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Gray MM, Naik A, Ebner TJ, Carter RE. Altered brain state during episodic dystonia in tottering mice decouples primary motor cortex from limb kinematics. DYSTONIA 2023; 2:10974. [PMID: 37800168 PMCID: PMC10554815 DOI: 10.3389/dyst.2023.10974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/07/2023]
Abstract
Episodic Ataxia Type 2 (EA2) is a rare neurological disorder caused by a mutation in the CACNA1A gene, encoding the P/Q-type voltage-gated Ca2+ channel important for neurotransmitter release. Patients with this channelopathy exhibit both cerebellar and cerebral pathologies, suggesting the condition affects both regions. The tottering (tg/tg) mouse is the most commonly used EA2 model due to an orthologous mutation in the cacna1a gene. The tg/tg mouse has three prominent behavioral phenotypes: a dramatic episodic dystonia; absence seizures with generalized spike and wave discharges (GSWDs); and mild ataxia. We previously observed a novel brain state, transient low-frequency oscillations (LFOs) in the cerebellum and cerebral cortex under anesthesia. In this study, we examine the relationships among the dystonic attack, GSWDs, and LFOs in the cerebral cortex. Previous studies characterized LFOs in the motor cortex of anesthetized tg/tg mice using flavoprotein autofluorescence imaging testing the hypothesis that LFOs provide a mechanism for the paroxysmal dystonia. We sought to obtain a more direct understanding of motor cortex (M1) activity during the dystonic episodes. Using two-photon Ca2+ imaging to investigate neuronal activity in M1 before, during, and after the dystonic attack, we show that there is not a significant change in the activity of M1 neurons from baseline through the attack. We also conducted simultaneous, multi-electrode recordings to further understand how M1 cellular activity and local field potentials change throughout the progression of the dystonic attack. Neither putative pyramidal nor inhibitory interneuron firing rate changed during the dystonic attack. However, we did observe a near complete loss of GSWDs during the dystonic attack in M1. Finally, using spike triggered averaging to align simultaneously recorded limb kinematics to the peak Ca2+ response, and vice versa, revealed a reduction in the spike triggered average during the dystonic episodes. Both the loss of GSWDs and the reduction in the coupling suggest that, during the dystonic attack, M1 is effectively decoupled from other structures. Overall, these results indicate that the attack is not initiated or controlled in M1, but elsewhere in the motor circuitry. The findings also highlight that LFOs, GSWDs, and dystonic attacks represent three brain states in tg/tg mice.
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Affiliation(s)
- Madelyn M Gray
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, United States
| | - Anant Naik
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States
| | - Timothy J Ebner
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, United States
| | - Russell E Carter
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, United States
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2
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Filippopulos FM, Schnabel L, Dunker K, Strobl R, Huppert D. Episodic ataxias in children and adolescents: Clinical findings and suggested diagnostic criteria. Front Neurol 2022; 13:1016856. [PMID: 36353133 PMCID: PMC9638128 DOI: 10.3389/fneur.2022.1016856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 10/06/2022] [Indexed: 11/15/2022] Open
Abstract
Background The main clinical presentation of episodic ataxias (EAs) consists of vertigo and dizziness attacks lasting for minutes to hours with widely varying accompanying symptoms. The differentiation of EA and episodic vertigo/dizziness syndromes in childhood and adolescence such as vestibular migraine (VM) and recurrent vertigo of childhood (RVC) can be challenging. Furthermore, only few prospective studies of children/adolescents with EA are available. Objective This study aims to characterize clinical and instrument-based findings in EA patients under 18 years of age, to delineate the clinical and therapeutic course in EA, and to present potentially new genetic mutations. Furthermore, the study aims to differentiate distinct characteristics between EA, VM, and RVC patients. Methods We prospectively collected clinical and instrument-based data of patients younger than 18 years, who presented at the German Center for Vertigo and Balance Disorders (DSGZ) at the LMU University Hospital in Munich with EA, VM, or RVC between January 2016 and December 2021. All patients underwent a comprehensive evaluation of neurological, ocular-motor, vestibular and cochlear function, including video-oculography with caloric testing, video head impulse test, vestibular evoked myogenic potentials, posturography, and gait analysis. Results Ten patients with EA, 15 with VM, and 15 with RVC were included. In EA the main symptoms were vertigo/dizziness attacks lasting between 5 min and 12 h. Common accompanying symptoms included walking difficulties, paleness, and speech difficulties. Six EA patients had a previously unknown gene mutation. In the interictal interval all EA patients showed distinct ocular-motor deficits. Significant differences between EA, VM, and RVC were found for accompanying symptoms such as speech disturbances and paleness, and for the trigger factor “physical activity”. Furthermore, in the interictal interval significant group differences were observed for different pathological nystagmus types, a saccadic smooth pursuit, and disturbed fixation suppression. Conclusion By combining clinical and ocular-motor characteristics we propose diagnostic criteria that can help to diagnose EA among children/adolescents and identify patients with EA even without distinct genetic findings. Nevertheless, broad genetic testing (e.g., next generation sequencing) in patients fulfilling the diagnostic criteria should be conducted to identify even rare or unknown genetic mutations for EA.
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Affiliation(s)
- Filipp Maximilian Filippopulos
- German Center for Vertigo and Balance Disorders (DSGZ), University Hospital, Ludwig-Maximilians-Universität, Munich, Germany
- Department of Neurology, University Hospital, Ludwig-Maximilians-Universität, Munich, Germany
- *Correspondence: Filipp Maximilian Filippopulos
| | - Lutz Schnabel
- German Center for Vertigo and Balance Disorders (DSGZ), University Hospital, Ludwig-Maximilians-Universität, Munich, Germany
- Department of Neurology, University Hospital, Ludwig-Maximilians-Universität, Munich, Germany
| | - Konstanze Dunker
- German Center for Vertigo and Balance Disorders (DSGZ), University Hospital, Ludwig-Maximilians-Universität, Munich, Germany
| | - Ralf Strobl
- German Center for Vertigo and Balance Disorders (DSGZ), University Hospital, Ludwig-Maximilians-Universität, Munich, Germany
| | - Doreen Huppert
- German Center for Vertigo and Balance Disorders (DSGZ), University Hospital, Ludwig-Maximilians-Universität, Munich, Germany
- Department of Neurology, University Hospital, Ludwig-Maximilians-Universität, Munich, Germany
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Castillo-Bustamante M, Barona Cabrera M, Suárez Angulo S, García Campuzano M, García A, Madrigal J. Facts of Vertigo in Adolescents: Controversies and Challenges – A Narrative Review. Cureus 2022; 14:e28294. [PMID: 36168384 PMCID: PMC9506299 DOI: 10.7759/cureus.28294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/23/2022] [Indexed: 11/27/2022] Open
Abstract
Vertigo is a common complaint in the general population affecting 5% of adults in one year. At least 29.5% of adults have referred vertigo during life. Even though the prevalence of vertigo is well known in adults the epidemiologic data in adolescents is sparse. To date, it is known that adolescent females are usually affected by vertigo and some conditions such as depression and anxiety are found in this population. However, the lack of information about the prevalence of most common types of vertigo in adolescents, predisposing factors, challenges, and controversies in clinics in the literature, present a challenge for clinicians regarding the approach and follow-up of this population. Herein, we performed a literature review including data about the prevalence, most common types of vertigo and controversial events in the approach of vertigo in adolescents over the last two decades.
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The efficacy of combining topiramate and 4-aminopyridine to reduce relapses and interictal progression in two cases of episodic ataxia type 2. Neurol Sci 2022; 43:5099-5101. [DOI: 10.1007/s10072-022-06144-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 05/13/2022] [Indexed: 10/18/2022]
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Batum M, Kısabay Ak A, Çetin G, Çelebi HBG, Çam S, Mavioğlu H. Coincidental occurance of episodic ataxia and multiple sclerosis: a case report and review of the literature. Int J Neurosci 2022; 132:656-661. [DOI: 10.1080/00207454.2020.1835896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Melike Batum
- Neurology Department, Celal Bayar Unıversity, Manisa, Turkey
| | | | - Güldeniz Çetin
- Neurology Department, Celal Bayar Unıversity, Manisa, Turkey
| | | | - Sırrı Çam
- Genetics Department, Celal Bayar Unıversity, Manisa, Turkey
| | - Hatice Mavioğlu
- Neurology Department, Celal Bayar Unıversity, Manisa, Turkey
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6
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Choi JH, Oh EH, Choi SY, Kim HJ, Lee SK, Choi JY, Kim JS, Choi KD. Vestibular impairments in episodic ataxia type 2. J Neurol 2021; 269:2687-2695. [PMID: 34709445 DOI: 10.1007/s00415-021-10856-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 10/20/2022]
Abstract
Episodic ataxia type 2 (EA2) can present diverse ocular motor abnormalities, but few studies have systematically evaluated vestibular function during the interictal periods. This study aimed to determine vestibular impairments in patients with EA2 during the interictal periods. We recruited 17 patients with genetically confirmed EA2 (10 men, age range = 16-85 years, median = 32 years). We systematically evaluated the vestibular function by measuring the semicircular canals (SCCs) function with bithermal caloric tests, rotatory chair test, and video head impulse test (vHIT), and the otolith function with subjective visual vertical (SVV) tilt and variability, and cervical and ocular vestibular-evoked myogenic potentials (VEMPs). Patients with EA2 commonly showed abnormal VOR responses at least for one SCC with high-acceleration, high-frequency head impulses (14/16, 88%), and impaired visual-vestibular interaction (7/12, 58%). In response to low acceleration and frequency stimuli, the VOR gains were generally normal. The majority of EA2 patients had impairments in at least one of the otolith function tests (13/16, 81%): SVV tilt or variability (7/14, 50%), oVEMP (8/15, 53%), and cVEMP (4/16, 25%). Vestibular impairments are common in EA2 even during the interictal periods. Selective decrease in the VOR responses during higher acceleration stimuli along with impaired visual-vestibular interaction and otolith function suggests degeneration of the vestibulocerebellum or vestibular nuclei.
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Affiliation(s)
- Jae-Hwan Choi
- Department of Neurology, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, South Korea
| | - Eun Hye Oh
- Department of Neurology, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, South Korea
| | - Seo Young Choi
- Department of Neurology, Pusan National University Hospital, Pusan National University School of Medicine and Biomedical Research Institute, Busan, South Korea
| | - Hyo Jung Kim
- Research Administration Team, Seoul National University Bundang Hospital, Seongnam, South Korea
| | - Seon Kyung Lee
- Dizziness Center, Clinical Neuroscience Center, Department of Neurology, Seoul National University Bundang Hospital, 173-82 Gumi-ro, Bundang-gu, Seongnam, Gyeonggi-do, 13620, South Korea
| | - Jeong Yoon Choi
- Dizziness Center, Clinical Neuroscience Center, Department of Neurology, Seoul National University Bundang Hospital, 173-82 Gumi-ro, Bundang-gu, Seongnam, Gyeonggi-do, 13620, South Korea
| | - Ji-Soo Kim
- Dizziness Center, Clinical Neuroscience Center, Department of Neurology, Seoul National University Bundang Hospital, 173-82 Gumi-ro, Bundang-gu, Seongnam, Gyeonggi-do, 13620, South Korea.
| | - Kwang-Dong Choi
- Department of Neurology, Pusan National University Hospital, Pusan National University School of Medicine and Biomedical Research Institute, Busan, South Korea. .,Department of Neurology, College of Medicine, Pusan National University Hospital, 1-10 Ami-dong, Seo-gu, Busan, 49241, South Korea.
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Verriello L, Pauletto G, Nilo A, Lonigro I, Betto E, Valente M, Curcio F, Gigli GL. Epilepsy and episodic ataxia type 2: family study and review of the literature. J Neurol 2021; 268:4296-4302. [PMID: 33983550 DOI: 10.1007/s00415-021-10555-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 04/05/2021] [Accepted: 04/09/2021] [Indexed: 10/21/2022]
Abstract
Episodic ataxia type 2 (EA2) is a hereditary disorder characterized by paroxysmal attacks of ataxia, vertigo and nausea, due to mutations in the CACNA1A gene, which encodes for α1 subunit of the P/Q-type voltage-gated Ca2+ channel (CaV2.1). Other manifestations may be associated to CACNA1A mutations, such as migraine and epilepsy. The correlation between episodic ataxia and epilepsy is often underestimated and misdiagnosed. Clinical presentation of EA2 varies among patients and within the same family, and the same genetic mutation can lead to different clinical phenotypes. We herewith describe an Italian family presenting with typical EA2 and, in two of the family members (patients II.3 and III.1), epileptic seizures. The sequencing revealed a heterozygous deletion of 6 nucleotides in exon 28 of CACNA1A gene, present in all affected patients. Evidence suggests that mutations of CACNA1A, conferring a loss/reduction of CaV2.1 function, lead to an increase of thalamocortical excitation that contributes to epileptiform discharges. Our description highlights intra-family variability of EA2 phenotype and suggests that mutations in the CACNA1A gene should be suspected in individuals with focal or generalized epilepsy, associated with a family history of episodic ataxia.
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Affiliation(s)
- Lorenzo Verriello
- Neurology Unit, Department of Neurosciences, Santa Maria della Misericordia University Hospital, ASUFC, Piazzale Santa Maria della Misericordia 15, 33100, Udine, Italy.
| | - Giada Pauletto
- Neurology Unit, Department of Neurosciences, Santa Maria della Misericordia University Hospital, ASUFC, Piazzale Santa Maria della Misericordia 15, 33100, Udine, Italy
| | - Annacarmen Nilo
- Clinical Neurology Unit, Department of Neurosciences, Santa Maria della Misericordia University Hospital, ASUFC, Udine, Italy
| | - Incoronata Lonigro
- Department of Medicine (DAME), University of Udine, Udine, Italy.,Department of Laboratory Medicine, Santa Maria della Misericordia University Hospital, ASUFC, Udine, Italy
| | - Elena Betto
- Department of Laboratory Medicine, Santa Maria della Misericordia University Hospital, ASUFC, Udine, Italy
| | - Mariarosaria Valente
- Department of Medicine (DAME), University of Udine, Udine, Italy.,Clinical Neurology Unit, Department of Neurosciences, Santa Maria della Misericordia University Hospital, ASUFC, Udine, Italy
| | - Francesco Curcio
- Department of Medicine (DAME), University of Udine, Udine, Italy.,Department of Laboratory Medicine, Santa Maria della Misericordia University Hospital, ASUFC, Udine, Italy
| | - Gian Luigi Gigli
- Clinical Neurology Unit, Department of Neurosciences, Santa Maria della Misericordia University Hospital, ASUFC, Udine, Italy.,Department of Mathematics, Informatics and Physics (DMIF), University of Udine, Udine, Italy
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8
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Verriello L, Carrera P, Pauletto G, Bernardini A, Valente M, Gigli GL. Case report and ten-year follow-up of episodic ataxia type 2 due to a novel variant in CACNA1A. eNeurologicalSci 2021; 23:100334. [PMID: 33786385 PMCID: PMC7994720 DOI: 10.1016/j.ensci.2021.100334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 02/23/2021] [Accepted: 03/06/2021] [Indexed: 11/16/2022] Open
Affiliation(s)
- Lorenzo Verriello
- Neurology Unit, Department of Neurosciences, Santa Maria della Misericordia University Hospital, Udine, Italy
| | - Paola Carrera
- Laboratory of Clinical and Molecular Biology and Unit of Genomics for Diagnosis of Genetic Diseases, IRCCS Ospedale San Raffaele, Milano, Italy
| | - Giada Pauletto
- Neurology Unit, Department of Neurosciences, Santa Maria della Misericordia University Hospital, Udine, Italy
| | - Andrea Bernardini
- Clinical Neurology Unit, Department of Neurosciences, Santa Maria della Misericordia University Hospital, Udine, Italy
| | - Mariarosaria Valente
- Clinical Neurology Unit, Department of Neurosciences, Santa Maria della Misericordia University Hospital, Udine, Italy.,Department of Medicine (DAME), University of Udine, Italy
| | - Gian Luigi Gigli
- Clinical Neurology Unit, Department of Neurosciences, Santa Maria della Misericordia University Hospital, Udine, Italy.,Department of Mathematics, Informatics and Physics (DMIF), University of Udine, Italy
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9
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Indelicato E, Unterberger I, Nachbauer W, Eigentler A, Amprosi M, Zeiner F, Haberlandt E, Kaml M, Gizewski E, Boesch S. The electrophysiological footprint of CACNA1A disorders. J Neurol 2021; 268:2493-2505. [PMID: 33544220 PMCID: PMC8217028 DOI: 10.1007/s00415-021-10415-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 01/16/2021] [Accepted: 01/17/2021] [Indexed: 12/14/2022]
Abstract
Objectives CACNA1A variants underlie three neurological disorders: familial hemiplegic migraine type 1 (FHM1), episodic ataxia type 2 (EA2) and spinocerebellar ataxia type 6 (SCA6). EEG is applied to study their episodic manifestations, but findings in the intervals did not gain attention up to date. Methods We analyzed repeated EEG recordings performed between 1994 and 2019 in a large cohort of genetically confirmed CACNA1A patients. EEG findings were compared with those of CACNA1A-negative phenocopies. A review of the related literature was performed. Results 85 EEG recordings from 38 patients (19 EA2, 14 FHM1, 5 SCA6) were analyzed. Baseline EEG was abnormal in 55% of cases (12 EA2, 9 FHM1). The most common finding was a lateralized intermittent slowing, mainly affecting the temporal region. Slowing was more pronounced after a recent attack but was consistently detected in the majority of patients also during the follow-up. Interictal epileptic discharges (IEDs) were detected in eight patients (7 EA2,1 FHM1). EEG abnormalities and especially IEDs were significantly associated with younger age at examination (16 ± 9 vs 43 ± 21 years in those without epileptic changes, p = 0.003) and with earlier onset of disease (1 (1–2) vs 12 (5–45) years, p = 0.0009). EEG findings in CACNA1A-negative phenocopies (n = 15) were largely unremarkable (p = 0.03 in the comparison with CACNA1A patients). Conclusions EEG abnormalities between attacks are highly prevalent in episodic CACNA1A disorders and especially associated with younger age at examination and earlier disease onset. Our findings underpin an age-dependent effect of CACNA1A variants, with a more severe impairment when P/Q channel dysfunction manifests early in life.
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Affiliation(s)
- Elisabetta Indelicato
- Center for Rare Movement Disorders Innsbruck, Department of Neurology, Medical University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria
| | - Iris Unterberger
- Epileptology Division, Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Wolfgang Nachbauer
- Center for Rare Movement Disorders Innsbruck, Department of Neurology, Medical University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria
| | - Andreas Eigentler
- Center for Rare Movement Disorders Innsbruck, Department of Neurology, Medical University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria
| | - Matthias Amprosi
- Center for Rare Movement Disorders Innsbruck, Department of Neurology, Medical University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria
| | - Fiona Zeiner
- Department of Pediatrics I, Medical University of Innsbruck, Innsbruck, Austria
| | - Edda Haberlandt
- Department of Pediatrics I, Medical University of Innsbruck, Innsbruck, Austria
- Department of Pediatrics, City Hospital, Dornbirn, Austria
| | - Manuela Kaml
- Epileptology Division, Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Elke Gizewski
- Department of Neuroradiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Sylvia Boesch
- Center for Rare Movement Disorders Innsbruck, Department of Neurology, Medical University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria.
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Mei C, Dong H, Nisenbaum E, Thielhelm T, Nourbakhsh A, Yan D, Smeal M, Lundberg Y, Hoffer ME, Angeli S, Telischi F, Nie G, Blanton SH, Liu X. Genetics and the Individualized Therapy of Vestibular Disorders. Front Neurol 2021; 12:633207. [PMID: 33613440 PMCID: PMC7892966 DOI: 10.3389/fneur.2021.633207] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 01/13/2021] [Indexed: 02/06/2023] Open
Abstract
Background: Vestibular disorders (VDs) are a clinically divergent group of conditions that stem from pathology at the level of the inner ear, vestibulocochlear nerve, or central vestibular pathway. No etiology can be identified in the majority of patients with VDs. Relatively few families have been reported with VD, and so far, no causative genes have been identified despite the fact that more than 100 genes have been identified for inherited hearing loss. Inherited VDs, similar to deafness, are genetically heterogeneous and follow Mendelian inheritance patterns with all modes of transmission, as well as multifactorial inheritance. With advances in genetic sequencing, evidence of familial clustering in VD has begun to highlight the genetic causes of these disorders, potentially opening up new avenues of treatment, particularly in Meniere's disease and disorders with comorbid hearing loss, such as Usher syndrome. In this review, we aim to present recent findings on the genetics of VDs, review the role of genetic sequencing tools, and explore the potential for individualized medicine in the treatment of these disorders. Methods: A search of the PubMed database was performed for English language studies relevant to the genetic basis of and therapies for vestibular disorders, using search terms including but not limited to: “genetics,” “genomics,” “vestibular disorders,” “hearing loss with vestibular dysfunction,” “individualized medicine,” “genome-wide association studies,” “precision medicine,” and “Meniere's syndrome.” Results: Increasing numbers of studies on vestibular disorder genetics have been published in recent years. Next-generation sequencing and new genetic tools are being utilized to unearth the significance of the genomic findings in terms of understanding disease etiology and clinical utility, with growing research interest being shown for individualized gene therapy for some disorders. Conclusions: The genetic knowledge base for vestibular disorders is still in its infancy. Identifying the genetic causes of balance problems is imperative in our understanding of the biology of normal function of the vestibule and the disease etiology and process. There is an increasing effort to use new and efficient genetic sequencing tools to discover the genetic causes for these diseases, leading to the hope for precise and personalized treatment for these patients.
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Affiliation(s)
- Christine Mei
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Hongsong Dong
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States.,Shenzhen Second People's Hospital, Shenzhen, China
| | - Eric Nisenbaum
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Torin Thielhelm
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Aida Nourbakhsh
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Denise Yan
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Molly Smeal
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Yesha Lundberg
- Department of Otolaryngology, Boys Town National Research Hospital, Omaha, NE, United States
| | - Michael E Hoffer
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Simon Angeli
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Fred Telischi
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Guohui Nie
- Shenzhen Second People's Hospital, Shenzhen, China
| | - Susan H Blanton
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Xuezhong Liu
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
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11
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Gur-Hartman T, Berkowitz O, Yosovich K, Roubertie A, Zanni G, Macaya A, Heimer G, Dueñas BP, Sival DA, Pode-Shakked B, López-Laso E, Humbertclaude V, Riant F, Bosco L, Cayron LB, Nissenkorn A, Nicita F, Bertini E, Hassin S, Ben Zeev B, Zerem A, Libzon S, Lev D, Linder I, Lerman-Sagie T, Blumkin L. Clinical phenotypes of infantile onset CACNA1A-related disorder. Eur J Paediatr Neurol 2021; 30:144-154. [PMID: 33349592 DOI: 10.1016/j.ejpn.2020.10.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 10/11/2020] [Accepted: 10/14/2020] [Indexed: 12/27/2022]
Abstract
BACKGROUND CACNA1A-related disorders present with persistent progressive and non-progressive cerebellar ataxia and paroxysmal events: epileptic seizures and non-epileptic attacks. These phenotypes overlap and co-exist in the majority of patients. OBJECTIVE To describe phenotypes in infantile onset CACNA1A-related disorder and to explore intra-familial variations and genotype-phenotype correlations. MATERIAL AND METHODS This study was a multicenter international collaboration. A retrospective chart review of CACNA1A patients was performed. Clinical, radiological, and genetic data were collected and analyzed in 47 patients with infantile-onset disorder. RESULTS Paroxysmal non-epileptic events (PNEE) were observed in 68% of infants, with paroxysmal tonic upward gaze (PTU) noticed in 47% of infants. Congenital cerebellar ataxia (CCA) was diagnosed in 51% of patients including four patients with developmental delay and only one neurological sign. PNEEs were found in 63% of patients at follow-up, with episodic ataxia (EA) in 40% of the sample. Cerebellar ataxia was found in 58% of the patients at follow-up. Four patients had epilepsy in infancy and nine in childhood. Seven infants had febrile convulsions, three of which developed epilepsy later; all three patients had CCA. Cognitive difficulties were demonstrated in 70% of the children. Cerebellar atrophy was found in only one infant but was depicted in 64% of MRIs after age two. CONCLUSIONS Nearly all of the infants had CCA, PNEE or both. Cognitive difficulties were frequent and appeared to be associated with CCA. Epilepsy was more frequent after age two. Febrile convulsions in association with CCA may indicate risk of epilepsy in later childhood. Brain MRI was normal in infancy. There were no genotype-phenotype correlations found.
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Affiliation(s)
- Tamar Gur-Hartman
- Pediatric Neurology Unit, Wolfson Medical Center, Holon, Israel; Pediatric Movement Disorders Service, Wolfson Medical Center, Holon, Israel; School of Psychological Sciences, Tel-Aviv University, Israel
| | - Oren Berkowitz
- Department of Health Systems Management, Ariel University, Ariel, Israel
| | - Keren Yosovich
- Molecular Genetics Laboratory, Wolfson Medical Center, Holon, Israel
| | - Agathe Roubertie
- Departement de Neuropediatrie, CHU Gui de Chauliac, Institut des Neurosciences de Montpellier, Montpellier, France
| | - Ginevra Zanni
- Unit of Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, IRCCS Bambino Gesu' Children's Hospital, Rome, Italy
| | - Alfons Macaya
- Vall d'Hebron Research Institute, Pediatric Neurology Research Group, Autonomous University of Barcelona, Barcelona, Spain
| | - Gali Heimer
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel; Pediatric Neurology Unit, Edmond and Lily Safra Children's Hospital, Chaim Sheba Medical Center, Ramat Gan, Israel
| | - Belén Pérez Dueñas
- Vall d'Hebron Research Institute, Pediatric Neurology Research Group, Autonomous University of Barcelona, Barcelona, Spain
| | - Deborah A Sival
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Ben Pode-Shakked
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel; The Institute for Rare Diseases, Edmond and Lily Safra Children's Hospital; Talpiot Medical Leadership Program, Sheba Medical Center, Ramat Gan, Israel
| | - Eduardo López-Laso
- University Hospital Reina Sofía, Pediatric Neurology Unit, IMIBIC and CIBERER, Córdoba, Spain
| | - Véronique Humbertclaude
- Service de Médecine Psychologique Enfants et Adolescents, CHU Saint Eloi, Montpellier, France
| | - Florence Riant
- AP-HP, GH Saint Louis-Lariboisière-Fernand Widal, Service de Génétique Moléculaire Neurovasculaire, Paris, France
| | - Luca Bosco
- Unit of Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, IRCCS Bambino Gesu' Children's Hospital, Rome, Italy
| | | | - Andreea Nissenkorn
- Pediatric Neurology Unit, Wolfson Medical Center, Holon, Israel; Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Francesco Nicita
- Unit of Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, IRCCS Bambino Gesu' Children's Hospital, Rome, Italy
| | - Enrico Bertini
- Unit of Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, IRCCS Bambino Gesu' Children's Hospital, Rome, Italy
| | - Sharon Hassin
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel; Movement Disorders Institute and Department of Neurology, Chaim Sheba Medical Center, Ramat Gan, Israel
| | - Bruria Ben Zeev
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel; Pediatric Neurology Unit, Edmond and Lily Safra Children's Hospital, Chaim Sheba Medical Center, Ramat Gan, Israel
| | - Ayelet Zerem
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel; Pediatric Neurology Unit TASMC, Tel-Aviv University, Israel
| | | | - Dorit Lev
- Molecular Genetics Laboratory, Wolfson Medical Center, Holon, Israel; Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel; Institute of Medical Genetics, Wolfson Medical Center, Holon, Israel
| | - Ilan Linder
- Pediatric Epilepsy & Neurology Service, Barzilay Medical Center, Ashkelon, Israel
| | - Tally Lerman-Sagie
- Pediatric Neurology Unit, Wolfson Medical Center, Holon, Israel; Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Lubov Blumkin
- Pediatric Neurology Unit, Wolfson Medical Center, Holon, Israel; Pediatric Movement Disorders Service, Wolfson Medical Center, Holon, Israel; Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
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12
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Ahn H, Ko TS. The Genetic Relationship between Paroxysmal Movement Disorders and Epilepsy. ANNALS OF CHILD NEUROLOGY 2020. [DOI: 10.26815/acn.2020.00073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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Zhang L, Wen Y, Zhang Q, Chen Y, Wang J, Shi K, Du L, Bao X. CACNA1A Gene Variants in Eight Chinese Patients With a Wide Range of Phenotypes. Front Pediatr 2020; 8:577544. [PMID: 33425808 PMCID: PMC7793878 DOI: 10.3389/fped.2020.577544] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 10/20/2020] [Indexed: 11/13/2022] Open
Abstract
Background: The CACNA1A gene encodes the voltage-dependent P/Q-type calcium channel subunit alpha-1A, which is widely expressed throughout the CNS. The biological roles of the P/Q channel are diverse and the phenotypic spectrum caused by CACNA1A mutations is wide. The aim of this study is to demonstrate its phenotypic diversity and analyze the genotype-phenotype correlations in a cohort of Chinese patients. Methods: Patients with hemiplegic migraine, cerebellar ataxia, developmental delay, or epilepsy without known causes were tested by trios whole-exome sequencing. Patients with pathogenic CACNA1A gene variants were recruited. The clinical information of the patients was collected, and the association between the genotype and the phenotype was investigated. Results: In total, eight patients (six females and two males) were found to have CACNA1A gene variants. All the variants were de novo including six missense variants and one frameshift variant. Four de novo missense variants were found in five patients located in the S4, S5, or S6 transmembrane segments of Domain II and III (p.R1352Q, p.G701V, p.A713T, p.V1393M). All of them were correlated with severe phenotypes, including three with sporadic hemiplegic migraine type 1 and epilepsy, and two with developmental and epileptic encephalopathy. The other two missense variants, p.Y62C and p.F1814L, located in the cytoplasmic side of the N-terminus and C-terminus, respectively. The variant p.Y62C was associated with severe hemiconvulsion-hemiplegia-epilepsy syndrome, and p.F1814L was associated with relatively mild phenotypes. All the missense variants were speculated as gain-of-function (GOF) mutations. The only frameshift variant, p.Q681Rfs*100, a lose-of-function (LOF) mutation, was found in a patient with episodic ataxia type 2. Meanwhile, all the patients had developmental delay ranging from mild to severe, as well as cerebellar ataxia including one with congenital ataxia, one with episodic ataxia, and six with non-progressive ataxia. Conclusions: CACNA1A variants could lead to a wide spectrum of neurological disorders including epileptic or non-epileptic paroxysmal events, cerebellar ataxia, and developmental delay. The variants could be both GOF and LOF mutations. There appeared to be some correlations between genotypes and phenotypes.
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Affiliation(s)
- Linxia Zhang
- Department of Pediatric, Peking University First Hospital, Beijing, China.,Department of Neurology, Children's Hospital of Shanxi, Taiyuan, China
| | - Yongxin Wen
- Department of Pediatric, Peking University First Hospital, Beijing, China
| | - Qingping Zhang
- Department of Pediatric, Peking University First Hospital, Beijing, China
| | - Yan Chen
- Department of Pediatric, Peking University First Hospital, Beijing, China
| | - Jiaping Wang
- Department of Pediatric, Peking University First Hospital, Beijing, China
| | - Kaili Shi
- Department of Neurology, Children's Hospital of Shanxi, Taiyuan, China
| | - Lijun Du
- Department of Neurology, Children's Hospital of Shanxi, Taiyuan, China
| | - Xinhua Bao
- Department of Pediatric, Peking University First Hospital, Beijing, China
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De Gusmao CM, Silveira-Moriyama L. Paroxysmal movement disorders - practical update on diagnosis and management. Expert Rev Neurother 2019; 19:807-822. [PMID: 31353980 DOI: 10.1080/14737175.2019.1648211] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Introduction: Paroxysmal dyskinesias and episodic ataxias are often caused by mutations in genes related to cell membrane and synaptic function. Despite the exponential increase in publications of genetically confirmed cases, management remains largely clinical based on non-systematic evidence. Areas covered: The authors provide a historical and clinical review of the main types of paroxysmal dyskinesias and episodic ataxias, with recommendations for diagnosis and management of patients suffering from these conditions. Expert opinion: After secondary paroxysmal dyskinesias, the most common paroxysmal movement disorders are likely to be PRRT2-associated paroxysmal kinesigenic dyskinesias, which respond well to small doses of carbamazepine, and episodic ataxia type 2, which often responds to acetazolamide. Familial paroxysmal non-kinesigenic dyskinesias are largely caused by mutations in PNKD and have poor response to therapy but improve with age. Exercise-induced dyskinesias are genetically heterogeneous, caused by disorders of glucose transport, mitochondrial function, dopaminergic pathways or neurodegenerative conditions amongst others. GNAO1 and ADCY5 mutations can also cause paroxysmal movement disorders, often in the context of ongoing motor symptoms. Although a therapeutic trial is justified for classic cases and in limited resource settings, genetic testing may help direct initial or rescue therapy. Deep brain stimulation may be an option for severe cases.
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Affiliation(s)
- Claudio M De Gusmao
- Department of Neurology, Harvard Medical School, Boston Children's Hospital , Boston , MA , USA.,Department of Neurology, Universidade Estadual de Campinas (UNICAMP) , São Paulo , Brazil
| | - Laura Silveira-Moriyama
- Department of Neurology, Universidade Estadual de Campinas (UNICAMP) , São Paulo , Brazil.,Education Unit, UCL Institute of Neurology, University College London , London , UK.,Department of Neurology, Hospital Bairral, Fundação Espírita Américo Bairral , Itapira , Brazil
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15
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Angelini C, Van Gils J, Bigourdan A, Jouk PS, Lacombe D, Menegon P, Moutton S, Riant F, Sole G, Tournier-Lasserve E, Trimouille A, Vincent M, Goizet C. Major intra-familial phenotypic heterogeneity and incomplete penetrance due to a CACNA1A pathogenic variant. Eur J Med Genet 2018; 62:103530. [PMID: 30142438 DOI: 10.1016/j.ejmg.2018.08.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 08/14/2018] [Accepted: 08/20/2018] [Indexed: 11/19/2022]
Abstract
The CACNA1A gene encodes a calcium-dependent voltage channel, localized in neuronal cells. Pathogenic variants in this gene are known to lead to a broad clinical spectrum including episodic ataxia type 2, spinocerebellar ataxia type 6, familial hemiplegic migraine, and more recently epileptic encephalopathy. We report a large family revealing a wide variability of neurological manifestations associated with a CACNA1A missense pathogenic variant. The index case had early-onset epileptic encephalopathy with progressive cerebellar atrophy, although his mother and his great-grandmother suffered from paroxystic episodic ataxia. His grandfather and great grand-aunt reported no symptoms, but two of her sons displayed early-onset ataxia with intellectual disability. Two of her little daughters suffered from gait disorders, and also from epilepsy for one of them. All these relatives were carriers of the previously described heterozygous variant in CACNA1A gene. We report here the first family leading to major clinical variability and incomplete penetrance. Our family highlights the difficulties to provide accurate genetic counselling concerning prenatal diagnosis regarding highly variable severity of the clinical presentation.
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Affiliation(s)
- Chloé Angelini
- Service de Génétique Médicale, CHU de Bordeaux and Laboratoire MRGM, INSERM U1211, Univ. Bordeaux, Bordeaux, France.
| | - Julien Van Gils
- Service de Génétique Médicale, CHU de Bordeaux and Laboratoire MRGM, INSERM U1211, Univ. Bordeaux, Bordeaux, France
| | | | | | - Didier Lacombe
- Service de Génétique Médicale, CHU de Bordeaux and Laboratoire MRGM, INSERM U1211, Univ. Bordeaux, Bordeaux, France
| | | | | | - Florence Riant
- Service de Génétique Moléculaire, Hôpital Lariboisière, Paris, France
| | - Guilhem Sole
- Service de Neurologie Médicale, CHU de Bordeaux, France
| | | | - Aurélien Trimouille
- Service de Génétique Médicale, CHU de Bordeaux and Laboratoire MRGM, INSERM U1211, Univ. Bordeaux, Bordeaux, France
| | - Marie Vincent
- Service de Génétique Médicale, CHU de Nantes, France
| | - Cyril Goizet
- Service de Génétique Médicale, CHU de Bordeaux and Laboratoire MRGM, INSERM U1211, Univ. Bordeaux, Bordeaux, France; Centre de Référence Neurogénétique, Service de Génétique Médicale, CHU de Bordeaux, France
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16
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Abstract
Background Although there is a great wealth of knowledge about the neurobiological processes underlying migraine and its accompanying symptoms, the mechanisms by which an attack starts remain elusive, and the disease remains undertreated. Although the vast majority of literature focuses on the involvement of the trigeminovascular systems and higher systems it innervates, such as thalamic and hypothalamic nuclei, several lines of evidence implicate the cerebellum in the pathophysiology of migraine. Aim In this review, we aim to summarize potential cerebellar involvement seen from different perspectives including the results from imaging studies, cerebellar connectivity to migraine-related brain structures, comorbidity with disorders implying cerebellar dysfunction, similarities in triggers precipitating both such disorders, and migraine and cerebellar expression of migraine-related genes and neuropeptides. We aim to inspire an increase in interest for future research on the subject. Conclusion It is hoped that future studies can provide an answer as to how the cerebellum may be involved and whether treatment options specifically targeting the cerebellum could provide alleviation of this disorder.
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Affiliation(s)
- Lieke Kros
- 1 Dominick P Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, USA.,2 Department of Neuroscience, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | - Kamran Khodakhah
- 1 Dominick P Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, USA
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17
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Abstract
The familial episodic ataxias (EAs) are prototypical channelopathies in the central nervous system clinically characterized by attacks of imbalance and incoordination variably associated with progressive ataxia and variable interictal features. EA1, EA2, and EA6 are caused by mutations in ion channel- and transporter-encoding genes that regulate neuronal excitability and neurotransmission.
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Affiliation(s)
- Joanna C Jen
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA, United States; Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, CA, United States.
| | - Jijun Wan
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA, United States
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Isaacs DA, Bradshaw MJ, Brown K, Hedera P. Case report of novel CACNA1A gene mutation causing episodic ataxia type 2. SAGE Open Med Case Rep 2017; 5:2050313X17706044. [PMID: 28540055 PMCID: PMC5431607 DOI: 10.1177/2050313x17706044] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 03/29/2017] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Episodic ataxia type 2 (OMIM 108500) is an autosomal dominant channelopathy characterized by paroxysms of ataxia, vertigo, nausea, and other neurologic symptoms. More than 50 mutations of the CACNA1A gene have been discovered in families with episodic ataxia type 2, although 30%-50% of all patients with typical episodic ataxia type 2 phenotype have no detectable mutation of the CACNA1A gene. CASE A 46-year-old Caucasian man, with a long history of bouts of imbalance, vertigo, and nausea, presented to our hospital with 2 weeks of ataxia and headache. Subsequent evaluation revealed a novel mutation in the CACNA1A gene: c.1364 G > A Arg455Gln. Acetazolamide was initiated with symptomatic improvement. CONCLUSION This case report expands the list of known CACNA1A mutations associated with episodic ataxia type 2.
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Affiliation(s)
| | | | - Kelly Brown
- Vanderbilt University Medical Center, Nashville, TN, USA
| | - Peter Hedera
- Vanderbilt University Medical Center, Nashville, TN, USA
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Reinson K, Õiglane-Shlik E, Talvik I, Vaher U, Õunapuu A, Ennok M, Teek R, Pajusalu S, Murumets Ü, Tomberg T, Puusepp S, Piirsoo A, Reimand T, Õunap K. BiallelicCACNA1Amutations cause early onset epileptic encephalopathy with progressive cerebral, cerebellar, and optic nerve atrophy. Am J Med Genet A 2016; 170:2173-6. [DOI: 10.1002/ajmg.a.37678] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 04/11/2016] [Indexed: 12/22/2022]
Affiliation(s)
- Karit Reinson
- Department of Genetics; United Laboratories; Tartu University Hospital; Tartu Estonia
- Department of Paediatrics; University of Tartu; Tartu Estonia
| | - Eve Õiglane-Shlik
- Department of Paediatrics; University of Tartu; Tartu Estonia
- Children's Clinic; Tartu University Hospital; Tartu Estonia
| | - Inga Talvik
- Department of Paediatrics; University of Tartu; Tartu Estonia
- Children's Clinic; Tartu University Hospital; Tartu Estonia
| | - Ulvi Vaher
- Children's Clinic; Tartu University Hospital; Tartu Estonia
| | - Anne Õunapuu
- Neurology Clinic; Tartu University Hospital; Tartu Estonia
| | - Margus Ennok
- Neurology Clinic; Tartu University Hospital; Tartu Estonia
- Department of Neurology and Neurosurgery; University of Tartu; Tartu Estonia
| | - Rita Teek
- Department of Genetics; United Laboratories; Tartu University Hospital; Tartu Estonia
- Department of Paediatrics; University of Tartu; Tartu Estonia
| | - Sander Pajusalu
- Department of Genetics; United Laboratories; Tartu University Hospital; Tartu Estonia
- Institute of Biomedicine and Translational Medicine; Department of Biomedicine; University of Tartu; Tartu Estonia
| | - Ülle Murumets
- Department of Genetics; United Laboratories; Tartu University Hospital; Tartu Estonia
| | - Tiiu Tomberg
- Radiology Clinic; Tartu University Hospital; Tartu Estonia
| | - Sanna Puusepp
- Department of Genetics; United Laboratories; Tartu University Hospital; Tartu Estonia
| | - Andres Piirsoo
- Institute of Biomedicine and Translational Medicine; Department of Biomedicine; University of Tartu; Tartu Estonia
| | - Tiia Reimand
- Department of Genetics; United Laboratories; Tartu University Hospital; Tartu Estonia
- Department of Paediatrics; University of Tartu; Tartu Estonia
- Institute of Biomedicine and Translational Medicine; Department of Biomedicine; University of Tartu; Tartu Estonia
| | - Katrin Õunap
- Department of Genetics; United Laboratories; Tartu University Hospital; Tartu Estonia
- Department of Paediatrics; University of Tartu; Tartu Estonia
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Kaido M, Furuta M, Nakamori M, Yuasa Y, Takahashi MP. Episodic ataxia type 2 manifests as epileptiform electroencephalographic activity with no epileptic attacks in two family members. Rinsho Shinkeigaku 2016; 56:260-4. [PMID: 27025991 DOI: 10.5692/clinicalneurol.cn-000854] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Here, we report two cases of episodic ataxia type 2 (EA2) in a 63-year-old woman and her 36-year-old daughter. The mother experienced recurrent attacks of cerebellar dysfunction lasting 4 to 5 hours since the age of 41 years. On several occasions, she was admitted to the emergency room, where she was diagnosed with epilepsy or stroke. Based on these diagnoses, she was treated with antiepileptic or anticoagulant drugs, but both treatments were eventually discontinued. The frequency of the attacks increased after the patient reached the age of 62. Interictal neurological examination demonstrated signs of slight cerebellar ataxia, i.e. saccadic eye movements, gaze-directed nystagmus, and mild truncal ataxia. Brain magnetic resonance imaging (MRI) showed cerebellar vermis atrophy. Electroencephalography (EEG) revealed various spike and wave patterns: solitary spikes, spike-and-slow wave complexes, and slow wave bursts. Photoparoxysmal response (PPR) type 3 was also observed. Treatment with acetazolamide abolished the patient's attacks almost completely. The daughter started experiencing 5- to 10-minute ataxic episodes at the age of 16 years. Based on her epileptiform EEG activities with PPR (type 2), antiepileptic drugs (valproate and zonisamide) were prescribed. Despite pharmacological treatment, the attacks recurred; however, their frequency gradually decreased with time, until they almost entirely disappeared when the patient was 33. Unfortunately, migraine-like headaches arose instead. Subtle truncal ataxia was observed during interictal periods. Sanger sequencing of the exons of the CACNA1A gene revealed a novel single base deletion (c.3575delA) in both patients. Despite the difference in age of onset and clinical course, both patients showed clearly epileptiform EEG activities without experiencing the concurrent epileptic episodes. Thus, EA2 is a disease that may be misdiagnosed as epilepsy or stroke in the field of emergency medicine.
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Affiliation(s)
- Misako Kaido
- Department of Neurology, Sakai City Medical Center
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21
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Abnormal excitability and episodic low-frequency oscillations in the cerebral cortex of the tottering mouse. J Neurosci 2015; 35:5664-79. [PMID: 25855180 DOI: 10.1523/jneurosci.3107-14.2015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The Ca(2+) channelopathies caused by mutations of the CACNA1A gene that encodes the pore-forming subunit of the human Cav2.1 (P/Q-type) voltage-gated Ca(2+) channel include episodic ataxia type 2 (EA2). Although, in EA2 the emphasis has been on cerebellar dysfunction, patients also exhibit episodic, nonmotoric abnormalities involving the cerebral cortex. This study demonstrates episodic, low-frequency oscillations (LFOs) throughout the cerebral cortex of tottering (tg/tg) mice, a widely used model of EA2. Ranging between 0.035 and 0.11 Hz, the LFOs in tg/tg mice can spontaneously develop very high power, referred to as a high-power state. The LFOs in tg/tg mice are mediated in part by neuronal activity as tetrodotoxin decreases the oscillations and cortical neuron discharge contain the same low frequencies. The high-power state involves compensatory mechanisms because acutely decreasing P/Q-type Ca(2+) channel function in either wild-type (WT) or tg/tg mice does not induce the high-power state. In contrast, blocking l-type Ca(2+) channels, known to be upregulated in tg/tg mice, reduces the high-power state. Intriguingly, basal excitatory glutamatergic neurotransmission constrains the high-power state because blocking ionotropic or metabotropic glutamate receptors results in high-power LFOs in tg/tg but not WT mice. The high-power LFOs are decreased markedly by acetazolamide and 4-aminopyridine, the primary treatments for EA2, suggesting disease relevance. Together, these results demonstrate that the high-power LFOs in the tg/tg cerebral cortex represent a highly abnormal excitability state that may underlie noncerebellar symptoms that characterize CACNA1A mutations.
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Ramirez-Zamora A, Zeigler W, Desai N, Biller J. Treatable causes of cerebellar ataxia. Mov Disord 2015; 30:614-23. [PMID: 25757427 DOI: 10.1002/mds.26158] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 12/09/2014] [Accepted: 12/29/2014] [Indexed: 12/21/2022] Open
Abstract
The cerebellar ataxia syndromes are a heterogeneous group of disorders clinically characterized by the presence of cerebellar dysfunction. Initial assessment of patients with progressive cerebellar ataxia is complex because of an extensive list of potential diagnoses. A detailed history and comprehensive examination are required for an accurate diagnosis and hierarchical diagnostic investigations. Although no cure exists for most of these conditions, a small group of metabolic, hereditary, inflammatory, and immune-mediated etiologies of cerebellar ataxia are amenable to disease-modifying, targeted therapies. Over the past years, disease-specific treatments have emerged. Thus, clinicians must become familiar with these disorders because maximal therapeutic benefit is only possible when done early. In this article, we review disorders in which cerebellar ataxia is a prominent clinical feature requiring targeted treatments along with specific management recommendations.
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CACNA1A haploinsufficiency causes cognitive impairment, autism and epileptic encephalopathy with mild cerebellar symptoms. Eur J Hum Genet 2015; 23:1505-12. [PMID: 25735478 DOI: 10.1038/ejhg.2015.21] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 01/15/2015] [Accepted: 01/20/2015] [Indexed: 01/25/2023] Open
Abstract
CACNA1A loss-of-function mutations classically present as episodic ataxia type 2 (EA2), with brief episodes of ataxia and nystagmus, or with progressive spinocerebellar ataxia (SCA6). A minority of patients carrying CACNA1A mutations develops epilepsy. Non-motor symptoms associated with these mutations are often overlooked. In this study, we report 16 affected individuals from four unrelated families presenting with a spectrum of cognitive impairment including intellectual deficiency, executive dysfunction, ADHD and/or autism, as well as childhood-onset epileptic encephalopathy with refractory absence epilepsy, febrile seizures, downbeat nystagmus and episodic ataxia. Sequencing revealed one CACNA1A gene deletion, two deleterious CACNA1A point mutations including one known stop-gain and one new frameshift variant and a new splice-site variant. This report illustrates the phenotypic heterogeneity of CACNA1A loss-of-function mutations and stresses the cognitive and epileptic manifestations caused by the loss of CaV2.1 channels function, presumably affecting cerebellar, cortical and limbic networks.
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Kipfer S, Strupp M. The Clinical Spectrum of Autosomal-Dominant Episodic Ataxias. Mov Disord Clin Pract 2014; 1:285-290. [PMID: 30713867 DOI: 10.1002/mdc3.12075] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Revised: 06/16/2014] [Accepted: 06/20/2014] [Indexed: 11/06/2022] Open
Abstract
Autosomal-dominant episodic ataxias (EAs) represent a clinically and genetically heterogeneous group of disorders characterized by recurrent episodes of cerebellar ataxia (CA). Ataxia episodes are usually of short duration and often triggered by specific stimuli. There are currently seven classified subtypes of EA. EA types 1 and 2 have the highest prevalence and are therefore the clinically most relevant. Between attacks, EA 1 is associated with myokymia. In EA 2, often an interictal downbeat nystagmus with other cerebellar ocular dysfunctions is present; patients with EA 2 may display slowly progessive ataxia and vermian atrophy. EA 1 and 2 are both channelopathies, affecting the potassium channel gene, KCNA1, in EA 1 and the PQ calcium channel-encoding gene, CACNA1A, in EA 2. The types EA 3 to 7 are very rare and have to be further elucidated. Here, we review the historical, clinical, and genetic aspects of autosomal-dominant EAs and their current treatment, focusing on EA 1 and 2.
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Affiliation(s)
- Stefan Kipfer
- Department of Neurology Kantonsspital Olten Switzerland
| | - Michael Strupp
- Department of Neurology and German Center for Vertigo and Balance Disorders University Hospital Munich Munich Germany
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Episodic ataxia type 2: phenotype characteristics of a novel CACNA1A mutation and review of the literature. J Neurol 2014; 261:983-91. [DOI: 10.1007/s00415-014-7310-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 03/05/2014] [Accepted: 03/05/2014] [Indexed: 10/25/2022]
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Kipfer S, Jung S, Lemke JR, Kipfer-Kauer A, Howell JP, Kaelin-Lang A, Nyffeler T, Gutbrod K, Abicht A, Müri RM. Novel CACNA1A mutation(s) associated with slow saccade velocities. J Neurol 2013; 260:3010-4. [DOI: 10.1007/s00415-013-7099-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Revised: 08/23/2013] [Accepted: 09/06/2013] [Indexed: 01/11/2023]
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Rüb U, Schöls L, Paulson H, Auburger G, Kermer P, Jen JC, Seidel K, Korf HW, Deller T. Clinical features, neurogenetics and neuropathology of the polyglutamine spinocerebellar ataxias type 1, 2, 3, 6 and 7. Prog Neurobiol 2013; 104:38-66. [PMID: 23438480 DOI: 10.1016/j.pneurobio.2013.01.001] [Citation(s) in RCA: 223] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 01/22/2013] [Accepted: 01/31/2013] [Indexed: 12/18/2022]
Abstract
The spinocerebellar ataxias type 1 (SCA1), 2 (SCA2), 3 (SCA3), 6 (SCA6) and 7 (SCA7) are genetically defined autosomal dominantly inherited progressive cerebellar ataxias (ADCAs). They belong to the group of CAG-repeat or polyglutamine diseases and share pathologically expanded and meiotically unstable glutamine-encoding CAG-repeats at distinct gene loci encoding elongated polyglutamine stretches in the disease proteins. In recent years, progress has been made in the understanding of the pathogenesis of these currently incurable diseases: Identification of underlying genetic mechanisms made it possible to classify the different ADCAs and to define their clinical and pathological features. Furthermore, advances in molecular biology yielded new insights into the physiological and pathophysiological role of the gene products of SCA1, SCA2, SCA3, SCA6 and SCA7 (i.e. ataxin-1, ataxin-2, ataxin-3, α-1A subunit of the P/Q type voltage-dependent calcium channel, ataxin-7). In the present review we summarize our current knowledge about the polyglutamine ataxias SCA1, SCA2, SCA3, SCA6 and SCA7 and compare their clinical and electrophysiological features, genetic and molecular biological background, as well as their brain pathologies. Furthermore, we provide an overview of the structure, interactions and functions of the different disease proteins. On the basis of these comprehensive data, similarities, differences and possible disease mechanisms are discussed.
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Affiliation(s)
- Udo Rüb
- Dr. Senckenberg Chronomedical Institute, Goethe-University, Theodor-Stern-Kai 7, D-60590 Frankfurt/Main, Germany.
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Furtado S, Das S, Suchowersky O. A review of the inherited ataxias: recent advances in genetic, clinical and neuropathologic aspects. Parkinsonism Relat Disord 2012; 4:161-9. [PMID: 18591106 DOI: 10.1016/s1353-8020(98)00030-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/1998] [Accepted: 10/01/1998] [Indexed: 12/01/2022]
Abstract
Inherited ataxias are a heterogeneous group of disorders characterized by autosomal dominant and recessive inheritance. Recent advances in genetic research have resulted in an improved comprehension of their clinical presentation. Autosomal dominant cerebellar ataxias (ADCAs) include spinocerebellar ataxias (SCAs) and dentatorubral-pallidoluysian atrophy (DRPLA); six of these have been found to be trinucleotide repeat disorders. Episodic ataxia, types 1 and 2, are at present recognized to be channelopathies, caused by point mutations. Friedreich's ataxia (FA) which is an autosomal recessive disorder, resulting from a a unique trinucleotide repeat, is now recognized to have a wide age of onset and clinical spectrum. Ataxia-telangiectasia (AT), also an autosomal recessive cerebellar ataxia, is characterized by immunodeficiency. In this article, the genetic and clinical characteristics of these diseases are reviewed in detail.
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Affiliation(s)
- S Furtado
- Department of Clinical Neurosciences, University of Calgary, Area 3, UCMC, 3350 Hospital Drive, Calgary NW Alta, Canada T2N 4N1
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Rajakulendran S, Kaski D, Hanna MG. Neuronal P/Q-type calcium channel dysfunction in inherited disorders of the CNS. Nat Rev Neurol 2012; 8:86-96. [PMID: 22249839 DOI: 10.1038/nrneurol.2011.228] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The past two decades have witnessed the emergence of a new and expanding field of neurological diseases--the genetic ion channelopathies. These disorders arise from mutations in genes that encode ion channel subunits, and manifest as paroxysmal attacks involving the brain or spinal cord, and/or muscle. The voltage-gated P/Q-type calcium channel (P/Q channel) is highly expressed in the cerebellum, hippocampus and cortex of the mammalian brain. The P/Q channel has a fundamental role in mediating fast synaptic transmission at central and peripheral nerve terminals. Autosomal dominant mutations in the CACNA1A gene, which encodes voltage-gated P/Q-type calcium channel subunit α(1) (the principal pore-forming subunit of the P/Q channel) are associated with episodic and progressive forms of cerebellar ataxia, familial hemiplegic migraine, vertigo and epilepsy. This Review considers, from both a clinical and genetic perspective, the various neurological phenotypes arising from inherited P/Q channel dysfunction, with a focus on recent advances in the understanding of the pathogenetic mechanisms underlying these disorders.
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Affiliation(s)
- Sanjeev Rajakulendran
- Medical Research Council Center for Neuromuscular Diseases, Box 102, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
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Parker JL, Santiago M. Oculomotor aspects of the hereditary cerebellar ataxias. HANDBOOK OF CLINICAL NEUROLOGY 2012; 103:63-83. [PMID: 21827881 DOI: 10.1016/b978-0-444-51892-7.00003-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Affiliation(s)
- J Larry Parker
- Department of Neurology, University of Mississippi Medical Center, Jackson, MS 39216-4505, USA.
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Abstract
The autosomal dominant spinocerebellar ataxias (SCA) are a genetically heterogeneous group of neurodegenerative disorders characterized by progressive motor incoordination, in some cases with ataxia alone and in others in association with additional progressive neurological deficits. Spinocerebellar ataxia type 6 (SCA6) is the prototype of a pure cerebellar ataxia, associated with a severe form of progressive ataxia and cerebellar dysfunction. SCA6, originally classified as such by Zhuchenko et al. (1997), is caused by a CAG repeat expansion in the CACNA1A gene which encodes the α1A subunit of the P/Q-type voltage-gated calcium channel. SCA6 is one of ten polyglutamine-encoding CAG nucleotide repeat expansion disorders comprising other neurodegenerative disorders such as Huntington's disease. The present review describes clinical, genetic, and pathological manifestations associated with this illness. Currently, there is no treatment for this neurodegenerative disease. Successful therapeutic strategies must target a valid pathological mechanism; thus, understanding the underlying mechanisms of disease is crucial to finding a proper treatment. Hence, this chapter will discuss as well the molecular mechanisms possibly associated with SCA6 pathology and their implication for the development of future treatment.
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Affiliation(s)
- Ana Solodkin
- Department of Neurology, University of Chicago Medical Center, Chicago, IL 606337, USA.
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Abstract
The episodic ataxias are autosomal dominant disorders usually beginning in the first two decades of life. Episodic ataxia type 1 (EA1) is characterized by brief episodes of ataxia, typically lasting seconds, and interictal myokymia, while episodic ataxia type 2 (EA2) is manifested by longer episodes of ataxia (hours) with interictal nystagmus. The EA1 gene (KCNA1) codes for the six transmembrane segments (S1 to S6) of the Kv1.1 potassium channel subunit and the EA2 gene (CACNA1A) encodes for the Ca(v)2.1 subunit of the P/Q calcium channel complex. EA1 mutations are always missense while most EA2 mutations disrupt the reading frame. Studies of the biophysical properties of the mutant Kv1.1 and Ca(v)2.1 channels in Xenopus oocytes and mammalian cell lines demonstrate clear physiologic consequences of the genetic mutations although no consistent pattern for genotype-phenotype correlation has emerged. Genetic testing for EA1 and EA2 is available, but since no single mutation is prominent for either KCNA1 or CACNA1A, all of the coding regions of the genes need to be screened for mutations. Acetazolamide can be dramatic in controlling episodes of ataxia with EA2 but is typically less beneficial with EA1.
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Affiliation(s)
- Robert W Baloh
- Department of Neurology, University of California, Los Angeles, CA 90095-1769, USA.
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Ethanol and Vestibular Stimulation Reveal Simple and Complex Aspects of Cerebellar Heterogeneity. THE CEREBELLUM 2010; 10:475-83. [DOI: 10.1007/s12311-010-0238-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Rajakulendran S, Graves TD, Labrum RW, Kotzadimitriou D, Eunson L, Davis MB, Davies R, Wood NW, Kullmann DM, Hanna MG, Schorge S. Genetic and functional characterisation of the P/Q calcium channel in episodic ataxia with epilepsy. J Physiol 2010; 588:1905-13. [PMID: 20156848 DOI: 10.1113/jphysiol.2009.186437] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Mutations in CACNA1A, which encodes the principal subunit of the P/Q calcium channel, underlie episodic ataxia type 2 (EA2). In addition, some patients with episodic ataxia complicated by epilepsy have been shown to harbour CACNA1A mutations, raising the possibility that P/Q channel dysfunction may be linked to human epilepsy. We undertook a review of all published CACNA1A EA2 cases and this showed that 7% have epilepsy--representing a sevenfold increased epilepsy risk compared to the background population risk (P<0.001). We also studied a series of 17 individuals with episodic ataxia accompanied by epilepsy and/or clearly epileptiform electroencephalograms (EEGs). We screened the entire coding region of CACNA1A for point mutations and rearrangements to determine if genetic variation in the gene is associated with the epilepsy phenotype, and measured the functional impact of all missense variations on heterologously expressed P/Q channels. We identified two large scale deletions and two new missense mutations in CACNA1A. When expressed, L621R had little detectable effect on P/Q channel function, while the other missense change, G540R, caused an approximately 30% reduction in current density. In nine patients we also identified the previously reported non-synonymous coding variants (E921D and E993V) which also resulted in impairment of P/Q channel function. Taken together, 12 of the 17 patients have genetic changes which decrease P/Q channel function. We conclude that variants in the coding region of CACNA1A that confer a loss of P/Q-type channel function are associated with episodic ataxia and epilepsy. Our data suggest that functional stratification of all variants, including common polymorphisms, rare variants and novel mutations, may provide new insights into the mechanisms of channelopathies.
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Affiliation(s)
- Sanjeev Rajakulendran
- MRC Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, University College London, Institute of Neurology, London WC1N 3BG, UK
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Rajakulendran S, Schorge S, Kullmann DM, Hanna MG. Dysfunction of the Ca(V)2.1 calcium channel in cerebellar ataxias. F1000 BIOLOGY REPORTS 2010; 2. [PMID: 20948794 PMCID: PMC2948357 DOI: 10.3410/b2-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Mutations in the CACNA1A gene are associated with episodic ataxia type 2 (EA2) and spinocerebellar ataxia type 6 (SCA6). CACNA1A encodes the α-subunit of the P/Q-type calcium channel or CaV2.1, which is highly enriched in the cerebellum. It is one of the main channels linked to synaptic transmission throughout the human central nervous system. Here, we compare recent advances in the understanding of the genetic changes that underlie EA2 and SCA6 and what these new findings suggest about the mechanism of the disease.
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Affiliation(s)
- Sanjeev Rajakulendran
- MRC Centre for Neuromuscular Diseases, Institute of Neurology, University College London Queen Square, London WC1N 3BG UK
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Tomlinson SE, Hanna MG, Kullmann DM, Tan SV, Burke D. Clinical neurophysiology of the episodic ataxias: insights into ion channel dysfunction in vivo. Clin Neurophysiol 2009; 120:1768-76. [PMID: 19734086 DOI: 10.1016/j.clinph.2009.07.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Revised: 07/03/2009] [Accepted: 07/03/2009] [Indexed: 01/02/2023]
Abstract
Clinical neurophysiology has become an invaluable tool in the diagnosis of muscle channelopathies, but the situation is less clear cut with neuronal channelopathies. The genetic episodic ataxias are a group of disorders with heterogeneous phenotype and genotype, but share in common the feature of intermittent cerebellar dysfunction. Episodic ataxia (EA) types 1 and 2 are the most widely recognised of the autosomal dominant episodic ataxias and are caused by dysfunction of neuronal voltage-gated ion channels. There are central and peripheral nervous system manifestations in both conditions, and they are therefore good models of neuronal channelopathies to study neurophysiologically. To date most work has focussed upon characterising the electrophysiological properties of mutant channels in vitro. This review summarises the role of voltage-gated potassium and calcium channels, mutations of which underlie the main types of episodic ataxia types 1 and 2. The clinical, genetic and electrophysiological features of EA1 and EA2 are outlined, and a protocol for the assessment of these patients is proposed.
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Affiliation(s)
- Susan E Tomlinson
- Institute of Clinical Neurosciences, Royal Prince Alfred Hospital and University of Sydney, Sydney, Australia.
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Krishnan AV, Lin CSY, Park SB, Kiernan MC. Axonal ion channels from bench to bedside: a translational neuroscience perspective. Prog Neurobiol 2009; 89:288-313. [PMID: 19699774 DOI: 10.1016/j.pneurobio.2009.08.002] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Revised: 08/17/2009] [Accepted: 08/17/2009] [Indexed: 12/13/2022]
Abstract
Over recent decades, the development of specialised techniques such as patch clamping and site-directed mutagenesis have established the contribution of neuronal ion channel dysfunction to the pathophysiology of common neurological conditions including epilepsy, multiple sclerosis, spinal cord injury, peripheral neuropathy, episodic ataxia, amyotrophic lateral sclerosis and neuropathic pain. Recently, these insights from in vitro studies have been translated into the clinical realm. In keeping with this progress, novel clinical axonal excitability techniques have been developed to provide information related to the activity of a variety of ion channels, energy-dependent pumps and ion exchange processes activated during impulse conduction in peripheral axons. These non-invasive techniques have been extensively applied to the study of the biophysical properties of human peripheral nerves in vivo and have provided important insights into axonal ion channel function in health and disease. This review will provide a translational perspective, focusing on an overview of the investigational method, the clinical utility in assessing the biophysical basis of ectopic symptom generation in peripheral nerve disease and a review of the major findings of excitability studies in acquired and inherited neurological disease states.
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Affiliation(s)
- Arun V Krishnan
- Translational Neuroscience Facility, University of New South Wales, Randwick, Sydney, NSW, Australia
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Globas C, du Montcel ST, Baliko L, Boesch S, Depondt C, DiDonato S, Durr A, Filla A, Klockgether T, Mariotti C, Melegh B, Rakowicz M, Ribai P, Rola R, Schmitz-Hubsch T, Szymanski S, Timmann D, Van de Warrenburg BP, Bauer P, Schols L. Early symptoms in spinocerebellar ataxia type 1, 2, 3, and 6. Mov Disord 2009; 23:2232-8. [PMID: 18759344 DOI: 10.1002/mds.22288] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Onset of genetically determined neurodegenerative diseases is difficult to specify because of their insidious and slowly progressive nature. This is especially true for spinocerebellar ataxia (SCA) because of varying affection of many parts of the nervous system and huge variability of symptoms. We investigated early symptoms in 287 patients with SCA1, SCA2, SCA3, or SCA6 and calculated the influence of CAG repeat length on age of onset depending on (1) the definition of disease onset, (2) people defining onset, and (3) duration of symptoms. Gait difficulty was the initial symptom in two-thirds of patients. Double vision, dysarthria, impaired hand writing, and episodic vertigo preceded ataxia in 4% of patients, respectively. Frequency of other early symptoms did not differ from controls and was regarded unspecific. Data about disease onset varied between patients and relatives for 1 year or more in 44% of cases. Influence of repeat length on age of onset was maximum when onset was defined as beginning of permanent gait disturbance and cases with symptoms for more than 10 years were excluded. Under these conditions, CAG repeat length determined 64% of onset variability in SCA1, 67% in SCA2, 46% in SCA3, and 41% in SCA6 demonstrating substantial influence of nonrepeat factors on disease onset in all SCA subtypes. Identification of these factors is of interest as potential targets for disease modifying compounds. In this respect, recognition of early symptoms that develop before onset of ataxia is mandatory to determine the shift from presymptomatic to affected status in SCA.
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Affiliation(s)
- Christoph Globas
- Department of Neurology and Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
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Cuenca-León E, Banchs I, Serra SA, Latorre P, Fernàndez-Castillo N, Corominas R, Valverde MA, Volpini V, Fernández-Fernández JM, Macaya A, Cormand B. Late-onset episodic ataxia type 2 associated with a novel loss-of-function mutation in the CACNA1A gene. J Neurol Sci 2009; 280:10-4. [PMID: 19232643 DOI: 10.1016/j.jns.2009.01.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2008] [Accepted: 01/06/2009] [Indexed: 11/30/2022]
Abstract
We report a patient with typical features of episodic ataxia type 2 (EA2) but with onset in the sixth decade and associated interictal hand dystonia. He was found to bear the novel heterozygous missense mutation p.Gly638Asp (c.1913G>A) in the CACNA1A gene. Functional analysis of the mutation on P/Q channels expressed in HEK 293 cells revealed a reduction of Ca(2+) current densities, a left-shift in the apparent reversal potential, the slowing of inactivation kinetics and the increase in the rate of current recovery from inactivation. These results are consistent with a decrease in Ca(2+) permeability through mutant P/Q channels. To our knowledge, this is just the second patient with late onset EA2 linked to a CACNA1A mutation and the first to carry a loss-of-function missense mutation.
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Affiliation(s)
- Ester Cuenca-León
- Grup de Recerca en Neurologia Infantil i Psiquiatria Genètica, Hospital Universitari Vall d'Hebron, Barcelona, Spain
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Chen G, Popa LS, Wang X, Gao W, Barnes J, Hendrix CM, Hess EJ, Ebner TJ. Low-frequency oscillations in the cerebellar cortex of the tottering mouse. J Neurophysiol 2008; 101:234-45. [PMID: 18987121 DOI: 10.1152/jn.90829.2008] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The tottering mouse is an autosomal recessive disorder involving a missense mutation in the gene encoding P/Q-type voltage-gated Ca2+ channels. The tottering mouse has a characteristic phenotype consisting of transient attacks of dystonia triggered by stress, caffeine, or ethanol. The neural events underlying these episodes of dystonia are unknown. Flavoprotein autofluorescence optical imaging revealed transient, low-frequency oscillations in the cerebellar cortex of anesthetized and awake tottering mice but not in wild-type mice. Analysis of the frequencies, spatial extent, and power were used to characterize the oscillations. In anesthetized mice, the dominant frequencies of the oscillations are between 0.039 and 0.078 Hz. The spontaneous oscillations in the tottering mouse organize into high power domains that propagate to neighboring cerebellar cortical regions. In the tottering mouse, the spontaneous firing of 83% (73/88) of cerebellar cortical neurons exhibit oscillations at the same low frequencies. The oscillations are reduced by removing extracellular Ca2+ and blocking L-type Ca2+ channels. The oscillations are likely generated intrinsically in the cerebellar cortex because they are not affected by blocking AMPA receptors or by electrical stimulation of the parallel fiber-Purkinje cell circuit. Furthermore, local application of an L-type Ca2+ agonist in the tottering mouse generates oscillations with similar properties. The beam-like response evoked by parallel fiber stimulation is reduced in the tottering mouse. In the awake tottering mouse, transcranial flavoprotein imaging revealed low-frequency oscillations that are accentuated during caffeine-induced attacks of dystonia. During dystonia, oscillations are also present in the face and hindlimb electromyographic (EMG) activity that become significantly coherent with the oscillations in the cerebellar cortex. These low-frequency oscillations and associated cerebellar cortical dysfunction demonstrate a novel abnormality in the tottering mouse. These oscillations are hypothesized to be involved in the episodic movement disorder in this mouse model of episodic ataxia type 2.
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Affiliation(s)
- Gang Chen
- Department of Neuroscience, University of Minnesota, Lions Research Building, Room 421, 2001 Sixth Street S.E., Minneapolis, MN 55455, USA
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Graves TD, Imbrici P, Kors EE, Terwindt GM, Eunson LH, Frants RR, Haan J, Ferrari MD, Goadsby PJ, Hanna MG, van den Maagdenberg AMJM, Kullmann DM. Premature stop codons in a facilitating EF-hand splice variant of CaV2.1 cause episodic ataxia type 2. Neurobiol Dis 2008; 32:10-5. [PMID: 18606230 DOI: 10.1016/j.nbd.2008.06.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2008] [Accepted: 06/05/2008] [Indexed: 10/22/2022] Open
Abstract
Premature stop codons in CACNA1A, which encodes the alpha(1A) subunit of neuronal P/Q-type (Ca(V)2.1) Ca(2+) channels, cause episodic ataxia type 2 (EA2). CACNA1A undergoes extensive alternative splicing, which contributes to the pharmacological and kinetic heterogeneity of Ca(V)2.1-mediated Ca(2+) currents. We identified three novel heterozygous stop codon mutations associated with EA2 in an alternately spliced exon (37A), which encodes part of an EF-hand motif required for Ca(2+)-dependent facilitation. One family had a C to G transversion (Y1854X). A dinucleotide deletion results in the same premature stop codon in a second family, and a further single nucleotide change leads to a different truncation (R1858X) in a de novo case of EA2. Expression studies of the Y1854X mutation revealed loss of Ca(V)2.1-mediated current. Because these mutations do not affect the alternate exon 37B, these findings reveal unexpected dependence of cerebellar function on intact exon 37A-containing Ca(V)2.1 channels.
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Affiliation(s)
- Tracey D Graves
- Institute of Neurology, University College London, Queen Square, London, United Kingdom
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Axonal function in a family with episodic ataxia type 2 due to a novel mutation. J Neurol 2008; 255:750-5. [DOI: 10.1007/s00415-008-0794-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2007] [Revised: 09/19/2007] [Accepted: 10/19/2007] [Indexed: 10/22/2022]
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Bernard G, Shevell MI. Channelopathies: a review. Pediatr Neurol 2008; 38:73-85. [PMID: 18206787 DOI: 10.1016/j.pediatrneurol.2007.09.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2007] [Revised: 07/05/2007] [Accepted: 09/13/2007] [Indexed: 10/22/2022]
Abstract
Channelopathies are a recently delineated, emerging group of neurologic disorders united by genetically determined defects in ion-channel function. These disorders are characterized by a prominent genetic and phenotypic heterogeneity that can make them challenging and bewildering to understand. This systematic review attempts to categorize these disorders according to their predominant clinical manifestations (i.e., myotonia, weakness, migraine, ataxia, epilepsy, and movement disorders) within the context of what is presently known about the molecular basis of recognized clinical syndromes. Areas of both genetic and phenotypic overlap are highlighted. The review is intended to assist clinicians in enhancing their diagnostic acumen and in targeting specific genetic tests.
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Affiliation(s)
- Genevieve Bernard
- Department of Neurology/Neurosurgery, McGill University, Montreal Children's Hospital-McGill University Health Center, Montreal, Quebec, Canada
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Abstract
Clinical and pathophysiological evidences connect migraine and the cerebellum. Literature on documented cerebellar abnormalities in migraine, however, is relatively sparse. Cerebellar involvement may be observed in 4 types of migraines: in the widespread migraine with aura (MWA) and migraine without aura (MWoA) forms; in particular subtypes of migraine such as basilar-type migraine (BTM); and in the genetically driven autosomal dominant familial hemiplegic migraine (FHM) forms. Cerebellar dysfunction in migraineurs varies largely in severity, and may be subclinical. Purkinje cells express calcium channels that are related to the pathophysiology of both inherited forms of migraine and primary ataxias, mostly spinal cerebellar ataxia type 6 (SCA-6) and episodic ataxia type 2 (EA-2). Genetically driven ion channels dysfunction leads to hyperexcitability in the brain and cerebellum, possibly facilitating spreading depression waves in both locations. This review focuses on the cerebellar involvement in migraine, the relevant ataxias and their association with this primary headache, and discusses some of the pathophysiological processes putatively underlying these diseases.
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Affiliation(s)
- Maurice Vincent
- Hospital Universitário Clementino Fraga Filho, Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Brazil
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Rajakulendran S, Schorge S, Kullmann DM, Hanna MG. Episodic ataxia type 1: a neuronal potassium channelopathy. Neurotherapeutics 2007; 4:258-66. [PMID: 17395136 DOI: 10.1016/j.nurt.2007.01.010] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Episodic ataxia type 1 is a paroxysmal neurological disorder characterized by short-lived attacks of recurrent midline cerebellar dysfunction and continuous motor activity. Mutations in KCN1A, the gene encoding Kv1.1, a voltage-gated neuronal potassium channel, are associated with the disorder. Although rare, the syndrome highlights the fundamental features of genetic ion-channel diseases and serves as a useful model for understanding more common paroxysmal disorders, such as epilepsy and migraine. This review examines our current understanding of episodic ataxia type 1, focusing on its clinical and genetic features, pathophysiology, and treatment.
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Affiliation(s)
- Sanjeev Rajakulendran
- Department of Molecular Neuroscience, Centre for Neuromuscular Disease, Queen Square, London WC1N 3BG, United Kingdom
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