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Pelzer N, Haan J, Stam AH, Vijfhuizen LS, Koelewijn SC, Smagge A, de Vries B, Ferrari MD, van den Maagdenberg AMJM, Terwindt GM. Clinical spectrum of hemiplegic migraine and chances of finding a pathogenic mutation. Neurology 2018; 90:e575-e582. [PMID: 29343472 DOI: 10.1212/wnl.0000000000004966] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 11/09/2017] [Indexed: 01/03/2023] Open
Abstract
OBJECTIVE To investigate whether the clinical characteristics of patients with hemiplegic migraine with and without autosomal dominant mutations in CACNA1A, ATP1A2, or SCN1A differ, and whether the disease may be caused by mutations in other genes. METHODS We compared the clinical characteristics of 208 patients with familial (n = 199) or sporadic (n = 9) hemiplegic migraine due to a mutation in CACNA1A, ATP1A2, or SCN1A with those of 73 patients with familial (n = 49) or sporadic (n = 24) hemiplegic migraine without a mutation in these genes. In addition, 47 patients (familial: n = 33; sporadic: n = 14) without mutations in CACNA1A, ATP1A2, or SCN1A were scanned for mutations in novel genes using whole exome sequencing. RESULTS Patients with mutations in CACNA1A, ATP1A2, or SCN1A had a lower age at disease onset, larger numbers of affected family members, and more often attacks (1) triggered by mild head trauma, (2) with extensive motor weakness, and (3) with brainstem features, confusion, and brain edema. Mental retardation and progressive ataxia were exclusively found in patients with a mutation. Whole exome sequencing failed to identify pathogenic mutations in new genes. CONCLUSIONS Most patients with hemiplegic migraine without a mutation in CACNA1A, ATP1A2, or SCN1A display a mild phenotype that is more akin to that of common (nonhemiplegic) migraine. A major fourth autosomal dominant gene for hemiplegic migraine remains to be identified. Our observations might guide physicians in selecting patients for mutation screening and in providing adequate genetic counseling.
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Affiliation(s)
- Nadine Pelzer
- From the Departments of Neurology (N.P., J.H., A.H.S., A.S., M.D.F., A.M.J.M.v.d.M., G.M.T.) and Human Genetics (L.S.V., S.C.K., B.d.V., A.M.J.M.v.d.M.), Leiden University Medical Centre; and Department of Neurology (J.H.), Alrijne Hospital, Leiderdorp, the Netherlands
| | - Joost Haan
- From the Departments of Neurology (N.P., J.H., A.H.S., A.S., M.D.F., A.M.J.M.v.d.M., G.M.T.) and Human Genetics (L.S.V., S.C.K., B.d.V., A.M.J.M.v.d.M.), Leiden University Medical Centre; and Department of Neurology (J.H.), Alrijne Hospital, Leiderdorp, the Netherlands
| | - Anine H Stam
- From the Departments of Neurology (N.P., J.H., A.H.S., A.S., M.D.F., A.M.J.M.v.d.M., G.M.T.) and Human Genetics (L.S.V., S.C.K., B.d.V., A.M.J.M.v.d.M.), Leiden University Medical Centre; and Department of Neurology (J.H.), Alrijne Hospital, Leiderdorp, the Netherlands
| | - Lisanne S Vijfhuizen
- From the Departments of Neurology (N.P., J.H., A.H.S., A.S., M.D.F., A.M.J.M.v.d.M., G.M.T.) and Human Genetics (L.S.V., S.C.K., B.d.V., A.M.J.M.v.d.M.), Leiden University Medical Centre; and Department of Neurology (J.H.), Alrijne Hospital, Leiderdorp, the Netherlands
| | - Stephany C Koelewijn
- From the Departments of Neurology (N.P., J.H., A.H.S., A.S., M.D.F., A.M.J.M.v.d.M., G.M.T.) and Human Genetics (L.S.V., S.C.K., B.d.V., A.M.J.M.v.d.M.), Leiden University Medical Centre; and Department of Neurology (J.H.), Alrijne Hospital, Leiderdorp, the Netherlands
| | - Amber Smagge
- From the Departments of Neurology (N.P., J.H., A.H.S., A.S., M.D.F., A.M.J.M.v.d.M., G.M.T.) and Human Genetics (L.S.V., S.C.K., B.d.V., A.M.J.M.v.d.M.), Leiden University Medical Centre; and Department of Neurology (J.H.), Alrijne Hospital, Leiderdorp, the Netherlands
| | - Boukje de Vries
- From the Departments of Neurology (N.P., J.H., A.H.S., A.S., M.D.F., A.M.J.M.v.d.M., G.M.T.) and Human Genetics (L.S.V., S.C.K., B.d.V., A.M.J.M.v.d.M.), Leiden University Medical Centre; and Department of Neurology (J.H.), Alrijne Hospital, Leiderdorp, the Netherlands
| | - Michel D Ferrari
- From the Departments of Neurology (N.P., J.H., A.H.S., A.S., M.D.F., A.M.J.M.v.d.M., G.M.T.) and Human Genetics (L.S.V., S.C.K., B.d.V., A.M.J.M.v.d.M.), Leiden University Medical Centre; and Department of Neurology (J.H.), Alrijne Hospital, Leiderdorp, the Netherlands
| | - Arn M J M van den Maagdenberg
- From the Departments of Neurology (N.P., J.H., A.H.S., A.S., M.D.F., A.M.J.M.v.d.M., G.M.T.) and Human Genetics (L.S.V., S.C.K., B.d.V., A.M.J.M.v.d.M.), Leiden University Medical Centre; and Department of Neurology (J.H.), Alrijne Hospital, Leiderdorp, the Netherlands
| | - Gisela M Terwindt
- From the Departments of Neurology (N.P., J.H., A.H.S., A.S., M.D.F., A.M.J.M.v.d.M., G.M.T.) and Human Genetics (L.S.V., S.C.K., B.d.V., A.M.J.M.v.d.M.), Leiden University Medical Centre; and Department of Neurology (J.H.), Alrijne Hospital, Leiderdorp, the Netherlands.
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Harper CB, Mancini GMS, van Slegtenhorst M, Cousin MA. Altered synaptobrevin-II trafficking in neurons expressing a synaptophysin mutation associated with a severe neurodevelopmental disorder. Neurobiol Dis 2017; 108:298-306. [PMID: 28887151 PMCID: PMC5673032 DOI: 10.1016/j.nbd.2017.08.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 07/27/2017] [Accepted: 08/31/2017] [Indexed: 11/17/2022] Open
Abstract
Following exocytosis, synaptic vesicles (SVs) have to be reformed with the correct complement of proteins in the correct stoichiometry to ensure continued neurotransmission. Synaptophysin is a highly abundant, integral SV protein necessary for the efficient retrieval of the SV SNARE protein, synaptobrevin II (sybII). However the molecular mechanism underpinning synaptophysin-dependent sybII retrieval is still unclear. We recently identified a male patient with severe intellectual disability, hypotonia, epilepsy and callosal agenesis who has a point mutation in the juxtamembrane region of the fourth transmembrane domain of synaptophysin (T198I). This mutation had no effect on the activity-dependent retrieval of synaptophysin that was tagged with the genetically-encoded pH-sensitive reporter (pHluorin) in synaptophysin knockout hippocampal cultures. This suggested the mutant has no global effect on SV endocytosis, which was confirmed when retrieval of a different SV cargo (the glutamate transporter vGLUT1) was examined. However neurons expressing this T198I mutant did display impaired activity-dependent sybII retrieval, similar to that observed in synaptophysin knockout neurons. Interestingly this impairment did not result in an increased stranding of sybII at the plasma membrane. Screening of known human synaptophysin mutations revealed a similar presynaptic phenotype between T198I and a mutation found in X-linked intellectual disability. Thus this novel human synaptophysin mutation has revealed that aberrant retrieval and increased plasma membrane localisation of SV cargo can be decoupled in human disease.
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Affiliation(s)
- Callista B Harper
- Centre for Integrative Physiology, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom; Simonds Initiative for the Developing Brain, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
| | - Grazia M S Mancini
- Department of Clinical Genetics, Erasmus University Medical Center, 3015CN Rotterdam, The Netherlands
| | - Marjon van Slegtenhorst
- Department of Clinical Genetics, Erasmus University Medical Center, 3015CN Rotterdam, The Netherlands
| | - Michael A Cousin
- Centre for Integrative Physiology, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom; Simonds Initiative for the Developing Brain, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom.
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Abstract
In an elegant publication in Cell Research, Tan and colleagues showed that ablation of PRRT2 in cerebellar granule cells is sufficient to induce paroxysmal kinesigenic dyskinesia. PRRT2 turns out to downregulate the presynaptic SNARE complex in granule cell axons, which in turn controls the activity patterns of Purkinje cells, the sole output of the cerebellar cortex.
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104
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Tan GH, Liu YY, Wang L, Li K, Zhang ZQ, Li HF, Yang ZF, Li Y, Li D, Wu MY, Yu CL, Long JJ, Chen RC, Li LX, Yin LP, Liu JW, Cheng XW, Shen Q, Shu YS, Sakimura K, Liao LJ, Wu ZY, Xiong ZQ. PRRT2 deficiency induces paroxysmal kinesigenic dyskinesia by regulating synaptic transmission in cerebellum. Cell Res 2017; 28:90-110. [PMID: 29056747 PMCID: PMC5752836 DOI: 10.1038/cr.2017.128] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 06/28/2017] [Accepted: 07/26/2017] [Indexed: 01/22/2023] Open
Abstract
Mutations in the proline-rich transmembrane protein 2 (PRRT2) are associated with paroxysmal kinesigenic dyskinesia (PKD) and several other paroxysmal neurological diseases, but the PRRT2 function and pathogenic mechanisms remain largely obscure. Here we show that PRRT2 is a presynaptic protein that interacts with components of the SNARE complex and downregulates its formation. Loss-of-function mutant mice showed PKD-like phenotypes triggered by generalized seizures, hyperthermia, or optogenetic stimulation of the cerebellum. Mutant mice with specific PRRT2 deletion in cerebellar granule cells (GCs) recapitulate the behavioral phenotypes seen in Prrt2-null mice. Furthermore, recording made in cerebellar slices showed that optogenetic stimulation of GCs results in transient elevation followed by suppression of Purkinje cell firing. The anticonvulsant drug carbamazepine used in PKD treatment also relieved PKD-like behaviors in mutant mice. Together, our findings identify PRRT2 as a novel regulator of the SNARE complex and provide a circuit mechanism underlying the PRRT2-related behaviors.
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Affiliation(s)
- Guo-He Tan
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.,Department of Human Anatomy, Guangxi Key Laboratory of Regenerative Medicine & Guangxi Collaborative Innovation Center of Biomedicine, Guangxi Medical University, Nanning, Guangxi 530021, China
| | - Yuan-Yuan Liu
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Lu Wang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Kui Li
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Ze-Qiang Zhang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hong-Fu Li
- Department of Neurology and Research Center of Neurology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, China
| | - Zhong-Fei Yang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yang Li
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Dan Li
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Ming-Yue Wu
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Chun-Lei Yu
- Shanghai Key Laboratory of Regulatory Biology, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Juan-Juan Long
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Ren-Chao Chen
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Li-Xi Li
- Department of Neurology and Research Center of Neurology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, China
| | - Lu-Ping Yin
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Ji-Wei Liu
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xue-Wen Cheng
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Qi Shen
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - You-Sheng Shu
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Kenji Sakimura
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Lu-Jian Liao
- Shanghai Key Laboratory of Regulatory Biology, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Zhi-Ying Wu
- Department of Neurology and Research Center of Neurology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, China
| | - Zhi-Qi Xiong
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.,University of Chinese Academy of Sciences, Beijing 100049, China
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105
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Tacke M, Neubauer BA, Gerstl L, Roser T, Rémi J, Borggraefe I. [Epilepsy-new diagnostic tools, old drugs? : Therapeutic consequences of epilepsy genetics]. DER NERVENARZT 2017; 88:1385-1394. [PMID: 28932874 DOI: 10.1007/s00115-017-0427-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Recent advances in the field of epilepsy genetics have led to an increased fraction of patients with epilepsies where the etiology of the disease could be identified. Nevertheless, there is some criticism regarding the use of epilepsy genetics because in many cases the identification of a pathogenetic mutation does not lead to an adaptation of therapy or to an improved prognosis. In addition, the interpretation of genetic results might be complicated due to the considerable numbers of variants of unclear significance. OBJECTIVE This publication presents the arguments in favour of a broad use of genetic investigations for children with epilepsies. Several diseases where a genetic diagnosis does in fact have direct therapeutic consequences are mentioned. In addition, the indirect impact of an established etiology, encompassing the avoidance of unnecessary diagnostic measures, possibility of genetic counselling, and the easing of the psychologic burden for the caregivers, should not be underestimated. CONCLUSION The arguments in favour of broad genetic diagnostics prevail notwithstanding the lack of relevant new developments regarding the therapy.
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Affiliation(s)
- M Tacke
- Abteilung für Pädiatrische Neurologie und Entwicklungsneurologie, LMU Zentrum - iSPZ Hauner, Sektion für Pädiatrische Epileptologie, Kinderklinik und Kinderpoliklinik im Dr. von Haunerschen Kinderspital, Universität München, Lindwurmstr. 4, 80337, München, Deutschland
| | - B A Neubauer
- Abteilung für Neuropädiatrie, Sozialpädiatrie und Epileptologie, Universitätskinderklinik, Universität Gießen-Marburg, Gießen, Deutschland
| | - L Gerstl
- Abteilung für Pädiatrische Neurologie und Entwicklungsneurologie, LMU Zentrum - iSPZ Hauner, Sektion für Pädiatrische Epileptologie, Kinderklinik und Kinderpoliklinik im Dr. von Haunerschen Kinderspital, Universität München, Lindwurmstr. 4, 80337, München, Deutschland
| | - T Roser
- Abteilung für Pädiatrische Neurologie und Entwicklungsneurologie, LMU Zentrum - iSPZ Hauner, Sektion für Pädiatrische Epileptologie, Kinderklinik und Kinderpoliklinik im Dr. von Haunerschen Kinderspital, Universität München, Lindwurmstr. 4, 80337, München, Deutschland
| | - J Rémi
- Neurologische Klinik und Poliklinik & Deutsches Schwindel- und Gleichgewichtszentrum (DSGZ), Campus Großhadern, Klinikum der Universität München, München, Deutschland.,Interdisziplinäres Epilepsiezentrum am Campus Großhadern und im Dr. von Haunerschen Kinderspital, Klinikum der Universität München, München, Deutschland
| | - I Borggraefe
- Abteilung für Pädiatrische Neurologie und Entwicklungsneurologie, LMU Zentrum - iSPZ Hauner, Sektion für Pädiatrische Epileptologie, Kinderklinik und Kinderpoliklinik im Dr. von Haunerschen Kinderspital, Universität München, Lindwurmstr. 4, 80337, München, Deutschland. .,Interdisziplinäres Epilepsiezentrum am Campus Großhadern und im Dr. von Haunerschen Kinderspital, Klinikum der Universität München, München, Deutschland.
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106
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Kang JQ. Defects at the crossroads of GABAergic signaling in generalized genetic epilepsies. Epilepsy Res 2017; 137:9-18. [PMID: 28865303 DOI: 10.1016/j.eplepsyres.2017.08.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 08/14/2017] [Accepted: 08/22/2017] [Indexed: 12/16/2022]
Abstract
Seizure disorders are very common and affect 3% of the general population. The recurrent unprovoked seizures that are also called epilepsies are highly diverse as to both underlying genetic basis and clinic presentations. Recent genetic advances and sequencing technologies indicate that many epilepsies previously thought to be without known causes, or idiopathic generalized epilepsies (IGEs), are virtually genetic epilepsy as they are caused by genetic variations. IGEs are estimated to account for ∼15-20% of all epilepsies. Initially IGEs were primarily considered channelopathies, because the first genetic defects identified in IGEs involved ion channel genes. However, new findings indicate that mutations in many non ion channel genes are also involved in addition to those in ion channel genes. Interestingly, mutations in many genes associated with epilepsy affect GABAergic signaling, a major biological pathway in epilepsy. Additionally, many antiepileptic drugs work via enhancing GABAergic signaling. Hence, the review will focus on the mutations that impair GABAergic signaling and selectively discuss the newly identified STXBP1, PRRT2, and DNM1 in addition to those long-established epilepsy ion channel genes that also impair GABAergic signaling like SCN1A and GABAA receptor subunit genes. GABAergic signaling includes the pre- and post- synaptic mechanisms. Some mutations, such as STXBP1, PRRT2, DNM1, and SCN1A, impair GABAergic signaling mainly via pre-synaptic mechanisms while those mutations in GABAA receptor subunit genes impair GABAergic signaling via post-synaptic mechanisms. Nevertheless, these findings suggest impaired GABAergic signaling is a converging pathway of defects for many ion channel or non ion channel mutations associated with genetic epilepsies.
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Affiliation(s)
- Jing-Qiong Kang
- Departments of Neurology, Vanderbilt University Medical Center, Nashville, TN, 37232-8552, USA; Affiliated Hospital of Nantong University, Jiangsu, 226001, China; Vanderbilt Brain Institute, Vanderbilt Kennedy Center of Human Development, Vanderbilt University, Nashville, TN, 37232-8522, USA.
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108
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109
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Kita M, Kuwata Y, Murase N, Akiyama Y, Usui T. A Novel Truncation Mutation of the PRRT2 Gene Resulting in a 16-Amino-Acid Protein Causes Self-inducible Paroxysmal Kinesigenic Dyskinesia. Mov Disord Clin Pract 2017; 4:625-628. [PMID: 30713971 DOI: 10.1002/mdc3.12500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 03/29/2017] [Accepted: 03/31/2017] [Indexed: 11/10/2022] Open
Abstract
Paroxysmal kinesigenic dyskinesia (PKD) is a sporadic or autosomal-dominant, hereditary disorder characterized by brief, recurrent attacks of involuntary movements triggered by sudden, voluntary movement that generally develops during childhood and adolescence and is typically treated with carbamazepine. The proline-rich transmembrane protein 2 (PRRT2) gene contains 4 exons that encode 340 amino acids as the major isoform, and recent research has identified PRRT2 as the primary causative gene in PKD, benign familial infantile epilepsy (BFIE), and infantile convulsions with PKD (PKD/IC). Here, the authors report the phenotype of a family with a novel p.E16X (c.46G>T) nonsense mutation of the PRRT2 gene that lacked almost a full allele. In this family, none of the individuals in the pedigree exhibited evidence of cognitive impairment: the elder brother had PKD/IC with migraine; the younger brother had PKD with ataxia; the father had PKD; both siblings experienced a sensory aura; and all 3 had a history of febrile seizures. This is the first report of a short nonsense mutation in PRRT2 and indicates that the manifestations of the disease, including other mutations to date, can be explained by haploinsufficiency and that 1 intact PRRT2 allele can allow normal cognitive development.
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Affiliation(s)
- Makoto Kita
- National Hospital Organization Kyoto Medical Center Department of Pediatrics Kyoto Japan
| | - Yasuhiro Kuwata
- National Hospital Organization Kyoto Medical Center Department of Neurology Kyoto Japan
| | - Nagako Murase
- National Hospital Organization Kyoto Medical Center Department of Neurology Kyoto Japan
| | - Yuichi Akiyama
- National Hospital Organization Kyoto Medical Center Department of Pediatrics Kyoto Japan
| | - Takeshi Usui
- Shizuoka General Hospital Department of Medical Genetics Shizuoka Japan
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110
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Orbitofrontal Neuroadaptations and Cross-Species Synaptic Biomarkers in Heavy-Drinking Macaques. J Neurosci 2017; 37:3646-3660. [PMID: 28270566 DOI: 10.1523/jneurosci.0133-17.2017] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 02/17/2017] [Accepted: 02/28/2017] [Indexed: 02/08/2023] Open
Abstract
Cognitive impairments, uncontrolled drinking, and neuropathological cortical changes characterize alcohol use disorder. Dysfunction of the orbitofrontal cortex (OFC), a critical cortical subregion that controls learning, decision-making, and prediction of reward outcomes, contributes to executive cognitive function deficits in alcoholic individuals. Electrophysiological and quantitative synaptomics techniques were used to test the hypothesis that heavy drinking produces neuroadaptations in the macaque OFC. Integrative bioinformatics and reverse genetic approaches were used to identify and validate synaptic proteins with novel links to heavy drinking in BXD mice. In drinking monkeys, evoked firing of OFC pyramidal neurons was reduced, whereas the amplitude and frequency of postsynaptic currents were enhanced compared with controls. Bath application of alcohol reduced evoked firing in neurons from control monkeys, but not drinking monkeys. Profiling of the OFC synaptome identified alcohol-sensitive proteins that control glutamate release (e.g., SV2A, synaptogyrin-1) and postsynaptic signaling (e.g., GluA1, PRRT2) with no changes in synaptic GABAergic proteins. Western blot analysis confirmed the increase in GluA1 expression in drinking monkeys. An exploratory analysis of the OFC synaptome found cross-species genetic links to alcohol intake in discrete proteins (e.g., C2CD2L, DIRAS2) that discriminated between low- and heavy-drinking monkeys. Validation studies revealed that BXD mouse strains with the D allele at the C2cd2l interval drank less alcohol than B allele strains. Thus, by profiling of the OFC synaptome, we identified changes in proteins controlling glutamate release and postsynaptic signaling and discovered several proteins related to heavy drinking that have potential as novel targets for treating alcohol use disorder.SIGNIFICANCE STATEMENT Clinical research identified cognitive deficits in alcoholic individuals as a risk factor for relapse, and alcoholic individuals display deficits on cognitive tasks that are dependent upon the orbitofrontal cortex (OFC). To identify neurobiological mechanisms that underpin OFC dysfunction, this study used electrophysiology and integrative synaptomics in a translational nonhuman primate model of heavy alcohol consumption. We found adaptations in synaptic proteins that control glutamatergic signaling in chronically drinking monkeys. Our functional genomic exploratory analyses identified proteins with genetic links to alcohol and cocaine intake across mice, monkeys, and humans. Future work is necessary to determine whether targeting these novel targets reduces excessive and harmful levels of alcohol drinking.
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111
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Lipstein N, Verhoeven-Duif NM, Michelassi FE, Calloway N, van Hasselt PM, Pienkowska K, van Haaften G, van Haelst MM, van Empelen R, Cuppen I, van Teeseling HC, Evelein AMV, Vorstman JA, Thoms S, Jahn O, Duran KJ, Monroe GR, Ryan TA, Taschenberger H, Dittman JS, Rhee JS, Visser G, Jans JJ, Brose N. Synaptic UNC13A protein variant causes increased neurotransmission and dyskinetic movement disorder. J Clin Invest 2017; 127:1005-1018. [PMID: 28192369 DOI: 10.1172/jci90259] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 12/15/2016] [Indexed: 12/13/2022] Open
Abstract
Munc13 proteins are essential regulators of neurotransmitter release at nerve cell synapses. They mediate the priming step that renders synaptic vesicles fusion-competent, and their genetic elimination causes a complete block of synaptic transmission. Here we have described a patient displaying a disorder characterized by a dyskinetic movement disorder, developmental delay, and autism. Using whole-exome sequencing, we have shown that this condition is associated with a rare, de novo Pro814Leu variant in the major human Munc13 paralog UNC13A (also known as Munc13-1). Electrophysiological studies in murine neuronal cultures and functional analyses in Caenorhabditis elegans revealed that the UNC13A variant causes a distinct dominant gain of function that is characterized by increased fusion propensity of synaptic vesicles, which leads to increased initial synaptic vesicle release probability and abnormal short-term synaptic plasticity. Our study underscores the critical importance of fine-tuned presynaptic control in normal brain function. Further, it adds the neuronal Munc13 proteins and the synaptic vesicle priming process that they control to the known etiological mechanisms of psychiatric and neurological synaptopathies.
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Long Z, Xu Q, Miao HH, Yu Y, Ding MP, Chen H, Liu ZR, Liao W. Thalamocortical dysconnectivity in paroxysmal kinesigenic dyskinesia: Combining functional magnetic resonance imaging and diffusion tensor imaging. Mov Disord 2017; 32:592-600. [PMID: 28186667 DOI: 10.1002/mds.26905] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 12/06/2016] [Accepted: 12/08/2016] [Indexed: 01/07/2023] Open
Affiliation(s)
- Zhiliang Long
- Key Laboratory for Neuroinformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology; University of Electronic Science and Technology of China; Chengdu P.R. China
| | - Qiang Xu
- Department of Medical Imaging, Jinling Hospital; Nanjing University School of Medicine; Nanjing P.R. China
| | - Huan-Huan Miao
- Center for Cognition and Brain Disorders and the Affiliated Hospital; Hangzhou Normal University; Hangzhou P.R. China
| | - Yang Yu
- Mental Health Education and Counseling Center; Zhejiang University; Hangzhou China
| | - Mei-Ping Ding
- Department of Neurology, the Second Affiliated Hospital of Medial College; Zhejiang University; Hangzhou P.R. China
| | - Huafu Chen
- Key Laboratory for Neuroinformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology; University of Electronic Science and Technology of China; Chengdu P.R. China
| | - Zhi-Rong Liu
- Department of Neurology, the Second Affiliated Hospital of Medial College; Zhejiang University; Hangzhou P.R. China
| | - Wei Liao
- Key Laboratory for Neuroinformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology; University of Electronic Science and Technology of China; Chengdu P.R. China
- Department of Medical Imaging, Jinling Hospital; Nanjing University School of Medicine; Nanjing P.R. China
- Center for Cognition and Brain Disorders and the Affiliated Hospital; Hangzhou Normal University; Hangzhou P.R. China
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113
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Erro R, Bhatia KP, Espay AJ, Striano P. The epileptic and nonepileptic spectrum of paroxysmal dyskinesias: Channelopathies, synaptopathies, and transportopathies. Mov Disord 2017; 32:310-318. [PMID: 28090678 DOI: 10.1002/mds.26901] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 11/28/2016] [Accepted: 12/01/2016] [Indexed: 12/12/2022] Open
Abstract
Historically, the syndrome of primary paroxysmal dyskinesias was considered a group of disorders as a result of ion channel dysfunction. This proposition was primarily based on the discovery of mutations in ion channels, which caused other episodic neurological disorders such as epilepsy and migraine and also supported by the frequent association between paroxysmal dyskinesias and epilepsy. However, the discovery of the genes responsible for the 3 classic forms of paroxysmal dyskinesias disproved this ion channel theory. On the other hand, novel gene mutations implicating ion channels have been recently reported to produce episodic movement disorders clinically similar to the classic paroxysmal dyskinesias. Here, we review the clinical and pathophysiological aspects of the paroxysmal dyskinesias, further proposing a pathophysiological framework according to which they can be classified as synaptopathies (proline-rich transmembrane protein 2 and myofibrillogenesis regulator gene), channelopathies (calcium-activated potassium channel subunit alpha-1 and voltage-gated sodium channel type 8), or transportopathies (solute carrier family 2 member 1). This proposal might serve to explain similarities and differences among the various paroxysmal dyskinesias in terms of clinical features, treatment response, and natural history. © 2017 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Roberto Erro
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London, Institute of Neurology, London, UK.,Department of Neuroscience, Biomedicine and Movement Science, University of Verona, Verona, Italy
| | - Kailash P Bhatia
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London, Institute of Neurology, London, UK
| | - Alberto J Espay
- Gardner Neuroscience Institute, Department of Neurology, Gardner Center for Parkinson's disease and Movement Disorders, University of Cincinnati, Ohio, USA
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, "G. Gaslini" Institute, Genova, Italy
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114
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Michetti C, Castroflorio E, Marchionni I, Forte N, Sterlini B, Binda F, Fruscione F, Baldelli P, Valtorta F, Zara F, Corradi A, Benfenati F. The PRRT2 knockout mouse recapitulates the neurological diseases associated with PRRT2 mutations. Neurobiol Dis 2016; 99:66-83. [PMID: 28007585 PMCID: PMC5321265 DOI: 10.1016/j.nbd.2016.12.018] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 12/06/2016] [Accepted: 12/18/2016] [Indexed: 11/05/2022] Open
Abstract
Heterozygous and rare homozygous mutations in PRoline-Rich Transmembrane protein 2 (PRRT2) underlie a group of paroxysmal disorders including epilepsy, kinesigenic dyskinesia episodic ataxia and migraine. Most of the mutations lead to impaired PRRT2 expression and/or function. Recently, an important role for PRTT2 in the neurotransmitter release machinery, brain development and synapse formation has been uncovered. In this work, we have characterized the phenotype of a mouse in which the PRRT2 gene has been constitutively inactivated (PRRT2 KO). β-galactosidase staining allowed to map the regional expression of PRRT2 that was more intense in the cerebellum, hindbrain and spinal cord, while it was localized to restricted areas in the forebrain. PRRT2 KO mice are normal at birth, but display paroxysmal movements at the onset of locomotion that persist in the adulthood. In addition, adult PRRT2 KO mice present abnormal motor behaviors characterized by wild running and jumping in response to audiogenic stimuli that are ineffective in wild type mice and an increased sensitivity to the convulsive effects of pentylentetrazol. Patch-clamp electrophysiology in hippocampal and cerebellar slices revealed specific effects in the cerebellum, where PRRT2 is highly expressed, consisting in a higher excitatory strength at parallel fiber-Purkinje cell synapses during high frequency stimulation. The results show that the PRRT2 KO mouse reproduces the motor paroxysms present in the human PRRT2-linked pathology and can be proposed as an experimental model for the study of the pathogenesis of the disease as well as for testing personalized therapeutic approaches. PRRT2 is intensely expressed in cerebellum and in restricted areas of the forebrain. PRRT2 KO mice display paroxysmal movements at the onset of locomotion. PRRT2 KO mice present abnormal motor behaviors in response to audiogenic stimuli. PRRT2 KO mice are more sensitive to the convulsive effects of pentylentetrazol. PRRT2 KO mice display an altered synaptic transmission in the cerebellar cortex.
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Affiliation(s)
- Caterina Michetti
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Enrico Castroflorio
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy; Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy
| | - Ivan Marchionni
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Nicola Forte
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Bruno Sterlini
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy
| | - Francesca Binda
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Floriana Fruscione
- Department Head and Neck Neuroscience, Laboratory of Neurogenetics and Neuroscience, Institute G. Gaslini, Via Gerolamo Gaslini, 5, 16148 Genova, Italy
| | - Pietro Baldelli
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy; Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy
| | - Flavia Valtorta
- San Raffaele Scientific Institute and Vita Salute University, Via Olgettina 58, 20132 Milano, Italy
| | - Federico Zara
- Department Head and Neck Neuroscience, Laboratory of Neurogenetics and Neuroscience, Institute G. Gaslini, Via Gerolamo Gaslini, 5, 16148 Genova, Italy
| | - Anna Corradi
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Fabio Benfenati
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy; Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy.
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115
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PRRT2: from Paroxysmal Disorders to Regulation of Synaptic Function. Trends Neurosci 2016; 39:668-679. [DOI: 10.1016/j.tins.2016.08.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 08/19/2016] [Accepted: 08/22/2016] [Indexed: 12/19/2022]
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116
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Dynamin 1 isoform roles in a mouse model of severe childhood epileptic encephalopathy. Neurobiol Dis 2016; 95:1-11. [PMID: 27363778 DOI: 10.1016/j.nbd.2016.06.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 06/23/2016] [Accepted: 06/26/2016] [Indexed: 01/05/2023] Open
Abstract
Dynamin 1 is a large neuron-specific GTPase involved in the endocytosis and recycling of pre-synaptic membranes and synaptic vesicles. Mutations in the gene encoding dynamin 1 (DNM1) underlie two epileptic encephalopathy syndromes, Lennox-Gastaut Syndrome and Infantile Spasms. Mice homozygous for the Dnm1 "fitful" mutation, a non-synonymous coding variant in an alternatively spliced exon of Dnm1 (exon 10a; isoform designation: Dnm1a(Ftfl)) have an epileptic encephalopathy-like disorder including lethal early onset seizures, locomotor and neurosensory deficits. Although fitful heterozygotes have milder recurrent seizures later in life, suggesting an additive or semi-dominant mechanism, the molecular etiology must also consider the fact that Dnm1a(Ftfl) exerts a dominant negative effect on endocytosis in vitro. Another complication is that the fitful mutation induces alterations in the relative abundance of Dnm1 splice variants; mutants have a downregulation of Dnm1a and an upregulation of Dnm1b, changes which may contribute to the epileptic pathology. To examine whether Dnm1a loss of function, Dnm1a(Ftfl) dominance or compensation by Dnm1b is the most critical for severe seizures, we studied alternate isoform-specific mutant mice. Mice lacking Dnm1 exon 10a or Dnm1 exon 10b have neither spontaneous seizures nor other overt abnormalities, suggesting that in normal conditions the major role of each isoform is redundant. However, in the presence of Dnm1a(Ftfl) only exon 10a deleted mice experience severe seizures. These results reveal functional differences between Dnm1a and Dnm1b isoforms in the presence of a challenge, i.e. toxic Dnm1(Ftfl), while reinforcing its effect explicitly in this model of severe pediatric epilepsy.
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117
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Castelnovo G, Renard D, De Verdal M, Luc J, Thouvenot E, Riant F. Progressive ataxia related to PRRT2 gene mutation. J Neurol Sci 2016; 367:220-1. [PMID: 27423591 DOI: 10.1016/j.jns.2016.05.058] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 05/04/2016] [Accepted: 05/30/2016] [Indexed: 11/30/2022]
Affiliation(s)
- Giovanni Castelnovo
- Department of Neurology, CHU Nîmes, Hôpital Caremeau, Place du Pr Debré, 30029 Nîmes Cedex 4, France.
| | - Dimitri Renard
- Department of Neurology, CHU Nîmes, Hôpital Caremeau, Place du Pr Debré, 30029 Nîmes Cedex 4, France
| | - Marie De Verdal
- Department of Neurology, CHU Nîmes, Hôpital Caremeau, Place du Pr Debré, 30029 Nîmes Cedex 4, France
| | - JeanJean Luc
- Department of Ophtalmology, CHU Nîmes, Hôpital Caremeau, Place du Pr Debré, 30029 Nîmes Cedex 4, France
| | - Eric Thouvenot
- Department of Ophtalmology, CHU Nîmes, Hôpital Caremeau, Place du Pr Debré, 30029 Nîmes Cedex 4, France
| | - Florence Riant
- Department of genetics, Hopital Lariboisiere, APHP Groupe Hospitalier Lariboisiere - Saint Louis - Fernand Widal, 75475 Paris Cedex 10, France
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