1
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Wright SE, Todd PK. Native functions of short tandem repeats. eLife 2023; 12:e84043. [PMID: 36940239 PMCID: PMC10027321 DOI: 10.7554/elife.84043] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 03/08/2023] [Indexed: 03/21/2023] Open
Abstract
Over a third of the human genome is comprised of repetitive sequences, including more than a million short tandem repeats (STRs). While studies of the pathologic consequences of repeat expansions that cause syndromic human diseases are extensive, the potential native functions of STRs are often ignored. Here, we summarize a growing body of research into the normal biological functions for repetitive elements across the genome, with a particular focus on the roles of STRs in regulating gene expression. We propose reconceptualizing the pathogenic consequences of repeat expansions as aberrancies in normal gene regulation. From this altered viewpoint, we predict that future work will reveal broader roles for STRs in neuronal function and as risk alleles for more common human neurological diseases.
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Affiliation(s)
- Shannon E Wright
- Department of Neurology, University of Michigan–Ann ArborAnn ArborUnited States
- Neuroscience Graduate Program, University of Michigan–Ann ArborAnn ArborUnited States
- Department of Neuroscience, Picower InstituteCambridgeUnited States
| | - Peter K Todd
- Department of Neurology, University of Michigan–Ann ArborAnn ArborUnited States
- VA Ann Arbor Healthcare SystemAnn ArborUnited States
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2
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Screening for the FMR1 premutation in Greek patients with late-onset movement disorders. Parkinsonism Relat Disord 2023; 107:105253. [PMID: 36549234 DOI: 10.1016/j.parkreldis.2022.105253] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/06/2022] [Accepted: 12/18/2022] [Indexed: 12/24/2022]
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset, X-linked, neurodegenerative disorder that affects premutation carriers of the FMR1 gene. FXTAS is often misdiagnosed as spinocerebellar ataxia (SCA) or Parkinson's disease (PD). Herein, we sought to investigate the frequency, genotypic and phenotypic profile of FXTAS in two cohorts of Greek patients with late-onset movement disorders, one with cerebellar ataxia and the other with PD. In total, 90 index patients with late-onset cerebellar ataxia and 171 with PD were selected. None of the cases had male-to-male transmission. Genetic screening for the FMR1 premutation was performed using standard methodology. The FMR1 premutation was detected in two ataxia patients (2.2%) and two PD patients (1.2%). Additional clinical features in FXTAS patients from the ataxia cohort included neuropathy, mild parkinsonism, cognitive impairment and pyramidal signs. The FXTAS patients from the PD cohort had typical PD. We conclude that, in the Greek population, the FMR1 premutation is an important, albeit rare, cause of late-onset movement disorders. Routine premutation screening should be considered in SCA panel-negative late-onset ataxia cases. Directed premutation screening should be considered in all ataxia and PD cases with additional features suggestive of FXTAS. Our study highlights the importance of FMR1 genetic testing in the diagnosis of late-onset movement disorders.
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Jiménez-Jiménez FJ, Alonso-Navarro H, García-Martín E, Álvarez I, Pastor P, Agúndez JAG. Genomic Markers for Essential Tremor. Pharmaceuticals (Basel) 2021; 14:ph14060516. [PMID: 34072005 PMCID: PMC8226734 DOI: 10.3390/ph14060516] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 05/23/2021] [Accepted: 05/24/2021] [Indexed: 12/13/2022] Open
Abstract
There are many reports suggesting an important role of genetic factors in the etiopathogenesis of essential tremor (ET), encouraging continuing the research for possible genetic markers. Linkage studies in families with ET have identified 4 genes/loci for familial ET, although the responsible gene(s) have not been identified. Genome-wide association studies (GWAS) described several variants in LINGO1, SLC1A2, STK32B, PPARGC1A, and CTNNA3, related with ET, but none of them have been confirmed in replication studies. In addition, the case-control association studies performed for candidate variants have not convincingly linked any gene with the risk for ET. Exome studies described the association of several genes with familial ET (FUS, HTRA2, TENM4, SORT1, SCN11A, NOTCH2NLC, NOS3, KCNS2, HAPLN4, USP46, CACNA1G, SLIT3, CCDC183, MMP10, and GPR151), but they were found only in singular families and, again, not found in other families or other populations, suggesting that some can be private polymorphisms. The search for responsible genes for ET is still ongoing.
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Affiliation(s)
- Félix Javier Jiménez-Jiménez
- Section of Neurology, Hospital Universitario del Sureste, E28500 Arganda del Rey, Spain;
- Correspondence: ; Tel.: +34-636-96-83-95; Fax: +34-913-28-07-04
| | | | - Elena García-Martín
- ARADyAL Instituto de Salud Carlos III, University Institute of Molecular Pathology Biomarkers, University of Extremadura, E10071 Caceres, Spain; (E.G.-M.); (J.A.G.A.)
| | - Ignacio Álvarez
- Movement Disorders Unit, Department of Neurology, University Hospital Mútua de Terrassa, Fundació Docencia i Recerça Mútua de Terrassa, E08221 Terrassa, Spain; (I.Á.); (P.P.)
| | - Pau Pastor
- Movement Disorders Unit, Department of Neurology, University Hospital Mútua de Terrassa, Fundació Docencia i Recerça Mútua de Terrassa, E08221 Terrassa, Spain; (I.Á.); (P.P.)
| | - José A. G. Agúndez
- ARADyAL Instituto de Salud Carlos III, University Institute of Molecular Pathology Biomarkers, University of Extremadura, E10071 Caceres, Spain; (E.G.-M.); (J.A.G.A.)
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4
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Robinson AC, Bajaj N, Hadjivassiliou M, Minshull J, Mahmood A, Roncaroli F. Neuropathology of a case of fragile X-associated tremor ataxia syndrome without tremor. Neuropathology 2020; 40:611-619. [PMID: 32830366 DOI: 10.1111/neup.12674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 05/08/2020] [Accepted: 05/08/2020] [Indexed: 12/01/2022]
Abstract
Fragile X-associated tremor ataxia syndrome (FXTAS) is a neurodegenerative disorder caused by a CGG trinucleotide expansion from 55 to 200 repeats in the non-coding region of the fragile X mental retardation 1 (FMR1) gene (FMR1). Clinical features include cognitive decline, progressive tremor, and gait ataxia. Neuropathologically, FXTAS shows white matter changes, hippocampal and cerebellar involvement, and p62-positive eosinophilic intranuclear inclusions in astrocytes and neurons. Here, we document the neuropathological findings from a subject who developed cognitive impairment but not tremor and was proved to have genetically confirmed FMR1 premutation. Microscopically, typical p62-postive intranuclear inclusions were present in all the regions examined. Neocortical regions demonstrated gliosis of layer I and mild degree of neuronal loss and atrophy across the other layers. The molecular, Purkinje's cell, and granule cell layers of the cerebellar folia demonstrated mild gliosis, and cerebellar white matter was mildly affected. Aside from p62-positive inclusions, the hippocampus was spared. Arteries in the deep white matter often showed changes consistent with moderate small vessel disease (SVD). Reactive gliosis and severe SVD were features of basal ganglia. Florid reactive astrocytosis was found in the white matter of all regions. Axonal loss and features of axonal damage were found in the white matter of the centrum semiovale. Microglial activation was widespread and evenly seen in both the white matter and grey matter, although the grey matter appeared more severely affected. Pathology associated with Alzheimer's disease was limited. Similarly, no abnormal accumulations of α-synuclein were present. We postulate that age at death and disease duration may play a role in the extent of the pathological features associated with FXTAS. The present results suggest that immunohistochemical staining for p62 can help with the diagnosis of cases with atypical phenotype. In addition, it is likely that the cognitive impairment observed was a result of white matter changes.
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Affiliation(s)
- Andrew C Robinson
- Faculty of Biology, Medicine and Health, School of Biological Sciences, Division of Neuroscience & Experimental Psychology, The University of Manchester, Salford Royal Hospital, Salford, UK
| | - Nin Bajaj
- Department of Neurology, University of Nottingham, Nottingham, UK
| | - Marios Hadjivassiliou
- Department of Neurology, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
| | - James Minshull
- Faculty of Biology, Medicine and Health, School of Biological Sciences, Division of Neuroscience & Experimental Psychology, The University of Manchester, Salford Royal Hospital, Salford, UK
| | - Aiza Mahmood
- Neuropathology Unit, Salford Royal Hospital, Manchester, UK
| | - Federico Roncaroli
- Faculty of Biology, Medicine and Health, School of Biological Sciences, Division of Neuroscience & Experimental Psychology, The University of Manchester, Salford Royal Hospital, Salford, UK.,Neuropathology Unit, Salford Royal Hospital, Manchester, UK
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5
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Robertson EE, Hall DA, Pal G, Ouyang B, Liu Y, Joyce JM, Berry-Kravis E, O'Keefe JA. Tremorography in fragile X-associated tremor/ataxia syndrome, Parkinson's disease and essential tremor. Clin Park Relat Disord 2020; 3:100040. [PMID: 34316626 PMCID: PMC8298795 DOI: 10.1016/j.prdoa.2020.100040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 11/07/2019] [Accepted: 11/22/2019] [Indexed: 11/25/2022] Open
Abstract
Background Fragile X-associated tremor/ataxia syndrome (FXTAS), a neurodegenerative disease affecting carriers of a 55-200 CGG repeat in the fragile X mental retardation 1 gene, may receive an initial diagnosis of Parkinson's disease (PD) or essential tremor (ET) due to overlapping motor symptoms. Therefore, tremor and bradykinesia were compared in these disorders using quantitative tremorography. Methods The inertial sensor based Kinesia ™ system was used to quantify upper extremity tremor and bradykinesia in participants with FXTAS (n = 25), PD (n = 23), ET (n = 18) and controls (n = 20) and regression analysis was performed to determine whether tremorography measures distinguished between the groups. The FXTAS Rating scale (FXTAS-RS) was administered to determine whether sub-score items on the clinician rated scale correlated with tremorography variables. Results FXTAS participants had reduced finger tap speed compared to those with ET, and ET had increased kinetic tremor compared to PD. Higher kinetic tremor distinguished FXTAS from PD (p = .02), and lower finger tap speed distinguished FXTAS from ET (p = .004). FXTAS-RS tremor and bradykinesia items correlated with tremorography measures (p = .005 to <0.0001). Conclusions This is the first quantitative study to compare tremor and bradykinesia in FXTAS, PD and ET. Kinetic tremor and bradykinesia measures using a quantitative inertial sensor system distinguished FXTAS from PD and ET, respectively. Such technologies may be useful for detecting precise tremor and bradykinesia abnormalities and distinguishing the tremor and bradykinesia profiles in each of these disorders.
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Affiliation(s)
- Erin E Robertson
- Department of Cell and Molecular Medicine, Rush University Medical Center, Chicago, IL, United States of America
| | - Deborah A Hall
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, United States of America
| | - Gian Pal
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, United States of America
| | - Bichun Ouyang
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, United States of America
| | - Yuanqing Liu
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, United States of America
| | - Jessica M Joyce
- Department of Cell and Molecular Medicine, Rush University Medical Center, Chicago, IL, United States of America
| | - Elizabeth Berry-Kravis
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, United States of America.,Department of Pediatrics, Rush University Medical Center, Chicago, IL, United States of America.,Department of Biochemistry, Rush University Medical Center, Chicago, IL, United States of America
| | - Joan A O'Keefe
- Department of Cell and Molecular Medicine, Rush University Medical Center, Chicago, IL, United States of America.,Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, United States of America.,Rush Medical College, Rush University Medical Center, Chicago, IL, United States of America
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6
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Fay-Karmon T, Hassin-Baer S. The spectrum of tremor among carriers of the FMR1 premutation with or without the fragile X-associated tremor/ataxia syndrome (FXTAS). Parkinsonism Relat Disord 2019; 65:32-38. [DOI: 10.1016/j.parkreldis.2019.05.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 05/01/2019] [Accepted: 05/06/2019] [Indexed: 10/26/2022]
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7
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Banez-Coronel M, Ranum LPW. Repeat-associated non-AUG (RAN) translation: insights from pathology. J Transl Med 2019; 99:929-942. [PMID: 30918326 PMCID: PMC7219275 DOI: 10.1038/s41374-019-0241-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 01/29/2019] [Indexed: 12/14/2022] Open
Abstract
More than 40 different neurological diseases are caused by microsatellite repeat expansions. Since the discovery of repeat-associated non-AUG (RAN) translation by Zu et al. in 2011, nine expansion disorders have been identified as RAN-positive diseases. RAN proteins are translated from different types of nucleotide repeat expansions and can be produced from both sense and antisense transcripts. In some diseases, RAN proteins have been shown to accumulate in affected brain regions. Here we review the pathological and molecular aspects associated with RAN protein accumulation for each particular disorder, the correlation between disease pathology and the available in vivo models and the common aspects shared by some of the newly discovered RAN proteins.
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Affiliation(s)
- Monica Banez-Coronel
- Center for NeuroGenetics, University of Florida, Gainesville, FL, 32610, USA
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, 32610, USA
| | - Laura P W Ranum
- Center for NeuroGenetics, University of Florida, Gainesville, FL, 32610, USA.
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, 32610, USA.
- Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.
- McKnight Brain Institute, University of Florida, Gainesville, FL, 32610, USA.
- Genetics Institute, University of Florida, Gainesville, FL, 32610, USA.
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Abstract
BACKGROUND Tremor is a symptom of many diseases and can constitute a disease of its own: essential tremor. OBJECTIVE The genetics of essential tremor and differential diagnosis of monogenic diseases with the symptom tremor. MATERIAL AND METHODS Literature search and search of clinical genetics databases, e.g. OMIM, GeneReviews, MDSGene and the German Neurological Society (DGN) guidelines. RESULTS The genetics of essential tremor remain unresolved in spite of large, adequately powered studies. Tremor is a symptom of differential diagnostic value in many movement disorders. A slight tremor might have been missed or not reported in many descriptions of movement disorders. CONCLUSION Progress in the genetics of essential tremor probably requires a more detailed phenotyping allowing stratification into phenotypically defined subgroups. Tremor should always be included in the examination and description of movement disorders even if tremor is not a cardinal symptom. Tremor might be helpful in the differential diagnosis of hereditary dystonia, hereditary ataxia, spastic paraplegia and other movement disorders.
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Affiliation(s)
- G Kuhlenbäumer
- Klinik für Neurologie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Christian-Albrechts-Universität Kiel, Arnold-Heller-Str. 3, 24105, Kiel, Deutschland.
| | - F Hopfner
- Klinik für Neurologie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Christian-Albrechts-Universität Kiel, Arnold-Heller-Str. 3, 24105, Kiel, Deutschland
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9
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Espay AJ, Lang AE, Erro R, Merola A, Fasano A, Berardelli A, Bhatia KP. Essential pitfalls in "essential" tremor. Mov Disord 2017; 32:325-331. [PMID: 28116753 DOI: 10.1002/mds.26919] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 12/11/2016] [Accepted: 12/19/2016] [Indexed: 12/13/2022] Open
Abstract
Although essential tremor has been considered the most common movement disorder, it has largely remained a diagnosis of exclusion: many tremor and nontremor features must be absent for the clinical diagnosis to stand. The clinical features of "essential tremor" overlap with or may be part of other tremor disorders and, not surprisingly, this prevalent familial disorder has remained without a gene identified, without a consistent natural history, and without an acceptable pathology or pathophysiologic underpinning. The collective evidence suggests that under the rubric of essential tremor there exists multiple unique diseases, some of which represent cerebellar dysfunction, but for which there is no intrinsic "essence" other than a common oscillatory behavior on posture and action. One approach may be to use the term essential tremor only as a transitional node in the deep phenotyping of tremor disorders based on historical, phenomenological, and neurophysiological features to facilitate its etiologic diagnosis or serve for future gene- and biomarker-discovery efforts. This approach deemphasizes essential tremor as a diagnostic entity and facilitates the understanding of the underlying disorders to develop biologically tailored diagnostic and therapeutic strategies. © 2017 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Alberto J Espay
- UC Gardner Neuroscience Institute, Department of Neurology, Gardner Center for Parkinson's Disease and Movement Disorders, University of Cincinnati, Ohio, USA
| | - Anthony E Lang
- Morton and Gloria Shulman Movement Disorders Center, Toronto Western Hospital and The Edmond J. Safra Program in PD, Toronto, Ontario, Canada, University of Toronto, Toronto, Ontario, Canada.,Krembil Research Institute, Toronto, Ontario, Canada
| | - Roberto Erro
- Department of Neuroscience, Biomedicine and Movement Science, University of Verona, Verona, Italy
| | - Aristide Merola
- UC Gardner Neuroscience Institute, Department of Neurology, Gardner Center for Parkinson's Disease and Movement Disorders, University of Cincinnati, Ohio, USA
| | - Alfonso Fasano
- Morton and Gloria Shulman Movement Disorders Center, Toronto Western Hospital and The Edmond J. Safra Program in PD, Toronto, Ontario, Canada, University of Toronto, Toronto, Ontario, Canada.,Krembil Research Institute, Toronto, Ontario, Canada
| | - Alfredo Berardelli
- Department of Neurology and Psychiatry, "Sapienza" University of Rome, Rome, Italy.,IRCCS Neuromed, Pozzilli, IS, Italy
| | - Kailash P Bhatia
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, UK
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10
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Ure RJ, Dhanju S, Lang AE, Fasano A. Unusual tremor syndromes: know in order to recognise. J Neurol Neurosurg Psychiatry 2016; 87:1191-1203. [PMID: 26985048 DOI: 10.1136/jnnp-2015-311693] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 02/28/2016] [Indexed: 11/04/2022]
Abstract
Tremor is a common neurological condition in clinical practice; yet, few syndromes are widely recognised and discussed in the literature. As a result, there is an overdiagnosis of well-known causes, such as essential tremor. Many important unusual syndromes should be considered in the differential diagnosis of patients with tremor. The objective of this review is to provide broad clinical information to aid in the recognition and treatment of various unusual tremor syndromes in the adult and paediatric populations. The review comprised of a comprehensive online search using PubMed, Ovid database and Google Scholar to identify the available literature for each unusual tremor syndrome. The review includes fragile X-associated tremor/ataxia syndrome, spinocerebellar ataxia type 12, tremors caused by autosomal recessive cerebellar ataxias, myorhythmia, isolated tongue tremor, Wilson's disease, slow orthostatic tremor, peripheral trauma-induced tremor, tardive tremor and rabbit syndrome, paroxysmal tremors (hereditary chin tremor, bilateral high-frequency synchronous discharges, head tremor, limb-shaking transient ischaemic attack), bobble-head doll syndrome, spasmus nutans and shuddering attacks. Rare tremors generally present with an action tremor and a variable combination of postural and kinetic components with resting tremors less frequently seen. The phenomenology of myorhythmia is still vague and a clinical definition is proposed. The recognition of these entities should facilitate the correct diagnosis and guide the physician to a prompt intervention.
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Affiliation(s)
- Robert J Ure
- Sheffield Teaching Hospitals NHS Foundation Trust, University of Sheffield, Sheffield, South Yorkshire, UK
| | - Sanveer Dhanju
- Faculty of Science, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Anthony E Lang
- Division of Neurology, Morton and Gloria Shulman Movement Disorders Clinic and the Edmond J. Safra Program in Parkinson's Disease, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Alfonso Fasano
- Division of Neurology, Morton and Gloria Shulman Movement Disorders Clinic and the Edmond J. Safra Program in Parkinson's Disease, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
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11
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Robertson EE, Hall DA, McAsey AR, O'Keefe JA. Fragile X-associated tremor/ataxia syndrome: phenotypic comparisons with other movement disorders. Clin Neuropsychol 2016; 30:849-900. [PMID: 27414076 PMCID: PMC7336900 DOI: 10.1080/13854046.2016.1202239] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 06/12/2016] [Indexed: 12/16/2022]
Abstract
OBJECTIVE The purpose of this paper is to review the typical cognitive and motor impairments seen in fragile X-associated tremor/ataxia syndrome (FXTAS), essential tremor (ET), Parkinson disease (PD), spinocerebellar ataxias (SCAs), multiple system atrophy (MSA), and progressive supranuclear palsy (PSP) in order to enhance diagnosis of FXTAS patients. METHODS We compared the cognitive and motor phenotypes of FXTAS with each of these other movement disorders. Relevant neuropathological and neuroimaging findings are also reviewed. Finally, we describe the differences in age of onset, disease severity, progression rates, and average lifespan in FXTAS compared to ET, PD, SCAs, MSA, and PSP. We conclude with a flow chart algorithm to guide the clinician in the differential diagnosis of FXTAS. RESULTS By comparing the cognitive and motor phenotypes of FXTAS with the phenotypes of ET, PD, SCAs, MSA, and PSP we have clarified potential symptom overlap while elucidating factors that make these disorders unique from one another. In summary, the clinician should consider a FXTAS diagnosis and testing for the Fragile X mental retardation 1 (FMR1) gene premutation if a patient over the age of 50 (1) presents with cerebellar ataxia and/or intention tremor with mild parkinsonism, (2) has the middle cerebellar peduncle (MCP) sign, global cerebellar and cerebral atrophy, and/or subcortical white matter lesions on MRI, or (3) has a family history of fragile X related disorders, intellectual disability, autism, premature ovarian failure and has neurological signs consistent with FXTAS. Peripheral neuropathy, executive function deficits, anxiety, or depression are supportive of the diagnosis. CONCLUSIONS Distinct profiles in the cognitive and motor domains between these movement disorders may guide practitioners in the differential diagnosis process and ultimately lead to better medical management of FXTAS patients.
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Affiliation(s)
- Erin E Robertson
- a Department of Anatomy and Cell Biology , Rush University , Chicago , IL , USA
| | - Deborah A Hall
- b Department of Neurological Sciences , Rush University , Chicago , IL , USA
| | - Andrew R McAsey
- a Department of Anatomy and Cell Biology , Rush University , Chicago , IL , USA
| | - Joan A O'Keefe
- a Department of Anatomy and Cell Biology , Rush University , Chicago , IL , USA
- b Department of Neurological Sciences , Rush University , Chicago , IL , USA
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12
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Grigsby J, Brega AG, Bennett RE, Bourgeois JA, Seritan AL, Goodrich GK, Hagerman RJ. Clinically significant psychiatric symptoms among male carriers of the fragile X premutation, with and without FXTAS, and the mediating influence of executive functioning. Clin Neuropsychol 2016; 30:944-59. [PMID: 27355103 PMCID: PMC5011752 DOI: 10.1080/13854046.2016.1185100] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 04/26/2016] [Indexed: 10/21/2022]
Abstract
OBJECTIVES To clarify the neuropsychiatric phenotype of fragile X-associated tremor/ataxia syndrome (FXTAS), and assess the extent to which it is mediated by the dysexecutive syndrome that is a major feature of the disorder. METHODS We examined the prevalence of clinically meaningful psychiatric symptoms among male carriers of the fragile X premutation, with and without FXTAS, in comparison with men with a normal allele. Measures included the Neuropsychiatric Inventory (NPI), Symptom Checklist-90-R (SCL-90-R), and the Behavioral Dyscontrol Scale, a measure of executive functioning. Between-group differences were evaluated using logistic regression, followed by a mediation analysis with ordinary least squares regression to assess the contribution of dysexecutive syndrome to the observed psychiatric domains. RESULTS Men with FXTAS showed higher rates of clinically significant symptoms overall and in specific domains: somatization, obsessive compulsive, depression, anxiety, psychoticism, agitation/aggression, apathy/indifference, irritability, and nighttime behavior problems. Post hoc analyses suggested that findings of psychoticism among men with FXTAS may be associated with participants' accurate acknowledgment of cognitive and physical dysfunction, rather than reflecting psychosis. Asymptomatic carriers showed no evidence of clinically significant psychiatric symptoms, but when all carriers were compared with men having a normal FMR1 allele, executive function deficits were found to mediate scores in several domains on both NPI and SCL-90-R. CONCLUSIONS Building on prior research, the results provide evidence that the psychiatric phenotype for men includes clinically meaningful depression, hostility, and irritability, in association with behavioral and attentional disinhibition. It is likely that these problems reflect the effects of impaired executive functioning.
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Affiliation(s)
- Jim Grigsby
- a Department of Psychology , University of Colorado Denver , Denver , CO , USA
- b Department of Medicine , University of Colorado Denver , Aurora , CO , USA
| | - Angela G Brega
- c Department of Community and Behavioral Health , Colorado School of Public Health, University of Colorado Denver , Aurora , CO , USA
| | - Rachael E Bennett
- b Department of Medicine , University of Colorado Denver , Aurora , CO , USA
| | - James A Bourgeois
- d Department of Psychiatry , University of California , San Francisco , CA , USA
- e Langley Porter Psychiatric Institute , University of California , San Francisco , CA , USA
| | - Andreea L Seritan
- d Department of Psychiatry , University of California , San Francisco , CA , USA
| | - Glenn K Goodrich
- f Kaiser Permanente Institute for Health Research , Denver , CO , USA
| | - Randi J Hagerman
- g M.I.N.D. Institute , University of California, Davis , Sacramento , CA , USA
- h Department of Pediatrics , University of California, Davis, Medical Center , Sacramento , CA , USA
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13
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Grigsby J. The fragile X mental retardation 1 gene (FMR1): historical perspective, phenotypes, mechanism, pathology, and epidemiology. Clin Neuropsychol 2016; 30:815-33. [PMID: 27356167 DOI: 10.1080/13854046.2016.1184652] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVES To provide an historical perspective and overview of the phenotypes, mechanism, pathology, and epidemiology of the fragile X-associated tremor/ataxia syndrome (FXTAS) for neuropsychologists. METHODS Selective review of the literature on FXTAS. RESULTS FXTAS is an X-linked neurodegenerative disorder of late onset. One of several phenotypes associated with different mutations of the fragile X mental retardation 1 gene (FMR1), FXTAS involves progressive action tremor, gait ataxia, and impaired executive functioning, among other features. It affects carriers of the FMR1 premutation, which may expand when passed from a mother to her children, in which case it is likely to cause fragile X syndrome (FXS), the most common inherited developmental disability. CONCLUSION This review briefly summarizes current knowledge of the mechanisms, epidemiology, and mode of transmission of FXTAS and FXS, as well as the neuropsychological, neurologic, neuropsychiatric, neuropathologic, and neuroradiologic phenotypes of FXTAS. Because it was only recently identified, FXTAS is not well known to most practitioners, and it remains largely misdiagnosed, despite the fact that its prevalence may be relatively high.
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Affiliation(s)
- Jim Grigsby
- a Departments of Psychology and Medicine , University of Colorado Denver , Denver , CO , USA
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FMR1 gene mutations in patients with fragile X syndrome and obligate carriers: 30 years of experience in Chile. Genet Res (Camb) 2016; 98:e11. [PMID: 27350105 DOI: 10.1017/s0016672316000082] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Fragile X syndrome (FXS) is the most common form of inherited intellectual disability (ID) and co-morbid autism. It is caused by an amplification of the CGG repeat (>200), which is known as the full mutation, within the 5'UTR of the FMR1 gene. Expansions between 55-200 CGG repeats are termed premutation and are associated with a greater risk for fragile X-associated tremor/ataxia syndrome and fragile X-associated premature ovarian insufficiency. Intermediate alleles, also called the grey zone, include approximately 45-54 repeats and are considered borderline. Individuals with less than 45 repeats have a normal FMR1 gene. We report the occurrence of CGG expansions of the FMR1 gene in Chile among patients with ID and families with a known history of FXS. Here, we present a retrospective review conducted on 2321 cases (2202 probands and 119 relatives) referred for FXS diagnosis and cascade screening at the Institute of Nutrition and Food Technology (INTA), University of Chile. Samples were analysed using traditional cytogenetic methods and/or PCR. Southern blot was used to confirm the diagnosis. Overall frequency of FMR1 expansions observed among probands was 194 (8·8%), the average age of diagnosis was 8·8 ± 5·4 years. Of 119 family members studied, 72 (60%) were diagnosed with a CGG expansion. Our results indicated that the prevalence of CGG expansions of the FMR1 gene among probands is relatively higher than other populations. The average age of diagnosis is also higher than reference values. PCR and Southern blot represent a reliable molecular technique in the diagnosis of FXS.
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Abstract
Many physicians are unaware of the many phenotypes associated with the fragile X premutation, an expansion in the 5' untranslated region of the fragile X mental retardation 1 (FMR1) gene that consists of 55-200 CGG repeats. The most severe of these phenotypes is fragile X-associated tremor/ataxia syndrome (FXTAS), which occurs in the majority of ageing male premutation carriers but in fewer than 20% of ageing women with the premutation. The prevalence of the premutation is 1 in 150-300 females, and 1 in 400-850 males, so physicians are likely to see people affected by FXTAS. Fragile X DNA testing is broadly available in the Western world. The clinical phenotype of FXTAS at presentation can vary and includes intention tremor, cerebellar ataxia, neuropathic pain, memory and/or executive function deficits, parkinsonian features, and psychological disorders, such as depression, anxiety and/or apathy. FXTAS causes brain atrophy and white matter disease, usually in the middle cerebellar peduncles, the periventricular area, and the splenium and/or genu of the corpus callosum. Here, we review the complexities involved in the clinical management of FXTAS and consider how targeted treatment for these clinical features of FXTAS will result from advances in our understanding of the molecular mechanisms that underlie this neurodegenerative disorder. Such targeted approaches should also be more broadly applicable to earlier forms of clinical involvement among premutation carriers.
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Eligibility Criteria for Deep Brain Stimulation in Parkinson’s Disease, Tremor, and Dystonia. Can J Neurol Sci 2016; 43:462-71. [DOI: 10.1017/cjn.2016.35] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractIn this review, the available evidence to guide clinicians regarding eligibility for deep brain stimulation (DBS) in the main conditions in which these forms of therapy are generally indicated—Parkinson’s disease (PD), tremor, and dystonia—is presented. In general, the literature shows that DBS is effective for PD, essential tremor, and idiopathic dystonia. In these cases, key points in patient selection must include the level of disability and inability to manage symptoms using the best available medical therapy. Results are, however, still not optimal when dealing with other aetiologies, such as secondary tremors and symptomatic dystonia. Also, in PD, issues such as age and neuropsychiatric profile are still debatable parameters. Overall, currently available literature is able to guide physicians on basic aspects of patient selection and indications for DBS; however, a few points are still debatable and controversial. These issues should be refined and clarified in future studies.
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Tamás G, Kovács N, Varga NÁ, Barsi P, Erőss L, Molnár MJ, Balás I. Deep brain stimulation or thalamotomy in fragile X-associated tremor/ataxia syndrome? Case report. Neurol Neurochir Pol 2016; 50:303-8. [PMID: 27375149 DOI: 10.1016/j.pjnns.2016.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 03/17/2016] [Accepted: 04/13/2016] [Indexed: 10/21/2022]
Abstract
We present the case of a 66-year-old man who has been treated for essential tremor since the age of 58. He developed mild cerebellar gait ataxia seven years after tremor onset. Moderate, global brain atrophy was identified on MRI scans. At the age of 68, only temporary tremor relief could be achieved by bilateral deep brain stimulation of the ventral intermedius nucleus of the thalamus. Bilateral stimulation of the subthalamic nucleus also resulted only in transient improvement. In the meantime, progressive gait ataxia and tetraataxia developed accompanied by other cerebellar symptoms, such as nystagmus and scanning speech. These correlated with progressive development of bilateral symmetric hyperintensity of the middle cerebellar peduncles on T2 weighted MRI scans. Genetic testing revealed premutation of the FMR1 gene, establishing the diagnosis of fragile X-associated tremor/ataxia syndrome. Although this is a rare disorder, it should be taken into consideration during preoperative evaluation of essential tremor. Postural tremor ceased two years later after thalamotomy on the left side, while kinetic tremor of the right hand also improved.
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Affiliation(s)
- Gertrúd Tamás
- Department of Neurology, Semmelweis University, Budapest, Hungary.
| | - Norbert Kovács
- Department of Neurology, University of Pécs, Pécs, Hungary
| | - Noémi Ágnes Varga
- Institute of Genomic Medicine and Rare Disorders, Semmelweis University, Budapest, Hungary
| | - Péter Barsi
- MR Research Centre, Semmelweis University, Budapest, Hungary
| | - Loránd Erőss
- National Institute of Clinical Neurosciences, Budapest, Hungary
| | - Mária Judit Molnár
- Institute of Genomic Medicine and Rare Disorders, Semmelweis University, Budapest, Hungary
| | - István Balás
- Department of Neurosurgery, University of Pécs, Pécs, Hungary
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Copf T. Importance of gene dosage in controlling dendritic arbor formation during development. Eur J Neurosci 2015; 42:2234-49. [PMID: 26108333 DOI: 10.1111/ejn.13002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 06/05/2015] [Accepted: 06/18/2015] [Indexed: 12/11/2022]
Abstract
Proper dendrite morphology is crucial for normal nervous system functioning. While a number of genes have been implicated in dendrite morphogenesis in both invertebrates and mammals, it remains unclear how developing dendrites respond to changes in gene dosage and what type of patterns their responses may follow. To understand this, I review here evidence from the recent literature, focusing on the genetic studies performed in the Drosophila larval dendritic arborization class IV neuron, an excellent cell type to understand dendrite morphogenesis. I summarize how class IV arbors change morphology in response to developmental fluctuations in the expression levels of 47 genes, studied by means of genetic manipulations such as loss-of-function and gain-of-function, and for which sufficient information is available. I find that arbors can respond to changing gene dosage in several distinct ways, each characterized by a singular dose-response curve. Interestingly, in 72% of cases arbors are sensitive, and thus adjust their morphology, in response to both decreases and increases in the expression of a given gene, indicating that dendrite morphogenesis is a process particularly sensitive to gene dosage. By summarizing the parallels between Drosophila and mammals, I show that many Drosophila dendrite morphogenesis genes have orthologs in mammals, and that some of these are associated with mammalian dendrite outgrowth and human neurodevelopmental disorders. One notable disease-related molecule is kinase Dyrk1A, thought to be a causative factor in Down syndrome. Both increases and decreases in Dyrk1A gene dosage lead to impaired dendrite morphogenesis, which may contribute to Down syndrome pathoetiology.
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Affiliation(s)
- Tijana Copf
- Institute of Molecular Biology and Biotechnology, Nikolaou Plastira 100, PO Box 1385, Heraklion, GR-70013, Crete, Greece
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Weiss D, Mielke C, Wächter T, Bender B, Liscic RM, Scholten M, Naros G, Plewnia C, Gharabaghi A, Krüger R. Long-term outcome of deep brain stimulation in fragile X-associated tremor/ataxia syndrome. Parkinsonism Relat Disord 2014; 21:310-3. [PMID: 25577024 DOI: 10.1016/j.parkreldis.2014.12.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 11/26/2014] [Accepted: 12/18/2014] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Fragile X-associated tremor/ataxia syndrome (FXTAS) presents as complex movement disorder including tremor and cerebellar ataxia. The efficacy and safety of deep brain stimulation of the nucleus ventralis intermedius of the thalamus in atypical tremor syndromes like FXTAS remains to be determined. METHODS Here, we report the long-term outcome of three male genetically confirmed FXTAS patients treated with bilateral neurostimulation of the nucleus ventralis intermedius for up to four years. RESULTS All patients demonstrated sustained improvement of both tremor and ataxia - the latter included improvement of intention tremor and axial tremor. Kinematic gait analyses further demonstrated a regularization of the gait cycle. Initial improvements of hand functional disability were not sustained and reached the preoperative level of impairment within one to two years from surgery. CONCLUSION Our data on patients with a genetic cause of tremor show favorable outcome and may contribute to improved patient stratification for neurostimulation therapy in the future.
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Affiliation(s)
- Daniel Weiss
- German Centre of Neurodegenerative Diseases (DZNE), Tübingen, Germany; Department for Neurodegenerative Diseases and Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; Werner Reichardt Centre for Integrative Neuroscience, Tübingen, Germany.
| | - Carina Mielke
- German Centre of Neurodegenerative Diseases (DZNE), Tübingen, Germany; Department for Neurodegenerative Diseases and Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; Werner Reichardt Centre for Integrative Neuroscience, Tübingen, Germany
| | - Tobias Wächter
- German Centre of Neurodegenerative Diseases (DZNE), Tübingen, Germany; Department for Neurodegenerative Diseases and Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; Werner Reichardt Centre for Integrative Neuroscience, Tübingen, Germany; Department of Neurology, Centre for Rehabilitation, Bad Goeggingen, Germany
| | | | - Rajka M Liscic
- Department of Neurology, County Hospitals of Altötting-Burghausen, Altötting, Germany
| | - Marlieke Scholten
- German Centre of Neurodegenerative Diseases (DZNE), Tübingen, Germany; Department for Neurodegenerative Diseases and Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; Werner Reichardt Centre for Integrative Neuroscience, Tübingen, Germany
| | - Georgios Naros
- Werner Reichardt Centre for Integrative Neuroscience, Tübingen, Germany; Division of Functional and Restorative Neurosurgery, Department of Neurosurgery, University of Tübingen, Tübingen, Germany
| | - Christian Plewnia
- Werner Reichardt Centre for Integrative Neuroscience, Tübingen, Germany; Department of Psychiatry and Psychotherapy, Neurophysiology & Interventional Neuropsychiatry, University of Tübingen, Germany
| | - Alireza Gharabaghi
- Werner Reichardt Centre for Integrative Neuroscience, Tübingen, Germany; Division of Functional and Restorative Neurosurgery, Department of Neurosurgery, University of Tübingen, Tübingen, Germany
| | - Rejko Krüger
- German Centre of Neurodegenerative Diseases (DZNE), Tübingen, Germany; Department for Neurodegenerative Diseases and Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; Werner Reichardt Centre for Integrative Neuroscience, Tübingen, Germany; Clinical and Experimental Neuroscience, Luxembourg Center for Systems Biomedicine (LCSB), University of Luxembourg and Centre Hospitalier de Luxembourg (CHL), Luxembourg.
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Sturm E, Stefanova N. Multiple system atrophy: genetic or epigenetic? Exp Neurobiol 2014; 23:277-91. [PMID: 25548529 PMCID: PMC4276800 DOI: 10.5607/en.2014.23.4.277] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 09/29/2014] [Accepted: 09/29/2014] [Indexed: 02/06/2023] Open
Abstract
Multiple system atrophy (MSA) is a rare, late-onset and fatal neurodegenerative disease including multisystem neurodegeneration and the formation of α-synuclein containing oligodendroglial cytoplasmic inclusions (GCIs), which present the hallmark of the disease. MSA is considered to be a sporadic disease; however certain genetic aspects have been studied during the last years in order to shed light on the largely unknown etiology and pathogenesis of the disease. Epidemiological studies focused on the possible impact of environmental factors on MSA disease development. This article gives an overview on the findings from genetic and epigenetic studies on MSA and discusses the role of genetic or epigenetic factors in disease pathogenesis.
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Affiliation(s)
- Edith Sturm
- Division of Neurobiology, Department of Neurology, Innsbruck Medical University, Innsbruck A-6020, Austria
| | - Nadia Stefanova
- Division of Neurobiology, Department of Neurology, Innsbruck Medical University, Innsbruck A-6020, Austria
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Oyama G, Umemura A, Shimo Y, Nishikawa N, Nakajima A, Jo T, Nakajima M, Ishii H, Yamada D, Takanashi M, Arai H, Nanba E, Hattori N. Posterior subthalamic area deep brain stimulation for fragile X-associated tremor/ataxia syndrome. Neuromodulation 2014; 17:721-3. [PMID: 24528808 DOI: 10.1111/ner.12150] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 09/07/2013] [Accepted: 11/19/2013] [Indexed: 11/27/2022]
Affiliation(s)
- Genko Oyama
- Department of Neurology, Juntendo University School of Medicine, Tokyo, Japan
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Hippolyte L, Battistella G, Perrin AG, Fornari E, Cornish KM, Beckmann JS, Niederhauser J, Vingerhoets FJG, Draganski B, Maeder P, Jacquemont S. Investigation of memory, executive functions, and anatomic correlates in asymptomatic FMR1 premutation carriers. Neurobiol Aging 2014; 35:1939-46. [PMID: 24612675 DOI: 10.1016/j.neurobiolaging.2014.01.150] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 12/30/2013] [Accepted: 01/30/2014] [Indexed: 01/26/2023]
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset movement disorder associated with FMR1 premutation alleles. Asymptomatic premutation (aPM) carriers have preserved cognitive functions, but they present subtle executive deficits. Current efforts are focusing on the identification of specific cognitive markers that can detect aPM carriers at higher risk of developing FXTAS. This study aims at evaluating verbal memory and executive functions as early markers of disease progression while exploring associated brain structure changes using diffusion tensor imaging. We assessed 30 aPM men and 38 intrafamilial controls. The groups perform similarly in the executive domain except for decreased performance in motor planning in aPM carriers. In the memory domain, aPM carriers present a significant decrease in verbal encoding and retrieval. Retrieval is associated with microstructural changes of the white matter (WM) of the left hippocampal fimbria. Encoding is associated with changes in the WM under the right dorsolateral prefrontal cortex, a region implicated in relational memory encoding. These associations were found in the aPM group only and did not show age-related decline. This may be interpreted as a neurodevelopmental effect of the premutation, and longitudinal studies are required to better understand these mechanisms.
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Affiliation(s)
- Loyse Hippolyte
- Service of Medical Genetics, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland
| | - Giovanni Battistella
- Department of Radiology, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland
| | - Aline G Perrin
- Service of Neurology, Department of Clinical Neurosciences, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland
| | - Eleonora Fornari
- Department of Radiology, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland; Centre d'Imagerie Biomédicale, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland
| | - Kim M Cornish
- School of Psychological Sciences, Monash University, Melbourne, Australia
| | - Jacques S Beckmann
- Service of Medical Genetics, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland; Swiss Institute of Bioinformatics, University of Lausanne, Lausanne, Switzerland
| | - Julien Niederhauser
- Centre d'Imagerie Biomédicale, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland
| | - François J G Vingerhoets
- Service of Neurology, Department of Clinical Neurosciences, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland
| | - Bogdan Draganski
- LREN-Departement des Neurosciences Cliniques, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland; Department of Neurology, Max-Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Philippe Maeder
- Department of Radiology, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland
| | - Sébastien Jacquemont
- Service of Medical Genetics, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland.
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Hunsaker MR. Neurocognitive endophenotypes in CGG KI and Fmr1 KO mouse models of Fragile X-Associated disorders: an analysis of the state of the field. F1000Res 2013; 2:287. [PMID: 24627796 PMCID: PMC3945770 DOI: 10.12688/f1000research.2-287.v1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/23/2013] [Indexed: 12/31/2022] Open
Abstract
It has become increasingly important that the field of behavioral genetics identifies not only the gross behavioral phenotypes associated with a given mutation, but also the behavioral endophenotypes that scale with the dosage of the particular mutation being studied. Over the past few years, studies evaluating the effects of the polymorphic CGG trinucleotide repeat on the
FMR1 gene underlying Fragile X-Associated Disorders have reported preliminary evidence for a behavioral endophenotype in human Fragile X Premutation carrier populations as well as the CGG knock-in (KI) mouse model. More recently, the behavioral experiments used to test the CGG KI mouse model have been extended to the
Fmr1 knock-out (KO) mouse model. When combined, these data provide compelling evidence for a clear neurocognitive endophenotype in the mouse models of Fragile X-Associated Disorders such that behavioral deficits scale predictably with genetic dosage. Similarly, it appears that the CGG KI mouse effectively models the histopathology in Fragile X-Associated Disorders across CGG repeats well into the full mutation range, resulting in a reliable histopathological endophenotype. These endophenotypes may influence future research directions into treatment strategies for not only Fragile X Syndrome, but also the Fragile X Premutation and Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS).
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Affiliation(s)
- Michael R Hunsaker
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, USA
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Jiménez-Jiménez FJ, Alonso-Navarro H, García-Martín E, Lorenzo-Betancor O, Pastor P, Agúndez JAG. Update on genetics of essential tremor. Acta Neurol Scand 2013; 128:359-71. [PMID: 23682623 DOI: 10.1111/ane.12148] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2013] [Indexed: 12/25/2022]
Abstract
Despite the research, few advances in the etiopathogenesis on essential tremor (ET) have been made to date. The high frequency of positive family history of ET and the observed high concordance rates in monozygotic compared with dizygotic twins support a major role of genetic factors in the development of ET. In addition, a possible role of environmental factors has been suggested in the etiology of ET (at least in non-familial forms). Although several gene variants in the LINGO1 gene may increase the risk of ET, to date no causative mutated genes have been identified. In this review, we summarize the studies performed on families with tremor, twin studies, linkage studies, case-control association studies, and exome sequencing in familial ET.
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Affiliation(s)
- F. J. Jiménez-Jiménez
- Section of Neurology; Hospital Universitario del Sureste; Arganda del Rey Madrid Spain
| | - H. Alonso-Navarro
- Section of Neurology; Hospital Universitario del Sureste; Arganda del Rey Madrid Spain
| | - E. García-Martín
- Department of Biochemistry and Molecular Biology; University of Extremadura; Cáceres Spain
- AMGenomics; Edificio Tajo, Avda. de la Universidad s/n; Cáceres Spain
| | - O. Lorenzo-Betancor
- Neurogenetics Laboratory; Division of Neurosciences; Center for Applied Medical Research (CIMA); University of Navarra; Pamplona Spain
- Department of Neurology; Clínica Universidad de Navarra; University of Navarra School of Medicine; Pamplona Spain
| | - P. Pastor
- Neurogenetics Laboratory; Division of Neurosciences; Center for Applied Medical Research (CIMA); University of Navarra; Pamplona Spain
- Department of Neurology; Clínica Universidad de Navarra; University of Navarra School of Medicine; Pamplona Spain
- CIBERNED; Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas; Instituto de Salud Carlos III; Madrid Spain
| | - J. A. G. Agúndez
- AMGenomics; Edificio Tajo, Avda. de la Universidad s/n; Cáceres Spain
- Department of Pharmacology; University of Extremadura; Cáceres Spain
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Which Approach is Better: Bilateral Versus Unilateral Thalamic Deep Brain Stimulation in Patients with Fragile X–Associated Tremor Ataxia Syndrome. THE CEREBELLUM 2013; 13:222-5. [DOI: 10.1007/s12311-013-0530-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Lozano A, Lipsman N. Probing and Regulating Dysfunctional Circuits Using Deep Brain Stimulation. Neuron 2013; 77:406-24. [DOI: 10.1016/j.neuron.2013.01.020] [Citation(s) in RCA: 423] [Impact Index Per Article: 38.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/22/2013] [Indexed: 01/04/2023]
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Bermejo-Pareja F, Puertas-Martín V. Cognitive features of essential tremor: a review of the clinical aspects and possible mechanistic underpinnings. TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2012; 2. [PMID: 23440004 PMCID: PMC3572680 DOI: 10.7916/d89w0d7w] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 05/08/2012] [Indexed: 01/10/2023]
Abstract
The classical concept of essential tremor (ET) as a monosymptomatic tremorogenic disorder has been questioned in the last decade as new evidence has been described. Clinical, neuroimaging, and pathological studies have described a probable structural basis (mainly in cerebellum) and evidence that ET is associated with subtle clinical cerebellar deficits and several non-motor clinical manifestations, such as cognitive and mood disorders. We performed literature searches in Medline, ISI Web of Knowledge, and PsycInfo databases. The aim of this review is to describe cognitive deficits associated with ET. First, we present a brief history of ET cognitive disorders presented. Second, we describe several clinical cross-sectional series demonstrating that ET is associated with mild cognitive deficits of attention, executive functions, several types of memory (working memory, immediate, short term, delayed, and possibly others) and, mood disorders (depression). Recent neuroimaging studies favor a cerebellar basis for these cognitive deficits. Population-based surveys confirm that mild cognitive dysfunction is not limited to severe ET cases, the entire ET group, including mild and undiagnosed cases, can be affected. Cohort studies indicated that ET cognitive deficits could be progressive and that ET patients had an increased risk of dementia. The mood and cognitive deficits in ET are in agreement with cognitive affective cerebellar syndrome described in patients with cerebellar disorders. New evidence, mainly from functional (neuroimaging) and prospective clinical studies would further bolster recent descriptions of ET clinical manifestations.
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Affiliation(s)
- Félix Bermejo-Pareja
- Head of the Neurology Department, University Hospital "12 de Octubre", Madrid, Spain ; Biomedical Research Network on Neurodegenerative Disorders (CIBERNED), Carlos III National Research Institute, Madrid, Spain ; Department of Biomedical Sciences (ANECA), Complutense University of Madrid, Spain
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Hunter JE, Sherman S, Grigsby J, Kogan C, Cornish K. Capturing the fragile X premutation phenotypes: a collaborative effort across multiple cohorts. Neuropsychology 2012; 26:156-64. [PMID: 22251309 PMCID: PMC3295926 DOI: 10.1037/a0026799] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVE To capture the neuropsychological profile among male carriers of the FMR1 premutation allele (55-200 CGG repeats) who do not meet diagnostic criteria for the late-onset fragile X-associated tremor/ataxia syndrome, FXTAS. METHOD We have initiated a multicenter collaboration that includes 3 independent cohorts, totaling 100 carriers of the premutation and 216 noncarriers. The initial focus of this collaboration has been on executive function. Four executive function scores are shared among the 3 cohorts (Controlled Oral Word Association Test, Stroop Color-Word Test, and Wechsler backward digit span and letter-number sequencing) whereas additional executive function scores are available for specific cohorts (Behavior Dyscontrol Scale, Hayling Sentence Completion Test Part B, and Wisconsin Card Sorting Test). Raw scores were analyzed by using statistical models that adjust for cohort-specific effects as well as age and education. RESULTS Carriers scored significantly lower compared to noncarriers on the Stroop Color-Word Test (p = .01), Hayling Sentence Completion Test Part B (p < .01), and Behavioral Dyscontrol Scale (p = .03), with the Hayling displaying a significant age-related decline (p = .01), as assessed by an age and repeat length-group interaction. Follow-up analysis of the collective data did not identify any specific age groups or repeat length ranges (i.e., low premutation = 55-70 repeats, midpremutation = 71-100 repeats, high premutation = 101-199 repeats) that were associated with an increased risk of executive function deficits. CONCLUSIONS Preliminary analyses do not indicate global executive function impairment among male carriers without FXTAS compared to noncarriers. However, impairment in inhibitory capacity may be present among a subset of carriers, though the risk factors for this group do not appear to be related to age or repeat length.
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Affiliation(s)
| | - Stephanie Sherman
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia
| | - Jim Grigsby
- Departments of Psychology and Medicine, University of Colorado Denver, Denver, Colorado
| | - Cary Kogan
- School of Psychology, University of Ottawa, Ottawa, Ontario, Canada
| | - Kim Cornish
- School of Psychology and Psychiatry, Monash University, Melbourne, Australia
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Senova S, Jarraya B, Iwamuro H, Tani N, Ouerchefani N, Lepetit H, Gurruchaga JM, Brugières P, Apartis E, de Broucker T, Palfi S. Unilateral thalamic stimulation safely improved fragile X-associated tremor ataxia: A case report. Mov Disord 2012; 27:797-9. [DOI: 10.1002/mds.24923] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 12/27/2011] [Accepted: 01/03/2012] [Indexed: 11/09/2022] Open
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Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is an under-recognized disorder that is a significant cause of late-adult-onset ataxia. The etiology is expansion of a trinucleotide repeat to the premutation range (55-200 CGG repeats) in the fragile X mental retardation 1 (FMR1) gene. Expansion to >200 CGGs causes fragile X syndrome, the most common heritable cause of cognitive impairment and autism. Core features of FXTAS include progressive action tremor and gait ataxia; with frequent, more variable features of cognitive decline, especially executive dysfunction, parkinsonism, neuropathy, and autonomic dysfunction. MR imaging shows generalized atrophy and frequently abnormal signal in the middle cerebellar peduncles. Autopsy reveals intranuclear inclusions in neurons and astrocytes and dystrophic white matter. FXTAS is likely due to an RNA toxic gain-of-function of the expanded-repeat mRNA. The disorder typically affects male premutation carriers over age 50, and, less often, females. Females also are at increased risk for primary ovarian insufficiency, chronic muscle pain, and thyroid disease. Treatment targets specific symptoms, but progression of disability is relentless. Although the contribution of FXTAS to the morbidity and mortality of the aging population requires further study, the disorder is likely the most common single-gene form of tremor and ataxia in the older adult population.
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Affiliation(s)
- Maureen A Leehey
- Department of Neurology, University of Colorado at Denver Health Sciences Center, Denver, CO, USA.
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Leehey MA. Fragile X-associated tremor/ataxia syndrome: clinical phenotype, diagnosis, and treatment. J Investig Med 2011; 57:830-6. [PMID: 19574929 DOI: 10.2310/jim.0b013e3181af59c4] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a neurodegenerative disorder caused by a CGG repeat expansion in the premutation range (55-200) in the fragile X mental retardation 1 gene. Onset is typically in the early seventh decade, and men are principally affected. The major signs are cerebellar gait ataxia, intention tremor, frontal executive dysfunction, and global brain atrophy. Other frequent findings are parkinsonism (mild), peripheral neuropathy, psychiatric symptoms (depression, anxiety, and agitation), and autonomic dysfunction. The clinical presentation is heterogeneous, with individuals presenting with varied dominating signs, such as tremor, dementia, or neuropathy. Magnetic resonance imaging shows atrophy and patchy white matter lesions in the cerebral hemispheres and middle cerebellar peduncles. The latter has been designated the middle cerebellar peduncle sign, which occurs in about 60% of affected men, and is relatively specific for FXTAS. Affected females generally have less severe disease, less cognitive decline, and some symptoms different from that of men, for example, muscle pain. Management of FXTAS is complex and includes assessment of the patient's neurological and medical deficits, treatment of symptoms, and provision of relevant referrals, especially genetic counseling. Treatment is empirical, based on anecdotal experience and on knowledge of what works for symptoms of other disorders that also exist in FXTAS. Presently, the disorder is underrecognized because the first published report was only in 2001 and because the presentation is variable and mainly consists of a combination of signs common in the elderly. However, accurate diagnosis is critical for the patient and for the family because they need education regarding their genetic and health risks.
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Affiliation(s)
- Maureen A Leehey
- Department of Neurology, University of Colorado Denver, Aurora, CO 80045, USA.
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Gallagher A, Hallahan B. Fragile X-associated disorders: a clinical overview. J Neurol 2011; 259:401-13. [PMID: 21748281 DOI: 10.1007/s00415-011-6161-3] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 06/24/2011] [Accepted: 06/25/2011] [Indexed: 01/13/2023]
Abstract
Fragile X Syndrome (FraX) is the most common inherited cause of learning disability worldwide. FraX is an X-linked neuro-developmental disorder involving an unstable trinucleotide repeat expansion of cytosine guanine guanine (CGG). Individuals with the full mutation of FraX have >200 GG repeats with premutation carriers having 55-200 GG repeats. A wide spectrum of physical, behavioural, cognitive, psychiatric and medical problems have been associated with both full mutation and premutation carriers of FraX. In this review, we detail the clinical profile and examine the aetiology, epidemiology, neuropathology, neuroimaging findings and possible management strategies for individuals with both the full mutation and premutation of FraX.
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Affiliation(s)
- Anne Gallagher
- Department of Psychiatry, Clinical Science Institute, National University of Ireland Galway, Galway, Ireland
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Cabanyes-Truffino J. Manifestaciones neurológicas en el adulto con premutación X frágil. Neurologia 2010. [DOI: 10.1016/j.nrl.2010.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Nitrini R, Gonçalves MRR, Capelli LP, Barbosa ER, Porto CS, Amaro E, Otto PA, Vianna-Morgante AM. Dementia in Fragile X-associated Tremor/Ataxia Syndrome. Dement Neuropsychol 2010; 4:79-83. [PMID: 29213666 PMCID: PMC5619536 DOI: 10.1590/s1980-57642010dn40100014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a cause of movement
disorders and cognitive decline which has probably been underdiagnosed,
especially if its prevalence proves similar to those of progressive supranuclear
palsy and amyotrophic lateral sclerosis. We report a case of a 74-year-old man
who presented with action tremor, gait ataxia and forgetfulness. There was a
family history of tremor and dementia, and one of the patient’s grandsons was
mentally deficient. Neuropsychological evaluation disclosed a frontal network
syndrome. MRI showed hyperintensity of both middle cerebellar peduncles, a major
diagnostic hallmark of FXTAS. Genetic testing revealed premutation of the
FMR1 gene with an expanded (CGG)90 repeat. The
diagnosis of FXTAS is important for genetic counseling because the daughters of
the affected individuals are at high risk of having offspring with fragile X
syndrome. Tremors and cognitive decline should raise the diagnostic hypothesis
of FXTAS, which MRI may subsequently reinforce, while the detection of the
FMR1 premutation can confirm the condition.
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Affiliation(s)
- Ricardo Nitrini
- MD, Departments of Neurology, School of Medicine, University of São Paulo, São Paulo SP, Brazil
| | | | - Leonardo P Capelli
- MSc, Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, São Paulo SP, Brazil
| | - Egberto Reis Barbosa
- MD, Departments of Neurology, School of Medicine, University of São Paulo, São Paulo SP, Brazil
| | - Cláudia Sellitto Porto
- PhD, Departments of Neurology, School of Medicine, University of São Paulo, São Paulo SP, Brazil
| | - Edson Amaro
- MD, Departments of Neurology and Radiology, School of Medicine, University of São Paulo, São Paulo SP, Brazil
| | - Paulo Alberto Otto
- MD, Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, São Paulo SP, Brazil
| | - Angela M Vianna-Morgante
- PhD, Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, São Paulo SP, Brazil
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Ishii K, Hosaka A, Adachi K, Nanba E, Tamaoka A. A Japanese case of fragile-X-associated tremor/ataxia syndrome (FXTAS). Intern Med 2010; 49:1205-8. [PMID: 20558944 DOI: 10.2169/internalmedicine.49.3258] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A 71-year-old man developed postural tremor and was treated as an essential tremor patient. Nine years after the tremor onset, he developed symptoms resembling Fragile-X-associated tremor/ataxia syndrome (FXTAS), including exacerbated (increased coarseness and amplitude) tremor in the right arm, ataxic gait, and brain MRI showed lesions in the bilateral middle cerebellar peduncles (MCP). Evidence of premutation in the form of 83 CGG repeats of the Fragile-X-mental retardation 1 (FMR1) gene confirmed the diagnosis of FXTAS. FXTAS causes various neurological symptoms including in some cases tremor resembling essential tremor in the early stages. FMR1 gene premutation should be checked when the patient develops intention tremor, cerebral dysfunction and/or a brain MRI shows MCP lesions.
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Affiliation(s)
- Kazuhiro Ishii
- Department of Neurology, Institute of Clinical Medicine, Majors of Medical Sciences, Graduate School of Comprehensive Human Sciences University of Tsukuba, Tsukuba, Japan.
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Neurological signs in the adult with fragile-X premutation. NEUROLOGÍA (ENGLISH EDITION) 2010. [DOI: 10.1016/s2173-5808(10)70045-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Galloway JN, Nelson DL. Evidence for RNA-mediated toxicity in the fragile X-associated tremor/ataxia syndrome. FUTURE NEUROLOGY 2009; 4:785. [PMID: 20161676 DOI: 10.2217/fnl.09.44] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Fragile X premutation carriers are at risk for developing a late-onset, progressive neurodegenerative disorder termed fragile X-associated tremor/ataxia syndrome (FXTAS). A growing body of evidence suggests the characteristic excess CGG repeat containing FMR1 mRNA observed in premutation carriers is pathogenic and leads to clinical features of FXTAS. The current model suggests premutation mRNA transcripts can induce the formation of intranuclear inclusions by the sequestration of RNA-binding proteins and other proteins. The sequestered proteins are prevented from performing their normal functions, which is thought to lead to the neuropathology-observed FXTAS. This paper discusses the existing evidence that microsatellite expansions at the level of RNA play a role in the disease pathogenesis of FXTAS and some of the approaches that may uncover downstream effects of expanded riboCGG expression.
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Affiliation(s)
- Jocelyn N Galloway
- Baylor College of Medicine, Interdepartmental Program in Cell & Molecular Biology, One Baylor Plaza, Room 904E, Houston, TX 77030, USA, Tel.: +1 713 798 7898, Fax.: +1 713 798 1116
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Pepper ASR, Beerman RW, Bhogal B, Jongens TA. Argonaute2 suppresses Drosophila fragile X expression preventing neurogenesis and oogenesis defects. PLoS One 2009; 4:e7618. [PMID: 19888420 PMCID: PMC2770736 DOI: 10.1371/journal.pone.0007618] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Accepted: 10/01/2009] [Indexed: 01/05/2023] Open
Abstract
Fragile X Syndrome is caused by the silencing of the Fragile X Mental Retardation gene (FMR1). Regulating dosage of FMR1 levels is critical for proper development and function of the nervous system and germ line, but the pathways responsible for maintaining normal expression levels are less clearly defined. Loss of Drosophila Fragile X protein (dFMR1) causes several behavioral and developmental defects in the fly, many of which are analogous to those seen in Fragile X patients. Over-expression of dFMR1 also causes specific neuronal and behavioral abnormalities. We have found that Argonaute2 (Ago2), the core component of the small interfering RNA (siRNA) pathway, regulates dfmr1 expression. Previously, the relationship between dFMR1 and Ago2 was defined by their physical interaction and co-regulation of downstream targets. We have found that Ago2 and dFMR1 are also connected through a regulatory relationship. Ago2 mediated repression of dFMR1 prevents axon growth and branching defects of the Drosophila neuromuscular junction (NMJ). Consequently, the neurogenesis defects in larvae mutant for both dfmr1 and Ago2 mirror those in dfmr1 null mutants. The Ago2 null phenotype at the NMJ is rescued in animals carrying an Ago2 genomic rescue construct. However, animals carrying a mutant Ago2 allele that produces Ago2 with significantly reduced endoribonuclease catalytic activity are normal with respect to the NMJ phenotypes examined. dFMR1 regulation by Ago2 is also observed in the germ line causing a multiple oocyte in a single egg chamber mutant phenotype. We have identified Ago2 as a regulator of dfmr1 expression and have clarified an important developmental role for Ago2 in the nervous system and germ line that requires dfmr1 function.
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Affiliation(s)
- Anita S.-R. Pepper
- Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Rebecca W. Beerman
- Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Balpreet Bhogal
- Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Thomas A. Jongens
- Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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Abstract
Tremor in childhood is not commonly described in the literature; but it is also likely underappreciated. The etiology of childhood tremor encompasses a wide variety of pathologic processes. Tremor may occur in isolation, or in association with other neurologic findings or systemic disorders. This article aims to provide an overview of tremorogenic mechanisms with respect to neuroanatomy and neurophysiology, particularly as they relate to children. Classification of tremors, diagnostic entities in childhood, and treatment will also be discussed. With improved recognition and characterization of childhood tremors, we may gain a better understanding of the pathophysiology of the disease and determine more age-appropriate treatment strategies.
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Affiliation(s)
- Stephanie Keller
- Department of Pediatrics, Division of Child Neurology, University of Alabama at Birmingham, The Children's Hospital of Alabama, Birmingham, AL 35233, USA.
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Schmahmann JD, Smith EE, Eichler FS, Filley CM. Cerebral white matter: neuroanatomy, clinical neurology, and neurobehavioral correlates. Ann N Y Acad Sci 2008; 1142:266-309. [PMID: 18990132 DOI: 10.1196/annals.1444.017] [Citation(s) in RCA: 336] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Lesions of the cerebral white matter (WM) result in focal neurobehavioral syndromes, neuropsychiatric phenomena, and dementia. The cerebral WM contains fiber pathways that convey axons linking cerebral cortical areas with each other and with subcortical structures, facilitating the distributed neural circuits that subserve sensorimotor function, intellect, and emotion. Recent neuroanatomical investigations reveal that these neural circuits are topographically linked by five groupings of fiber tracts emanating from every neocortical area: (1) cortico-cortical association fibers; (2) corticostriatal fibers; (3) commissural fibers; and cortico-subcortical pathways to (4) thalamus and (5) pontocerebellar system, brain stem, and/or spinal cord. Lesions of association fibers prevent communication between cortical areas engaged in different domains of behavior. Lesions of subcortical structures or projection/striatal fibers disrupt the contribution of subcortical nodes to behavior. Disconnection syndromes thus result from lesions of the cerebral cortex, subcortical structures, and WM tracts that link the nodes that make up the distributed circuits. The nature and the severity of the clinical manifestations of WM lesions are determined, in large part, by the location of the pathology: discrete neurological and neuropsychiatric symptoms result from focal WM lesions, whereas cognitive impairment across multiple domains--WM dementia--occurs in the setting of diffuse WM disease. We present a detailed review of the conditions affecting WM that produce these neurobehavioral syndromes, and consider the pathophysiology, clinical effects, and broad significance of the effects of aging and vascular compromise on cerebral WM, in an attempt to help further the understanding, diagnosis, and treatment of these disorders.
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Affiliation(s)
- Jeremy D Schmahmann
- Ataxia Unit, Cognitive/Behavioral Neurology Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA.
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Brega AG, Goodrich G, Bennett RE, Hessl D, Engle K, Leehey MA, Bounds LS, Paulich MJ, Hagerman RJ, Hagerman PJ, Cogswell JB, Tassone F, Reynolds A, Kooken R, Kenny M, Grigsby J. The primary cognitive deficit among males with fragile X-associated tremor/ataxia syndrome (FXTAS) is a dysexecutive syndrome. J Clin Exp Neuropsychol 2008; 30:853-69. [PMID: 18608667 PMCID: PMC4098148 DOI: 10.1080/13803390701819044] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a neurodegenerative disorder associated with a premutation trinucleotide repeat expansion in the fragile X mental retardation 1 gene. Symptoms include gait ataxia, action tremor, and cognitive impairment. The objectives of the study were to clarify the nature of the dysexecutive syndrome observed in FXTAS and to assess the contribution of executive impairment to deficits in nonexecutive cognitive functions. Compared to controls, men with FXTAS demonstrated significant executive impairment, which was found to mediate group differences in most other cognitive abilities. Asymptomatic premutation carriers performed similarly to controls on all but two measures of executive functioning. These findings suggest that the impairment of nonexecutive cognitive skills in FXTAS is in large part secondary to executive dysfunction.
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Affiliation(s)
- Angela G. Brega
- Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora, CO
| | - Glenn Goodrich
- Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora, CO
| | - Rachael E. Bennett
- Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora, CO
| | - David Hessl
- M.I.N.D. Institute, University of California, Davis, Medical Center, Sacramento, CA
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Medical Center, Sacramento, CA
| | - Karen Engle
- Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora, CO
| | - Maureen A. Leehey
- Department of Neurology, University of Colorado at Denver and Health Sciences Center, Denver, CO
| | - Lanee S. Bounds
- Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora, CO
| | - Marsha J. Paulich
- Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora, CO
| | - Randi J. Hagerman
- M.I.N.D. Institute, University of California, Davis, Medical Center, Sacramento, CA
- Department of Pediatrics, University of California, Davis, Medical Center, Sacramento, CA
| | - Paul J. Hagerman
- Department of Biochemistry and Molecular Medicine, University of California, Davis, School of Medicine, Davis, CA
| | - Jennifer B. Cogswell
- M.I.N.D. Institute, University of California, Davis, Medical Center, Sacramento, CA
| | - Flora Tassone
- Department of Biochemistry and Molecular Medicine, University of California, Davis, School of Medicine, Davis, CA
| | | | | | - Michael Kenny
- C.U. Aging Center, University of Colorado at Colorado Springs, Colorado Springs, CO
| | - Jim Grigsby
- Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora, CO
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Chaussenot A, Borg M, Bayreuther C, Lebrun C. Ataxie cérébelleuse tardive due à la prémutation de l’X fragile. Rev Neurol (Paris) 2008; 164:957-63. [DOI: 10.1016/j.neurol.2008.03.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2007] [Revised: 02/05/2008] [Accepted: 03/11/2008] [Indexed: 10/22/2022]
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Ferrara JM, Adam OR, Ondo WG. Treatment of fragile X associated tremor/ataxia syndrome with deep brain stimulation. Mov Disord 2008; 24:149-51. [DOI: 10.1002/mds.22354] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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48
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Hagerman RJ, Hall DA, Coffey S, Leehey M, Bourgeois J, Gould J, Zhang L, Seritan A, Berry-Kravis E, Olichney J, Miller JW, Fong AL, Carpenter R, Bodine C, Gane LW, Rainin E, Hagerman H, Hagerman PJ. Treatment of fragile X-associated tremor ataxia syndrome (FXTAS) and related neurological problems. Clin Interv Aging 2008; 3:251-62. [PMID: 18686748 PMCID: PMC2546470 DOI: 10.2147/cia.s1794] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a progressive neurological disorder that affects older adult carriers, predominantly males, of premutation alleles (55 to 200 CGG repeats) of the fragile X (FMR1) gene. Principal features of FXTAS are intention tremor, ataxia, parkinsonism, cognitive decline, and peripheral neuropathy; ancillary features include, autonomic dysfunction, and psychiatric symptoms of anxiety, depression, and disinhibition. Although controlled trials have not been carried out in individuals with FXTAS, there is a significant amount of anecdotal information regarding various treatment modalities. Moreover, there exists a great deal of evidence regarding the efficacy of various medications for treatment of other disorders (eg, Alzheimer disease) that have substantial phenotypic overlap with FXTAS. The current review summarizes what is currently known regarding the symptomatic treatment, or potential for treatment, of FXTAS.
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Affiliation(s)
- Randi J Hagerman
- MIND Institute, University of California, Davis, School of Medicine, Sacramento, CA 95817, USA.
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Kogan CS, Turk J, Hagerman RJ, Cornish KM. Impact of the Fragile X mental retardation 1 (FMR1) gene premutation on neuropsychiatric functioning in adult males without fragile X-associated Tremor/Ataxia syndrome: a controlled study. Am J Med Genet B Neuropsychiatr Genet 2008; 147B:859-72. [PMID: 18165971 DOI: 10.1002/ajmg.b.30685] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Fragile X Syndrome is the most common heritable form of mental retardation caused by silencing of the FMR1 gene, which arises from intergenerational trinucleotide repeat expansion leading to full mutation. An intermediary carrier condition, known as the premutation, is characterized by expansion up to 200 repeats without concomitant gene silencing. This prevalent allelic variant was initially thought to be free of phenotypic effects. However, recent reports have identified a degenerative disease, Fragile X-associated Tremor/Ataxia Syndrome (FXTAS) in older men as well as premature ovarian failure in women. Previously reports are inconsistent regarding the neuropsychiatric phenotype associated with premutation due to small sample sizes, ascertainment bias, lack of adequate control groups, administration of measures with poor psychometric properties, and the confounding effects of FXTAS. We addressed these problems by conducting a controlled study of male carriers (n = 40) of the premutation without manifest symptoms of FXTAS, comparing their responses on specific, reliable, and valid measures of neuropsychiatric functioning to those of individuals with shared family environment (n = 22) and non-carrier comparison males (n = 43). Multivariate analyses revealed that the premutation confers significant risk for working memory difficulties, an associated feature of Attention-Deficit Disorder. Furthermore, both the family controls and men with premutation exhibited higher rates of Alcohol Abuse as compared to non-carrier control men. These findings highlight the importance of recognizing the distinct phenotypic outcomes that characterize the Fragile X premutation and the subtle risk factors that can act as precursors to more significant psychiatric impairment.
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Affiliation(s)
- Cary S Kogan
- School of Psychology, University of Ottawa, Ottawa, Canada.
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Cornish KM, Li L, Kogan CS, Jacquemont S, Turk J, Dalton A, Hagerman RJ, Hagerman PJ. Age-dependent cognitive changes in carriers of the fragile X syndrome. Cortex 2008; 44:628-36. [PMID: 18472033 PMCID: PMC11060834 DOI: 10.1016/j.cortex.2006.11.002] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2006] [Revised: 06/26/2006] [Accepted: 11/20/2006] [Indexed: 11/16/2022]
Abstract
Fragile X syndrome is a neurodevelopmental disorder that is caused by the silencing of a single gene on the X chromosome, the fragile X mental retardation 1 (FMR1) gene. Affected individuals display a unique neurocognitive phenotype that includes significant impairment in inhibitory control, selective attention, working memory, and visual-spatial cognition. In contrast, little is known about the trajectory and specificity of any cognitive impairment associated with the fragile X premutation (i.e., "carrier status") or its relationship with the recently identified neurodegenerative disorder, fragile X-associated tremor/ataxia syndrome (FXTAS). In the present study, we evaluated a broad sample of 40 premutation males (PM) aged 18-69 years matched on age and IQ to 67 unaffected comparison males (NC). Performance was compared across a range of cognitive domains known to be impaired in fragile X syndrome (i.e., "full mutation"). Tremor was also assessed using a self-report neurological questionnaire. PM displayed statistically significant deficits in their ability to inhibit prepotent responses, differentiating them from NC from age 30 onwards. With increasing age, the two groups follow different trajectories, with PM developing progressively more severe problems in inhibitory control. This deficit also has a strong co-occurrence in males displaying FXTAS-related symptomatology (p<.001). Selective attention was also impaired in PM but did not show any disproportionate aging effect. No other cognitive deficits were observed. We conclude that an inhibitory deficit and its impact across the lifespan are specifically associated with the fragile X premutation status, and may be a precursor for development of a more severe form of cognitive impairment or dementia, which has been reported in patients with the diagnosis of FXTAS.
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Affiliation(s)
- Kim M Cornish
- Neuroscience Laboratory for Research and Education in Developmental Disorders, McGill University, Montreal, Canada.
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