1
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Berry DS, Hernandez N, Clark LN, Louis ED. Lack of Familial Aggregation of the "Essential Tremor-Plus" Phenotype in Familial Essential Tremor. Neuroepidemiology 2022; 56:373-379. [PMID: 35940165 PMCID: PMC9633447 DOI: 10.1159/000526278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 07/20/2022] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Essential tremor (ET) is a highly prevalent neurological disease that frequently runs in families. A recent and controversial proposal is to separate ET patients into two distinct groups - ET versus ET-plus. If this were a valid construct, one would expect in familial aggregation studies to observe that ET-plus would cluster in some families yet be absent in others, rather than being randomly distributed across families. We examined whether there is evidence of familial aggregation of ET-plus. METHODS Probands (n = 84 [56 ET-plus and 28 ET]) and their first- and second-degree relatives (n = 182 and 48) enrolled in a genetics study. χ2 and generalized estimating equations (GEE) tested associations between probands' ET-plus status and the ET-plus status of their relatives. RESULTS χ2 analyses revealed that ET-plus was no more prevalent in relatives of probands diagnosed with ET-plus than in relatives of probands diagnosed with ET, p > 0.05. Restricting relatives to first-degree relatives similarly did not detect a significant association (p = 0.88). GEE yielded similar results (respective p's = 0.39 and 0.81). CONCLUSION The data demonstrate that ET-plus does not seem to aggregate in families. As such, they do not lend support to the notion that ET-plus is a valid biological construct.
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Affiliation(s)
- Diane S Berry
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, Texas, USA,
| | - Nora Hernandez
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Lorraine N Clark
- The Taub Institute for Research on Alzheimer's Disease and The Aging Brain, Columbia University Irving Medical Center, New York, New York, USA
- Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, New York, USA
| | - Elan D Louis
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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2
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Zhou M, Melin MD, Xu W, Südhof TC. Dysfunction of parvalbumin neurons in the cerebellar nuclei produces an action tremor. J Clin Invest 2020; 130:5142-5156. [PMID: 32634124 PMCID: PMC7524475 DOI: 10.1172/jci135802] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 06/24/2020] [Indexed: 12/16/2022] Open
Abstract
Essential tremor is a common brain disorder affecting millions of people, yet the neuronal mechanisms underlying this prevalent disease remain elusive. Here, we showed that conditional deletion of synaptotagmin-2, the fastest Ca2+ sensor for synaptic neurotransmitter release, from parvalbumin neurons in mice caused an action tremor syndrome resembling the core symptom of essential tremor patients. Combining brain region-specific and cell type-specific genetic manipulation methods, we found that deletion of synaptotagmin-2 from excitatory parvalbumin-positive neurons in cerebellar nuclei was sufficient to generate an action tremor. The synaptotagmin-2 deletion converted synchronous into asynchronous neurotransmitter release in projections from cerebellar nuclei neurons onto gigantocellular reticular nucleus neurons, which might produce an action tremor by causing signal oscillations during movement. The tremor was rescued by completely blocking synaptic transmission with tetanus toxin in cerebellar nuclei, which also reversed the tremor phenotype in the traditional harmaline-induced essential tremor model. Using a promising animal model for action tremor, our results thus characterized a synaptic circuit mechanism that may underlie the prevalent essential tremor disorder.
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Affiliation(s)
- Mu Zhou
- Department of Molecular and Cellular Physiology and
| | | | - Wei Xu
- Department of Molecular and Cellular Physiology and
| | - Thomas C. Südhof
- Department of Molecular and Cellular Physiology and
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California, USA
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3
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Hale EA, Hickman R, Dowd H, Varathan D, Liu G, Louis ED. Subtle Cerebellar Features in Relatives of Essential Tremor Cases. Front Neurol 2020; 11:605. [PMID: 32765392 PMCID: PMC7379149 DOI: 10.3389/fneur.2020.00605] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 05/25/2020] [Indexed: 12/03/2022] Open
Abstract
Background: Essential tremor (ET) cases often exhibit a range of mild cerebellar signs. Their unaffected relatives have been shown in prior studies to exhibit subtle (i.e., preclinical) disease features. Objective: To quantify subtle cerebellar signs in unaffected first-degree relatives of ET cases stratified based on their tremor severity. Methods: Two hundred sixty-nine first-degree relatives of ET cases, none of whom reported tremor or a diagnosis of ET, or were diagnosed with ET based on detailed neurological examination, were stratified based on total tremor score (TTS) into two groups (lower TTS vs. higher TTS) and quartiles. Changes in gait, balance, and intention tremor were quantified on neurological examination. Results: Higher TTS performed worse on the tandem stance task (p = 0.011). When stratified into TTS quartiles, higher quartile was associated with worse performance in tandem stance (p = 0.011) and stance with feet together (p = 0.028). Similarly, intention tremor in the arms (p = 0.0002) and legs (p = 0.047) were higher in the groups with more tremor. Discussion: The links between ET and the cerebellum are multiple. These data provide intriguing evidence that subtle cerebellar signs (i.e., changes in balance and intention tremor) are more prevalent among first-degree relatives of ET cases with more tremor (i.e., those who may be themselves on the pathway to developing ET). These data contribute to a better characterization of what may be an early subclinical stage of the disease.
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Affiliation(s)
- Evan A Hale
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Ruby Hickman
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Hollie Dowd
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Deepti Varathan
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Gina Liu
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Elan D Louis
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, United States.,Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, CT, United States.,Department of Neurology and Neurotherapeutics, University of Texas Southwestern, Dallas, TX, United States
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4
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Louis ED, Eliasen EH, Ferrer M, Iglesias Hernandez D, Gaini S, Jiang W, Zheng W, Nielsen F, Petersen MS. Blood Harmane (1-Methyl-9H-Pyrido[3,4-b]indole) and Mercury in Essential Tremor: A Population-Based, Environmental Epidemiology Study in the Faroe Islands. Neuroepidemiology 2020; 54:272-280. [PMID: 32007995 PMCID: PMC7210050 DOI: 10.1159/000505874] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 01/08/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Essential tremor (ET) is among the most prevalent neurological diseases. Its environmental determinants are poorly understood. Harmane (1-methyl-9H-pyrido[3, 4-b]indole), a dietary tremor-producing neurotoxin, has been linked to ET in a few studies in New York and Madrid. Mercury, also a tremor-producing neurotoxin, has not been studied in ET. The Faroe Islands have been the focus of epidemiological investigations of numerous neurological disorders. OBJECTIVE In this population-based, case-control study, we directly measured blood harmane concentrations (HA) and blood mercury concentrations (Hg) in ET cases and controls. METHODS In total, 1,328 Faroese adults were screened; 26 ET cases were identified whose (HA) and (Hg) were compared to 197 controls. RESULTS Although there were no statistically significant differences between diagnostic groups, median (HA) was 2.7× higher in definite ET (4.13 g-10/mL) and 1.5× higher in probable ET (2.28 g-10/mL) than controls (1.53 g-10/mL). Small sample size was a limitation. For definite ET versus controls, p = 0.126. (Hg) were similar between groups. CONCLUSIONS We demonstrated marginally elevated (HA) in definite and probable ET. These data are similar to those previously published and possibly extend etiological links between this neurotoxin and ET to a third locale. The study did not support a link between mercury and ET.
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Affiliation(s)
- Elan D Louis
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, Connecticut, USA,
- Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, Connecticut, USA,
- Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, Connecticut, USA,
| | - Eina H Eliasen
- Department of Occupational Medicine and Public Health, The Faroese Hospital System, Tórshavn, Faeroe Islands
| | - Monica Ferrer
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, Connecticut, USA
| | | | - Shahin Gaini
- Centre for Health Science, Faculty of Health Sciences, University of the Faroe Islands, Tórshavn, Faeroe Islands
- Infectious Diseases Division, National Hospital Faroe Islands, Tórshavn, Faeroe Islands
- Department of Infectious Diseases, Odense University Hospital/University of Southern Denmark, Odense, Denmark
| | - Wendy Jiang
- Purdue University School of Health Sciences, West Lafayette, Indiana, USA
| | - Wei Zheng
- Purdue University School of Health Sciences, West Lafayette, Indiana, USA
| | - Flemming Nielsen
- Department of Environmental Medicine, University of Southern Denmark, Odense, Denmark
| | - Maria Skaalum Petersen
- Department of Occupational Medicine and Public Health, The Faroese Hospital System, Tórshavn, Faeroe Islands
- Centre for Health Science, Faculty of Health Sciences, University of the Faroe Islands, Tórshavn, Faeroe Islands
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5
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Essential tremor pathology: neurodegeneration and reorganization of neuronal connections. Nat Rev Neurol 2020; 16:69-83. [PMID: 31959938 DOI: 10.1038/s41582-019-0302-1] [Citation(s) in RCA: 92] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/10/2019] [Indexed: 01/26/2023]
Abstract
Essential tremor (ET) is the most common tremor disorder globally and is characterized by kinetic tremor of the upper limbs, although other clinical features can also occur. Postmortem studies are a particularly important avenue for advancing our understanding of the pathogenesis of ET; however, until recently, the number of such studies has been limited. Several recent postmortem studies have made important contributions to our understanding of the pathological changes that take place in ET. These studies identified abnormalities in the cerebellum, which primarily affected Purkinje cells (PCs), basket cells and climbing fibres, in individuals with ET. We suggest that some of these pathological changes (for example, focal PC axonal swellings, swellings in and regression of the PC dendritic arbor and PC death) are likely to be primary and degenerative. By contrast, other changes, such as an increase in PC recurrent axonal collateral formation and hypertrophy of GABAergic basket cell axonal processes, could be compensatory responses to restore cerebellar GABAergic tone and cerebellar cortical inhibitory efficacy. Such compensatory responses are likely to be insufficient, enabling the disease to progress. Here, we review the results of recent postmortem studies of ET and attempt to place these findings into an anatomical-physiological disease model.
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6
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Eliasen EH, Ferrer M, Gaini S, Louis ED, Petersen MS. Prevalence of Essential Tremor in the Faroe Islands: A Population-Based Study. Neuroepidemiology 2019; 52:227-236. [PMID: 30889566 DOI: 10.1159/000499070] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 02/22/2019] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND No studies of the prevalence of one of the most common movement disorders, essential tremor (ET), have been undertaken in the Faroe Islands. Given the potential for founder effects in the Islands, and the highly genetic nature of ET, the Faroe Islands provide a particularly interesting setting in which to study the prevalence of ET. OBJECTIVE To estimate the prevalence of ET and study its characteristics. METHODS We used a 2-phase, population-based design, screening 1,328 randomly selected Faroese individuals aged ≥40 years. A subsample of 282 individuals who had returned the spirals and questionnaire was selected to participate in an in-person clinical evaluation. Tremor was systematically quantified by a senior movement disorder neurologist with particular specialization in tremor using a reliable and valid clinical rating scale followed by the application of rigorous diagnostic criteria used by tremor investigators internationally. RESULTS The overall crude prevalence was 2.9%. The age-adjusted prevalence was 3.1%. There was an age-associated rise in prevalence; by age ≥70, prevalence reached 4.8%. Twenty six of 27 (96.2%) were previously undiagnosed. CONCLUSIONS This is the first population-based study of the prevalence of ET in the Faroe Islands. The estimated prevalence was similar to studies using the same or comparable methodologies.
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Affiliation(s)
- Eina H Eliasen
- Department of Occupational Medicine and Public Health, The Faroese Hospital Systems, Tórshavn, Faeroe Islands,
| | - Monica Ferrer
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, Connecticut, USA
| | - Shahin Gaini
- Centre for Health Science, Faculty of Health Sciences, University of the Faroe Islands, Tórshavn, Faeroe Islands.,Infectious Diseases Division, National Hospital Faroe Islands, Tórshavn, Faeroe Islands.,Department of Infectious Diseases, Odense University Hospital/University of Southern Denmark, Odense, Denmark
| | - Elan D Louis
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, Connecticut, USA.,Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, Connecticut, USA.,Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, Connecticut, USA
| | - Maria Skaalum Petersen
- Department of Occupational Medicine and Public Health, The Faroese Hospital Systems, Tórshavn, Faeroe Islands.,Centre for Health Science, Faculty of Health Sciences, University of the Faroe Islands, Tórshavn, Faeroe Islands
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7
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Louis ED, Meyers JH, Cristal AD, Factor-Litvak P. Caffeine Consumption in First-Degree Relatives of Essential Tremor Cases: Evidence of Dietary Modification Before Disease Onset. Neuroepidemiology 2018; 51:64-70. [PMID: 29953981 DOI: 10.1159/000489960] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 05/08/2018] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Caffeine can exacerbate tremor. Reducing caffeine intake or switching to decaffeinated beverages can lessen tremor. Unaffected relatives of essential tremor (ET) cases often have mild, subclinical tremor. One question is whether the coffee and tea consumption pattern in these individuals differs from that of controls (Co). METHODS We ascertained the patterns of coffee and tea intake using a structured questionnaire, and compared the use in unaffected first-degree relatives of ET cases (FD-ET) to the use in age-matched Co. Three measures of relative caffeinated coffee + tea to decaffeinated coffee + tea were constructed. Caffeine index 1 = (cups of caffeinated coffee + tea) - (cups of decaffeinated coffee + tea) consumed on the day of evaluation. Caffeine index 2 = (cups of caffeinated coffee + tea) - (cups of decaffeinated coffee + tea) consumed in a typical month. The percentage of coffee and tea that was caffeinated in a typical month was also calculated. RESULTS There were 263 individuals (190 FD-ET, 73 Co). Caffeine index 1 in FD-ET was less than 1-half that of Co (p = 0.001). Caffeine index 2 was similarly lower in FD-ET than Co (p = 0.027). The percentage of coffee and tea that was caffeinated in a typical month was also significantly lower in FD-ET than Co (p = 0.018). CONCLUSION The balance of caffeinated to decaffeinated beverages is different in FD-ET than Co. These data raise several intriguing questions. Among these is whether relatives of ET cases modify their caffeine consumption before disease onset.
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Affiliation(s)
- Elan D Louis
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, Connecticut, USA.,Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, Connecticut, USA.,Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, Connecticut, USA
| | - James H Meyers
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, Connecticut, USA
| | - Ashley D Cristal
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, Connecticut, USA
| | - Pam Factor-Litvak
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York, USA
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8
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Naranjo KV, Park J, Chen KP, Hernandez N, Clark LN, Ottman R, Louis ED. Genetic Testing Preferences of Individuals in Families with Essential Tremor. TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2018; 8:545. [PMID: 29607242 PMCID: PMC5876471 DOI: 10.7916/d8b296rk] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 03/02/2018] [Indexed: 01/15/2023]
Abstract
Background The search for essential tremor (ET) genes is active, and it is only a matter of time before genetic tests become available. Genetic testing preferences in families have been studied in numerous other neurological disorders but there are no published data about ET. Methods We surveyed 34 ET probands and their relatives (43 affected, 28 unaffected) enrolled in our Family Study of Essential Tremor to assess their interest in genetic testing. We examined whether clinical factors influenced their interest in testing. Clinical utility (“Your physician will be able to use the information obtained to improve your care”) and penetrance (“How likely an individual who carries an ET gene is to develop ET”) were defined for participants. Results Interest in genetic testing was high in ET families (90/105 [85.7%]). There was a significant difference between affected (including probands and affected relatives) and unaffected relatives in terms of their interest in genetic testing, with the former being more interested (70/77 [90.9%] vs. 20/28 [71.4%] p = 0.04). Participants were more likely to want testing in the scenarios with high clinical utility; disease penetrance was not a determining factor (all p < 0.05). Sixteen hypothetical factors were identified that might influence a participant’s decision to undergo genetic testing for ET. Discussion Interest in genetic testing was high in ET families. While genetic testing is not currently available for ET, the hunt for ET genes is ongoing, and this is a highly familial disorder. Understanding genetic testing preferences will greatly aid clinicians once a genetic test becomes available.
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Affiliation(s)
- Kelly V Naranjo
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Jemin Park
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Karen P Chen
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Nora Hernandez
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Lorraine N Clark
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, USA.,Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Ruth Ottman
- G.H. Sergievsky Center, College of Physicians and Surgeons, 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
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA.,Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, CT, USA.,Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, CT, USA
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9
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Cristal AD, Chen KP, Hernandez NC, Factor-Litvak P, Clark LN, Ottman R, Louis ED. Knowledge about Essential Tremor: A Study of Essential Tremor Families. Front Neurol 2018; 9:27. [PMID: 29434571 PMCID: PMC5790790 DOI: 10.3389/fneur.2018.00027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 01/12/2018] [Indexed: 01/17/2023] Open
Abstract
Background Essential tremor (ET) is among the most common neurological diseases and it often runs in families. How knowledgeable ET patients and their families are about their disease has been the subject of surprisingly little scholarship. Methods To fill this gap in knowledge, we administered a comprehensive 32-item survey (i.e., questions about etiology, pathophysiology, symptoms and signs, natural history, and treatments) to 427 participants, including 76 ET probands, 74 affected relatives (AFRs), 238 unaffected relatives, and 39 spouses of unaffected relatives, all of whom were participating in two ET family studies. We hypothesized that there would be gaps in knowledge about ET and furthermore, that probands and AFRs would be the most knowledgeable, followed by unaffected relatives and then spouses of unaffected relatives, who would be the least knowledgeable. Results Overall, ET patients lacked knowledge about their disease. Nearly one-third of probands answered "yes" or "do not know" to the question, "is ET the same or different from the type of tremor that many normal people can get when they become old and frail?" A similar proportion did not know whether children could get ET or they responded "no." Nearly one-fourth of affecteds (i.e., probands and AFRs) did not know whether or to what degree (e.g., very well, moderately well, not well) the symptoms of ET could be medically controlled, and 38.0% either reported that there was no brain surgery for ET or reported that they did not know. Nearly 17% of affecteds did not endorse genes as a cause for ET, which was surprising given the fact that this was a family study of ET. Probands and AFRs were the most knowledgeable, followed by unaffected relatives. Spouses of unaffected relatives were the least knowledgeable. Conclusion We targeted a large group of ET patients and their families, as this group is perhaps most likely to be informed about the disease. ET patients and their AFRs were more knowledgeable about the features of ET than their family members without ET. Overall, however, knowledge of ET was very limited and this lack of knowledge encompassed all aspects of the disease including its underlying causes, the nature of the symptoms and signs, its natural history and its treatment. Further ET awareness education and programs targeting both families of ET patients and the public would help alleviate this gap in knowledge.
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Affiliation(s)
- Ashley D Cristal
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Karen P Chen
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Nora Cristina Hernandez
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Pam Factor-Litvak
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, United States
| | - Lorraine N Clark
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, United States.,Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, United States
| | - Ruth Ottman
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, United States.,G.H. Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, NY, United States.,Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, United States.,Department of Epidemiology, New York State Psychiatric Institute, New York, NY, United States
| | - Elan D Louis
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, CT, United States.,Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, CT, United States
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10
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Louis ED, Meyers JH, Badejo OM, Cristal AD, Hickman R, Factor-Litvak P. Comparative Burden of Subclinical Tremor in a Cohort of Normal Individuals Stratified by Familial Risk for Essential Tremor. Neuroepidemiology 2018; 50:41-46. [PMID: 29339654 DOI: 10.1159/000486485] [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: 10/30/2017] [Accepted: 12/22/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The burden of mild (i.e., subclinical) tremor within essential tremor (ET) families is not fully understood. We assessed the burden of mild tremor in a cohort of 287 adults, none of whom reported tremor or were diagnosed with ET. METHODS We recruited adults in 2 groups based on the familial risk for ET: 244 high-risk individuals (i.e., reporting one or more first-degree relative with ET) and 43 low-risk individuals (i.e., reporting no relatives with ET). Tremor was objectively assessed on 4 hand-drawn spirals (total spiral score = 0-12). Mild tremor was defined using 3 different cut points. RESULTS The prevalence rates of mild tremor among high-risk individuals ranged from 41.4 to 98.4% and were highly dependent on the cut point. Above a certain threshold (i.e., a total spiral score ≥5), 1-in-5 (i.e., 19.7%) high-risk individuals exhibited mild tremor, whereas no low-risk individuals did. High-risk individuals were 3.09-4.50 times more likely than low-risk individuals to exhibit mild tremor. CONCLUSION The burden of ET extends beyond the boundaries of the clinically defined disease, and partially expressed forms of ET are abundant in ET families. This fact greatly complicates gene-finding studies and epidemiological studies whose goal is to detect disease-linked associations.
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Affiliation(s)
- Elan D Louis
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, Connecticut, USA.,Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, Connecticut, USA.,Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, Connecticut, USA
| | - James H Meyers
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, Connecticut, USA
| | - Olufunmilayo M Badejo
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, Connecticut, USA
| | - Ashley D Cristal
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, Connecticut, USA
| | - Ruby Hickman
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, Connecticut, USA
| | - Pam Factor-Litvak
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York, USA
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11
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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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12
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Louis ED, Hernandez N, Chen KP, Naranjo KV, Park J, Clark LN, Ottman R. Action Tremor Asymmetry Profile Does Not Aggregate in Families with Essential Tremor. Front Neurol 2017; 8:148. [PMID: 28469594 PMCID: PMC5395646 DOI: 10.3389/fneur.2017.00148] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 03/31/2017] [Indexed: 12/18/2022] Open
Abstract
Background Action tremor is the hallmark feature of essential tremor (ET). While the tremor typically is mildly asymmetric, in some patients, it is markedly asymmetric. There are few data on factors that influence this asymmetry. ET is also a highly familial disease. Whether the tremor asymmetry profile (i.e., differential expression of tremor in each arm in a given patient) is similar across family members is not known. The alternative possibility is that this feature is not heritable. There are no published data addressing this issue. The aim of this study was to determine whether the extent of action tremor asymmetry ran in ET families. Methods ET probands and relatives were enrolled in a genetic study at Yale and Columbia Universities. An in-person evaluation included a videotaped neurological examination, including a detailed assessment of tremors. A senior movement disorders neurologist reviewed all videotaped examinations, and the severity of postural and kinetic arm tremors was rated on 12 examination items using a reliable rating scale. The tremor asymmetry index = right arm tremor score − left arm tremor score. We used a bivariate linear regression model to assess the predictors of the tremor asymmetry index in relatives; this model used the tremor asymmetry index in the proband as a primary predictor of interest. In an analysis of variance (ANOVA), we tested for heterogeneity across families in the tremor asymmetry index (i.e., to see whether there was a significant family effect). Results There were 187 enrollees (59 probands, 128 affected relatives). In a bivariate linear regression model, the tremor asymmetry index in the proband was not a predictor of the tremor asymmetry index in their relatives (p = 0.66). In an ANOVA, family grouping did not explain a significant proportion of the total variance in the tremor asymmetry index (p = 0.56). Conclusion Tremor asymmetry did not aggregate in families with ET. Therefore, this does not seem to be a disease feature that is heritable. These data will provide added value to the clinical dialog, giving patients one more piece of information about the way the disease manifests within families.
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Affiliation(s)
- Elan D Louis
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA.,Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, CT, USA.,Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Nora Hernandez
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Karen P Chen
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Kelly V Naranjo
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Jemin Park
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Lorraine N Clark
- College of Physicians and Surgeons, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA.,Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Ruth Ottman
- G.H. Sergievsky Center, College of Physicians and Surgeons, 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
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Abstract
A fundamental question about essential tremor (ET) is whether its associated pathological changes and disease mechanisms are linkable to a specific brain region. To that end, recent tissue-based studies have made significant strides in elucidating changes in the ET brain. Emerging from these studies is increasing neuropathological evidence linking ET to the cerebellum. These studies have systematically identified a broad range of structural, degenerative changes in the ET cerebellum, spanning across all Purkinje cell compartments. These include the dendritic compartment (where there is an increase in number of Purkinje cell dendritic swellings, a pruning of the dendritic arbor, and a reduction in spine density), the cell body (where, aside from reductions in Purkinje cell linear density in some studies, there is an increase in the number of heterotopic Purkinje cell soma), and the axonal compartment (where a plethora of changes in axonal morphology have been observed, including an increase in the number of thickened axonal profiles, torpedoes, axonal recurrent collaterals, axonal branching, and terminal axonal sprouting). Additional changes, possibly due to secondary remodeling, have been observed in neighboring neuronal populations. These include a hypertrophy of basket cell axonal processes and changes in the distribution of climbing fiber-Purkinje cell synapses. These changes all distinguish ET from normal control brains. Initial studies further indicate that the profile (i.e., constellation) of these changes may separate ET from other diseases of the cerebellum, thereby serving as a disease signature. With the discovery of these changes, a new model of ET has arisen, which posits that it may be a neurodegenerative disorder centered in the cerebellar cortex. These newly emerging neuropathological studies pave the way for anatomically focused, hypothesis-driven, molecular mechanistic studies of disease pathogenesis.
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Louis ED, Hernandez N, Chen KP, Naranjo KV, Park J, Clark LN, Ottman R. Familial Aggregation of the Cerebellar Signs in Familial Essential Tremor. TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2017; 7:439. [PMID: 28176975 PMCID: PMC5288993 DOI: 10.7916/d8kk9c8q] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 12/21/2016] [Indexed: 12/13/2022]
Abstract
Background Although the hallmark feature of essential tremor (ET) is kinetic tremor, patients may exhibit additional motor features (e.g., intention tremor and mild gait ataxia) that are markers of an underlying abnormality of cerebellar function. ET is also a highly familial disorder, but we do not know whether the presence and expression of cerebellar signs are similar across family members. There are simply no published data. The alternative possibility is that these features are not heritable. We tested the specific hypothesis that the presence of cerebellar signs (i.e., intention tremor, tandem gait difficulty) ran in ET families. Methods ET probands and relatives enrolled in a genetic study at Yale and Columbia universities underwent a detailed videotaped neurological examination. Results There were 187 enrollees (59 probands, 128 affected relatives). In a bivariate logistic regression model, the presence of intention tremor in the proband was not a predictor of the presence of intention tremor in the relatives (odds ratio [OR] = 0.60, 95% confidence interval [CI] = 0.28–1.27, p = 0.18). In a similar model, the presence of greater tandem gait difficulty (i.e., a tandem gait score in the upper quartile) in the proband was not a predictor of the presence of such difficulty in the relatives (OR = 1.22, 95% CI = 0.41–3.66, p = 0.73). Discussion The presence of cerebellar signs did not aggregate in families with ET. In the current dataset, these did not seem to be disease features that were heritable.
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Affiliation(s)
- Elan D Louis
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA; Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, CT, USA; Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Nora Hernandez
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Karen P Chen
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Kelly V Naranjo
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Jemin Park
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Lorraine N Clark
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, USA; Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Ruth Ottman
- G.H. Sergievsky Center, College of Physicians and Surgeons, 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
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15
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Hor H, Francescatto L, Bartesaghi L, Ortega-Cubero S, Kousi M, Lorenzo-Betancor O, Jiménez-Jiménez FJ, Gironell A, Clarimón J, Drechsel O, Agúndez JAG, Kenzelmann Broz D, Chiquet-Ehrismann R, Lleó A, Coria F, García-Martin E, Alonso-Navarro H, Martí MJ, Kulisevsky J, Hor CN, Ossowski S, Chrast R, Katsanis N, Pastor P, Estivill X. Missense mutations in TENM4, a regulator of axon guidance and central myelination, cause essential tremor. Hum Mol Genet 2015; 24:5677-86. [PMID: 26188006 DOI: 10.1093/hmg/ddv281] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 07/13/2015] [Indexed: 12/16/2022] Open
Abstract
Essential tremor (ET) is a common movement disorder with an estimated prevalence of 5% of the population aged over 65 years. In spite of intensive efforts, the genetic architecture of ET remains unknown. We used a combination of whole-exome sequencing and targeted resequencing in three ET families. In vitro and in vivo experiments in oligodendrocyte precursor cells and zebrafish were performed to test our findings. Whole-exome sequencing revealed a missense mutation in TENM4 segregating in an autosomal-dominant fashion in an ET family. Subsequent targeted resequencing of TENM4 led to the discovery of two novel missense mutations. Not only did these two mutations segregate with ET in two additional families, but we also observed significant over transmission of pathogenic TENM4 alleles across the three families. Consistent with a dominant mode of inheritance, in vitro analysis in oligodendrocyte precursor cells showed that mutant proteins mislocalize. Finally, expression of human mRNA harboring any of three patient mutations in zebrafish embryos induced defects in axon guidance, confirming a dominant-negative mode of action for these mutations. Our genetic and functional data, which is corroborated by the existence of a Tenm4 knockout mouse displaying an ET phenotype, implicates TENM4 in ET. Together with previous studies of TENM4 in model organisms, our studies intimate that processes regulating myelination in the central nervous system and axon guidance might be significant contributors to the genetic burden of this disorder.
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Affiliation(s)
- Hyun Hor
- Bioinformatics and Genomics Program, Centre for Genomic Regulation (CRG), Barcelona, Spain, Universitat Pompeu Fabra (UPF), Barcelona, Spain, Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain, CRG CIBER de Epidemiología y Salud Pública (CIBERESP), Barcelona, Catalonia 08003, Spain,
| | - Ludmila Francescatto
- Center for Human Disease Modeling, Duke University, Duke University Medical Center, Durham NC 27710, USA
| | - Luca Bartesaghi
- Department of Medical Genetics, University of Lausanne, Lausanne 1005, Switzerland, Department of Neuroscience and Department of Clinical Neuroscience, Karolinska Institutet, Stockholm 171 77, Sweden
| | - Sara Ortega-Cubero
- Neurogenetics Laboratory, Division of Neurosciences, Center for Applied Medical Research (CIMA), and Department of Neurology, Clínica Universidad de Navarra, University of Navarra School of Medicine and Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Pamplona, Navarra 31008, Spain
| | - Maria Kousi
- Center for Human Disease Modeling, Duke University, Duke University Medical Center, Durham NC 27710, USA
| | - Oswaldo Lorenzo-Betancor
- Neurogenetics Laboratory, Division of Neurosciences, Center for Applied Medical Research (CIMA), and Department of Neurology, Clínica Universidad de Navarra, University of Navarra School of Medicine and Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Pamplona, Navarra 31008, Spain
| | - Felix J Jiménez-Jiménez
- Section of Neurology, Hospital Universitario del Sureste, Arganda del Rey, Madrid 28030, Spain
| | - Alexandre Gironell
- Movement Disorders Unit, Neurology Department, Hospital de Sant Pau, Barcelona, Spain, Sant Pau Biomedical Research Institute, Barcelona, Spain
| | - Jordi Clarimón
- Sant Pau Biomedical Research Institute, Barcelona, Spain, Universitat Autònoma de Barcelona and CIBERNED, Barcelona, Catalonia 08026, Spain
| | - Oliver Drechsel
- Bioinformatics and Genomics Program, Centre for Genomic Regulation (CRG), Barcelona, Spain, Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | | | - Daniela Kenzelmann Broz
- Faculty of Sciences and Department of Biomedicine, Friedrich Miescher Institute of Biomedical Research, Novartis Research Foundation and University of Basel, Basel 4058, Switzerland
| | - Ruth Chiquet-Ehrismann
- Faculty of Sciences and Department of Biomedicine, Friedrich Miescher Institute of Biomedical Research, Novartis Research Foundation and University of Basel, Basel 4058, Switzerland
| | - Alberto Lleó
- Sant Pau Biomedical Research Institute, Barcelona, Spain
| | - Francisco Coria
- Clinic for Nervous Disorders, Service of Neurology, Son Espases University Hospital, Palma de Mallorca 07120, Spain
| | - Elena García-Martin
- Department of Biochemistry and Molecular Biology, University of Extremadura, Cáceres 10071, Spain
| | | | - Maria J Martí
- Movement Disorders Unit, Neurology Service, Hospital Clinic, CIBERNED and Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Catalonia 08036, Spain and
| | - Jaume Kulisevsky
- Movement Disorders Unit, Neurology Department, Hospital de Sant Pau, Barcelona, Spain, Universitat Autònoma de Barcelona and CIBERNED, Barcelona, Catalonia 08026, Spain
| | - Charlotte N Hor
- Bioinformatics and Genomics Program, Centre for Genomic Regulation (CRG), Barcelona, Spain, Universitat Pompeu Fabra (UPF), Barcelona, Spain, Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain, CRG CIBER de Epidemiología y Salud Pública (CIBERESP), Barcelona, Catalonia 08003, Spain
| | - Stephan Ossowski
- Bioinformatics and Genomics Program, Centre for Genomic Regulation (CRG), Barcelona, Spain, Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Roman Chrast
- Department of Medical Genetics, University of Lausanne, Lausanne 1005, Switzerland, Department of Neuroscience and Department of Clinical Neuroscience, Karolinska Institutet, Stockholm 171 77, Sweden
| | - Nicholas Katsanis
- Center for Human Disease Modeling, Duke University, Duke University Medical Center, Durham NC 27710, USA
| | - Pau Pastor
- Neurogenetics Laboratory, Division of Neurosciences, Center for Applied Medical Research (CIMA), and Department of Neurology, Clínica Universidad de Navarra, University of Navarra School of Medicine and Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Pamplona, Navarra 31008, Spain,
| | - Xavier Estivill
- Bioinformatics and Genomics Program, Centre for Genomic Regulation (CRG), Barcelona, Spain, Universitat Pompeu Fabra (UPF), Barcelona, Spain, Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain, CRG CIBER de Epidemiología y Salud Pública (CIBERESP), Barcelona, Catalonia 08003, Spain, Dexeus Women's Health, University Hospital Quiron-Dexeus, Barcelona, Catalonia 08028, Spain
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16
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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.
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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.
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Park YG, Choi JH, Lee C, Kim S, Kim Y, Chang KY, Paek SH, Kim D. Heterogeneity of tremor mechanisms assessed by tremor-related cortical potential in mice. Mol Brain 2015; 8:3. [PMID: 25588467 PMCID: PMC4304607 DOI: 10.1186/s13041-015-0093-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Accepted: 01/06/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Identifying a neural circuit mechanism that is differentially involved in tremor would aid in the diagnosis and cure of such cases. Here, we demonstrate that tremor-related cortical potential (TRCP) is differentially expressed in two different mouse models of tremor. RESULTS Hybrid tremor analysis of harmaline-induced and genetic tremor in mice revealed that two authentic tremor frequencies for each type of tremor were conserved and showed an opposite dependence on CaV3.1 T-type Ca(2+) channels. Electroencephalogram recordings revealed that α1(-/-);α1G(-/-) mice double-null for the GABA receptor α1 subunit (Gabra1) and CaV3.1 T-type Ca(2+) channels (Cacna1g), in which the tremor caused by the absence of Gabra1 is potentiated by the absence of Cacna1g, showed a coherent TRCP that exhibited an onset that preceded the initiation of behavioral tremor by 3 ms. However, harmaline-induced tremor, which is known to be abolished by α1G(-/-), showed no TRCP. CONCLUSIONS Our results demonstrate that the α1(-/-);α1G(-/-) double-knockout tremor model is useful for studying cortical mechanisms of tremor.
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Affiliation(s)
- Young-Gyun Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), 335 Gwahak-ro, Yuseong-gu, Daejeon, 305-701, Republic of Korea.
| | - Jee Hyun Choi
- Center for Neural Science, Division of Life Science, Korea Institute of Science and Technology, Seoul, 136-79, Republic of Korea.
| | - Chungki Lee
- Center for Neural Science, Division of Life Science, Korea Institute of Science and Technology, Seoul, 136-79, Republic of Korea.
| | - Sehyun Kim
- Department of Physics, KAIST, Daejeon, 305-701, Republic of Korea.
| | - Youngsoo Kim
- Department of Medical Science and Engineering, KAIST, Daejeon, 305-701, Republic of Korea.
| | - Ki-Young Chang
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), 335 Gwahak-ro, Yuseong-gu, Daejeon, 305-701, Republic of Korea.
| | - Sun Ha Paek
- Department of Neurosurgery, Hypoxia/Ischemia Disease Institute, Seoul National University College of Medicine, Seoul, 110-744, Republic of Korea.
| | - Daesoo Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), 335 Gwahak-ro, Yuseong-gu, Daejeon, 305-701, Republic of Korea.
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18
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Gonzalez-Alegre P, Di Paola J, Wang K, Fabbro S, Yu HC, Shaikh TH, Darbro BW, Bassuk AG. Evaluating Familial Essential Tremor with Novel Genetic Approaches: Is it a Genotyping or Phenotyping Issue? TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2014; 4:258. [PMID: 25374765 PMCID: PMC4219111 DOI: 10.7916/d8fb51g3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 09/15/2014] [Indexed: 12/12/2022]
Abstract
Background Essential tremor is a common movement disorder with a strong heritable component. Large families with inherited forms of essential tremor have undergone genetic analyses by different approaches. However, our knowledge of genetic variants unequivocally linked to essential tremor is remarkably limited. Several explanations have been put forth to explain this challenge, including the possibility of mutations in non-coding areas of the genome. Methods We encountered a family with highly penetrant, autosomal dominant tremor. We hypothesized that, if a single coding gene mutation was responsible for the phenotype, novel genetic tools would allow us to identify it. We employed single nucleotide polymorphism (SNP) arrays in 17 members of this family followed by next generation whole-exome sequencing in five affected subjects. Results We did not identify any copy number variant or mutation that segregated with the disease phenotype. Discussion This study emphasizes the remarkably challenging field of tremor genetics and indicates that future studies should perhaps shift to analysis of the non-coding genome.
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Affiliation(s)
- Pedro Gonzalez-Alegre
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Jorge Di Paola
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Kai Wang
- Department of Biostatistics, College of Public Health, University of Iowa, Iowa City, IA, USA
| | - Shay Fabbro
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Hung-Chun Yu
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Tamim H Shaikh
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Benjamin W Darbro
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Alexander G Bassuk
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA ; Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
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Abstract
For many years, little was written about the underlying biology of ET, despite its high prevalence. Discussions of disease mechanisms were dominated by a focus on tremor physiology. The traditional model of ET, the olivary model, was proposed in the 1970s. The model suffers from several critical problems, and its relevance to ET has been questioned. Recent mechanistic research has focused on the cerebellum. Clinical and neuroimaging studies strongly implicate the importance of this brain region in ET. Recent mechanistic research has been grounded more in tissue-based changes (i.e., postmortem studies of the brain). These studies have collectively and systematically identified a sizable number of changes in the ET cerebellum, and have led to a new model of ET, referred to as the cerebellar degenerative model. Hence, there is a renewed interest in the science behind the biology of ET. How the new understanding of ET will translate into treatment changes is an open question.
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Affiliation(s)
- Elan D Louis
- GH Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, NY, USA,
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20
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Wu Y, Ding J, Gao Y, Chen S, Li L, Li R. Mini Review: linkages between essential tremor and Parkinson's disease? Front Cell Neurosci 2013; 7:118. [PMID: 23914155 PMCID: PMC3728484 DOI: 10.3389/fncel.2013.00118] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 07/07/2013] [Indexed: 11/17/2022] Open
Abstract
Essential tremor (ET) and Parkinson’s disease (PD) are two of the most common movement disorders. Tremors are the primary symptoms of ET and of some PD patients, the two are often mistaken for each other. Especially since there are no available differentiate tests for the tremor of ET or PD, the early diagnoses mainly based on clinical assessments of medical symptoms, family and medication history, and examination by physicians. There is increasing evidence suggesting an association between ET and PD, such as a similar tremor frequency, overlapping resting tremors (a typical PD tremor), postural tremors (mainly in ET patients) in both ET and PD patients, and many ET patients develop PD later in life. Although it is difficult to make a differential diagnosis of ET and tremor-dominant PD based on clinical assessment, recent developments of objective measurements, such as brain imaging, neuropathology, and genetic analysis, has opened a helpful window for distinguishing ET from PD. In this mini review, we included literatures of ET and PD studies and discussed various advanced methods for differential diagnosis between ET and PD such as neuroimaging, genetic markers, tremor intensity and frequency, and drug-responses.
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Affiliation(s)
- Yiwen Wu
- 1 Department of Neurology and Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine Shanghai, China
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