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Clark LN, Gao Y, Wang GT, Hernandez N, Ashley-Koch A, Jankovic J, Ottman R, Leal SM, Rodriguez SMB, Louis ED. Whole genome sequencing identifies candidate genes for familial essential tremor and reveals biological pathways implicated in essential tremor aetiology. EBioMedicine 2022; 85:104290. [PMID: 36183486 PMCID: PMC9525816 DOI: 10.1016/j.ebiom.2022.104290] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 08/25/2022] [Accepted: 09/13/2022] [Indexed: 12/13/2022] Open
Abstract
Background Essential tremor (ET), one of the most common neurological disorders, has a phenotypically heterogeneous presentation characterized by bilateral kinetic tremor of the arms and, in some patients, tremor involving other body regions (e.g., head, voice). Genetic studies suggest that ET is genetically heterogeneous. Methods We analyzed whole genome sequence data (WGS) generated on 104 multi-generational white families with European ancestry affected by ET. Genome-wide parametric linkage and association scans were analyzed using adjusted logistic regression models through the application of the Pseudomarker software. To investigate the additional contribution of rare variants in familial ET, we also performed an aggregate variant non-parametric linkage (NPL) analysis using the collapsed haplotype method implemented in CHP-NPL software. Findings Parametric linkage analysis of common variants identified several loci with significant evidence of linkage (HLOD ≥3.6). Among the gene regions within the strongest ET linkage peaks were BTC (4q13.3, HLOD=4.53), N6AMT1 (21q21.3, HLOD=4.31), PCDH9 (13q21.32, HLOD=4.21), EYA1 (8q13.3, HLOD=4.04), RBFOX1 (16p13.3, HLOD=4.02), MAPT (17q21.31, HLOD=3.99) and SCARB2 (4q21.1, HLOD=3.65). CHP-NPL analysis identified fifteen additional genes with evidence of significant linkage (LOD ≥3.8). These genes include TUBB2A, VPS33B, STEAP1B, SPINK5, ZRANB1, TBC1D3C, PDPR, NPY4R, ETS2, ZNF736, SPATA21, ARL17A, PZP, BLK and CCDC94. In one ET family contributing to the linkage peak on chromosome 16p13.3, we identified a likely pathogenic heterozygous canonical splice acceptor variant in exon 2 of RBFOX1 (ENST00000547372; c.4-2A>G), that co-segregated with the ET phenotype in the family. Interpretation Linkage and association analyses of WGS identified several novel ET candidate genes, which are implicated in four major pathways that include 1) the epidermal growth factor receptor-phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha-AKT serine/threonine kinase 1 (EGFR-PI3K-AKT) and Mitogen-activated protein Kinase 1 (ERK) pathways, 2) Reactive oxygen species (ROS) and DNA repair, 3) gamma-aminobutyric acid-ergic (GABAergic) system and 4) RNA binding and regulation of RNA processes. Our study provides evidence for a possible overlap in the genetic architecture of ET, neurological disease, cancer and aging. The genes and pathways identified can be prioritized in future genetic and functional studies. Funding National Institutes of Health, NINDS, NS073872 (USA) and NIA AG058131(USA).
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Affiliation(s)
- Lorraine N Clark
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA; The Taub Institute for Research on Alzheimer's Disease and The Aging Brain, Columbia University Irving Medical Center, New York, NY, USA.
| | - Yizhe Gao
- The G.H. Sergievsky Center, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA; Department of Neurology, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA; The Center for Statistical Genetics, Columbia University Irving Medical Center, New York, NY, USA
| | - Gao T Wang
- The G.H. Sergievsky Center, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA; Department of Neurology, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA; The Center for Statistical Genetics, Columbia University Irving Medical Center, New York, NY, USA
| | - Nora Hernandez
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas TX, USA
| | - Allison Ashley-Koch
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC, USA
| | - Joseph Jankovic
- Parkinson's Disease Center and Movement Disorders Clinic, Department of Neurology, Baylor College of Medicine, Houston TX, USA
| | - Ruth Ottman
- The G.H. Sergievsky Center, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA; Department of Neurology, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA; Department of Epidemiology, Mailman School of Public Health, Columbia University Irving Medical Center, New York, NY, USA; Division of Translational Epidemiology, New York State Psychiatric Institute, New York, NY, USA
| | - Suzanne M Leal
- The Taub Institute for Research on Alzheimer's Disease and The Aging Brain, Columbia University Irving Medical Center, New York, NY, USA; The G.H. Sergievsky Center, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA; Department of Neurology, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA; The Center for Statistical Genetics, Columbia University Irving Medical Center, New York, NY, USA
| | - Sandra M Barral Rodriguez
- The Taub Institute for Research on Alzheimer's Disease and The Aging Brain, Columbia University Irving Medical Center, New York, NY, USA; The G.H. Sergievsky Center, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA; Department of Neurology, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA.
| | - Elan D Louis
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas TX, USA.
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Cosentino S, Shih LC. Does essential tremor increase risk of cognitive impairment and dementia? Yes. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2022; 163:195-231. [PMID: 35750363 DOI: 10.1016/bs.irn.2022.02.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Essential Tremor (ET), by definition, is a disorder of movement. Yet over the years, epidemiologic, clinical, pathologic, and neuroimaging studies have converged to reveal a cognitive side of ET. The cognitive symptoms in ET are heterogeneous and are likely to reflect heterogeneous underlying mechanisms. In this chapter, we review and synthesize a diverse set of studies from both population-based settings to cohorts with more detailed investigations into cognition to consider the various mechanisms by which cognitive symptoms may emerge in a subset of individuals with ET. As part of our analysis, we consider questions surrounding ET diagnosis and the possibility of comorbid disease as potential factors that, upon closer examination, appear to strengthen the argument in favor of ET as a risk factor for dementia. Importantly, we also consider the clinical relevance of cognitive impairment in ET. While ET is not universally characterized by significant cognitive deficits, the data from epidemiological, cognitive, neuroimaging, and postmortem neuropathologic studies converge to reveal an increased risk for cognitive impairment and dementia among individuals with ET. We conclude by offering directions for future research, and a neurocognitive framework with which to consider existing findings and to use in the design of novel studies dedicated to clarifying the basis, nature, and course of cognitive impairments in ET.
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Affiliation(s)
- Stephanie Cosentino
- Cognitive Neuroscience Division of the Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Irving Medical Center, New York, United States; Department of Neurology, Columbia University Irving Medical Center, New York, United States.
| | - Ludy C Shih
- Department of Neurology, Parkinson's Disease and Movement Disorders Center, Boston Medical Center, Boston, Massachusetts, United States; Department of Neurology, Boston University School of Medicine, Boston, Massachusetts, United States.
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Kim SH, Farrell K, Cosentino S, Vonsattel JPG, Faust PL, Cortes EP, Bennet DA, Louis ED, Crary JF. Tau Isoform Profile in Essential Tremor Diverges From Other Tauopathies. J Neuropathol Exp Neurol 2021; 80:835-843. [PMID: 34363663 DOI: 10.1093/jnen/nlab073] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Patients with essential tremor (ET) frequently develop concurrent dementia, which is often assumed to represent co-morbid Alzheimer disease (AD). Autopsy studies have identified a spectrum of tau pathologies in ET and tau isoforms have not been examined in ET. We performed immunoblotting using autopsy cerebral cortical tissue from patients with ET (n = 13), progressive supranuclear palsy ([PSP], n = 10), Pick disease ([PiD], n = 2), and AD (n = 7). Total tau in ET samples was similar to that in PSP and PiD but was significantly lower than that in AD. Abnormal tau levels measured using the AT8 phospho-tau specific (S202/T205/S208) monoclonal antibody in ET were similar to those in PSP but were lower than in PiD and AD. In aggregates, tau with 3 microtubule-binding domain repeats (3R) was significantly higher in AD than ET, while tau with 4 repeats (4R) was significantly higher in PSP. Strikingly, the total tau without N-terminal inserts in ET was significantly lower than in PSP, PiD, and AD, but total tau with other N-terminal inserts was not. Monomeric tau with one insert in ET was similar to that in PSP and PiD was lower than in AD. Thus, ET brains exhibit an expression profile of tau protein isoforms that diverges from that of other tauopathies.
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Affiliation(s)
- Soong Ho Kim
- From the Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC).,Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, JFC).,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC).,Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC)
| | - Kurt Farrell
- From the Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC).,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC).,Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC)
| | - Stephanie Cosentino
- Cognitive Neuroscience Division, Department of Neurology, Columbia University Medical Center, New York, New York, USA (SC); G.H. Sergievsky Center, Columbia University Medical Center, New York, New York, USA (SC, JPV).,Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, New York, USA (SC, JPV)
| | - Jean-Paul G Vonsattel
- Cognitive Neuroscience Division, Department of Neurology, Columbia University Medical Center, New York, New York, USA (SC); G.H. Sergievsky Center, Columbia University Medical Center, New York, New York, USA (SC, JPV).,Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, New York, USA (SC, JPV).,Department of Pathology & Cell Biology, Columbia University Medical Center and the New York Presbyterian Hospital, New York, New York, USA (JPV, PLF)
| | - Phyllis L Faust
- Department of Pathology & Cell Biology, Columbia University Medical Center and the New York Presbyterian Hospital, New York, New York, USA (JPV, PLF)
| | - Etty P Cortes
- From the Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC).,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC).,Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC).,Neuropathology Brain Bank & Research CoRE, Icahn School of Medicine at Mount Sinai, New York, New York, USA (EC, JFC)
| | - David A Bennet
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, Illinois, USA (DAB)
| | - Elan D Louis
- Department of Neurology, University of Texas Southwestern, Dallas, Texas, USA (EDL)
| | - John F Crary
- From the Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC).,Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, JFC).,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC).,Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC).,Neuropathology Brain Bank & Research CoRE, Icahn School of Medicine at Mount Sinai, New York, New York, USA (EC, JFC)
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Abstract
Highlights In the current review, we thoroughly reviewed 74 identified articles regarding genes and genetic loci that confer susceptibility to ET. Over 50 genes/genetic loci have been examined for possible association with ET, but consistent results failed to be reported raising the need for collaborative multiethnic studies. Background: Essential tremor (ET) is a common movement disorder, which is mainly characterized by bilateral tremor (postural and/or kinetic) in the upper limbs, with other parts of the body possibly involved. While the pathophysiology of ET is still unclear, there is accumulating evidence indicating that genetic variability may be heavily involved in ET pathogenesis. This review focuses on the role of genetic risk factors in ET susceptibility. Methods: The PubMed database was searched for articles written in English, for studies with humans with ET, controls without ET, and genetic variants. The terms “essential tremor” and “polymorphism” (as free words) were used during search. We also performed meta-analyses for the most examined genetic variants. Results: Seventy four articles concerning LINGO1, LINGO2, LINGO4, SLC1A2, STK32B, PPARGC1A, CTNNA3, DRD3, ALAD, VDR, HMOX1, HMOX2, LRRK1,LRRK2, GBA, SNCA, MAPT, FUS, CYPsIL17A, IL1B, NOS1, ADH1B, TREM2, RIT2, HNMT, MTHFR, PPP2R2B, GSTP1, PON1, GABA receptors and GABA transporter, HS1BP3, ADH2, hSKCa3 and CACNL1A4 genes, and ETM genetic loci were included in the current review. Results from meta-analyses revealed a marginal association for the STK32B rs10937625 and a marginal trend for association (in sensitivity analysis) for the LINGO1 rs9652490, with ET. Discussion: Quite a few variants have been examined for their possible association with ET. LINGO1 rs9652490 and STK32B rs10937625 appear to influence, to some extent, ET susceptibility. However, the conflicting results and the lack of replication for many candidate genes raise the need for collaborative multiethnic studies.
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Tau and TDP-43 proteinopathies: kindred pathologic cascades and genetic pleiotropy. J Transl Med 2019; 99:993-1007. [PMID: 30742063 PMCID: PMC6609463 DOI: 10.1038/s41374-019-0196-y] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 01/04/2019] [Accepted: 01/07/2019] [Indexed: 12/11/2022] Open
Abstract
We review the literature on Tau and TDP-43 proteinopathies in aged human brains and the relevant underlying pathogenetic cascades. Complex interacting pathways are implicated in Alzheimer's disease and related dementias (ADRD), wherein multiple proteins tend to misfold in a manner that is "reactive," but, subsequently, each proteinopathy may contribute strongly to the clinical symptoms. Tau proteinopathy exists in brains of individuals across a broad spectrum of primary underlying conditions-e.g., developmental, traumatic, and inflammatory/infectious diseases. TDP-43 proteinopathy is also expressed in a wide range of clinical disorders. Although TDP-43 proteinopathy was first described in the central nervous system of patients with amyotrophic lateral sclerosis (ALS) and in subtypes of frontotemporal dementia (FTD/FTLD), TDP-43 proteinopathy is also present in chronic traumatic encephalopathy, cognitively impaired persons in advanced age with hippocampal sclerosis, Huntington's disease, and other diseases. We list known Tau and TDP-43 proteinopathies. There is also evidence of cellular co-localization between Tau and TDP-43 misfolded proteins, suggesting common pathways or protein interactions facilitating misfolding in one protein by the other. Multiple pleiotropic gene variants can alter risk for Tau or TDP-43 pathologies, and certain gene variants (e.g., APOE ε4, Huntingtin triplet repeats) are associated with increases of both Tau and TDP-43 proteinopathies. Studies of genetic risk factors have provided insights into multiple nodes of the pathologic cascades involved in Tau and TDP-43 proteinopathies. Variants from a specific gene can be either a low-penetrant risk factor for a group of diseases, or alternatively, a different variant of the same gene may be a disease-driving allele that is associated with a relatively aggressive and early-onset version of a clinically and pathologically specific disease type. Overall, a complex but enlightening paradigm has emerged, wherein both Tau and TDP-43 proteinopathies are linked to numerous overlapping upstream influences, and both are associated with multiple downstream pathologically- and clinically-defined deleterious effects.
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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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Jiménez-Jiménez FJ, García-Martín E, Alonso-Navarro H, Lorenzo-Betancor O, Ortega-Cubero S, Pastor P, Calleja M, Agúndez JAG. A family study of DRD3 rs6280, SLC1A2 rs3794087 and MAPT rs1052553 variants in essential tremor. Neurol Res 2016; 38:880-7. [PMID: 27456607 DOI: 10.1080/01616412.2016.1210355] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND/OBJECTIVE Despite many data suggesting a role of genetic factors in the risk for essential tremor (ET), the responsible genes have not been identified. We analyzed in ET Spanish families three single nucleotide polymorphisms (SNPs): DRD3 rs6280, SLC1A2 rs3794087, and MAPT rs1052553) previously related to an increased risk for developing the disease. METHODS We recruited 45 subjects with ET and 13 subjects without tremor belonging to 11 families who were evaluated because of familial tremor. Diagnosis of probable or definite ET was done according to TRIG criteria. Genotyping of the 3 SNPs was done using TaqMan-based qPCR assays. Data were compared with those of healthy controls of our laboratory. Family-based association testing for disease traits was performed as well. RESULTS rs6280 and rs3794087 genotype and allelic frequencies did not differ significantly between subjects with ET and healthy controls. However, rs1052553AA genotype and the allele rs1052553A allele were significantly more frequent among ET patients. rs1052553A allele was non-significantly overrepresented in ET patients compared with controls when considering only the more severely affected member of each ET family. Family-based association test for disease traits showed lack of association between ET and the three SNPs studied. CONCLUSIONS Our results showed a lack of association between rs6280 and rs3794087 with the risk for ET, though a marginal increased risk for ET was observed among the rs1052553A allele carriers, which was not confirmed with a family-based association study.
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Affiliation(s)
- Félix Javier Jiménez-Jiménez
- a Section of Neurology , Hospital Universitario del Sureste , Arganda del Rey , Spain.,b Department of Medicine-Neurology , Hospital "Príncipe de Asturias", Universidad de Alcalá , Alcalá de Henares , Spain
| | | | - Hortensia Alonso-Navarro
- a Section of Neurology , Hospital Universitario del Sureste , Arganda del Rey , Spain.,b Department of Medicine-Neurology , Hospital "Príncipe de Asturias", Universidad de Alcalá , Alcalá de Henares , Spain
| | - Oswaldo Lorenzo-Betancor
- d Neurogenetics Laboratory, Division of Neurosciences , Center for Applied Medical Research, Universidad de Navarra , Pamplona , Spain.,e Department of Neurology , Complejo Asistencial Universitario de Palencia , Palencia , Spain
| | - Sara Ortega-Cubero
- d Neurogenetics Laboratory, Division of Neurosciences , Center for Applied Medical Research, Universidad de Navarra , Pamplona , Spain.,e Department of Neurology , Complejo Asistencial Universitario de Palencia , Palencia , Spain.,f CIBERNED,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas , Instituto de Salud Carlos III , Madrid , Spain
| | - Pau Pastor
- d Neurogenetics Laboratory, Division of Neurosciences , Center for Applied Medical Research, Universidad de Navarra , Pamplona , Spain.,f CIBERNED,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas , Instituto de Salud Carlos III , Madrid , Spain.,g Movement Disorders Unit, Deparment of of Neurology , Hospital Mutua de Terrassa , Terrassa , Spain
| | - Marisol Calleja
- a Section of Neurology , Hospital Universitario del Sureste , Arganda del Rey , Spain
| | - José A G Agúndez
- c Department of Pharmacology , Universidad de Extremadura , Cáceres , Spain
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Robakis D, Cortes E, Clark LN, Vonsattel JPG, Virmani T, Alcalay RN, Crary JF, Levy OA. The effect of MAPT haplotype on neocortical Lewy body pathology in Parkinson disease. J Neural Transm (Vienna) 2016; 123:583-8. [PMID: 27098667 DOI: 10.1007/s00702-016-1552-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 04/09/2016] [Indexed: 11/28/2022]
Abstract
The H1 haplotype of the microtubule-associated protein tau gene (MAPT) is associated with an increased risk of Parkinson disease (PD) compared with the H2 haplotype, but its effect on Lewy body (LB) formation is unclear. In this study, we compared the MAPT haplotype frequency between pathologically confirmed PD patients (n = 71) and controls (n = 52). We analyzed Braak LB stage, Braak neurofibrillary tangle (NFT) stage, and CERAD amyloid score by haplotype. We further tested the association between MAPT haplotype and semi-quantitative counts of LBs, NFTs, and neuritic plaques (NPs) in multiple neocortical regions. Consistent with previous reports, PD cases had an increased likelihood of carrying an H1/H1 genotype compared to controls (OR = 5.72, 95 % CI 1.80-18.21, p = 0.003). Braak LB, Braak NFT and CERAD scores did not differ by haplotype. However, H1/H1 carriers had higher LB counts in parietal cortex (p = 0.02) and in overall neocortical LBs (p = 0.03) compared to non-H1/H1 cases. Our analyses suggest that PD patients homozygous for the H1 haplotype have a higher burden of neocortical LB pathology.
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Affiliation(s)
- Daphne Robakis
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA
- Departments of Neurology, Yale School of Medicine, New Haven, CT, USA
| | - Etty Cortes
- Department of Pathology and Cell Biology, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Lorraine N Clark
- Department of Pathology and Cell Biology, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Jean Paul G Vonsattel
- Department of Pathology and Cell Biology, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Tuhin Virmani
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Roy N Alcalay
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA
| | - John F Crary
- Department of Pathology and Cell Biology, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, USA
- Departments of Pathology and Neuroscience, Friedman Brain Institute, Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Oren A Levy
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA.
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Affiliation(s)
- A H V Schapira
- Department of Clinical Neurosciences, UCL Institute of Neurology, London, UK.
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10
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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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