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Li Z, Li Y, Chu X, Du K, Tang Y, Xie Z, Yu M, Deng J, Lv H, Zhang W, Wang Z, Meng L, Yuan Y. Novel mutations in FLVCR1 cause tremors, sensory neuropathy with retinitis pigmentosa. Neuropathology 2024; 44:87-95. [PMID: 37469134 DOI: 10.1111/neup.12936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 07/03/2023] [Accepted: 07/05/2023] [Indexed: 07/21/2023]
Abstract
The mutations of the feline leukemia virus subgroup C receptor-related protein 1 (FLVCR1) cause ataxia with retinitis pigmentosa. Recent studies indicated a large variation in the phenotype of FLVCR1-associated diseases. In this report, we describe an adult male who manifested first with tremors in his third decade, followed by retinitis pigmentosa, sensory ataxia, and sensory neuropathy in his fourth decade. While retinitis pigmentosa and sensory ataxia are well-recognized features of FLVCR1-associated disease, tremor is rarely described. Whole-exome sequencing revealed novel compound heterozygous pathogenic FLVCR1 variants: c.498 G > A; p.(Trp166*) and c.369 T > G; p.(Phe123Leu). In addition, we have highlighted the ultrastructural abnormalities of the sural biopsy in this patient.
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Affiliation(s)
- Zhenyu Li
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Yize Li
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Xujun Chu
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Kang Du
- Department of Neurology, Qujing First People's Hospital, Qujing, China
| | - Yuwei Tang
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Zhiying Xie
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Meng Yu
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Jianwen Deng
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - He Lv
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Wei Zhang
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Zhaoxia Wang
- Department of Neurology, Peking University First Hospital, Beijing, China
- Beijing Key Laboratory for Neurovascular Disease Discovery, Peking University First Hospital, Beijing, China
- Key Laboratory for Neuroscience, National Health Commission of the People's Republic of China, Peking University, Beijing, China
| | - Lingchao Meng
- Department of Neurology, Peking University First Hospital, Beijing, China
- Beijing Key Laboratory for Neurovascular Disease Discovery, Peking University First Hospital, Beijing, China
- Key Laboratory for Neuroscience, National Health Commission of the People's Republic of China, Peking University, Beijing, China
| | - Yun Yuan
- Department of Neurology, Peking University First Hospital, Beijing, China
- Beijing Key Laboratory for Neurovascular Disease Discovery, Peking University First Hospital, Beijing, China
- Key Laboratory for Neuroscience, National Health Commission of the People's Republic of China, Peking University, Beijing, China
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2
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Silsby M, Yiannikas C, Fois AF, Kennerson ML, Kiernan MC, Fung VSC, Vucic S. Upper and lower limb tremor in Charcot-Marie-Tooth neuropathy type 1A and the implications for standing balance. J Neurol 2024; 271:1776-1786. [PMID: 38051345 PMCID: PMC10972941 DOI: 10.1007/s00415-023-12124-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 11/17/2023] [Accepted: 11/18/2023] [Indexed: 12/07/2023]
Abstract
BACKGROUND Neuropathic tremor occurs in Charcot-Marie-Tooth neuropathy type 1A (CMT1A; hereditary motor and sensory neuropathy, HMSN), although the pathophysiological mechanisms remain to be elucidated. Separately, lower limb tremor has not been explored in CMT1A and could be associated with imbalance as in other neuropathies. The present study aimed to determine tremor characteristics in the upper and lower limbs in CMT1A and relate these findings to clinical disability, particularly imbalance. METHODS Tremor and posturography studies were undertaken in phenotyped and genotyped CMT1A patients. Participants underwent detailed clinical assessment, tremor study recordings, and nerve conduction studies. Tremor stability index was calculated for upper limb tremor and compared to essential tremor. RESULTS Seventeen patients were enrolled. Postural and kinetic upper limb tremors were evident in 65%, while postural and orthostatic lower limb tremors were seen in 35% of CMT1A patients. Peak upper limb frequencies were lower distally (~ 6 Hz) and higher proximally (~ 9 Hz), were unchanged by weight-loading, and not impacted by fatigue. The tremor stability index was significantly higher in CMT1A than in essential tremor. A 5-6 Hz lower limb tremor was recorded which did not vary along the limb and was unaffected by fatigue. Balance was impaired in patients with postural lower limb tremor. A high frequency peak on posturography was associated with 'good' balance. CONCLUSIONS Tremor is a common clinical feature in CMT1A, distinct from essential tremor, mediated by a complex interaction between peripheral and central mechanisms. Postural lower limb tremor is associated with imbalance; strategies aimed at tremor modulation could be of therapeutic utility.
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Affiliation(s)
- Matthew Silsby
- Neurology Department, Westmead Hospital, Westmead Clinical School, University of Sydney, Sydney, NSW, Australia
- Brain and Nerve Research Centre, University of Sydney, Concord, NSW, Australia
- Neurology Department, Concord Hospital, Sydney, NSW, Australia
| | - Con Yiannikas
- Neurology Department, Concord Hospital, Sydney, NSW, Australia
- Neurology Department, Royal North Shore Hospital, Sydney, NSW, Australia
| | - Alessandro F Fois
- Neurology Department, Westmead Hospital, Westmead Clinical School, University of Sydney, Sydney, NSW, Australia
| | - Marina L Kennerson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, University of Sydney, Sydney, NSW, Australia
- Molecular Medicine Laboratory, Concord Hospital, Concord, NSW, Australia
| | - Matthew C Kiernan
- Neurology Department, Royal Prince Alfred Hospital Sydney, Sydney, NSW, Australia
- Brain and Mind Centre, University of Sydney, Camperdown, NSW, Australia
| | - Victor S C Fung
- Neurology Department, Westmead Hospital, Westmead Clinical School, University of Sydney, Sydney, NSW, Australia
| | - Steve Vucic
- Brain and Nerve Research Centre, University of Sydney, Concord, NSW, Australia.
- Neurology Department, Concord Hospital, Sydney, NSW, Australia.
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Lenka A, Jankovic J. Peripherally-induced Movement Disorders: An Update. Tremor Other Hyperkinet Mov (N Y) 2023; 13:8. [PMID: 37008994 PMCID: PMC10064913 DOI: 10.5334/tohm.758] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Accepted: 03/14/2023] [Indexed: 03/30/2023] Open
Abstract
Background Peripherally-induced movement disorders (PIMD) should be considered when involuntary or abnormal movements emerge shortly after an injury to a body part. A close topographic and temporal association between peripheral injury and onset of the movement disorders is crucial to diagnosing PIMD. PIMD is under-recognized and often misdiagnosed as functional movement disorder, although both may co-exist. Given the considerable diagnostic, therapeutic, and psychosocial-legal challenges associated with PIMD, it is crucial to update the clinical and scientific information about this important movement disorder. Methods A comprehensive PubMed search through a broad range of keywords and combinations was performed in February 2023 to identify relevant articles for this narrative review. Results The spectrum of the phenomenology of PIMD is broad and it encompasses both hyperkinetic and hypokinetic movements. Hemifacial spasm is probably the most common PIMD. Others include dystonia, tremor, parkinsonism, myoclonus, painful leg moving toe syndrome, tics, polyminimyoclonus, and amputation stump dyskinesia. We also highlight conditions such as neuropathic tremor, pseudoathetosis, and MYBPC1-associated myogenic tremor as examples of PIMD. Discussion There is considerable heterogeneity among PIMD in terms of severity and nature of injury, natural course, association with pain, and response to treatment. As some patients may have co-existing functional movement disorder, neurologists should be able to differentiate the two disorders. While the exact pathophysiology remains elusive, aberrant central sensitization after peripheral stimuli and maladaptive plasticity in the sensorimotor cortex, on a background of genetic (two-hit hypothesis) or other predisposition, seem to play a role in the pathogenesis of PIMD.
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Movement disorders and neuropathies: overlaps and mimics in clinical practice. J Neurol 2022; 269:4646-4662. [PMID: 35657406 DOI: 10.1007/s00415-022-11200-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 05/16/2022] [Indexed: 10/18/2022]
Abstract
Movement disorders as well as peripheral neuropathies are extremely frequent in the general population; therefore, it is not uncommon to encounter patients with both these conditions. Often, the coexistence is coincidental, due to the high incidence of common causes of peripheral neuropathy, such as diabetes and other age-related disorders, as well as of Parkinson disease (PD), which has a typical late onset. Nonetheless, there is broad evidence that PD patients may commonly develop a sensory and/or autonomic polyneuropathy, triggered by intrinsic and/or extrinsic mechanisms. Similarly, some peripheral neuropathies may develop some movement disorders in the long run, such as tremor, and rarely dystonia and myoclonus, suggesting that central mechanisms may ensue in the pathogenesis of these diseases. Although rare, several acquired or hereditary causes may be responsible for the combination of movement and peripheral nerve disorders as a unique entity, some of which are potentially treatable, including paraneoplastic, autoimmune and nutritional aetiologies. Finally, genetic causes should be pursued in case of positive family history, young onset or multisystemic involvement, and examined for neuroacanthocytosis, spinocerebellar ataxias, mitochondrial disorders and less common causes of adult-onset cerebellar ataxias and spastic paraparesis. Deep phenotyping in terms of neurological and general examination, as well as laboratory tests, neuroimaging, neurophysiology, and next-generation genetic analysis, may guide the clinician toward the correct diagnosis and management.
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Rare tremors and tremors occurring in other neurological disorders. J Neurol Sci 2022; 435:120200. [DOI: 10.1016/j.jns.2022.120200] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 02/07/2022] [Accepted: 02/17/2022] [Indexed: 12/21/2022]
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Parkinsonism and tremor syndromes. J Neurol Sci 2021; 433:120018. [PMID: 34686357 DOI: 10.1016/j.jns.2021.120018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 06/06/2021] [Accepted: 09/29/2021] [Indexed: 01/22/2023]
Abstract
Tremor, the most common movement disorder, may occur in isolation or may co-exist with a variety of other neurologic and movement disorders including parkinsonism, dystonia, and ataxia. When associated with Parkinson's disease, tremor may be present at rest or as an action tremor overlapping in phenomenology with essential tremor. Essential tremor may be associated not only with parkinsonism but other neurological disorders, suggesting the possibility of essential tremor subtypes. Besides Parkinson's disease, tremor can be an important feature of other parkinsonian disorders, such as atypical parkinsonism and drug-induced parkinsonism. In addition, tremor can be a prominent feature in patients with other movement disorders such as fragile X-associated tremor/ataxia syndrome, and Wilson's disease in which parkinsonian features may be present. This article is part of the Special Issue "Parkinsonism across the spectrum of movement disorders and beyond" edited by Joseph Jankovic, Daniel D. Truong and Matteo Bologna.
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Abstract
Tremor is the most commonly encountered movement disorder in clinical practice. A wide range of pathologies may manifest with tremor either as a presenting or predominant symptom. Considering the marked etiological and phenomenological heterogeneity, it would be desirable to develop a classification of tremors that reflects their underlying pathophysiology. The tremor task force of the International Parkinson Disease and Movement Disorders Society has worked toward this goal and proposed a new classification system. This system has remained a prime topic of scientific communications on tremor in recent times. The new classification is based on two axes: 1. based on the clinical features, history, and tremor characteristics and 2. based on the etiology of tremor. In this article, we discuss the key aspects of the new classification, review various tremor syndromes, highlight some of the controversies in the field of tremor, and share the potential future perspectives.
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Affiliation(s)
- Abhishek Lenka
- Department of Neurology, Medstar Georgetown University Hospital, Washington, DC, United States
| | - Joseph Jankovic
- Parkinson's Disease Center and Movement Disorders Clinic, Department of Neurology, Baylor College of Medicine, Houston, TX, United States
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Abstract
Tremor and myoclonus are two common hyperkinetic movement disorders. Tremor is characterized by rhythmic oscillatory movements while myoclonic jerks are usually arrhythmic. Tremor can be classified into subtypes including the most common types: essential, enhanced physiological, and parkinsonian tremor. Myoclonus classification is based on its anatomic origin: cortical, subcortical, spinal, and peripheral myoclonus. The clinical presentations are unfortunately not always classic and electrophysiologic investigations can be helpful in making a phenotypic diagnosis. Video-polymyography is the main technique to (sub)classify the involuntary movements. In myoclonus, advanced electrophysiologic testing, such as back-averaging, coherence analysis, somatosensory-evoked potentials, and the C-reflex can be of additional value. Recent developments in tremor point toward a role for intermuscular coherence analysis to differentiate between tremor subtypes. Classification of the movement disorder based on clinical and electrophysiologic features is important, as it enables the search for an etiological diagnosis and guides tailored treatment.
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Affiliation(s)
- R Zutt
- Department of Neurology, University Medical Center Groningen, Groningen, The Netherlands
| | - J W Elting
- Department of Neurology, University Medical Center Groningen, Groningen, The Netherlands
| | - M A J Tijssen
- Department of Neurology, University Medical Center Groningen, Groningen, The Netherlands.
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Canepa C. Waldenstrom-associated anti-MAG paraprotein polyneuropathy with neurogenic tremor. BMJ Case Rep 2019; 12:12/3/e228376. [PMID: 30936346 DOI: 10.1136/bcr-2018-228376] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
A 71-year-old female patient presented with a 14-year history of slowly progressive distal limb numbness, paraesthesia and reduced vibration perception, ataxic gait and intentional tremor. Examination revealed with a length-dependent sensory neuropathy. Nerve conduction studies showed a chronic sensorimotor inflammatory demyelinating polyneuropathy. Intravenous immunoglobulin treatment (on two occasions) proved ineffective. Serum electrophoresis showed increased monoclonal IgM with kappa light chains. Anti-myelin-associated glycoprotein (MAG) levels were extremely elevated, >70 000 BTU. Bone marrow biopsy revealed 15%-20% small B cells and positive MYD88 mutation, indicative of Waldenstrom macroglobulinaemia. A diagnosis of Waldenstrom-associated anti-MAG paraprotein neuropathy with intentional (neurogenic) tremor was made. Repeat nerve conduction study showed a severe sensory demyelinating neuropathy with no axonal lesion. Treatment with rituximab was given for 1 month with minimal improvement. Repeat anti-MAG levels dropped to 53 670 BTU, with minimal clinical improvement.
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Affiliation(s)
- Carlo Canepa
- Department of Neurology, James Paget University Hospital, Great Yarmouth, UK
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Abstract
PURPOSE OF REVIEW Tremor, which is a rhythmic oscillation of a body part, is among the most common involuntary movements. Rhythmic oscillations may manifest in a variety of ways; as a result, a rich clinical phenomenology surrounds tremor. For this reason, diagnosing tremor disorders can be particularly challenging. The aim of this article is to provide the reader with a straightforward approach to the diagnosis and management of patients with tremor. RECENT FINDINGS Scientific understanding of the pathophysiologic basis of tremor disorders has grown considerably in recent years with the use of a broad range of neuroimaging approaches and rigorous, controlled postmortem studies. The basal ganglia and cerebellum are structures that seem to play a prominent role. SUMMARY The diagnosis of tremor disorders is challenging. The approach to tremor involves a history and a neurologic examination that is focused on the nuances of tremor phenomenology, of which there are many. The evaluation should begin with a tremor history and a focused neurologic examination. The examination should attend to the many subtleties of tremor phenomenology. Among other things, the history and examination are used to establish whether the main type of tremor is an action tremor (ie, postural, kinetic, or intention tremor) or a resting tremor. The clinician should then formulate two sets of differential diagnoses: disorders in which action tremor is the predominant tremor versus those in which resting tremor is the main tremor. Among the most common of the former type are essential tremor, enhanced physiologic tremor, drug-induced tremor, dystonic tremor, orthostatic tremor, and cerebellar tremor. Parkinson disease is the most common form of resting tremor, along with drug-induced resting tremor. This article details the clinical features of each of these as well as other tremor disorders.
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11
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Guimarães-Costa R, Iancu Ferfoglia R, Leonard-Louis S, Ziegler F, Magy L, Fournier E, Dubourg O, Bouche P, Maisonobe T, Lacour A, Moerman A, Latour P, Stojkovic T. Phenotypic spectrum of Charcot-Marie-Tooth disease due to LITAF/SIMPLE mutations: a study of 18 patients. Eur J Neurol 2017; 24:530-538. [PMID: 28211240 DOI: 10.1111/ene.13239] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 11/30/2016] [Indexed: 01/11/2023]
Abstract
BACKGROUND AND PURPOSE Charcot-Marie-Tooth (CMT) 1C due to mutations in LITAF/SIMPLE is a rare subtype amongst the autosomal dominant demyelinating forms of CMT. Our objective was to report the clinical and electrophysiological characteristics of 18 CMT1C patients and compare them to 20 patients with PMP22 mutations: 10 CMT1A patients and 10 patients with hereditary neuropathy with liability to pressure palsies (HNPP). METHODS Charcot-Marie-Tooth 1C patients were followed-up in referral centres for neuromuscular diseases or were identified by familial survey. All CMT1A and HNPP patients were recruited at the referral centre for neuromuscular diseases of Pitié-Salpêtrière Hospital. RESULTS Two phenotypes were identified amongst 18 CMT1C patients: the classical CMT form ('CMT-like', 11 cases) and a predominantly sensory form ('sensory form', seven cases). The mean CMT neuropathy score was 4.45 in CMT1C patients. Motor nerve conduction velocities in the upper limbs were significantly more reduced in CMT1A than in CMT1C patients. On the other hand, the motor nerve conduction velocity of the median nerve was significantly lower in CMT1C compared to the HNPP group. Distal motor latency was significantly more prolonged in CMT1A patients compared to the CMT1C and HNPP groups, the latter two groups having similar distal motor latency values. Molecular analysis revealed five new LITAF/SIMPLE mutations (Ala111Thr, Gly112Ala, Trp116Arg, Pro135Leu, Arg160Cys). CONCLUSIONS Our study delineates CMT1C as mostly a mild form of neuropathy, and gives clinical and electrophysiological clues differentiating CMT1C from CMT1A and HNPP. Delineating phenotypes in CMT subtypes is important to orient molecular diagnosis and to help to interpret complex molecular findings.
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Affiliation(s)
- R Guimarães-Costa
- Centre de Référence des Maladies Neuromusculaires Paris Est, Institut de Myologie, Hôpital Pitié-Salpêtrière, Paris, France
| | - R Iancu Ferfoglia
- Centre de Référence des Maladies Neuromusculaires Paris Est, Institut de Myologie, Hôpital Pitié-Salpêtrière, Paris, France
| | - S Leonard-Louis
- Centre de Référence des Maladies Neuromusculaires Paris Est, Institut de Myologie, Hôpital Pitié-Salpêtrière, Paris, France
| | - F Ziegler
- Service de Neurologie, Centre Hospitalier Intercommunale de la Haute Saône, Vesoul, France
| | - L Magy
- Centre de Référence Neuropathies Périphérique Rares, CHU de Limoges - Hôpital Dupuytren, Limoges, France
| | - E Fournier
- Département de Neurophysiologie Clinique, Hôpital Pitié-Salpêtrière, Paris, France
| | - O Dubourg
- Centre de Référence des Maladies Neuromusculaires Paris Est, Institut de Myologie, Hôpital Pitié-Salpêtrière, Paris, France
| | - P Bouche
- Département de Neurophysiologie Clinique, Hôpital Pitié-Salpêtrière, Paris, France
| | - T Maisonobe
- Département de Neurophysiologie Clinique, Hôpital Pitié-Salpêtrière, Paris, France
| | - A Lacour
- Clinique Neurologique, Centre Hospitalier Universitaire de Lille, Lille, France
| | - A Moerman
- Département de Génétique Médicale, Hôpital Jeanne de Flandres, Centre Hospitalier Universitaire de Lille, Lille, France
| | - P Latour
- Service de Neurobiologie, Centre de Biologie et Pathologie Est, Centre Hospitalier Universitaire de Lyon HCL, GH Est, Lyon, France
| | - T Stojkovic
- Centre de Référence des Maladies Neuromusculaires Paris Est, Institut de Myologie, Hôpital Pitié-Salpêtrière, Paris, France
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Cabañes-Martínez L, Del Álamo de Pedro M, de Blas Beorlegui G, Bailly-Bailliere IR. Long-Term Effective Thalamic Deep Brain Stimulation for Neuropathic Tremor in Two Patients with Charcot-Marie-Tooth Disease. Stereotact Funct Neurosurg 2017; 95:102-106. [PMID: 28297702 DOI: 10.1159/000457963] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 01/18/2017] [Indexed: 11/19/2022]
Abstract
BACKGROUND It has been described that many Charcot-Marie-Tooth syndrome type 2 patients are affected by a very disabling type of tremor syndrome, the pathophysiology of which remains unclear. Deep brain stimulation (DBS) has been successfully applied to treat most types of tremors by implanting electrodes in the ventral intermediate nucleus of the thalamus (Vim). METHODS We used DBS applied to the Vim in 2 patients with severe axonal inherited polyneuropathies who developed a disabling tremor. RESULTS Both patients responded positively to stimulation, with a marked reduction of the tremor and with an improvement of their quality of life. CONCLUSION We report 2 cases of tremor associated with a hereditary neuropathy with a good response to DBS.
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Saifee TA, Pareés I, Kassavetis P, Kaski D, Bronstein AM, Rothwell JC, Sadnicka A, Lunn MP, Manji H, Teo JT, Bhatia KP, Reilly MM, Edwards MJ. Tremor in Charcot-Marie-Tooth disease: No evidence of cerebellar dysfunction. Clin Neurophysiol 2015; 126:1817-24. [PMID: 25641441 DOI: 10.1016/j.clinph.2014.12.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 12/03/2014] [Accepted: 12/16/2014] [Indexed: 10/24/2022]
Abstract
OBJECTIVES Tremor in Charcot-Marie-Tooth disease (CMT) can be disabling. Cerebellar abnormalities are thought to underpin neuropathic tremor. Here, we aim to clarify the potential role of the cerebellum in CMT tremor. METHODS We assessed prevalence of tremor by questionnaire in 84 patients with CMT. Of those, 23 patients with CMT with and without arm tremor and healthy controls underwent a clinical assessment, classical eyeblink conditioning, electro-oculography, visuomotor adaptation test, tremor recording with surface EMG and accelerometry, and retrospective correlation with nerve conduction studies to investigate the possible mechanisms of tremor generation. RESULTS The prevalence study revealed tremor in 21% of patients and in 42% of those it caused impairment of function. Tremor recordings revealed a mild-to-moderate amplitude tremor with a weight load-invariant 7.7 Hz frequency component. Performance on classical eyeblink conditioning, visuomotor adaptation and electro-oculography were no different between tremulous and non-tremulous patients and healthy controls. CONCLUSIONS These results argue against a prominent role for an abnormal cerebellum in tremor generation in the patients studied with CMT. Rather, our results suggest an enhancement of the central neurogenic component of physiological tremor as a possible mechanism for tremor in the patients studied. SIGNIFICANCE This study is the first to propose differing pathogenic mechanisms for subtypes of neuropathic tremor.
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Affiliation(s)
- Tabish A Saifee
- Sobell Department for Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, 33 Queen Square, London WC1N 3BG, UK.
| | - Isabel Pareés
- Sobell Department for Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, 33 Queen Square, London WC1N 3BG, UK
| | - Panagiotis Kassavetis
- Sobell Department for Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, 33 Queen Square, London WC1N 3BG, UK
| | - Diego Kaski
- Academic Department of Neuro-otology, Faculty of Medicine, Imperial College London, London, UK
| | - Adolfo M Bronstein
- Academic Department of Neuro-otology, Faculty of Medicine, Imperial College London, London, UK
| | - John C Rothwell
- Sobell Department for Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, 33 Queen Square, London WC1N 3BG, UK
| | - Anna Sadnicka
- Sobell Department for Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, 33 Queen Square, London WC1N 3BG, UK
| | - Michael P Lunn
- MRC Centre for Neuromuscular Diseases, Department of Molecular Neurosciences, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Hadi Manji
- MRC Centre for Neuromuscular Diseases, Department of Molecular Neurosciences, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - James T Teo
- Sobell Department for Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, 33 Queen Square, London WC1N 3BG, UK
| | - Kailash P Bhatia
- Sobell Department for Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, 33 Queen Square, London WC1N 3BG, UK
| | - Mary M Reilly
- MRC Centre for Neuromuscular Diseases, Department of Molecular Neurosciences, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Mark J Edwards
- Sobell Department for Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, 33 Queen Square, London WC1N 3BG, UK
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Louis ED, Hernandez N, Ottman R, Ionita-Laza I, Clark LN. Essential Tremor in a Charcot-Marie-Tooth Type 2C Kindred Does Not Segregate with the TRPV4 R269H Mutation. Case Rep Neurol 2014; 6:1-6. [PMID: 24575025 PMCID: PMC3934698 DOI: 10.1159/000357665] [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: 11/19/2022] Open
Abstract
BACKGROUND We investigated 4 members of a family with type 2C Charcot-Marie-Tooth (CMT) and self-reported essential tremor (ET). A heterozygous missense mutation, R269H, in the TRPV4 gene was previously reported in this family. Our genotypic data provided a rare opportunity to determine the etiology of the tremor. METHODS Family study; the 4 tremor cases underwent a detailed neurological assessment. RESULTS The clinical diagnosis of ET was confirmed in all 4 tremor cases based on stringent published research criteria. Two of these also had CMT. We genotyped all 4 family members for the TRPV4 R269H mutation. We confirmed the presence of the TRPV4 R269H mutation in the 2 family members with ET and CMT; however, the TRPV4 R269H mutation did not segregate with ET in the same family. CONCLUSIONS In this particular CMT family, the tremor was clinically attributed to ET. Furthermore, genotype data indicated that the tremor was unlikely to be caused by incomplete penetrance or variable expressivity of the TRPV4 R269H mutation. Hence, the tremor likely represents ET. This establishes that in some CMT families the tremor diathesis likely represents a second disorder, namely ET.
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Affiliation(s)
- Elan D Louis
- G.H. Sergievsky Center, Columbia University, N.Y., USA ; Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, N.Y., USA ; Department of Neurology, College of Physicians and Surgeons, Columbia University, N.Y., USA ; Department of Epidemiology, Mailman School of Public Health, Columbia University, N.Y., USA
| | | | - Ruth Ottman
- G.H. Sergievsky Center, Columbia University, N.Y., USA ; Department of Neurology, College of Physicians and Surgeons, Columbia University, N.Y., USA ; Department of Epidemiology, Mailman School of Public Health, Columbia University, N.Y., USA ; Division of Epidemiology, New York State Psychiatric Institute, New York, N.Y., USA
| | - Iuliana Ionita-Laza
- Department of Biostatistics, Mailman School of Public Health, Columbia University, N.Y., USA
| | - Lorraine N Clark
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, N.Y., USA ; Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, N.Y., USA
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Abstract
INTRODUCTION Tremor is the most prevalent movement disorder, defined as rhythmic oscillations of a body part, caused by alternating or synchronic contractions of agonistic or antagonistic muscles. The aim of the study was to assess prevalence and to characterize parameters of tremor accompanying de-generative ataxias, Huntington disease (HD) and tic disorders in comparison with a control group. MATERIAL AND METHODS Forty-three patients with degenerative ataxias, 28 with HD and 26 with tic disorders together with 51 healthy controls were included in the study. For each participant, clinical and instrumental assessment (accelerometer, electromyography [EMG], graphic tablet) of hand tremor was performed. Frequency and severity of tremor were assessed in three positions: at rest (rest tremor), with hands extended (postural tremor), during the 'finger-to-nose' test and during Archimedes spiral drawing (kinetic tremor). Based on the mass load test, the type of tremor was determined as essential tremor type or enhanced physiological tremor type. RESULTS The incidence of tremor in the accelerometry in patients with degenerative ataxia (50%) significantly differs from controls (10%) (p = 0.001). The dominant tremor was postural, low-intense, with 7-Hz frequency, essential tremor (23%) or other tremor type (23%), while enhanced physiological tremor was the least frequent (2%). Tremor in patients with HD and tic disorders was found in 10% and 20% of patients, respectively, similarly to the control group. Tremor was mild, postural and of essential tremor type, less frequently of enhanced physiological tremor type. No correlation between severity of tremor and severity of disease was found. CONCLUSIONS The prevalence of tremor is considerably higher among patients with degenerative ataxias compared with HD, tic disorder and the control group. The most common type of tremor accompanying ataxias, HD and tic disorders is essential tremor type.
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Hanajima R, Terao Y, Nakatani-Enomoto S, Hamada M, Yugeta A, Matsumoto H, Yamamoto T, Tsuji S, Ugawa Y. Postural tremor in X-linked spinal and bulbar muscular atrophy. Mov Disord 2010; 24:2063-9. [PMID: 19746452 DOI: 10.1002/mds.22566] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Postural tremor is a common initial symptom in spinal and bulbar muscular atrophy (SBMA), but its pathophysiological mechanisms remain to be studied. This study was undertaken to examine the physiological mechanisms underlying postural tremor in SBMA. For eight patients (36-63 years old) with genetically confirmed SBMA, we recorded surface electromyograms (EMGs) from the forearm muscles and hand movements with an accelerometer (ACC) while maintaining a posture with and without a weight load. We then analyzed their power spectra and coherence. The peak tremor frequency was 6-9 Hz in seven patients and 2-3 Hz in one patient. Oscillatory movements were associated with EMG activity in five patients, but not in three patients. Weight loads and postural changes affected the tremor frequency in all patients. Tremor was classified as "reflex tremor" in five patients and "mechanical tremor" in three patients. These results suggest that peripheral factors play important roles in tremor genesis in SBMA, although its clinical features resemble essential tremor. Subclinical sensory disturbance or a decrease of motor unit numbers might be candidates for such peripheral factors contributing to tremor genesis in SBMA.
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Affiliation(s)
- Ritsuko Hanajima
- Department of Neurology, The University of Tokyo Hospital, Tokyo, Japan.
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18
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Tremor associated with chronic inflammatory demyelinating peripheral neuropathy: treatment with pregabalin. Clin Neuropharmacol 2008; 31:241-4. [PMID: 18670249 DOI: 10.1097/wnf.0b013e3181585b71] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To report a case of a patient with tremor associated with chronic inflammatory demyelinating neuropathy (CIDP) that improved after treatment with pregabalin. CASE REPORT A 68-year-old man diagnosed as having CIDP at age 63 years developed postural and kinetic tremor in both hands at age 64 years. Tremor did not improve with propranolol, primidone, phenobarbital, clonazepam, alprazolam, gabapentin, and topiramate, but improved markedly with pregabalin. Tremor worsened after pregabalin withdrawal and improved again after its reintroduction. CONCLUSIONS Pregabalin could be useful in the treatment of postural tremor associated with CIDP resistant to other therapies.
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20
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ZIELASEK JÜRGEN, TOYKA KLAUSV. Nerve Conduction Abnormalities and Neuromyotonia in Genetically Engineered Mouse Models of Human Hereditary Neuropathies. Ann N Y Acad Sci 2006; 883:310-320. [DOI: 10.1111/j.1749-6632.1999.tb08593.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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21
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Marques W, Freitas MR, Nascimento OJM, Oliveira AB, Calia L, Melo A, Lucena R, Rocha V, Barreira AA. 17p duplicated Charcot-Marie-Tooth 1A: characteristics of a new population. J Neurol 2005; 252:972-9. [PMID: 15765265 DOI: 10.1007/s00415-005-0797-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2004] [Revised: 12/16/2004] [Accepted: 12/17/2004] [Indexed: 01/24/2023]
Abstract
The most frequent type of Charcot-Marie-Tooth (CMT) neuropathy is that associated with the 17p11.2-p12 chromosome duplication, whose characteristics have been well described in European and North American populations. In this study, we analyzed a Brazilian population exhibiting the mutation, found in 57 patients from 42 families (79%) of a cohort of 53 families with demyelinating CMT. Almost 20% of the duplicated cases were sporadic. In 77% of the duplicated families the mutation event occurred in the hot spot area of the CMT1A-Rep region. Forty-five percent of patients were females, 84% were Caucasians and 13% of African descent. Distal limb weakness was the most frequent abnormality, appearing in 84% of patients, although uncommon manifestations such as severe proximal weakness, floppy baby syndrome, diaphragmatic weakness and severe scoliosis were also observed. One patient was wheelchair-bound, and three suffered severe hand weakness. Sensory abnormalities were detected in 84% of the cases, but 80% were unaware of this impairment. Twelve patients complained of positive sensory manifestations such as pain and paresthesias. Progression was reported by 40%. Motor conduction velocities in the upper limbs were always less than 35 m/s, and less than 30.4 m/s in the peroneal nerve. The findings of this study expand the clinical spectrum of the disease.
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Affiliation(s)
- Wilson Marques
- School of Medicine of Ribeirão Preto, University of São Paulo, Department of Neurology, 3900 Ribeirão Preto, São Paulo, Brazil CEP 14048-900.
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22
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Stadler TS, Ross D. Charcot-marie-tooth disease in a high school tennis player. PHYSICIAN SPORTSMED 2002; 30:47-52. [PMID: 20086495 DOI: 10.3810/psm.2002.10.498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A high school tennis player had recurrent ankle sprains that were initially attributed to incomplete rehabilitation. A closer look revealed subtle symptoms of Charcot-Marie-Tooth disease (CMT), a common, inherited neuromuscular disorder. This case underscores the importance of a wide differential diagnosis when encountering recurrent conditions. Early diagnosis of CMT is imperative so that appropriate injury-prevention measures can be taken.
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Affiliation(s)
- Teresa S Stadler
- Department of Orthopedic Surgery, Scott & White Memorial Hospital and Clinic, Texas A&M University Health Science Center, College of Medicine, Temple, TX, 76508, USA.
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23
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Affiliation(s)
- Rodger J Elble
- Department of Neurology, Southern Illinois University School of Medicine, Springfield, Illinois 62794-9643, USA.
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24
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Affiliation(s)
- Joseph Jankovic
- Parkinson's Disease Center and Movement Disorders Clinic, Baylor College of Medicine, Houston, Texas 77030, USA.
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25
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Deuschl G, Bain P. Deep brain stimulation for tremor [correction of trauma]: patient selection and evaluation. Mov Disord 2002; 17 Suppl 3:S102-11. [PMID: 11948763 DOI: 10.1002/mds.10150] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The selection of patients with movement disorders for deep brain stimulation is becoming a common neurological and neurosurgical task. Deep brain stimulation is suitable for different forms of tremor, which can often not be treated with medication. This suitability applies for essential tremor, monosymptomatic tremor at rest, cerebellar or multiple sclerosis tremor, Holmes' tremor, primary writing tremor or tremor in neuropathies. The appropriate selection of patients is critical for the outcome of surgical relief of tremors. Considering the risks of any stereotactic intervention, the following must apply: (1) motor symptoms lead to a relevant disability in activities of daily living, despite optimal medical treatment; (2) biological age of the patient; (3) neurosurgical contraindications; (4) the patient is neither demented nor severely depressed. If these conditions are fulfilled, the individual chances of improvement of the target symptoms need to be checked, based on the following guidelines: (1) the kind of tremor, (2) the natural course of the tremor, (3) the chances for medical treatment in a particular patient, (4) the outcome of surgery in a specific condition, (5) the individual risks for a patient to suffer from complications. The outcome of surgery for tremor depends on the clinical type and distribution. Distal limb tremors are easier to treat than proximal limb tremors. Intention tremor is more difficult to treat than rest or postural tremor. The indication for surgical treatment depends on the analysis of the individual risk-benefit ratio, which also has to take into account the patients' social, professional, and familial background. The patient needs to be well informed about his individual risk-benefit ratio and of alternative treatments, before undergoing stereotactic surgery.
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Affiliation(s)
- Günther Deuschl
- Department of Neurology, Christian-Albrechts-University Kiel, Germany.
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26
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Abstract
The purpose of this study was to further characterize neuromyotonia in mice with deletions and point mutations of myelin protein genes. Clinical observation showed irregular stretching of the hindlimbs, tremor and generalized myokymia in mice with targeted deletions of the genes encoding myelin protein zero (P0-/-) or peripheral myelin protein 22 (Pmp22-/-), and Trembler mice, which carry a point mutation of Pmp22. By electromyography (EMG), we found irregular high-frequency bursts of spontaneous motor unit activity and rhythmic doublet or multiplet discharges of motor units in these mouse models of human hereditary neuropathies. The EMG signs are typical for neuromyotonia and myokymia, respectively. The activity persisted after a proximal nerve section in many cases, localizing the generator to the peripheral nerve or the muscle. We now show that blocking neuromuscular transmission with suxamethonium abolished the spontaneous activity, ruling out a muscle origin. Phenytoin ameliorated the motor behavior. Taken together, our study shows that neuromyotonia develops in different mouse models of hereditary myelinopathies. This indicates that spontaneous motor unit activity may underlie neuromyotonia, which is occasionally observed in Charcot-Marie-Tooth disease. These animal models will be useful to study the pathogenesis of neuromyotonia.
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Affiliation(s)
- J Zielasek
- Department of Neurology, Julius-Maximilians-University, Josef-Schneider-Str. 11, D-97080 Würzburg, Germany.
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27
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Jetten AM, Suter U. The peripheral myelin protein 22 and epithelial membrane protein family. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2000; 64:97-129. [PMID: 10697408 DOI: 10.1016/s0079-6603(00)64003-5] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The peripheral myelin protein 22 (PMP22) and the epithelial membrane proteins (EMP-1, -2, and -3) comprise a subfamily of small hydrophobic membrane proteins. The putative four-transmembrane domain structure as well as the genomic structure are highly conserved among family members. PMP22 and EMPs are expressed in many tissues, and functions in cell growth, differentiation, and apoptosis have been reported. EMP-1 is highly up-regulated during squamous differentiation and in certain tumors, and a role in tumorigenesis has been proposed. PMP22 is most highly expressed in peripheral nerves, where it is localized in the compact portion of myelin. It plays a crucial role in normal physiological and pathological processes in the peripheral nervous system. Progress in molecular genetics has revealed that genetic alterations in the PMP22 gene, including duplications, deletions, and point mutations, are responsible for several forms of hereditary peripheral neuropathies, including Charcot-Marie-Tooth disease type 1A (CMT1A), Dejerine-Sottas syndrome (DDS), and hereditary neuropathy with liability to pressure palsies (HNPP). The natural mouse mutants Trembler and Trembler-J contain a missense mutation in different hydrophobic domains of PMP22, resulting in demyelination and Schwann cell proliferation. Transgenic mice carrying many copies of the PMP22 gene and PMP22-null mice display a variety of defects in the initial steps of myelination and/or maintenance of myelination, whereas no pathological alterations are detected in other tissues normally expressing PMP22. Further characterization of the interactions of PMP22 and EMPs with other proteins as well as their regulation will provide additional insight into their normal physiological function and their roles in disease and possibly will result in the development of therapeutic tools.
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Affiliation(s)
- A M Jetten
- Cell Biology Section, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA
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28
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Senderek J, Hermanns B, Bergmann C, Boroojerdi B, Bajbouj M, Hungs M, Ramaekers VT, Quasthoff S, Karch D, Schröder JM. X-linked dominant Charcot-Marie-Tooth neuropathy: clinical, electrophysiological, and morphological phenotype in four families with different connexin32 mutations(1). J Neurol Sci 1999; 167:90-101. [PMID: 10521546 DOI: 10.1016/s0022-510x(99)00146-x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The sensorimotor neuropathy of the Charcot-Marie-Tooth type (CMT) is the most common hereditary disorder of the peripheral nervous system. The X-linked dominant form of CMT (CMTX) is associated with mutations in the gene for the gap junction protein connexin32. We examined four CMTX pedigrees two of which had potentially novel mutations in the only coding exon of connexin32. One previously unreported missense mutation, Ala39Val, was found in a family displaying a CMT phenotype with additional upper limb postural tremor reminiscent of a Roussy-Lévy syndrome. A novel single base insertion, 679insT, is among the first mutations found in the fourth transmembrane domain of connexin32. Frameshift and premature stop of translation are supposed to result in a non-functional carboxy-terminus. Two further families had the known missense mutations Arg15Trp and Arg22Gln. Several female carriers were found normal on clinical presentation, however, the genotype was paralleled by decreased nerve conduction velocities (NCV) and slowed central conduction of brain stem auditory evoked responses (BAER). Median motor NCVs showed mild (in women) to intermediate (in males) reduction, indicating a peripheral neuropathy with a predominating axonal component. Nerve biopsy findings were consistent with the electrophysiological data showing a marked loss of large myelinated fibres and clusters of regenerating axons. Electron microscopy revealed various alterations of the axoglial attachment zone. This suggests defective axon-Schwann cell interactions which may induce the axonopathy in CMTX.
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Affiliation(s)
- J Senderek
- Institut für Neuropathologie, Universitätsklinikum der Rheinisch-Westfälischen Technischen Hochschule, Pauwelsstrasse 30, D-52074, Aachen, Germany
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29
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Deuschl G, Bain P, Brin M. Consensus statement of the Movement Disorder Society on Tremor. Ad Hoc Scientific Committee. Mov Disord 1998; 13 Suppl 3:2-23. [PMID: 9827589 DOI: 10.1002/mds.870131303] [Citation(s) in RCA: 873] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
This is a proposal of the Movement Disorder Society for a clinical classification of tremors. The classification is based on the distinction between rest, postural, simple kinetic, and intention tremor (tremor during target-directed movements). Additional data from a medical history and the results of a neurologic examination can be combined into one of the following clinical syndromes defined in this statement: enhanced physiologic tremor, classical essential tremor (ET), primary orthostatic tremor, task- and position-specific tremors, dystonic tremor, tremor in Parkinson's disease (PD), cerebellar tremor, Holmes' tremor, palatal tremor, drug-induced and toxic tremor, tremor in peripheral neuropathies, or psychogenic tremor. Conditions such as asterixis, epilepsia partialis continua, clonus, and rhythmic myoclonus can be misinterpreted as tremor. The features distinguishing these conditions from tremor are described. Controversial issues are outlined in a comment section for each item and thus reflect the open questions that at present cannot be answered on a scientific basis. We hope that this statement provides a basis for better communication among clinicians working in the field and stimulates tremor research.
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Affiliation(s)
- G Deuschl
- Neurologische Klinik der Christian-Albrechts-Universität zu Kiel, Germany
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30
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Abstract
Tremor is a common neurologic symptom that can also be incapacitating to the patient, so effective therapy is needed. The causes of tremor are heterogeneous. Essential tremor (ET) and the tremor associated with Parkinson's disease (PD) are the most common encountered in clinical practice. Beta-adrenergic blockers and primidone remain the mainstay of treatment for ET, whereas carbidopa/levodopa and anticholinergics are most beneficial in PD. However, the efficacy of various other medications has been studied in ET and PD, and also in patients with tremor resulting from other conditions, with varying results.
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Affiliation(s)
- P G Wasielewski
- Department of Neurology, University of Kansas Medical Center, Kansas City 66160-7314, USA
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31
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Abstract
Essential tremor (ET) is one of the most common movement disorders. However, the etiology and pathogenesis are as yet unknown. Continued research will give us clues to understanding the impact on society, identifying genetic and environmental contributors to the disease, understanding the significance of a sporadic case, the phenotypic spectrum and timing of presentation, and the relationship with other neurologic disorders. Because the condition is both clinically and genetically heterogeneous and there is overlap with these other disorders, such as dystonia, parkinsonism, peripheral neuropathy, and migraine, the definition of phenotype plagues research in this area. Advances in understanding the genetic and molecular underpinnings of tremor should provide additional tools to unravel the clinical phenotype (including physiology), genotype-phenotype relationships, and the epidemiology of tremor.
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Affiliation(s)
- M F Brin
- Mount Sinai Medical Center, Department of Neurology, New York, NY 10029, USA
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32
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Auer-Grumbach M, Strasser-Fuchs S, Wagner K, Körner E, Fazekas F. Roussy-Lévy syndrome is a phenotypic variant of Charcot-Marie-Tooth syndrome IA associated with a duplication on chromosome 17p11.2. J Neurol Sci 1998; 154:72-5. [PMID: 9543325 DOI: 10.1016/s0022-510x(97)00218-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The Roussy-Lévy syndrome (MIM #180800) was described in 1926 as a disorder presenting with pes cavus and tendon areflexia, distal limb weakness, tremor in the upper limbs, gait ataxia and distal sensory loss. We report a family with affected members in four generations, showing these clinical signs of Roussy-Lévy syndrome and a partial duplication at chromosome 17p11.2. This genetic defect is commonly found in patients with the hypertrophic form of the Charcot-Marie-Tooth syndrome. Our finding provides evidence against the Roussy-Lévy syndrome as a distinct entity but suggests a close relation with the Charcot-Marie-Tooth syndrome. What causes the additional features of gait ataxia and essential tremor needs further clarification.
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Affiliation(s)
- M Auer-Grumbach
- Department of Neurology, Karl-Franzens-University Graz, Austria
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33
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Shaibani A, Gooch C, Harati Y. Moving toes and myoclonus associated with hereditary neuropathy with liability to pressure palsy (HNPP). Muscle Nerve 1997; 20:881-3. [PMID: 9179161 DOI: 10.1002/(sici)1097-4598(199707)20:7<881::aid-mus13>3.0.co;2-v] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A 22-year-old male awoke with right foot drop and numbness. Nerve conduction studies, sural nerve biopsy, and molecular genetic analysis were consistent with hereditary neuropathy with liability to pressure palsy (HNPP). Two months later he developed involuntary flexion/extension movements of the right toes with associated intermittent dystonic flexion of the right foot. Over the next 2 months these movements spread to the left foot and hand and myoclonus of the left trapezius and rhomboid appeared. This is the first case report of moving toes syndrome and segmental myoclonus in association with HNPP. The temporal and topographic patterns of spread of the abnormal movements suggest a central mechanism probably induced by peripheral pathology.
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Affiliation(s)
- A Shaibani
- Department of Neurology, Baylor College of Medicine, Houston, Texas, USA
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34
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Pedersen SF, Pullman SL, Latov N, Brannagan TH. Physiological tremor analysis of patients with anti-myelin-associated glycoprotein associated neuropathy and tremor. Muscle Nerve 1997; 20:38-44. [PMID: 8995581 DOI: 10.1002/(sici)1097-4598(199701)20:1<38::aid-mus5>3.0.co;2-i] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Tremor is often associated with anti-myelin-associated glycoprotein (anti-MAG) peripheral neuropathy (PN), but its physiology has never been accurately described. This study quantified the physiological characteristics of tremors in patients with anti-MAG demyelinating PN. Eighteen patients with tremor and PN with demyelinating features (ages 30-86, mean = 66.5 years) were evaluated for anti-MAG antibodies (positive considered > or = 1:3200) and for tremor amplitude, frequency, side-to-side relationships, and electromyographic (EMG) activation patterns. Thirteen patients had anti-MAG titers >1:3200 and 8 had both positive anti-MAG titers and tremors. Anti-MAG PN patients revealed tremors higher in amplitude, lower in frequency, with greater side-to-side amplitude ratios, greater amplitude variability, and more consistent cocontracting antagonist EMG patterns that do not attenuate with inertial loading. We conclude that anti-MAG PN tremor is not due only to exaggerated physiologic mechanisms but may reflect a distinctive form of neurogenic tremor.
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Affiliation(s)
- S F Pedersen
- Department of Neurology, College of Physicians and Surgeons of Columbia University, New York, New York, USA
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35
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Murakami T, Garcia CA, Reiter LT, Lupski JR. Charcot-Marie-Tooth disease and related inherited neuropathies. Medicine (Baltimore) 1996; 75:233-50. [PMID: 8862346 DOI: 10.1097/00005792-199609000-00001] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Charcot-Marie-Tooth disease (CMT) was initially described more than 100 years ago by Charcot, Marie, and Tooth. It was only recently, however, that molecular genetic studies of CMT have uncovered the underlying causes of most forms of the diseases. Most cases of CMT1 are associated with a 1.5-Mb tandem duplication in 17p11.2-p12 that encompasses the PMP22 gene. Although many genes may exist in this large duplicated region, PMP22 appears to be the major dosage-sensitive gene. CMT1A is the first autosomal dominant disease associated with a gene dosage effect due to an inherited DNA rearrangement. There is no mutant gene, but instead the disease phenotype results from having 3 copies of a normal gene. Furthermore, these findings suggest that therapeutic intervention in CMT1A duplication patients may be possible by normalizing the amount of PMP22 mRNA levels. Alternatively, CMT1A can be caused by mutations in the PMP22 gene. Other forms of CMT are associated with mutations in the MPZ (CMT1B) and Cx32 (CMTX) genes. Thus, mutations in different genes can cause similar CMT phenotypes. The related but more severe neuropathy, Dejerine-Sottas syndrome (DSS), can also be caused by mutations in the PMP22 and MPZ genes. All 3 genes thus far identified by CMT researchers appear to play an important role in the myelin formation or maintenance of peripheral nerves. CMT1A, CMT1B, CMTX, hereditary neuropathy with liability to pressure palsies (HNPP), and DSS have been called myelin disorders or "myelino-pathies." Other demyelinating forms, CMT1C and CMT-AR, may be caused by mutations of not yet identified myelin genes expressed in Schwann cells. The clinically distinct disease HNPP is caused by a 1.5-Mb deletion in 17p11.2-p12, which spans the same region duplicated in most CMT1A patients. Underexpression of the PMP22 gene causes HNPP just as overexpression of PMP22 causes CMT1A. Thus, 2 different phenotypes can be caused by dosage variations of the same gene. It is apparent that the CMT1A duplication and HNPP deletion are the reciprocal products of a recombination event during meiosis mediated through the CMT1A-REPs. CMT1A and HNPP could be thought of as a "genomic disease" more than single gene disorders. Other genetic disorders may also prove to arise from recombination events mediated by specific chromosomal structural features of the human genome (102). Further studies on the recombination mechanism of CMT and HNPP might reveal the causes of site specific homologous recombination in the human genome. The discovery of the PMP22 gene in the 1.5-Mb CMT1A duplication/HNPP deletion critical region also suggests that the clinical phenotype of chromosome aneuploid syndromes may result from the effect of a small subset of dosage-sensitive genes mapping within the region of aneuploidy. The understanding of the molecular basis of CMT1 and related disorders has allowed accurate DNA diagnosis and genetic counseling of inherited peripheral neuropathies and will make it possible to develop rational strategies for therapy. As several loci for CMT2 have been identified, the genes responsible for CMT2 will most likely be disclosed using positional cloning and candidate gene approaches in the near future.
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Affiliation(s)
- T Murakami
- Departments of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
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36
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Snipes GJ, Suter U. Molecular basis of common hereditary motor and sensory neuropathies in humans and in mouse models. Brain Pathol 1995; 5:233-47. [PMID: 8520723 DOI: 10.1111/j.1750-3639.1995.tb00600.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The Hereditary Motor and Sensory Neuropathies (HMSNs) are well known to be clinically, morphologically, and genetically heterogeneous. Yet, recent advances in the cellular and molecular biology of the peripheral nervous system coupled with remarkable progress in human and mouse genetics have provided a framework that has profoundly changed our understanding of the pathogenesis of these diseases. It now appears that most of the HMSNs are related to mutations affecting genes encoding Schwann cell proteins, specifically the Peripheral Myelin Protein PMP22, Myelin Protein Zero, and one of the gap junction proteins, connexin-32. Accordingly, these findings are discussed in the context of the clinical and pathologic features of the human HMSNs, but are interpreted in the context of basic research findings on the cellular and molecular biology of the peripheral nervous system derived from in vivo and in vitro studies in spontaneously-occurring and genetically engineered animal models for the HMSNs.
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Affiliation(s)
- G J Snipes
- Department of Neurobiology, Stanford University School of Medicine, California 94305, USA
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