1
|
Skuladottir AT, Stefansdottir L, Halldorsson GH, Stefansson OA, Bjornsdottir A, Jonsson P, Palmadottir V, Thorgeirsson TE, Walters GB, Gisladottir RS, Bjornsdottir G, Jonsdottir GA, Sulem P, Gudbjartsson DF, Knowlton KU, Jones DA, Ottas A, Pedersen OB, Didriksen M, Brunak S, Banasik K, Hansen TF, Erikstrup C, Haavik J, Andreassen OA, Rye D, Igland J, Ostrowski SR, Milani LA, Nadauld LD, Stefansson H, Stefansson K. GWAS meta-analysis reveals key risk loci in essential tremor pathogenesis. Commun Biol 2024; 7:504. [PMID: 38671141 PMCID: PMC11053069 DOI: 10.1038/s42003-024-06207-4] [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: 12/04/2023] [Accepted: 04/17/2024] [Indexed: 04/28/2024] Open
Abstract
Essential tremor (ET) is a prevalent neurological disorder with a largely unknown underlying biology. In this genome-wide association study meta-analysis, comprising 16,480 ET cases and 1,936,173 controls from seven datasets, we identify 12 sequence variants at 11 loci. Evaluating mRNA expression, splicing, plasma protein levels, and coding effects, we highlight seven putative causal genes at these loci, including CA3 and CPLX1. CA3 encodes Carbonic Anhydrase III and carbonic anhydrase inhibitors have been shown to decrease tremors. CPLX1, encoding Complexin-1, regulates neurotransmitter release. Through gene-set enrichment analysis, we identify a significant association with specific cell types, including dopaminergic and GABAergic neurons, as well as biological processes like Rho GTPase signaling. Genetic correlation analyses reveals a positive association between ET and Parkinson's disease, depression, and anxiety-related phenotypes. This research uncovers risk loci, enhancing our knowledge of the complex genetics of this common but poorly understood disorder, and highlights CA3 and CPLX1 as potential therapeutic targets.
Collapse
Affiliation(s)
- Astros Th Skuladottir
- deCODE genetics/Amgen Inc., Reykjavik, Iceland.
- Faculty of Medicine, University of Iceland, Reykjavik, Iceland.
| | | | | | | | | | - Palmi Jonsson
- Faculty of Medicine, University of Iceland, Reykjavik, Iceland
- Department of Geriatric Medicine, Landspitali University Hospital, Reykjavik, Iceland
| | - Vala Palmadottir
- Department of Internal Medicine, Landspitali University Hospital, Reykjavik, Iceland
| | | | | | - Rosa S Gisladottir
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- Faculty of Icelandic and Comparative Cultural Studies, University of Iceland, Reykjavik, Iceland
| | | | | | | | - Daniel F Gudbjartsson
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- Faculty of Engineering and Natural Sciences, University of Iceland, Reykjavik, Iceland
| | - Kirk U Knowlton
- Intermountain Medical Center, Intermountain Heart Institute, Salt Lake City, USA
| | - David A Jones
- Precision Genomics, Intermountain Healthcare, Saint George, Utah, UK
| | - Aigar Ottas
- Estonian Genome Centre, Institute of Genomics, University of Tartu, Tartu, Estonia
| | - Ole B Pedersen
- Department of Clinical Immunology, Zealand University Hospital, Køge, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Maria Didriksen
- Department of Clinical Immunology, Copenhagen University Hospital, Righospitale, Copenhagen, Denmark
| | - Søren Brunak
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Karina Banasik
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Folkmann Hansen
- Danish Headache Center, Department of Neurology, Copenhagen University Hospital, Righospitalet-Glostrup, Copenhagen, Denmark
| | - Christian Erikstrup
- Department of Clinical Immunology, Aarhus University Hospital, Righospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, Aarhus University, Aarhus, Denmark
| | - Jan Haavik
- Department of Biomedicine, University of Bergen, Bergen, Norway
- Bergen Center of Brain Plasticity, Division of Psychiatry, Haukeland University Hospital, Bergen, Norway
| | - Ole A Andreassen
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- NORMENT, Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway
| | - David Rye
- Emory Department of Neurology, Wesley Woods Health Center, Atlanta, GA, USA
| | - Jannicke Igland
- Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway
- Department of Health and Caring sciences, Western Norway University of Applied Sciences, Bergen, Norway
| | - Sisse Rye Ostrowski
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Immunology, Copenhagen University Hospital, Righospitale, Copenhagen, Denmark
| | - Lili A Milani
- Estonian Genome Centre, Institute of Genomics, University of Tartu, Tartu, Estonia
| | - Lincoln D Nadauld
- Precision Genomics, Intermountain Healthcare, Saint George, Utah, UK
- Stanford University, School of Medicine, Stanford, CA, USA
| | | | - Kari Stefansson
- deCODE genetics/Amgen Inc., Reykjavik, Iceland.
- Faculty of Medicine, University of Iceland, Reykjavik, Iceland.
| |
Collapse
|
2
|
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] [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.
Collapse
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.)
| |
Collapse
|
3
|
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.
Collapse
|
4
|
Tian J, Vemula SR, Xiao J, Valente EM, Defazio G, Petrucci S, Gigante AF, Rudzińska‐Bar M, Wszolek ZK, Kennelly KD, Uitti RJ, van Gerpen JA, Hedera P, Trimble EJ, LeDoux MS. Whole-exome sequencing for variant discovery in blepharospasm. Mol Genet Genomic Med 2018; 6:601-626. [PMID: 29770609 PMCID: PMC6081235 DOI: 10.1002/mgg3.411] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 04/01/2018] [Accepted: 04/16/2018] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Blepharospasm (BSP) is a type of focal dystonia characterized by involuntary orbicularis oculi spasms that are usually bilateral, synchronous, and symmetrical. Despite strong evidence for genetic contributions to BSP, progress in the field has been constrained by small cohorts, incomplete penetrance, and late age of onset. Although several genetic etiologies for dystonia have been identified through whole-exome sequencing (WES), none of these are characteristically associated with BSP as a singular or predominant manifestation. METHODS We performed WES on 31 subjects from 21 independent pedigrees with BSP. The strongest candidate sequence variants derived from in silico analyses were confirmed with bidirectional Sanger sequencing and subjected to cosegregation analysis. RESULTS Cosegregating deleterious variants (GRCH37/hg19) in CACNA1A (NM_001127222.1: c.7261_7262delinsGT, p.Pro2421Val), REEP4 (NM_025232.3: c.109C>T, p.Arg37Trp), TOR2A (NM_130459.3: c.568C>T, p.Arg190Cys), and ATP2A3 (NM_005173.3: c.1966C>T, p.Arg656Cys) were identified in four independent multigenerational pedigrees. Deleterious variants in HS1BP3 (NM_022460.3: c.94C>A, p.Gly32Cys) and GNA14 (NM_004297.3: c.989_990del, p.Thr330ArgfsTer67) were identified in a father and son with segmental cranio-cervical dystonia first manifest as BSP. Deleterious variants in DNAH17, TRPV4, CAPN11, VPS13C, UNC13B, SPTBN4, MYOD1, and MRPL15 were found in two or more independent pedigrees. To our knowledge, none of these genes have previously been associated with isolated BSP, although other CACNA1A mutations have been associated with both positive and negative motor disorders including ataxia, episodic ataxia, hemiplegic migraine, and dystonia. CONCLUSIONS Our WES datasets provide a platform for future studies of BSP genetics which will demand careful consideration of incomplete penetrance, pleiotropy, population stratification, and oligogenic inheritance patterns.
Collapse
Affiliation(s)
- Jun Tian
- Departments of Neurology and Anatomy and NeurobiologyUniversity of Tennessee Health Science CenterMemphisTennessee
- Department of NeurologySecond Affiliated HospitalSchool of MedicineZhejiang UniversityHangzhouZhejiangChina
| | - Satya R. Vemula
- Departments of Neurology and Anatomy and NeurobiologyUniversity of Tennessee Health Science CenterMemphisTennessee
| | - Jianfeng Xiao
- Departments of Neurology and Anatomy and NeurobiologyUniversity of Tennessee Health Science CenterMemphisTennessee
| | - Enza Maria Valente
- Department of Molecular MedicineUniversity of PaviaPaviaItaly
- Neurogenetics UnitIRCCS Santa Lucia FoundationRomeItaly
| | - Giovanni Defazio
- Department of Basic Clinical Sciences, Neuroscience and Sense OrgansAldo Moro University of BariBariItaly
- Department of Medical Sciences and Public HealthUniversity of CagliariCagliariItaly
| | - Simona Petrucci
- Department of Neurology and PsychiatrySapienza University of RomeRomeItaly
| | - Angelo Fabio Gigante
- Department of Basic Clinical Sciences, Neuroscience and Sense OrgansAldo Moro University of BariBariItaly
| | - Monika Rudzińska‐Bar
- Department of NeurologyFaculty of MedicineMedical University of SilesiaKatowicePoland
| | | | | | - Ryan J. Uitti
- Department of NeurologyMayo Clinic FloridaJacksonvilleFlorida
| | | | - Peter Hedera
- Department of NeurologyVanderbilt UniversityNashvilleTennessee
| | - Elizabeth J. Trimble
- Departments of Neurology and Anatomy and NeurobiologyUniversity of Tennessee Health Science CenterMemphisTennessee
| | - Mark S. LeDoux
- Departments of Neurology and Anatomy and NeurobiologyUniversity of Tennessee Health Science CenterMemphisTennessee
| |
Collapse
|
5
|
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.
Collapse
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.
| |
Collapse
|
6
|
Silva D, Matias C, Bourne S, Nagel S, Machado A, Lobel D. Effects of chronic alcohol consumption on long-term outcomes of thalamic deep brain stimulation for essential tremor. J Clin Neurosci 2016; 31:142-6. [PMID: 27401226 DOI: 10.1016/j.jocn.2016.03.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 03/08/2016] [Indexed: 11/28/2022]
Abstract
The prevalence of essential tremor (ET) is about 4% above 40years of age. Chronic alcohol consumption is present in around 20% of patients with ET. Our objective was to identify whether chronic alcohol consumption was associated with a negative effect on tremor outcome after thalamic deep brain stimulation (DBS) in ET patients. We conducted a retrospective chart review, from January 2005 to December 2012, from which 23 patients who had ventral intermediate nucleus (Vim)-DBS surgery for ET were identified. Seven patients had a positive history of chronic alcohol consumption. We defined as chronic alcohol users those patients with a habit of drinking alcohol every day in order to suppress tremor. In the overall group of 23 patients, there was a reduction in the median tremor score from 8 pre-operatively, to 1 post-operatively (p<0.0001). The alcohol consumers group experienced a reduction in the median tremor score from 6 pre-operatively to 0 post-operatively (p=0.03). The non-alcohol consumers group had a reduction in the median tremor score from 8 pre-operatively to 1.7 post-operatively (p<0.0001). Both groups of patients experienced significant benefit from thalamic DBS. A larger study may reveal statistically significant differences between subgroups.
Collapse
Affiliation(s)
- Danilo Silva
- Center for Neurological Restoration, Department of Neurosurgery, Neurological Institute, Cleveland Clinic, OH 44124, USA.
| | - Caio Matias
- Center for Neurological Restoration, Department of Neurosurgery, Neurological Institute, Cleveland Clinic, OH 44124, USA
| | - Sarah Bourne
- Center for Neurological Restoration, Department of Neurosurgery, Neurological Institute, Cleveland Clinic, OH 44124, USA
| | - Sean Nagel
- Center for Neurological Restoration, Department of Neurosurgery, Neurological Institute, Cleveland Clinic, OH 44124, USA
| | - Andre Machado
- Center for Neurological Restoration, Department of Neurosurgery, Neurological Institute, Cleveland Clinic, OH 44124, USA
| | - Darlene Lobel
- Center for Neurological Restoration, Department of Neurosurgery, Neurological Institute, Cleveland Clinic, OH 44124, USA
| |
Collapse
|
7
|
Liu X, Hernandez N, Kisselev S, Floratos A, Sawle A, Ionita-Laza I, Ottman R, Louis ED, Clark LN. Identification of candidate genes for familial early-onset essential tremor. Eur J Hum Genet 2016; 24:1009-15. [PMID: 26508575 PMCID: PMC5070884 DOI: 10.1038/ejhg.2015.228] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 09/23/2015] [Accepted: 09/24/2015] [Indexed: 12/17/2022] Open
Abstract
Essential tremor (ET) is one of the most common causes of tremor in humans. Despite its high heritability and prevalence, few susceptibility genes for ET have been identified. To identify ET genes, whole-exome sequencing was performed in 37 early-onset ET families with an autosomal-dominant inheritance pattern. We identified candidate genes for follow-up functional studies in five ET families. In two independent families, we identified variants predicted to affect function in the nitric oxide (NO) synthase 3 gene (NOS3) that cosegregated with disease. NOS3 is highly expressed in the central nervous system (including cerebellum), neurons and endothelial cells, and is one of three enzymes that converts l-arginine to the neurotransmitter NO. In one family, a heterozygous variant, c.46G>A (p.(Gly16Ser)), in NOS3, was identified in three affected ET cases and was absent in an unaffected family member; and in a second family, a heterozygous variant, c.164C>T (p.(Pro55Leu)), was identified in three affected ET cases (dizygotic twins and their mother). Both variants result in amino-acid substitutions of highly conserved amino-acid residues that are predicted to be deleterious and damaging by in silico analysis. In three independent families, variants predicted to affect function were also identified in other genes, including KCNS2 (KV9.2), HAPLN4 (BRAL2) and USP46. These genes are highly expressed in the cerebellum and Purkinje cells, and influence function of the gamma-amino butyric acid (GABA)-ergic system. This is in concordance with recent evidence that the pathophysiological process in ET involves cerebellar dysfunction and possibly cerebellar degeneration with a reduction in Purkinje cells, and a decrease in GABA-ergic tone.
Collapse
Affiliation(s)
- Xinmin Liu
- Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Nora Hernandez
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA
- Department of Chronic Disease Epidemiology, Yale School of Public Health, New Haven, CT, USA
| | - Sergey Kisselev
- Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Aris Floratos
- Department of Biomedical Informatics, Columbia University, New York, NY, USA
- Center for Computational Biology and Bioinformatics, Columbia University, New York, NY, USA
| | - Ashley Sawle
- Department of Biomedical Informatics, Columbia University, New York, NY, USA
- Center for Computational Biology and Bioinformatics, Columbia University, New York, NY, USA
| | - Iuliana Ionita-Laza
- Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Ruth Ottman
- G.H Sergievsky Center, Columbia University, New York, NY, USA
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, USA
- Division of Epidemiology, New York State Psychiatric Institute, New York, NY, USA
| | - Elan D Louis
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA
- Department of Chronic Disease Epidemiology, Yale School of Public Health, New Haven, CT, USA
| | - Lorraine N Clark
- Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| |
Collapse
|
8
|
Clark LN, Louis ED. Challenges in essential tremor genetics. Rev Neurol (Paris) 2015; 171:466-74. [PMID: 26003805 PMCID: PMC4863985 DOI: 10.1016/j.neurol.2015.02.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 01/28/2015] [Accepted: 02/02/2015] [Indexed: 12/17/2022]
Abstract
The field of essential tremor (ET) genetics remains extremely challenging. The relative lack of progress in understanding the genetic etiology of ET, however, does not reflect the lack of a genetic contribution, but rather, the presence of substantial phenotypic and genotypic heterogeneity. A meticulous approach to phenotyping is important for genetic research in ET. The only tool for phenotyping is the clinical history and examination. There is currently no ET-specific serum or imaging biomarker or defining neuropathological feature (e.g., a protein aggregate specific to ET) that can be used for phenotyping, and there is considerable clinical overlap with other disorders such as Parkinson's disease (PD) and dystonia. These issues greatly complicate phenotyping; thus, in some studies, as many as 30-50% of cases labeled as "ET" have later been found to carry other diagnoses (e.g., dystonia, PD) rather than ET. A cursory approach to phenotyping (e.g., merely defining ET as an "action tremor") is likely a major issue in some family studies of ET, and this as well as lack of standardized phenotyping across studies and patient centers is likely to be a major contributor to the relative lack of success of genome wide association studies (GWAS). To dissect the genetic architecture of ET, whole genome sequencing (WGS) in carefully characterized and well-phenotyped discovery and replication datasets of large case-control and familial cohorts will likely be of value. This will allow specific hypotheses about the mode of inheritance and genetic architecture to be tested. There are a number of approaches that still remain unexplored in ET genetics, including the contribution of copy number variants (CNVs), '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 non-coding variation. Using these approaches is likely to yield new ET genes.
Collapse
Affiliation(s)
- L N Clark
- Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, 650 West 168th Street, New York, NY, 10032, USA; Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA
| | - E D Louis
- Department of Neurology, Yale School of Medicine, Yale University, 800 Howard Ave # 2, New Haven, CT 06519, USA.
| |
Collapse
|
9
|
Van Gerpen JA, Ross OA. Essential Tremor. Mov Disord 2015. [DOI: 10.1016/b978-0-12-405195-9.00036-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
|
10
|
Klaming R, Annese J. Functional anatomy of essential tremor: lessons from neuroimaging. AJNR Am J Neuroradiol 2014; 35:1450-7. [PMID: 23620075 DOI: 10.3174/ajnr.a3586] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The neuropathogenetic processes underlying essential tremor appear to cause subtle morphologic changes in neural networks that include multiple brain structures, primarily the cerebellum, brain stem, frontal lobes, and thalamus. One of the main challenges of neuroimaging in essential tremor is differentiating disease-specific markers from the spectrum of structural changes that occur due to aging. This review discusses recent neuroimaging studies in the light of current knowledge of the neuropsychology and pathology of the disease. We suggest that the application of multiple macroscopic and microscopic neuroimaging modalities, combined with personalized information relative to cognitive and behavioral symptoms, is the prerequisite for a comprehensive classification and correct diagnosis of essential tremor.
Collapse
Affiliation(s)
- R Klaming
- From The Brain Observatory, San Diego, California; and Department of Radiology, University of California, San Diego, San Diego, California
| | - J Annese
- From The Brain Observatory, San Diego, California; and Department of Radiology, University of California, San Diego, San Diego, California.
| |
Collapse
|
11
|
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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 04/16/2014] [Accepted: 05/02/2014] [Indexed: 11/30/2022]
|
12
|
Apartis E, Jedynak CP. Tremori. Neurologia 2014. [DOI: 10.1016/s1634-7072(14)66663-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
|
13
|
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] [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.
Collapse
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
| |
Collapse
|
14
|
Investigation of the prevalence of essential tremor in individuals aged 18-60 in Erzurum. Acta Neurol Belg 2013; 113:127-31. [PMID: 23111777 DOI: 10.1007/s13760-012-0147-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Accepted: 10/09/2012] [Indexed: 10/27/2022]
Abstract
Essential tremor (ET) is one of the common neurological diseases and it is the most common movement disorder in adults. The main clinical finding in patients with ET is kinetic tremor in the arms. There is no adequate study investigating the prevalence of ET in Turkey. Therefore, this study was planned in the center of the city of Erzurum in order to determine the prevalence of essential tremor in our region. This study was performed door to door in the center of the city of Erzurum. ET screening questionnaires were administered to all participants between the ages of 18-60 at first stage. Those who answer yes to any of the first five questions of the questionnaire were evaluated. Patients without a clear differential diagnosis were called for examination to the neurology department and they were re-evaluated by a faculty member specializing in movement disorders. Patients were classified by using Washington Heights-Inwood Genetic Study of Essential Tremor diagnostic and clinical evaluation scale. The prevalence of ET was calculated as 1.60 % (64 out of 4,024 participants). 30 of the cases were male and 34 were female. First-degree relatives of 30 patients with ET had a history of tremor. While 52 patients had tremor only in their hands, 11 patients had in various organs including hands. There was isolated head tremor in one patient. ET prevalence was increasing with age. The prevalence of ET in people between the ages of 18 and 60 was calculated as 1.60 %. This value is compatible with other measurements of the prevalence of ET.
Collapse
|
15
|
Testa CM. Key issues in essential tremor genetics research: Where are we now and how can we move forward? TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, 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] [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.
Collapse
Affiliation(s)
- Claudia M Testa
- Virginia Commonwealth University, Parkinson's and Movement Disorders Center, Richmond Virginia, USA
| |
Collapse
|
16
|
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.
Collapse
Affiliation(s)
- H Deng
- Center for Experimental Medicine, Department of Neurology, the Third Xiangya Hospital, Central South University, Changsha, HN, China.
| | | | | |
Collapse
|
17
|
Ross OA, Conneely KN, Wang T, Vilarino-Guell C, Soto-Ortolaza AI, Rajput A, Wszolek ZK, Uitti RJ, Louis ED, Clark LN, Farrer MJ, Testa CM. Genetic variants of α-synuclein are not associated with essential tremor. Mov Disord 2011; 26:2552-6. [PMID: 22025277 DOI: 10.1002/mds.23909] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 05/25/2011] [Accepted: 07/18/2011] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Given the overlap between Parkinson's disease and essential tremor, we examined genetic variants in α-synuclein (SNCA) as risk determinants for essential tremor. METHODS Samples from 661 essential tremor subjects and 1316 control subjects from 4 participating North American sites were included in this study. Parkinson's disease samples (n = 427) were compared against controls. Twenty variants were selected for association analysis within the SNCA locus. Individual logistic regression analyses against essential tremor diagnosis were run for each variant and then combined using meta-analysis. RESULTS Our results do not show a significant association between variants in the SNCA locus and risk of essential tremor, whereas the established association of SNCA variants with Parkinson's disease risk was observed. CONCLUSIONS Whereas genetic factors are likely to play a large role in essential tremor pathogenesis, our results do not support a role for common SNCA genetic variants in risk for essential tremor.
Collapse
Affiliation(s)
- Owen A Ross
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
|
19
|
Abstract
Essential tremor (ET) is among the most common neurological disorders. This chapter reviews the epidemiology, clinical features, and pathophysiology of ET. The defining feature is a kinetic tremor of the arms. Patients often have a postural tremor as well. Other body regions may also be involved (especially the head). The severity of tremor may range from mild cases in population settings to more severe cases in treatment settings. Motor features aside from tremor have been described in ET, including tandem gait difficulty. Mild cognitive changes (especially executive dysfunction) have been documented in many studies as well. Despite being regarded as one of the most common hyperkinetic movement disorders, establishing a precise prevalence has been difficult, yet the prevalence among persons aged 40 and older seems to be 4% or higher. There are numerous examples of families in which the disease appears to be inherited yet genetic studies have not progressed to the point where ET genes have been identified. There is also a growing understanding that environmental factors are likely to contribute to the etiology of ET. More recent postmortem studies have helped localize the possible source of ET to structural alterations in the cerebellum and its connecting pathways.
Collapse
|
20
|
Pharmacological characterization of harmaline-induced tremor activity in mice. Eur J Pharmacol 2009; 616:73-80. [DOI: 10.1016/j.ejphar.2009.05.031] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Revised: 05/12/2009] [Accepted: 05/19/2009] [Indexed: 01/06/2023]
|
21
|
Abstract
Tremor in childhood is not commonly described in the literature; but it is also likely underappreciated. The etiology of childhood tremor encompasses a wide variety of pathologic processes. Tremor may occur in isolation, or in association with other neurologic findings or systemic disorders. This article aims to provide an overview of tremorogenic mechanisms with respect to neuroanatomy and neurophysiology, particularly as they relate to children. Classification of tremors, diagnostic entities in childhood, and treatment will also be discussed. With improved recognition and characterization of childhood tremors, we may gain a better understanding of the pathophysiology of the disease and determine more age-appropriate treatment strategies.
Collapse
Affiliation(s)
- Stephanie Keller
- Department of Pediatrics, Division of Child Neurology, University of Alabama at Birmingham, The Children's Hospital of Alabama, Birmingham, AL 35233, USA.
| | | |
Collapse
|
22
|
Inashkina I, Radovica I, Smeltere L, Vitols E, Jankevics E. Case-control study of patients with essential tremor in Latvia. Eur J Neurol 2008; 15:988-90. [DOI: 10.1111/j.1468-1331.2008.02225.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
23
|
Louis ED. Environmental epidemiology of essential tremor. Neuroepidemiology 2008; 31:139-49. [PMID: 18716411 PMCID: PMC2683985 DOI: 10.1159/000151523] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Accepted: 06/04/2008] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Essential tremor (ET) is one of the most common neurological disorders. Despite this, the disease mechanisms and etiology are not well understood. While susceptibility genotypes undoubtedly underlie many ET cases, no ET genes have been identified thus far. As with many other progressive, degenerative neurological disorders, it is likely that environmental factors contribute to the etiology of ET. Environmental epidemiology is the study in specific populations or communities of the effect on human health of physical, biologic and chemical factors in the external environment. The purpose of this article is to review current knowledge with regards to the environmental epidemiology of ET. RESULTS As will be discussed, a series of preliminary case-control studies in recent years has begun to explore several candidate toxins/exposures, including harmane (1-methyl-9H-pyrido[3,4-b]indole), lead and agricultural exposures/pesticides. CONCLUSIONS While several initial results are promising, as will be discussed, additional studies are needed to more definitively establish whether these exposures are associated with ET and if they are of etiological importance.
Collapse
Affiliation(s)
- Elan D Louis
- GH Sergievsky Center, Department of Neurology, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Mailman School of Public Health, Columbia University, New York, NY 10032, USA.
| |
Collapse
|
24
|
The nonsynonymous Thr105Ile polymorphism of the histamine N-methyltransferase is associated to the risk of developing essential tremor. Neuromolecular Med 2008; 10:356-61. [PMID: 18543121 DOI: 10.1007/s12017-008-8040-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2007] [Accepted: 05/06/2008] [Indexed: 10/22/2022]
Abstract
OBJECTIVE We analyzed in patients with essential tremor (ET) the Thr105Ile polymorphism of the Histamine N-methyltransferase (HNMT) enzyme that is associated to Parkinson's disease (PD) risk. METHODS Leukocytary DNA from 204 ET patients and a control group of 295 unrelated healthy individuals was studied for the nonsynonymous HNMT Thr105Ile polymorphism by using amplification-restriction analyses. RESULTS Patients with ET showed a higher frequency of homozygous HNMT 105Thr genotypes leading to high metabolic activity (p < 0.015) with a statistically significant gene-dose effect, as compared to healthy subjects. These findings were independent of gender, and of tremor localization, but the association of the HNMT polymorphism is more prominent among patients with late-onset ET (p < 0.007). CONCLUSION These results, combined with previous findings indicating alterations in the frequency for the HNMT Thr105Ile polymorphism in patients with PD, suggest that alterations of histamine homeostasis in the SNC are associated with the risk of movement disorders.
Collapse
|
25
|
Louis ED, Benito-León J, Bermejo-Pareja F. Population-based prospective study of cigarette smoking and risk of incident essential tremor. Neurology 2008; 70:1682-7. [PMID: 18458228 DOI: 10.1212/01.wnl.0000311271.42596.32] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Smoking cigarettes is associated with lower risk of Parkinson disease (PD). Despite the clinical links between PD and essential tremor (ET), there are few data on smoking in ET. One study showed an association between smoking and lower ET prevalence. We now study whether baseline smoking is associated with lower risk of incident ET. METHODS Using a population-based, cohort design, baseline cigarette smoking habits were assessed in 3,348 participants in an epidemiologic study in Spain, among whom 77 developed incident ET. RESULTS There were 3,348 participants, among whom 397 (11.9%) were smokers at baseline. Five (6.5%) of 77 incident ET cases had been smokers at baseline, compared with 392 (12.0%) of 3,271 controls (p = 0.14). Baseline pack-years were lower in incident ET cases than in controls (9.2 +/- 17.7 vs 15.7 +/- 28.4, p = 0.002). Participants were stratified into baseline pack-year tertiles, and few incident ET cases were in the highest tertile (4 [5.2%] cases vs 431 [13.2%] controls, p = 0.039). In Cox proportional hazards models, the highest baseline pack-year tertile was associated with lower risk of incident ET; those in the highest pack-year tertile were one-third as likely to develop ET when compared with nonsmokers (relative risk [RR] 0.37, 95% CI 0.14-1.03, p = 0.057 [unadjusted model] and RR 0.29, 95% CI 0.09-0.90, p = 0.03 [adjusted model]). CONCLUSIONS We demonstrated an association between baseline heavy cigarette smoking and lower risk of incident essential tremor. The biologic basis for this association requires future investigation.
Collapse
Affiliation(s)
- Elan D Louis
- G.H. Sergievsky Center, Department of Neurology, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
| | | | | | | |
Collapse
|
26
|
Benito-León J, Louis ED, Bermejo-Pareja F. Population-based case-control study of cigarette smoking and essential tremor. Mov Disord 2008; 23:246-52. [PMID: 17999431 DOI: 10.1002/mds.21810] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Parkinson's disease (PD) is inversely associated with smoking cigarettes. Despite long-standing clinical links between PD and essential tremor (ET), there are surprisingly few data on smoking in ET. We studied whether smoking cigarettes is inversely associated with ET. Using a population-based, case-control design, cigarette smoking habits were assessed in 221 prevalent ET cases (75.5 +/- 7.1 years old) and 663 matched controls (74.6 +/- 7.0 years old). In logistical regression analyses, diagnosis (ET vs. control) was the dependent variable, and cigarette smoking status, the independent variable. Ever smokers were marginally less likely to have ET than were never smokers (22.0% vs. 27.0%, odds ratio [OR] 0.76, 95% confidence interval [CI] 0.55-1.04, P = 0.09). In an analysis that adjusted for confounding factors (drink-years and depressive symptoms), ever smokers were nearly half less likely to have ET than the never smokers (OR 0.58, 95% CI 0.40-0.84, P = 0.004). There was a strong inverse association between pack-years and odds of ET (adjusted OR 0.991, 95% CI 0.984-0.997, P = 0.005, i.e., with every 10 pack-year increase, odds of ET were lowered 10%). Ever smokers in the highest pack-year tertile were one-third as likely to have ET than the never smokers (adjusted OR 0.39, 95% CI 0.22-0.69, P = 0.001). We demonstrated an inverse association between ever smoking and ET. Additional studies are needed to reproduce these findings and assess whether this association is due to a biologically protective effect.
Collapse
Affiliation(s)
- Julián Benito-León
- Department of Neurology, University Hospital 12 de Octubre, Madrid, Spain.
| | | | | | | |
Collapse
|
27
|
Morrison PJ. Paediatric and adult movement disorders (update 2). Eur J Paediatr Neurol 2008; 12:253-6. [PMID: 17855134 DOI: 10.1016/j.ejpn.2007.07.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2007] [Accepted: 07/26/2007] [Indexed: 11/16/2022]
|
28
|
Louis ED, Keating GA, Bogen KT, Rios E, Pellegrino KM, Factor-Litvak P. Dietary epidemiology of essential tremor: meat consumption and meat cooking practices. Neuroepidemiology 2008; 30:161-6. [PMID: 18382115 DOI: 10.1159/000122333] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2007] [Accepted: 01/23/2008] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIM Harmane [1-methyl-9H-pyrido(3,4-b)indole] is a tremor-producing neurotoxin. Blood harmane concentrations are elevated in essential tremor (ET) patients for unclear reasons. Potential mechanisms include increased dietary harmane intake (especially through well-cooked meat) or genetic-metabolic factors. We tested the hypothesis that meat consumption and level of meat doneness are higher in ET cases than in controls. METHODS Detailed data were collected using the Lawrence Livermore National Laboratory Meat Questionnaire. RESULTS Total current meat consumption was greater in men with than without ET (135.3 +/- 71.1 vs. 110.6 +/- 80.4 g/day, p = 0.03) but not in women with versus without ET (80.6 +/- 50.0 vs. 79.3 +/- 51.0 g/day, p = 0.76). In an adjusted logistic regression analysis in males, higher total current meat consumption was associated with ET (OR = 1.006, p = 0.04, i.e., with 10 additional g/day of meat, odds of ET increased by 6%). Male cases had higher odds of being in the highest than lowest quartile of total current meat consumption (adjusted OR = 21.36, p = 0.001). Meat doneness level was similar in cases and controls. CONCLUSION This study provides evidence of a dietary difference between male ET cases and male controls. The etiological ramifications of these results warrant additional investigation.
Collapse
|
29
|
Zhang J, Williams MA, Rigamonti D. Heritable essential tremor-idiopathic normal pressure hydrocephalus (ETINPH). Am J Med Genet A 2008; 146A:433-9. [PMID: 18203159 DOI: 10.1002/ajmg.a.31958] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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.
Collapse
Affiliation(s)
- Jun Zhang
- Department of Neurosurgery, University of Mississippi Medical Center, Jackson, Mississippi 39216-4505, USA.
| | | | | |
Collapse
|
30
|
Yoo YM, Lee CJ, Lee U, Kim YJ. Mitochondrial DNA in patients with essential tremor. Neurosci Lett 2008; 434:29-34. [PMID: 18262358 DOI: 10.1016/j.neulet.2008.01.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Revised: 12/19/2007] [Accepted: 01/11/2008] [Indexed: 10/22/2022]
Abstract
Essential tremor (ET) is one of the most common of the movement disorders. However, there has been little agreement in the neurological literature regarding diagnostic criteria for ET. It is not clear to what extent ET is associated with defects of mitochondrial DNA. In this study, we analyzed mitochondrial DNA (mtDNA) from the blood cells of the normal and ET patients using the long and accurate polymerase chain reaction (LA-PCR) and PCR. The large deletions were detected within several regions of mtDNA, but were not detected in the D-loop or CO I regions in ET patients. From our study, it is suggested that ET is a disorder showing a deficiency of mtDNA multicomplexes, and it also appears that mitochondrial dysfunction could be one of the causative factors of ET.
Collapse
Affiliation(s)
- Young-Mi Yoo
- Department of Neurosurgery, Gachon Medical College, Gil Medical Center, Incheon, South Korea
| | | | | | | |
Collapse
|
31
|
Aridon P, Ragonese P, De Fusco M, Salemi G, Casari G, Savettieri G. Further evidence of genetic heterogeneity in familial essential tremor. Parkinsonism Relat Disord 2008; 14:15-8. [PMID: 17703985 DOI: 10.1016/j.parkreldis.2007.05.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2007] [Revised: 04/18/2007] [Accepted: 05/01/2007] [Indexed: 10/22/2022]
Abstract
Familial essential tremor (FET) is a common hereditary movement disorder with phenotypic variability and genetic heterogeneity. To date, linkage analyses revealed three loci associated to essential tremor (ET) (ETM1 on 3q13, ETM2 on 2p22-25, and a locus on 6p23). We performed a genetic analysis of these candidate chromosomal regions in a fifth-generation Italian kindred with autosomal-dominant ET. Of the 22 clinically evaluated family members, nine were affected by ET. The genetic study indicates that the ET in this family is not associated to any of the known ET loci. These findings support evidence of further genetic heterogeneity for such disease.
Collapse
Affiliation(s)
- Paolo Aridon
- Dipartimento Universitario di Neuroscienze Cliniche, University of Palermo, Italy
| | | | | | | | | | | |
Collapse
|
32
|
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. ENVIRONMENTAL HEALTH PERSPECTIVES 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] [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.
Collapse
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
| |
Collapse
|
33
|
Martínez C, García-Martín E, Alonso-Navarro H, Jiménez-Jiménez FJ, Benito-León J, García-Ferrer I, Vázquez-Torres P, Puertas I, Zurdo JM, López-Alburquerque T, Agúndez JAG. Changes at the CYP2C locus and disruption of CYP2C8/9 linkage disequilibrium in patients with essential tremor. Neuromolecular Med 2007; 9:195-204. [PMID: 17627038 DOI: 10.1007/bf02685892] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Revised: 10/16/2006] [Accepted: 10/18/2006] [Indexed: 10/22/2022]
Abstract
To identify low-penetrance genes related to sporadic essential tremor (ET) at the CYP2C locus, located in chromosome 10 q23.33. Leukocytary DNA from 200 ET patients and a control group of 300 unrelated healthy individuals with known CYP2C19 genotypes was studied for common CYP2C8 and CYP2C9 allelic variants by using amplification-restriction analyses. Patients with ET showed the following differences compared with healthy subjects: a 1.6-fold reduction in the frequency for CYP2C8*3 (p=0.006), a 1.35-fold reduction of CYP2C9*2 (p=0.05) and a 1.52-fold reduction in the frequency for CYP2C9*3 (p=0.07). The frequency for patients with ET carrying at least one defective allele was 1.33-fold reduced as compared with healthy subjects (p=0.002). In addition, a disruption of the CYP2C8*3/CYP2C9*2 linkage disequilibrium was observed in ET patients, with a 2.1-fold reduction in the percentage for carriers of the haplotype CYP2C8*3 plus CYP2C9*2 in ET patients (p=0.0001). These findings were independent of gender, age, age of onset, or clinical symptoms. These results suggest that alterations at the CYP2C gene locus are associated with the risk for ET.
Collapse
Affiliation(s)
- Carmen Martínez
- Department of Pharmacology and Psychiatry, Medical School, University of Extremadura, Badajoz, and Department of Medicine-Neurology, Príncipe de Asturias Hospital, Alcalá de Henares, Madrid, Spain
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
34
|
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] [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.
Collapse
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.
| | | |
Collapse
|
35
|
Louis ED, Ottman R. Study of possible factors associated with age of onset in essential tremor. Mov Disord 2007; 21:1980-6. [PMID: 16991147 DOI: 10.1002/mds.21102] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Factors associated with the age of onset of essential tremor (ET) have not been studied in detail. Identification of modifiable factors could lead to strategies to delay disease onset and identification of nonmodifiable factors would be useful while counseling at risk individuals. The objective of this study was to identify factors associated with age of onset of tremor in ET. One hundred ninety-five ET cases were enrolled in an environmental epidemiological study. Clinical questionnaires included questions on age of onset, demographics (age, sex, race, education), early-life exposures (birth order, childhood household size), exposures prior to tremor onset (head trauma, well water, rural living, estrogen replacement therapy), and family history. In unadjusted analyses, age of onset was associated with family history of tremor (40.9 +/- 22.0 years for cases with a family history of tremor vs. 57.3 +/- 18.4 years for cases without a history; P < 0.001), history of head trauma, younger current age, greater tremor severity, and white race. Ninety-one percent of cases with onset before age 20 years had a family history of tremor. Age ofonset was not associated with other variables of interest (e.g., sex, well water, rural living). In an adjusted linear regression model, age of tremor onset was strongly associated with family history of tremor (P < 0.001). The familial form of ET is characterized by an earlier age of onset than the sporadic form. This study did not detect any other exposures that modified the age of onset of ET. Follow-up studies are needed to examine additional factors of potential interest.
Collapse
Affiliation(s)
- Elan D Louis
- Gertrude H. Sergievsky Center, Columbia University, New York, New York, USA.
| | | |
Collapse
|
36
|
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] [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.
Collapse
Affiliation(s)
- Shaochun Ma
- Department of Neurology, Vanderbilt University, Nashville, Tennessee, USA
| | | | | | | | | | | | | |
Collapse
|
37
|
Abstract
Essential tremor (ET) is among the most common neurologic disorders. The traditional view of this disorder as a benign, monosymptomatic, familial condition is being replaced by a more complex view of ET as perhaps a family of diseases with etiologic, clinical, and pathologic heterogeneity. This article discusses the major clinical features of ET and approaches to its diagnosis and treatment.
Collapse
Affiliation(s)
- Elan D Louis
- Department of Neurology, College of Physicians and Surgeons, Columbia University, 710 West 168th Street, New York, NY 10032, USA.
| |
Collapse
|
38
|
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] [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.
Collapse
|
39
|
Abstract
After observing that several families with essential tremor (ET) clinically cosegregated with restless legs syndrome (RLS), we prospectively evaluated for the presence of RLS in 100 patients presenting to the Baylor College of Medicine with ET and prospectively examined all patients presenting with RLS for the presence of tremor during the same time frame. Of 100 consecutive ET patients (60 women and 75 with a family history of ET) seen over 19 weeks (current age, 65.2 +/- 16.3 years; age at tremor onset, 37.8 +/- 19.9 years) 33 met all criteria for RLS, of which 25 had never been diagnosed previously. A family history of RLS was reported in 57.6% of these 33 patients and was the only significant predictor of RLS in the ET population. Their International Restless Legs Syndrome Rating Scale score was 16.6 +/- 8.1. Over 19 weeks, we also examined 68 consecutive RLS patients (63.2% women and 54.4% with a family history of RLS) for the presence of tremor. Their current age was 55.8 +/- 14.4 years, and age at RLS onset was 33.7 +/- 19.5 years. Overtly pathological tremor was rare, but trace tremor was very common. Overall, we found a very high rate of undiagnosed RLS in patients presenting for tremor, but unlike other "secondary" forms of RLS, this finding was also associated with a high familial history of RLS, suggesting that they share some genetic similarities.
Collapse
|
40
|
Higgins JJ, Lombardi RQ, Pucilowska J, Jankovic J, Golbe LI, Verhagen L. HS1-BP3 gene variant is common in familial essential tremor. Mov Disord 2006; 21:306-9. [PMID: 16211613 DOI: 10.1002/mds.20692] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Essential tremor (ET) is a movement disorder characterized by a postural or kinetic tremor of the hands, head, or voice. It is typically a familial condition and affects 1% to 4% of the general population. The trait is genetically linked to chromosome 2p in some families. A variant (828C-->G) in exon 7 of the hematopoietic-specific protein 1 binding protein 3 gene (HS1-BP3) on chromosome 2p recently has been found to segregate with ET in 2 families. To determine the frequency of this variant in a larger series, we studied patients with ET, Parkinson disease (PD), and controls without tremor. Affected singletons representing 73 families from the United States with dominantly inherited ET, 35 individuals with PD, and 304 healthy controls older than age 60 were tested for the 828C-->G variant in exon 7 of the HS1-BP3 gene by a BseYI restriction enzyme digest of the polymerase chain reaction product. Heterozygous carriers of the mutant allele were identified in 12 individuals with ET (16.4%) and in 1 individual with PD and postural tremor (3%). All of the healthy controls (608 chromosomes) were homozygous for the wild-type allele. The 828C-->G genetic variant in the HS1-BP3 gene occurs relatively frequently in subjects with ET. The variant may also be found in some individuals with PD and postural tremor. The HS1-BP3 gene plays a putative role in regulating catecholamine and serotonin metabolism, but the functional consequences of the amino acid substitution (A265G) caused by this genetic variant is unknown.
Collapse
Affiliation(s)
- Joseph J Higgins
- Center for Human Genetics and Child Neurology, Mid-Hudson Family Health Institute, New Paltz, New York, USA.
| | | | | | | | | | | |
Collapse
|
41
|
Rajput AH, Rajput A. Increased tremor severity in bilineal essential tremor: A report of two families. Parkinsonism Relat Disord 2006; 12:323-6. [PMID: 16459122 DOI: 10.1016/j.parkreldis.2005.06.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2005] [Accepted: 06/16/2005] [Indexed: 11/15/2022]
Abstract
Up to 6% of the general population have essential tremor (ET). In a number of couples both partners may have ET. The clinical profile of ET in children and the parents where both parents and the child have ET remains to be established. We report on two families where both parents and one child have ET. The severity of ET was greater in the children than in either parent. Such families could provide special opportunity to determine relation between genotype and phenotypic expression of ET.
Collapse
Affiliation(s)
- Alexander H Rajput
- Department of Medicine, Division of Neurology, Royal University Hospital, University of Saskatchewan, 103 Hospital Drive, Saskatoon, Sask., Canada S7N 0W8.
| | | |
Collapse
|
42
|
Ondo W. VIM deep brain stimulation does not improve pre-existing restless legs syndrome in patients with essential tremor. Parkinsonism Relat Disord 2006; 12:113-4. [PMID: 16446110 DOI: 10.1016/j.parkreldis.2004.10.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2004] [Revised: 10/05/2004] [Accepted: 10/08/2004] [Indexed: 10/25/2022]
Abstract
The neuroanatomic substrate for restless legs syndrome (RLS) is not known. We implanted deep brain stimulators into the ventralis intermedius nucleus (VIM) of the thalamus in nine subjects for essential tremor (ET) whom all concurrently had RLS. Although the VIM DBS improved tremor, none of the subjects felt there was any meaningful effect on their RLS symptoms. The VIM thalamus, which is involved in ET and Parkinson's disease, does not seem to be primarily involved in RLS.
Collapse
Affiliation(s)
- William Ondo
- Baylor College of Medicine, 6550 Fannin, Ste 1801, Houston, TX77030 , USA.
| |
Collapse
|
43
|
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.
Collapse
Affiliation(s)
- Rodger J Elble
- Department of Neurology, Southern Illinois University School of Medicine, Springfield, Illinois 62794, USA.
| |
Collapse
|
44
|
Higgins JJ, Lombardi RQ, Pucilowska J, Jankovic J, Tan EK, Rooney JP. A variant in the HS1-BP3 gene is associated with familial essential tremor. Neurology 2005; 64:417-21. [PMID: 15699368 PMCID: PMC1201396 DOI: 10.1212/01.wnl.0000153481.30222.38] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Genetic linkage studies have identified two susceptibility loci for essential tremor (ET) on chromosomes 3q13 (ETM1) and 2p24.1 (ETM2). Linkage disequilibrium studies in separate population samples from the United States and Singapore suggest an association between ET and loci at ETM2. METHODS Fine mapping studies were conducted on multiplex and singleton US families linked to ETM2 using newly detected loci within the candidate interval to establish the minimal critical region (MCR) harboring an ET gene. The genes and transcripts within this interval were systematically analyzed by single-strand conformational polymorphism analysis and DNA sequencing. RESULTS A 464-kb region between loci D2S2150 and etm1231 was defined as the MCR. The coding regions and flanking intronic splice sites of two genes and seven transcripts in this interval were evaluated for mutations. A missense mutation (828C-->G) in the transcript FLJ14249 (HS1-BP3) was identified in one US family. This mutation was found in another apparently unrelated US family with ET and was absent in 150 control samples (300 chromosomes). The 828C-->G mutation causes a substitution of a glycine for an alanine residue in the HS1-BP3 protein. The HS1-BP3 protein binds to proteins that are highly expressed in motor neurons and Purkinje cells and regulate the Ca2+/calmodulin-dependent protein kinase activation of tyrosine and tryptophan hydroxylase. CONCLUSIONS A rare variant in the HS1-BP3 gene that is associated with essential tremor (ET) in two families is reported. This finding will facilitate research on the functional role of this gene and related genes in the pathogenesis of ET.
Collapse
Affiliation(s)
- J J Higgins
- Center for Human Genetics and Child Neurology, Mid-Hudson Family Health Institute, 279 Main St., Suite 203A, New Paltz, NY 12561, USA.
| | | | | | | | | | | |
Collapse
|
45
|
Kim JH, Cho YH, Kim JK, Park YG, Chang JW. Frequent sequence variation at the
ETM2
locus and its association with sporadic essential tremor in Korea. Mov Disord 2005; 20:1650-3. [PMID: 16092108 DOI: 10.1002/mds.20646] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Essential tremor (ET) is the most common but a complex neurological movement disorder. ET usually affects hands, but it may also affect head, neck, face, jaw, tongue, voice, trunk and, rarely, legs and feet. Although two susceptibility loci were identified on chromosome 2p24 (ETM2) and 3q13 (ETM1 or FET1), the exact transcript(s) has not been cloned. We analyzed unrelated Korean individuals with ET for a genetic association with three reported polymorphic loci (STS-etm1240, STS-etm1231, and STS-etm1234) in a candidate region on chromosome 2p24.1. We investigated sequence polymorphisms at these three loci in 30 ET patients and 30 controls using polymerase chain reaction (PCR) amplification followed by sequence analysis. Eight different sequence variants (5 at etm1234, 2 at etm1240, and 1 at etm1231) were detected from 7 patients. Of interest, sequence variants were found only in classic ET patients but not in nonclassic ET patients and healthy individuals. Additionally, we also observed that a decrease in the number of short tandem repeats within etm1234 locus is more frequent in ET patients compared to controls. Our data thus support that ET development would be linked with the ETM2 locus and will facilitate the search for the ETM2 gene transcript.
Collapse
Affiliation(s)
- Jeong-Hyun Kim
- School of Life Sciences and Biotechnology, Korea University, Seoul, Korea
| | | | | | | | | |
Collapse
|
46
|
Louis ED, Applegate L, Factor-Litvak P, Parides MK. Factor Structure of Motor Signs in Essential Tremor. Neuroepidemiology 2005; 25:42-7. [PMID: 15855804 DOI: 10.1159/000085312] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Motor signs in essential tremor (ET) are varied. Patients may have limb tremors, including postural, kinetic (e.g. writing, pouring), and rest tremors, head tremor, voice tremor, or chin tremor. Factor analysis allows one to determine whether these signs fall into a smaller number of discrete domains. Such an analysis has not been performed on a group of ET cases. ET cases (n = 168) were recruited from the Neurological Institute of New York and a videotaped examination was performed. A factor analysis was performed on 17 motor items. Four distinct factors emerged, explaining 68.7% of the total variance. These were factor I (action tremor in the dominant arm), factor II (action tremor in the nondominant arm), factor III (tremor at rest) and factor IV (chin tremor, head tremor, and voice tremor). The demonstration of these four factors will be of potential use for pathological and genetic studies as well as interventional studies, as will be discussed.
Collapse
Affiliation(s)
- Elan D Louis
- G.H. Sergievsky Center, Department of Neurology, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
| | | | | | | |
Collapse
|
47
|
|
48
|
Abstract
OBJECTIVE To characterize the clinical and therapeutic aspects of essential tremor (ET) among children. BACKGROUND ET, an autosomal dominant disorder, has been studied extensively among adults, but little is known regarding its occurrence, clinical characteristics, treatment, and prognosis in pediatric populations. Often stigmatized as a disorder of the elderly, ET may be misdiagnosed among children. Previous studies of childhood-onset ET were limited by small sample sizes. METHODS Clinical data, including gender, age at onset, family history, associated disorders, and response to treatment, were collected for consecutive patients diagnosed with childhood-onset ET at the Movement Disorders Clinic at Baylor College of Medicine. RESULTS Of the 39 patients with ET, 29 (74.4%) were male. The mean age at onset was 8.8 +/- 5.0 years, and the mean age at evaluation was 20.3 +/- 14.4 years. A family history of tremor was noted for 79.5% of the patients. Eighteen (46.2%) had some neurologic comorbidity, such as dystonia, which was noted for 11 patients (28.2%). Only 24 of the patients (61.5%) were treated with a specific antitremor medication; 5 of the 12 patients treated with propranolol experienced improvement. CONCLUSIONS Concomitant movement disorders, such as dystonia, are common among patients with childhood-onset ET, which supports the concept that ET is a heterogeneous disorder. Treatment strategies used for adult patients with ET seem to be effective also for children with ET, although controlled therapeutic trials in this population of patients with ET are lacking.
Collapse
Affiliation(s)
- Joseph Jankovic
- Department of Neurology, Parkinson's Disease Center and Movement Disorders Clinic, Baylor College of Medicine, 6550 Fannin St, Suite 1801, Houston, TX 77030, USA.
| | | | | |
Collapse
|
49
|
Higgins JJ, Lombardi RQ, Tan EK, Jankovic J, Pucilowska J, Rooney JP. Haplotype analysis at the ETM2 locus in a Singaporean sample with familial essential tremor. Clin Genet 2004; 66:353-7. [PMID: 15355439 DOI: 10.1111/j.1399-0004.2004.00306.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An ancestral haplotype on chromosome 2p24.1 described in an American sample with familial essential tremor (ET) was analyzed in a different ethnic sample from Singapore. Six polymorphic loci (etm1240, etm1231, etm1234, APOB, etm1241, and etm1242) in a 274-kb interval within an ET gene candidate region (ETM2) were analyzed in Singaporean individuals with a family history of ET (n = 52) and compared to Singaporean controls older than age 65 (n = 49). The allele frequencies were significantly different between cases and controls for the loci etm1234 (p = 0.0001) and APOB (p = 0.0320). An extended haplotype formed by the loci etm1231, etm1234, and APOB occurred with a frequency of 31% in Singaporean cases and in 1.8% of elderly Singaporean controls (p = 0.0005). Haplotype studies in two different population samples suggest that a disease locus for ET lies near or within the 100-kb interval between the loci etm1231 and APOB.
Collapse
Affiliation(s)
- J J Higgins
- Center for Human Genetics and Child Neurology, Mid-Hudson Family Health Institute, New Paltz, NY 12561, USA.
| | | | | | | | | | | |
Collapse
|
50
|
Higgins JJ, Lombardi RQ, Pucilowska J, Ruszczyk MU. Integrated physical map of the human essential tremor gene region (ETM2) on chromosome 2p24.3-p24.2. Am J Med Genet B Neuropsychiatr Genet 2004; 127B:128-30. [PMID: 15108195 DOI: 10.1002/ajmg.b.20152] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A gene for autosomal dominant familial essential tremor maps to a 9.1 cM interval flanked by loci D2S224 and D2S405 (ETM2) on human chromosome 2p24.3-p24.2. The recombinatorial boundaries of the interval were refined on a radiation hybrid map to a 123 cR minimal critical region (MCR) between D2S224 and D2S2221. High-throughput non-isotopic screening of bacterial artificial chromosomes (BACs) was used to assemble a physical map of the region. A scaffold BAC map of 31 overlapping clones was ordered by their sequence tagged site (STS) content using PCR and Southern blotting. A complementary 3.9 Mb integrated physical map of the human ETM2 region was constructed by identifying GenBank contigs that contained seven BAC DNA sequences and common STSs. Thirty-three transcripts including five known genes (MATN3, LAPTM4A, SDC1, PUM2, and APOB) were identified in the MCR and ordered on an integrated contig by PCR and virtual mapping. This physical map will provide a template for genomic sequencing and the identification of a gene for essential tremor.
Collapse
Affiliation(s)
- Joseph J Higgins
- Center for Human Genetics and Child Neurology, Mid-Hudson Family Health Institute, New Paltz, New York 12561, USA.
| | | | | | | |
Collapse
|