lulufer Tamer
- Department of Biochemistry, Faculty of Medicine, Mersin University, Mersin, Turkey
| | - Ozgur Unal
- Department of Neurology, Faculty of Medicine, Mersin University, Mersin, Turkey
| | - Arda Yilmaz
- Department of Neurology, Faculty of Medicine, Mersin University, Mersin, Turkey
| | - Hakan Kaleagasi
- Department of Neurology, Faculty of Medicine, Mersin University, Mersin, Turkey
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Shahed J, Jankovic J. Exploring the relationship between essential tremor and Parkinson's disease. Parkinsonism Relat Disord 2007; 13:67-76. [PMID: 16887374 DOI: 10.1016/j.parkreldis.2006.05.033] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2006] [Revised: 05/16/2006] [Accepted: 05/23/2006] [Indexed: 10/24/2022]
Abstract
Although essential tremor (ET) and Parkinson's disease (PD) are considered distinct disorders, there is overlap in some clinical features. In some PD patients, a long-standing postural tremor in the hands may precede the onset of parkinsonian features by several years or decades. Furthermore, large families with both ET and PD phenotypes have been described and autopsy studies have demonstrated Lewy body pathology in brains of ET patients. Functional neuroimaging suggests that some ET patients have dopaminergic deficit. We examine here the evidence for and against an association between ET and PD, and critically review data supporting the notion that a subset of ET patients is predisposed to developing PD.
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Affiliation(s)
- Joohi Shahed
- Parkinson's Disease Center and Movement Disorders Clinic, Baylor College of Medicine, Department of Neurology, 6550 Fannin, Suite 1801, Houston, TX, USA.
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Ma S, Davis TL, Blair MA, Fang JY, Bradford Y, Haines JL, Hedera P. Familial essential tremor with apparent autosomal dominant inheritance: should we also consider other inheritance modes? Mov Disord 2007; 21:1368-74. [PMID: 16721753 DOI: 10.1002/mds.20950] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
A positive family history is present in many patients with essential tremor (ET), but twin studies and segregation analysis have suggested that ET is not entirely a genetic disorder. Two genetic loci have been identified in autosomal dominant (AD) ET and polymorphisms in the DRD3 and HS1-BP3 genes have been proposed as the possible susceptibility factors for ET. There is also evidence for further genetic heterogeneity. We evaluated 4 unrelated large kindreds with ET with an apparent AD mode of transmission. Each kindred spanned at least 3 generations and contained at least 13 living affected subjects who met criteria for definitive ET. None of the pedigrees had evidence for inheritance of ET from both parents. Known genetic ET loci were excluded in these families. We detected a preferential transmission of ET in every kindred and the proportion of affected offspring varied from 75% to 90% (P < 0.05) in the generations with complete ascertainment. Our data indicate that non-Mendelian preferential transmission of an affected allele is a feature in many ET kindreds with multiple affected members and an apparent AD mode of inheritance. ET may have a complex etiology. Additional genetic models need to be considered, including an interaction of susceptibility genes and environmental risk factors.
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Affiliation(s)
- Shaochun Ma
- Department of Neurology, Vanderbilt University, Nashville, Tennessee, USA
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Benito-León J, Louis ED. Essential tremor: emerging views of a common disorder. ACTA ACUST UNITED AC 2006; 2:666-78; quiz 2p following 691. [PMID: 17117170 DOI: 10.1038/ncpneuro0347] [Citation(s) in RCA: 194] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2006] [Accepted: 09/15/2006] [Indexed: 11/08/2022]
Abstract
Essential tremor (ET) is the most prevalent tremor disorder. ET has traditionally been viewed as a monosymptomatic disorder characterized by a kinetic arm tremor, but this definition is gradually being replaced. The clinical spectrum has come to include several motor features, including tremor and ataxia, and several non-motor features, including possible cognitive impairment and personality disturbances. Postmortem studies are revealing several different patterns of pathology. The emerging view is that ET might be a family of diseases, unified by the presence of kinetic tremor, but further characterized by etiological, clinical and pathological heterogeneity. Effective pharmacological treatments for the disorder remain limited, although new insights into disease mechanisms might result in more-effective therapies. In addition, recent investigations of environmental toxicants that might be linked to ET open the way towards primary disease prevention through a reduction in exposure to these factors.
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Jeanneteau F, Funalot B, Jankovic J, Deng H, Lagarde JP, Lucotte G, Sokoloff P. A functional variant of the dopamine D3 receptor is associated with risk and age-at-onset of essential tremor. Proc Natl Acad Sci U S A 2006; 103:10753-8. [PMID: 16809426 PMCID: PMC1502303 DOI: 10.1073/pnas.0508189103] [Citation(s) in RCA: 154] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Familial essential tremor (ET), the most common inherited movement disorder, is generally transmitted as an autosomal dominant trait. A genome-wide scan for ET revealed one major locus on chromosome 3q13. Here, we report that the Ser9Gly variant in the dopamine D(3) receptor gene (DRD3), localized on 3q13.3, is associated and cosegregates with familial ET in 23 out of 30 French families. Sequencing revealed no other nonsynonymous variants in the DRD3-coding sequence and in the first 871 bp of the 5' flanking region. Moreover, Gly-9 homozygous patients presented with more severe and/or earlier onset forms of the disease than heterozygotes. A replication study comparing 276 patients with ET and 184 normal controls confirmed the association of the Gly-9 variant with risk and age-at-onset of ET. In human embryonic kidney (HEK) 293-transfected cells, the Gly-9 variant did not differ from the Ser-9 variant with respect to glycosylation and to anterograde and retrograde trafficking, but dopamine had an affinity that was four to five times higher. With the Gly-9 variant, the dopamine-mediated cAMP response was increased, and the mitogen-associated protein kinase (MAPK) signal was prolonged, as compared with the Ser-9 variant. The gain-of-function produced by the Gly-9 variant may explain why drugs active against tremor in Parkinson's disease (PD) are usually not effective in the treatment of ET and suggests that DRD3 partial agonists or antagonists should be considered as novel therapeutic options for patients with ET.
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Affiliation(s)
- Freddy Jeanneteau
- *Institut National de la Santé et de la Recherche Médicale, Unité de Neurobiologie et Pharmacologie Moléculaire, U573, Centre Paul Broca, 75014 Paris, France
| | - Benoît Funalot
- *Institut National de la Santé et de la Recherche Médicale, Unité de Neurobiologie et Pharmacologie Moléculaire, U573, Centre Paul Broca, 75014 Paris, France
- Service de Neurologie, Centre Hospitalier Ste-Anne, 75014 Paris, France
| | - Joseph Jankovic
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030
| | - Hao Deng
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030
| | - Jean-Pierre Lagarde
- Laboratoire de Génétique Moléculaire, Hôpital de la Pitié-Salpétrière, 75013 Paris, France; and
| | - Gérard Lucotte
- Centre de Neurogénétique Moléculaire, 75005 Paris, France
| | - Pierre Sokoloff
- *Institut National de la Santé et de la Recherche Médicale, Unité de Neurobiologie et Pharmacologie Moléculaire, U573, Centre Paul Broca, 75014 Paris, France
- To whom correspondence should be addressed. E-mail:
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Deng H, Xie WJ, Le WD, Huang MS, Jankovic J. Genetic analysis of the GABRA1 gene in patients with essential tremor. Neurosci Lett 2006; 401:16-9. [PMID: 16530959 DOI: 10.1016/j.neulet.2006.02.066] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Revised: 02/20/2006] [Accepted: 02/22/2006] [Indexed: 11/22/2022]
Abstract
The gamma-aminobutyric acid A (GABA-A) receptor mediates inhibitory neurotransmission in the brain and as such may be involved in certain neurological movement disorders, such as tremor. GABA-A receptor alpha 1 (Gabra)(-/-) mice have been reported to exhibit postural and kinetic, alcohol-responsive, tremor that is characteristic of essential tremor (ET), the most common form of tremor. To determine whether ET is associated with the GABRA1 gene mutation, we screened 76 patients with familial ET and found a novel nucleotide variant: IVS8+24 G>T (nt 6119289) in a male patient, and a known 156T>C polymorphism (nt 6090903) in exon 4 in 41% patients, which results in a silent mutation (G52G). No significant association between 156T>C variant and disease risk was found (adjusted OR=0.95, 95% CI=0.57-1.61; p=0.858) by further analysis of 121 familial ET patients and 114 normal controls, except a novel 96A>G (Q32Q; nt 6090743) variant, found in a normal control. Since the 156T>C variant appears to be not pathogenically relevant, our results suggest that missense, nonsense or splice site mutation in the coding region of the GABRA1 gene is not a major genetic cause of ET in Caucasian subjects.
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Affiliation(s)
- Hao Deng
- Department of Neurology, Baylor College of Medicine, 6501 Fannin Street, Houston, TX 77030, USA
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Abstract
Seventy researchers met in Washington, DC, on 20-21 October 2005 to identify and discuss the most pressing research issues in essential tremor (ET). The conference attendees concluded that the following six objectives are of immediate and overriding importance: (1) a collaborative network of research centers; (2) an international committee for developing a standard protocol for the diagnosis and quantification of ET; (3) the identification of one or more genes for ET; (4) a centralized repository of DNA and, ideally, immortalized cell lines from well-characterized ET families and healthy controls; (5) a reliable and efficient repository of optimally prepared and categorized brain samples for hypothesis-driven neuropathological examinations in well-characterized ET patients; and (6) animal models of ET for screening promising drugs. The conference attendees hope that this statement from the United States will engender international collaboration in finding a cure for ET.
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Affiliation(s)
- Rodger J Elble
- Department of Neurology, Southern Illinois University School of Medicine, Springfield, Illinois 62794, USA.
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