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Lazar SM, Abid F. Pearls & Oy-sters: CACNA1A-Related Paroxysmal Tonic Upgaze With Ataxia Responsive to Acetazolamide. Neurology 2024; 102:e207992. [PMID: 38175838 PMCID: PMC10834120 DOI: 10.1212/wnl.0000000000207992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 09/20/2023] [Indexed: 01/06/2024] Open
Abstract
A 9-month-old male infant was evaluated for sudden onset of paroxysmal episodes of forced, conjugate upward eye deviation. Extensive in-hospital evaluation including electrophysiology and neuroimaging studies were reassuring against seizures or a structural abnormality. Given the clinical presentation of sudden onset intermittent upward eye deviations, downbeating saccades, associated ataxia, and typical development, a clinical diagnosis of paroxysmal tonic upgaze (PTU) with ataxia was made. Targeted genetic testing of CACNA1A was performed, which revealed a variant of undetermined significance, which was later classified as a de novo pathogenic variant after protein modeling and parental testing performed. Off-label use of oral acetazolamide was prescribed, which led to dose-responsive decrease in the frequency and intensity of eye movement episodes. After 6 months of episode freedom at 2 years of age, acetazolamide was discontinued without return of episodes. Neurodevelopmental assessments revealed continued typical development. This case is presented to describe the diagnostic formulation, etiologic evaluation, and symptomatic treatment of CACNA1A-related PTU with ataxia.
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Affiliation(s)
- Steven M Lazar
- From the Section of Pediatric Neurology and Developmental Neuroscience (S.M.L., F.A.), Baylor College of Medicine, Houston, TX; and Meyer Center for Developmental Pediatrics & Autism (S.M.L.), Texas Children's Hospital, Houston
| | - Farida Abid
- From the Section of Pediatric Neurology and Developmental Neuroscience (S.M.L., F.A.), Baylor College of Medicine, Houston, TX; and Meyer Center for Developmental Pediatrics & Autism (S.M.L.), Texas Children's Hospital, Houston
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2
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Massuyama BK, Tonholo Silva TY, Gambirasio BG, Pedroso JL, Barsottini OGP. Paroxysmal Tonic Upward Gaze: A Clinical Clue for CACNA1A-Related Disorders. Mov Disord Clin Pract 2023; 10:1225-1227. [PMID: 37635773 PMCID: PMC10450236 DOI: 10.1002/mdc3.13809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 05/19/2023] [Accepted: 05/24/2023] [Indexed: 08/29/2023] Open
Affiliation(s)
| | | | | | - José Luiz Pedroso
- Ataxia Unit, Department of NeurologyFederal University of Sao PauloSao PauloBrazil
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3
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Riquet A, Cleuziou P, Floret V, Quesque F, Defoort S, Smol T. Paroxysmal Tonic Upgaze in a Patient With Congenital Ataxia due to a De Novo Missense Variant of CACNA1G. Pediatr Neurol 2023; 139:22-23. [PMID: 36508879 DOI: 10.1016/j.pediatrneurol.2022.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 09/09/2022] [Accepted: 11/04/2022] [Indexed: 11/21/2022]
Abstract
BACKGROUND Paroxysmal tonic upgaze (PTU), defined as an involuntary upward movement of the eyes, has been considered as a benign phenomenon but may also be associated with ataxia and developmental delay. To date, CACNA1G mutations have been reported in autosomal dominant spinocerebellar ataxia designated SCA42 and in early encephalopathies with cerebellar atrophy but never in periodic childhood manifestations of PTU type. METHODS AND RESULTS We report the case of a two-month-old infant with a de novo pathogenic variation of CACNA1G who presented with PTU associated with congenital ataxia and other periodic neurological manifestations. CONCLUSIONS Although the link between CACNA1G mutations and periodic neurological manifestations remains unclear, we provide detailed video documentations of PTU, paroxysmal torticollis, and ataxia in a patient with a CACNA1G mutation. This case allows a better understanding of the underlying mechanisms of PTU and suggests potential new avenues for clinical treatments.
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Affiliation(s)
- Audrey Riquet
- CHU Lille, Centre de Référence Malformations et Maladies Congénitales du Cervelet, Lille, France; University of Lille, ULR7364-RADEME, Lille, France; Department of Pediatric Neurology, Saint Vincent de Paul Hospital, Groupement des Hôpitaux de l'Institut Catholique de Lille (GHICL), Catholic University of Lille, Lille, France.
| | - Pierre Cleuziou
- CHU Lille, Centre de Référence Malformations et Maladies Congénitales du Cervelet, Lille, France
| | - Valentine Floret
- CHU Lille, Centre de Référence Malformations et Maladies Congénitales du Cervelet, Lille, France
| | - Francois Quesque
- CHU Lille, Centre de Référence Malformations et Maladies Congénitales du Cervelet, Lille, France
| | - Sabine Defoort
- CHU Lille, Service d'exploration de la vision et neuro-ophtalmologie, Lille, France
| | - Thomas Smol
- University of Lille, ULR7364-RADEME, Lille, France; CHU Lille, Institut de Génétique Médicale, Lille, France
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4
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Indelicato E, Boesch S. CACNA1A-Related Channelopathies: Clinical Manifestations and Treatment Options. Handb Exp Pharmacol 2023; 279:227-248. [PMID: 36592223 DOI: 10.1007/164_2022_625] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In the last decade, variants in the Ca2+ channel gene CACNA1A emerged as a frequent aetiology of rare neurological phenotypes sharing a common denominator of variable paroxysmal manifestations and chronic cerebellar dysfunction. The spectrum of paroxysmal manifestations encompasses migraine with hemiplegic aura, episodic ataxia, epilepsy and paroxysmal non-epileptic movement disorders. Additional chronic neurological symptoms range from severe developmental phenotypes in early-onset cases to neurobehavioural disorders and chronic cerebellar ataxia in older children and adults.In the present review we systematically approach the clinical manifestations of CACNA1A variants, delineate genotype-phenotype correlations and elaborate on the emerging concept of an age-dependent phenotypic spectrum in CACNA1A disease. We furthermore reflect on different therapy options available for paroxysmal symptoms in CACNA1A and address open issues to prioritize in the future clinical research.
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Affiliation(s)
- Elisabetta Indelicato
- Center for Rare Movement Disorders Innsbruck, Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria.
| | - Sylvia Boesch
- Center for Rare Movement Disorders Innsbruck, Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
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5
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The complexities of CACNA1A in clinical neurogenetics. J Neurol 2021; 269:3094-3108. [PMID: 34806130 DOI: 10.1007/s00415-021-10897-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 11/03/2021] [Accepted: 11/05/2021] [Indexed: 12/25/2022]
Abstract
Variants in CACNA1A are classically related to episodic ataxia type 2, familial hemiplegic migraine type 1, and spinocerebellar ataxia type 6. Over the years, CACNA1A has been associated with a broader spectrum of phenotypes. Targeted analysis and unbiased sequencing of CACNA1A result not only in clear molecular diagnoses, but also in large numbers of variants of uncertain significance (VUS), or likely pathogenic variants with a phenotype that does not directly match the CACNA1A spectrum. Over the last years, targeted and clinical exome sequencing in our center has identified 41 CACNA1A variants. Ultimately, variants were considered pathogenic or likely pathogenic in 23 cases, with most phenotypes ranging from episodic or progressive ataxia to more complex ataxia syndromes, as well as intellectual disability and epilepsy. In two cases, the causality of the variant was discarded based on non-segregation or an alternative diagnosis. In the remaining 16 cases, the variant was classified as uncertain, due to lack of opportunities for segregation analysis or uncertain association with a non-classic phenotype. Phenotypic variability and the large number of VUS make CACNA1A a challenging gene for neurogenetic diagnostics. Accessible functional read-outs are clearly needed, especially in cases with a non-classic phenotype.
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Webb BD, Evans A, Naidich TP, M Bird L, Parikh S, Fernandez Garcia M, Henderson LB, Millan F, Si Y, Brennand KJ, Hung P, Rucker JC, Wheeler PG, Schadt EE. Haploinsufficiency of POU4F1 causes an ataxia syndrome with hypotonia and intention tremor. Hum Mutat 2021; 42:685-693. [PMID: 33783914 DOI: 10.1002/humu.24201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 03/25/2021] [Accepted: 03/26/2021] [Indexed: 11/06/2022]
Abstract
De novo, heterozygous, loss-of-function variants were identified in Pou domain, class 4, transcription factor 1 (POU4F1) via whole-exome sequencing in four independent probands presenting with ataxia, intention tremor, and hypotonia. POU4F1 is expressed in the developing nervous system, and mice homozygous for null alleles of Pou4f1 exhibit uncoordinated movements with newborns being unable to successfully right themselves to feed. Head magnetic resonance imaging of the four probands was reviewed and multiple abnormalities were noted, including significant cerebellar vermian atrophy and hypertrophic olivary degeneration in one proband. Transcriptional activation of the POU4F1 p.Gln306Arg protein was noted to be decreased when compared with wild type. These findings suggest that heterozygous, loss-of-function variants in POU4F1 are causative of a novel ataxia syndrome.
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Affiliation(s)
- Bryn D Webb
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Anthony Evans
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Thomas P Naidich
- Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Lynne M Bird
- Department of Pediatrics, University of California San Diego, Rady Children's Hospital, San Diego, California, USA
| | - Sumit Parikh
- Neurometabolism & Neurogenetics, Cleveland Clinic, Cleveland, Ohio, USA
| | - Meilin Fernandez Garcia
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | | | | | - Yue Si
- GeneDx, Gaithersburg, Maryland, USA
| | - Kristen J Brennand
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Peter Hung
- Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Janet C Rucker
- Department of Neurology, New York University Grossman School of Medicine, New York, New York, USA.,Department of Ophthalmology, New York University Grossman School of Medicine, New York, New York, USA
| | | | - Eric E Schadt
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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7
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Indelicato E, Boesch S. From Genotype to Phenotype: Expanding the Clinical Spectrum of CACNA1A Variants in the Era of Next Generation Sequencing. Front Neurol 2021; 12:639994. [PMID: 33737904 PMCID: PMC7960780 DOI: 10.3389/fneur.2021.639994] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 02/08/2021] [Indexed: 12/15/2022] Open
Abstract
Ion channel dysfunction is a key pathological substrate of episodic neurological disorders. A classical gene associated to paroxysmal movement disorders is CACNA1A, which codes for the pore-forming subunit of the neuronal calcium channel P/Q. Non-polyglutamine CACNA1A variants underlie familial hemiplegic ataxia type 1 (FHM1) and episodic ataxia type 2 (EA2). Classical paroxysmal manifestations of FHM1 are migraine attacks preceded by motor aura consisting of hemiparesis, aphasia, and disturbances of consciousness until coma. Patients with EA2 suffer of recurrent episodes of vertigo, unbalance, diplopia, and vomiting. Beyond these typical presentations, several reports highlighted manifold clinical features associated with P/Q channelopathies, from chronic progressive cerebellar ataxia to epilepsy and psychiatric disturbances. These manifestations may often outlast the burden of classical episodic symptoms leading to pitfalls in the diagnostic work-up. Lately, the spreading of next generation sequencing techniques linked de novo CACNA1A variants to an even broader phenotypic spectrum including early developmental delay, autism spectrum disorders, epileptic encephalopathy, and early onset paroxysmal dystonia. The age-dependency represents a striking new aspect of these phenotypes und highlights a pivotal role for P/Q channels in the development of the central nervous system in a defined time window. While several reviews addressed the clinical presentation and treatment of FHM1 and EA2, an overview of the newly described age-dependent manifestations is lacking. In this Mini-Review we present a clinical update, delineate genotype-phenotype correlations as well as summarize evidence on the pathophysiological mechanisms underlying the expanded phenotype associated with CACNA1A variants.
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Affiliation(s)
| | - Sylvia Boesch
- Center for Rare Movement Disorders Innsbruck, Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
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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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Zhang LP, Jia Y, Wang YP. Identification of Two de novo Variants of CACNA1A in Pediatric Chinese Patients With Paroxysmal Tonic Upgaze. Front Pediatr 2021; 9:722105. [PMID: 34631621 PMCID: PMC8500051 DOI: 10.3389/fped.2021.722105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 08/12/2021] [Indexed: 11/13/2022] Open
Abstract
Objective: Investigate the clinical manifestations and genotypes of paroxysmal tonic upgaze (PTU) in Chinese children. Patients and Methods: We report the clinical manifestations and genetic test results of four pediatric PTU patients in China. Recent articles on PTU cases are also summarized and analyzed. Results: The onset age of all four cases was at early infancy, and they presented as episodic binocular upward gaze with mild growth retardation. Two patients each carried a novel de novo variant in the CACNA1A gene, c.4046C>T (p.R1349X), and c.4415C>T (p.S1472L). Conclusion: Patients with infantile-onset paroxysmal binocular upward gaze should be considered to diagnose as PTU.
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Affiliation(s)
- Li-Ping Zhang
- Department of Pediatric, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yu Jia
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yu-Ping Wang
- Department of Pediatric, Xuanwu Hospital, Capital Medical University, Beijing, China.,Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
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Clinical and Genetic Overview of Paroxysmal Movement Disorders and Episodic Ataxias. Int J Mol Sci 2020; 21:ijms21103603. [PMID: 32443735 PMCID: PMC7279391 DOI: 10.3390/ijms21103603] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 05/11/2020] [Accepted: 05/13/2020] [Indexed: 12/15/2022] Open
Abstract
Paroxysmal movement disorders (PMDs) are rare neurological diseases typically manifesting with intermittent attacks of abnormal involuntary movements. Two main categories of PMDs are recognized based on the phenomenology: Paroxysmal dyskinesias (PxDs) are characterized by transient episodes hyperkinetic movement disorders, while attacks of cerebellar dysfunction are the hallmark of episodic ataxias (EAs). From an etiological point of view, both primary (genetic) and secondary (acquired) causes of PMDs are known. Recognition and diagnosis of PMDs is based on personal and familial medical history, physical examination, detailed reconstruction of ictal phenomenology, neuroimaging, and genetic analysis. Neurophysiological or laboratory tests are reserved for selected cases. Genetic knowledge of PMDs has been largely incremented by the advent of next generation sequencing (NGS) methodologies. The wide number of genes involved in the pathogenesis of PMDs reflects a high complexity of molecular bases of neurotransmission in cerebellar and basal ganglia circuits. In consideration of the broad genetic and phenotypic heterogeneity, a NGS approach by targeted panel for movement disorders, clinical or whole exome sequencing should be preferred, whenever possible, to a single gene approach, in order to increase diagnostic rate. This review is focused on clinical and genetic features of PMDs with the aim to (1) help clinicians to recognize, diagnose and treat patients with PMDs as well as to (2) provide an overview of genes and molecular mechanisms underlying these intriguing neurogenetic disorders.
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