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Deng X, Yuan L, Jankovic J, Deng H. The role of the PLA2G6 gene in neurodegenerative diseases. Ageing Res Rev 2023; 89:101957. [PMID: 37236368 DOI: 10.1016/j.arr.2023.101957] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 05/12/2023] [Accepted: 05/17/2023] [Indexed: 05/28/2023]
Abstract
PLA2G6-associated neurodegeneration (PLAN) represents a continuum of clinically and genetically heterogeneous neurodegenerative disorders with overlapping features. Usually, it encompasses three autosomal recessive diseases, including infantile neuroaxonal dystrophy or neurodegeneration with brain iron accumulation (NBIA) 2A, atypical neuronal dystrophy with childhood-onset or NBIA2B, and adult-onset dystonia-parkinsonism form named PARK14, and possibly a certain subtype of hereditary spastic paraplegia. PLAN is caused by variants in the phospholipase A2 group VI gene (PLA2G6), which encodes an enzyme involved in membrane homeostasis, signal transduction, mitochondrial dysfunction, and α-synuclein aggregation. In this review, we discuss PLA2G6 gene structure and protein, functional findings, genetic deficiency models, various PLAN disease phenotypes, and study strategies in the future. Our primary aim is to provide an overview of genotype-phenotype correlations of PLAN subtypes and speculate on the role of PLA2G6 in potential mechanisms underlying these conditions.
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Affiliation(s)
- Xinyue Deng
- Health Management Center, the Third Xiangya Hospital, Central South University, Changsha 410013, Hunan, China; Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, Changsha 410013, Hunan, China; Department of Neurology, the Third Xiangya Hospital, Central South University, Changsha 410013, Hunan, China
| | - Lamei Yuan
- Health Management Center, the Third Xiangya Hospital, Central South University, Changsha 410013, Hunan, China; Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, Changsha 410013, Hunan, China; Disease Genome Research Center, Central South University, Changsha 410013, Hunan, China
| | - Joseph Jankovic
- Parkinson's Disease Center and Movement Disorders Clinic, Department of Neurology, Baylor College of Medicine, Houston, TX 77030-4202, USA
| | - Hao Deng
- Health Management Center, the Third Xiangya Hospital, Central South University, Changsha 410013, Hunan, China; Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, Changsha 410013, Hunan, China; Department of Neurology, the Third Xiangya Hospital, Central South University, Changsha 410013, Hunan, China; Disease Genome Research Center, Central South University, Changsha 410013, Hunan, China.
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Corbett MA, Depienne C, Veneziano L, Klein KM, Brancati F, Guerrini R, Zara F, Tsuji S, Gecz J. Genetics of familial adult myoclonus epilepsy: From linkage studies to noncoding repeat expansions. Epilepsia 2023; 64 Suppl 1:S14-S21. [PMID: 37021642 PMCID: PMC10952679 DOI: 10.1111/epi.17610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 03/27/2023] [Accepted: 04/04/2023] [Indexed: 04/07/2023]
Abstract
Familial adult myoclonus epilepsy (FAME) is a genetic epilepsy syndrome that for many years has resisted understanding of its underlying molecular cause. This review covers the history of FAME genetic studies worldwide, starting with linkage and culminating in the discovery of noncoding TTTTA and inserted TTTCA pentanucleotide repeat expansions within six different genes to date (SAMD12, STARD7, MARCHF6, YEATS2, TNRC6A, and RAPGEF2). FAME occurs worldwide; however, repeat expansions in particular genes have regional geographical distributions. FAME repeat expansions are dynamic in nature, changing in length and structure within germline and somatic tissues. This variation poses challenges for molecular diagnosis such that molecular methods used to identify FAME repeat expansions typically require a trade-off between cost and efficiency. A rigorous evaluation of the sensitivity and specificity of each molecular approach remains to be performed. The origin of FAME repeat expansions and the genetic and environmental factors that modulate repeat variability are not well defined. Longer repeats and particular arrangements of the TTTTA and TTTCA motifs within an expansion are correlated with earlier onset and increased severity of disease. Other factors such as maternal or paternal inheritance, parental age, and repeat length alone have been suggested to influence repeat variation; however, further research is required to confirm this. The history of FAME genetics to the present is a chronicle of perseverance and predominantly collaborative efforts that yielded a successful outcome. The discovery of FAME repeats will spark progress toward a deeper understanding of the molecular pathogenesis of FAME, discovery of new loci, and development of cell and animal models.
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Affiliation(s)
- Mark A. Corbett
- Robinson Research Institute and Adelaide Medical SchoolUniversity of AdelaideAdelaideSouth AustraliaAustralia
| | - Christel Depienne
- Institute of Human GeneticsUniversity Hospital Essen, University Duisburg–EssenEssenGermany
| | - Liana Veneziano
- Institute of Translational PharmacologyNational Research CouncilRomeItaly
| | - Karl Martin Klein
- Departments of Clinical Neurosciences, Medical Genetics, and Community Health Sciences, Hotchkiss Brain Institute and Alberta Children's HospitalResearch Institute, Cumming School of Medicine, University of CalgaryCalgaryAlbertaCanada
- Epilepsy Center Frankfurt Rhine–Main, Department of Neurology, Center of Neurology and NeurosurgeryCenter for Personalized Translational Epilepsy Research, University Hospital, Goethe University FrankfurtFrankfurt am MainGermany
| | - Francesco Brancati
- Institute of Translational PharmacologyNational Research CouncilRomeItaly
- Medical Genetics, Department of Life, Health, and Environmental SciencesUniversity of L'AquilaL'AquilaItaly
- Laboratory of Human Functional GenomicsIstituto di Ricovero e Cura a Carattere Scientifico (IRCCS) San RaffaeleRomeItaly
| | - Renzo Guerrini
- Neuroscience and Neurogenetics DepartmentMeyer Children's HospitalFlorenceItaly
| | - Federico Zara
- Laboratory of NeurogeneticsIRCCS Institute "G. Gaslini"GenoaItaly
| | - Shoji Tsuji
- Department of Neurology, Graduate School of MedicineUniversity of TokyoTokyoJapan
- Institute of Medical GenomicsInternational University of Health and WelfareChibaJapan
| | - Jozef Gecz
- Robinson Research Institute and Adelaide Medical SchoolUniversity of AdelaideAdelaideSouth AustraliaAustralia
- South Australian Health and Medical Research InstituteAdelaideSouth AustraliaAustralia
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Dubbioso R, Suppa A, Tijssen MAJ, Ikeda A. Familial adult myoclonus epilepsy: Neurophysiological investigations. Epilepsia 2023. [PMID: 36806000 DOI: 10.1111/epi.17553] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Revised: 02/14/2023] [Accepted: 02/16/2023] [Indexed: 02/20/2023]
Abstract
Familial adult myoclonus epilepsy (FAME) also described as benign adult familial myoclonus epilepsy (BAFME) is a high-penetrant autosomal dominant condition featuring cortical myoclonus of varying frequency and occasional/rare convulsive seizures. In this update we provide a detailed overview of the main neurophysiological findings so far reported in patients with FAME/BAFME. After reviewing the diagnostic contribution of each neurophysiological technique, we discuss the possible mechanisms underlying cortical hyperexcitability and suggest the involvement of more complex circuits engaging cortical and subcortical structures, such as the cerebellum. We, thus, propose that FAME/BAFME clinical features should arise from an "abnormal neuronal network activity," where the cerebellum represents a possible common denominator. In the last part of the article, we suggest that future neurophysiological studies using more advanced transcranial magnetic stimulation (TMS) protocols could be used to evaluate the functional connectivity between the cerebellum and cortical structures. Finally, non-invasive brain stimulation techniques such as repetitive TMS or transcranial direct current stimulation could be assessed as potential therapeutic tools to ameliorate cortical excitability.
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Affiliation(s)
- Raffaele Dubbioso
- Department of Neuroscience, Reproductive Sciences and Odontostomatology, Federico II University of Naples, Napoli, Italy
| | - Antonio Suppa
- Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy.,IRCCS Neuromed, Pozzilli, Italy
| | - Marina A J Tijssen
- Department of Neurology, University of Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands.,Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
| | - Akio Ikeda
- Department of Epilepsy, Movement Disorders and Physiology Kyoto University Graduate School of Medicine Shogoin, Kyoto, Japan
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Zhou Y, Sood R, Wang Q, Carrington B, Park M, Young AC, Birnbaum D, Liu Z, Ashizawa T, Mullikin JC, Koubeissi MZ, Liu P. Clinical and genomic analysis of a large Chinese family with familial cortical myoclonic tremor with epilepsy and SAMD12 intronic repeat expansion. Epilepsia Open 2021; 6:102-111. [PMID: 33681653 PMCID: PMC7918340 DOI: 10.1002/epi4.12450] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 11/07/2020] [Accepted: 11/14/2020] [Indexed: 01/13/2023] Open
Abstract
Objective Our goal was to perform detailed clinical and genomic analysis of a large multigenerational Chinese family with 21 individuals showing symptoms of Familial Cortical Myoclonic Tremor with Epilepsy (FCMTE) that we have followed for over 20 years. Methods Patients were subjected to clinical evaluation, routine EEG, and structural magnetic resonance imaging. Whole exome sequencing, repeat-primed PCR, long-range PCR, and PacBio sequencing were performed to characterize the disease-causing mutation in this family. Results All evaluated patients manifested adult-onset seizures and presented with progressive myoclonic postural tremors starting after the third or fourth decade of life. Seizures typically diminished markedly in frequency with implementation of antiseizure medications but did not completely cease. The electroencephalogram of affected individuals showed generalized or multifocal spikes and slow wave complexes. An expansion of TTTTA motifs with addition of TTTCA motifs in intron 4 of SAMD12 was identified to segregate with the disease phenotype in this family. Furthermore, we found that the mutant allele is unstable and can undergo both contraction and expansion by changes in the number of repeat motifs each time it is passed to the next generation. The size of mutant allele varied from 5 to 5.5 kb with 549-603 copies of TTTTA and 287-343 copies of TTTCA repeat motifs in this family. Significance Our study provides a detailed description of clinical progression of FCMTE symptoms and its management with antiseizure medications. Our method of repeat analysis by PacBio sequencing of long-range PCR products does not require high-quality DNA and hence can be easily applied to other families to elucidate any correlation between the repeat size and phenotypic variables, such as, age of onset, and severity of symptoms.
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Affiliation(s)
- Yongxing Zhou
- Department of NeurologyMedStar St Mary’s Hospital/Georgetown University HospitalMedStar Medical GroupLeonardtownMDUSA
| | - Raman Sood
- Translational and Functional Genomics BranchNational Human Genome Research InstituteNational Institutes of HealthBethesdaMDUSA
| | - Qun Wang
- Epilepsy CenterDepartment of NeurologyBeijing Tiantan HospitalCapital Medical UniversityBeijingChina
- China National Clinical Research Center for Neurological DiseasesBeijingChina
| | - Blake Carrington
- Translational and Functional Genomics BranchNational Human Genome Research InstituteNational Institutes of HealthBethesdaMDUSA
| | - Morgan Park
- NIH Intramural Sequencing CenterNational Human Genome Research InstituteNational Institutes of HealthRockvilleMDUSA
| | - Alice C. Young
- NIH Intramural Sequencing CenterNational Human Genome Research InstituteNational Institutes of HealthRockvilleMDUSA
| | - Daniel Birnbaum
- Department of NeurologyEinstein Medical CenterPhiladelphiaPAUSA
| | - Zhao Liu
- Division of Pediatric NeurologyChildren's Hospital of IllinoisUniversity of Illinois College of MedicineChicagoILUSA
| | - Tetsuo Ashizawa
- Houston Methodist Neurological Institute and Research InstituteHoustonTXUSA
| | - James C. Mullikin
- NIH Intramural Sequencing CenterNational Human Genome Research InstituteNational Institutes of HealthRockvilleMDUSA
| | - Mohamad Z. Koubeissi
- Epilepsy CenterDepartment of NeurologyGeorge Washington UniversityWashingtonDCUSA
| | - Paul Liu
- Translational and Functional Genomics BranchNational Human Genome Research InstituteNational Institutes of HealthBethesdaMDUSA
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Pan S, Li X, Li L, Lin H, Wang D, Zhang X, Zhao X, Ye J, Huang Z, Lin Y, Duan Y, Ma R, Gao L, Wang C, Wang Y. Comprehensive genetic, clinical and electrophysiological studies of familial cortical myoclonic tremor with epilepsy 1 highlight the role of gene configurations. Seizure 2021; 87:69-74. [PMID: 33721773 DOI: 10.1016/j.seizure.2021.02.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 02/19/2021] [Accepted: 02/21/2021] [Indexed: 01/17/2023] Open
Abstract
OBJECTIVES Two configurations of TTTTA/TTTCA expansion in SAMD12 have been identified in familial cortical myoclonic tremor with epilepsy type 1 (FCMTE1). This study investigated the clinical and neurophysiological features of FCMTE1 and their association with TTTTA/TTTCA expansion patterns. METHODS In total, 76 patients from 20 Chinese pedigrees were enrolled. Genetic (TTTTA/TTTCA configuration), clinical (e.g., onset, medication, prognosis, and anticipation) and neurophysiological examination (e.g., electroencephalogram and magnetoencephalography) data were evaluated, and associations between these parameters were analyzed. RESULTS All patients carried the TTTTA/TTTCA expansion mutation, 19 displayed the (TTTTA)exp(TTTCA)exp (type I) configuration and 1 displayed the (TTTTA)exp (TTTCA)exp(TTTTA)exp (type II) configuration. All patients manifested as progressive tremor, but symptoms of patients carrying type II expansion were more severe. The onset of tremor but not generalized tonic and clonic seizures displayed clinical anticipation between generations of 7 pedigrees, but the pedigree carrying the type II mutation did not show anticipation. Nanopore sequencing showed that the repeats expanded during maternal/offspring transmission (pedigree #7) but shrank during paternal/offspring transmission (pedigree #9). Magnetoencephalographic dipoles were localized in the right frontal lobe near the central sulcus in 4 patients carrying the type I mutation and on the left side in one patient carrying the type II mutation. SIGNIFICANCE We confirmed the causative roles played by TTTTA/TTTCA repeat expansion in the SAMD12 gene in FCTME1. Both the length and the configuration of the repeats contribute to the clinical and neurophysiological characteristics of the disease.
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Affiliation(s)
- Sipei Pan
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China; Beijing Key Laboratory of Neuromodulation, Beijing, 100053, China
| | - Xuying Li
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China
| | - Liping Li
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China
| | - Hua Lin
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China
| | - Dequan Wang
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China
| | - Xiating Zhang
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China
| | - Xin Zhao
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China
| | - Jing Ye
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China
| | - Zhaoyang Huang
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China; Beijing Key Laboratory of Neuromodulation, Beijing, 100053, China
| | - Yicong Lin
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China; Beijing Key Laboratory of Neuromodulation, Beijing, 100053, China
| | - Yiran Duan
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China; Beijing Key Laboratory of Neuromodulation, Beijing, 100053, China
| | - Rui Ma
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China; Beijing Key Laboratory of Neuromodulation, Beijing, 100053, China
| | - Lehong Gao
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China; Beijing Key Laboratory of Neuromodulation, Beijing, 100053, China.
| | - Chaodong Wang
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China; National Clinical Research Center for Geriatric Diseases, Beijing, 100053, China.
| | - Yuping Wang
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China; Beijing Key Laboratory of Neuromodulation, Beijing, 100053, China.
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Latorre A, Rocchi L, Magrinelli F, Mulroy E, Berardelli A, Rothwell JC, Bhatia KP. Unravelling the enigma of cortical tremor and other forms of cortical myoclonus. Brain 2021; 143:2653-2663. [PMID: 32417917 DOI: 10.1093/brain/awaa129] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 02/11/2020] [Accepted: 02/27/2020] [Indexed: 12/21/2022] Open
Abstract
Cortical tremor is a fine rhythmic oscillation involving distal upper limbs, linked to increased sensorimotor cortex excitability, as seen in cortical myoclonus. Cortical tremor is the hallmark feature of autosomal dominant familial cortical myoclonic tremor and epilepsy (FCMTE), a syndrome not yet officially recognized and characterized by clinical and genetic heterogeneity. Non-coding repeat expansions in different genes have been recently recognized to play an essential role in its pathogenesis. Cortical tremor is considered a rhythmic variant of cortical myoclonus and is part of the 'spectrum of cortical myoclonus', i.e. a wide range of clinical motor phenomena, from reflex myoclonus to myoclonic epilepsy, caused by abnormal sensorimotor cortical discharges. The aim of this update is to provide a detailed analysis of the mechanisms defining cortical tremor, as seen in FCMTE. After reviewing the clinical and genetic features of FCMTE, we discuss the possible mechanisms generating the distinct elements of the cortical myoclonus spectrum, and how cortical tremor fits into it. We propose that the spectrum is due to the evolution from a spatially limited focus of excitability to recruitment of more complex mechanisms capable of sustaining repetitive activity, overcoming inhibitory mechanisms that restrict excitatory bursts, and engaging wide areas of cortex. Finally, we provide evidence for a possible common denominator of the elements of the spectrum, i.e. the cerebellum, and discuss its role in FCMTE, according to recent genetic findings.
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Affiliation(s)
- Anna Latorre
- Department of Clinical and Movement Neurosciences, Queen Square Institute of Neurology, University College London, London, UK
- Department of Human Neurosciences, Sapienza University of Rome, Italy
| | - Lorenzo Rocchi
- Department of Clinical and Movement Neurosciences, Queen Square Institute of Neurology, University College London, London, UK
| | - Francesca Magrinelli
- Department of Clinical and Movement Neurosciences, Queen Square Institute of Neurology, University College London, London, UK
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Eoin Mulroy
- Department of Clinical and Movement Neurosciences, Queen Square Institute of Neurology, University College London, London, UK
| | - Alfredo Berardelli
- Department of Human Neurosciences, Sapienza University of Rome, Italy
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, Pozzilli, IS, Italy
| | - John C Rothwell
- Department of Clinical and Movement Neurosciences, Queen Square Institute of Neurology, University College London, London, UK
| | - Kailash P Bhatia
- Department of Clinical and Movement Neurosciences, Queen Square Institute of Neurology, University College London, London, UK
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Mahadevan R, Bhoyar RC, Viswanathan N, Rajagopal RE, Essaki B, Suroliya V, Chelladurai R, Sankaralingam S, Shanmugam G, Vayanakkan S, Shamim U, Mathur A, Jain A, Imran M, Faruq M, Scaria V, Sivasubbu S, Kalyanaraman S. Genomic analysis of patients in a South Indian Community with autosomal dominant cortical tremor, myoclonus and epilepsy suggests a founder repeat expansion mutation in the SAMD12 gene. Brain Commun 2021; 3:fcaa214. [PMID: 33501421 PMCID: PMC7811760 DOI: 10.1093/braincomms/fcaa214] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 10/15/2020] [Accepted: 10/25/2020] [Indexed: 12/11/2022] Open
Abstract
Autosomal Dominant Cortical Tremor, Myoclonus and Epilepsy is a non-progressive disorder characterized by distal tremors. Autosomal Dominant Cortical Tremor, Myoclonus and Epilepsy has been reported globally with different genetic predispositions of autosomal dominant inheritance with a high degree of penetrance. In south India, Autosomal Dominant Cortical Tremor, Myoclonus and Epilepsy has been reported in a large cohort of 48 families, in which the genetic defect was not identified. This report pertains to the whole-genome analysis of four individuals followed by repeat-primed PCR for 102 patients from a familial cohort of 325 individuals. All the patients underwent extensive clinical evaluation including neuropsychological examinations. The whole-genome sequencing was done for two affected and two unaffected individuals, belonging to two different families. The whole-genome sequencing analysis revealed the repeat expansion of TTTTA and TTTCA in intron 4 of the SAMD12 gene located on chromosome 8 in the patients affected with Autosomal Dominant Cortical Tremor, Myoclonus and Epilepsy, whereas the unaffected family members were negative for the similar expansion. Further, the repeat-primed PCR analysis of 102 patients showed the expansion of the TTTCA repeats in the intron 4 of SAMD12 gene. All patients registered for this study belong to a single community called “Nadar” whose nativity is confined to the southern districts of India, with reported unique genetic characteristics. This is the largest and most comprehensive single report on clinically and genetically characterized Autosomal Dominant Cortical Tremor, Myoclonus and Epilepsy patients belonging to a unique ethnic group worldwide.
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Affiliation(s)
- Radha Mahadevan
- Department of Neurology, Tirunelveli Medical College, Tirunelveli 627011, Tamil Nadu, India
| | - Rahul C Bhoyar
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi 110025, India
| | | | - Raskin Erusan Rajagopal
- Multidisciplinary Research Unit, Tirunelveli Medical College, Tirunelveli 627011, Tamil Nadu, India
| | - Bobby Essaki
- Department of Neurology, Tirunelveli Medical College, Tirunelveli 627011, Tamil Nadu, India
| | - Varun Suroliya
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi 110025, India
| | - Rachel Chelladurai
- Department of Neurology, Tirunelveli Medical College, Tirunelveli 627011, Tamil Nadu, India
| | | | | | | | - Uzma Shamim
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi 110025, India
| | - Aradhana Mathur
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi 110025, India
| | - Abhinav Jain
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi 110025, India
| | - Mohamed Imran
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi 110025, India
| | - Mohammed Faruq
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi 110025, India
| | - Vinod Scaria
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi 110025, India
| | - Sridhar Sivasubbu
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi 110025, India
| | - Shantaraman Kalyanaraman
- Multidisciplinary Research Unit, Tirunelveli Medical College, Tirunelveli 627011, Tamil Nadu, India
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Khan MI, Hariprasad G. Human Secretary Phospholipase A2 Mutations and Their Clinical Implications. J Inflamm Res 2020; 13:551-561. [PMID: 32982370 PMCID: PMC7502393 DOI: 10.2147/jir.s269557] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 08/13/2020] [Indexed: 01/05/2023] Open
Abstract
Phospholipases A2 (PLA2s) belong to a superfamily of enzymes responsible for hydrolysis of the sn-2 fatty acids of membrane phospholipids to release arachidonic acid. PLA2s are the rate limiting enzyme for the downstream synthesis of prostaglandins and leukotrienes that are the main mediators of inflammation. The extracellular forms of this enzyme are also called the secretary phospholipase A2 (sPLA2) and are distributed extensively in most of the tissues in the human body. Their integral role in inflammatory pathways has been the primary reason for the extensive research on this molecule. The catalytic mechanism of sPLA2 is initiated by a histidine/aspartic acid/calcium complex within the active site. Though they are known to have certain housekeeping functions, certain mutations of sPLA2 are known to be implicated in causation of certain pathologies leading to diseases such as atherosclerosis, cardiovascular diseases, benign fleck retina, neurodegeneration, and asthma. We present an overview of human sPLA2 and a comprehensive compilation of the mutations that result in various disease phenotypes. The study not only helps to have a holistic understanding of human sPLA2 mutations and their clinical implications, but is also a useful platform to initiate research pertaining to structure–function relationship of the mutations to develop effective therapies for management of these diseases.
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Affiliation(s)
- Mohd Imran Khan
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Gururao Hariprasad
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110029, India
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9
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Ge Y, Ding D, Zhu G, Kwan P, Wang W, Hong Z, Sander JW. Genetic variants in incident SUDEP cases from a community-based prospective cohort with epilepsy. J Neurol Neurosurg Psychiatry 2020; 91:126-131. [PMID: 31776209 DOI: 10.1136/jnnp-2019-321983] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 10/21/2019] [Accepted: 11/05/2019] [Indexed: 11/03/2022]
Abstract
OBJECTIVE Sudden unexpected death in epilepsy (SUDEP) is a leading cause of epilepsy-related mortality in young adults. It has been suggested that SUDEP may kill over 20 000 people with epilepsy in China yearly. The aetiology of SUDEP is unclear. Little is known about candidate genes for SUDEP in people of Chinese origin as most studies have ascertained this in Caucasians. No candidate genes for SUDEP in Chinese people have been identified. METHODS We performed whole exome sequencing (WES) in DNA samples collected from five incident cases of SUDEP identified in a large epilepsy cohort in rural China. We filtered rare variants identified from these cases as well as screened for SUDEP, epilepsy, heart disease or respiratory disease-related genes from previous published reports and compared them with publicly available data, living epilepsy controls and ethnicity-match non-epilepsy controls, to identify potential candidate genes for SUDEP. RESULTS After the filtering process, the five cases carried 168 qualified mutations in 167 genes. Among these genetic anomalies, we identified rare variants in SCN5A (1/5:20% in our cases), KIF6 (1/5:20% in our cases) and TBX18 (1/5:20% in our cases) which were absent in 330 living epilepsy control alleles from the same original cohort and 320 ethnicity-match non-epilepsy control alleles. CONCLUSIONS These three genes were previously related to heart disease, providing support to the hypothesis that underlying heart disorder may be a driver of SUDEP risk.
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Affiliation(s)
- Yan Ge
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China
| | - Ding Ding
- Institute of Neurology, WHO Collaborating Center for Research and Training in Neurosciences, Huashan Hospital, Fudan University, Shanghai, China
| | - Guoxing Zhu
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China
| | - Patrick Kwan
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - Wenzhi Wang
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China
| | - Zhen Hong
- Institute of Neurology, WHO Collaborating Center for Research and Training in Neurosciences, Huashan Hospital, Fudan University, Shanghai, China
| | - Josemir W Sander
- NIHR University College London Hospitals Biomedical Research Centre, UCL Queen Square Institute of Neurology, London, United Kingdom.,Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, the Netherlands
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10
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Shangguan Y, Xu X, Ganbat B, Li Y, Wang W, Yang Y, Lu X, Du C, Tian X, Wang X. CNTNAP4 Impacts Epilepsy Through GABAA Receptors Regulation: Evidence From Temporal Lobe Epilepsy Patients and Mouse Models. Cereb Cortex 2019; 28:3491-3504. [PMID: 28968899 DOI: 10.1093/cercor/bhx215] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Indexed: 12/11/2022] Open
Abstract
Epilepsy is a serious neurological condition characterized by recurrent unprovoked seizures. The exact etiology of epilepsy is not fully understood. Here, we demonstrated that the expression of contactin-associated protein-like 4 (CNTNAP4) was decreased in the temporal neocortex of epileptic patients and in the hippocampus and cortex of epileptic mice. Lentivirus-mediated knock-down of CNTNAP4 in the hippocampus increased mice susceptibility to epilepsy. Conversely, lentivirus-mediated overexpression of CNTNAP4 decreased epileptic behavior in mice. CNTNAP4 affected neuronal excitability and inhibitory synaptic transmission via postsynaptic receptors in Mg2+-free epilepsy cell model. Down-regulation or overexpression of CNTNAP4 in the hippocampus influenced the expression of gamma-aminobutyric acid A receptor β2/3 (GABAARβ2/3) membrane protein, without affecting total GABAARβ2/3 protein concentration in epileptic mice. Protein interactions between CNTNAP4, GABAARβ2/3 and gamma-aminobutyric acid receptor-associated protein (GABARAP) were observed in the hippocampus of epileptic mice. These findings suggest CNTNAP4 may be involved in the occurrence and development of epilepsy through the regulation of GABAAR function, and may be a promising target for the development of epilepsy treatment.
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Affiliation(s)
- Yafei Shangguan
- Department of Neurology, Chongqing Key Laboratory of Neurology, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Chongqing, China
| | - Xin Xu
- Department of Neurology, Chongqing Key Laboratory of Neurology, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Chongqing, China
| | - Baigalimaa Ganbat
- Department of Neurology, Chongqing Key Laboratory of Neurology, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Chongqing, China
| | - Yun Li
- Department of Neurology, Chongqing Key Laboratory of Neurology, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Chongqing, China
| | - Wei Wang
- Department of Neurology, Chongqing Key Laboratory of Neurology, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Chongqing, China
| | - Yong Yang
- Department of Neurology, Chongqing Key Laboratory of Neurology, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Chongqing, China
| | - Xi Lu
- Department of Neurology, Chongqing Key Laboratory of Neurology, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Chongqing, China
| | - Chao Du
- Department of Neurology, Chongqing Key Laboratory of Neurology, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Chongqing, China
| | - Xin Tian
- Department of Neurology, Chongqing Key Laboratory of Neurology, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Chongqing, China
| | - Xuefeng Wang
- Department of Neurology, Chongqing Key Laboratory of Neurology, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Chongqing, China
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11
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Cen Z, Jiang Z, Chen Y, Zheng X, Xie F, Yang X, Lu X, Ouyang Z, Wu H, Chen S, Yin H, Qiu X, Wang S, Ding M, Tang Y, Yu F, Li C, Wang T, Ishiura H, Tsuji S, Jiao C, Liu C, Xiao J, Luo W. Intronic pentanucleotide TTTCA repeat insertion in the SAMD12 gene causes familial cortical myoclonic tremor with epilepsy type 1. Brain 2019; 141:2280-2288. [PMID: 29939203 DOI: 10.1093/brain/awy160] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 04/18/2018] [Indexed: 12/16/2022] Open
Abstract
Familial cortical myoclonic tremor with epilepsy is an autosomal dominant neurodegenerative disease, characterized by cortical tremor and epileptic seizures. Although four subtypes (types 1-4) mapped on different chromosomes (8q24, 2p11.1-q12.2, 5p15.31-p15.1 and 3q26.32-3q28) have been reported, the causative gene has not yet been identified. Here, we report the genetic study in a cohort of 20 Chinese pedigrees with familial cortical myoclonic tremor with epilepsy. Linkage and haplotype analysis in 11 pedigrees revealed maximum two-point logarithm of the odds (LOD) scores from 1.64 to 3.77 (LOD scores in five pedigrees were >3.0) in chromosomal region 8q24 and narrowed the candidate region to an interval of 4.9 Mb. Using whole-genome sequencing, long-range polymerase chain reaction and repeat-primed polymerase chain reaction, we identified an intronic pentanucleotide (TTTCA)n insertion in the SAMD12 gene as the cause, which co-segregated with the disease among the 11 pedigrees mapped on 8q24 and additional seven unmapped pedigrees. Only two pedigrees did not contain the (TTTCA)n insertion. Repeat-primed polymerase chain reaction revealed that the sizes of (TTTCA)n insertion in all affected members were larger than 105 repeats. The same pentanucleotide insertion (ATTTCATTTC)58 has been reported to form RNA foci resulting in neurotoxicity in spinocerebellar ataxia type 37, which suggests the similar pathogenic process in familial cortical myoclonic tremor with epilepsy type 1.
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Affiliation(s)
- Zhidong Cen
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Zhengwen Jiang
- Genesky Diagnostics Inc, Biobay, SIP, Suzhou, Jiangsu, China
| | - You Chen
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiaosheng Zheng
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Intensive Care Unit, Zhejiang Hospital, Hangzhou, Zhejiang, China
| | - Fei Xie
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Department of Neurology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiaodong Yang
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Xingjiao Lu
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Department of Neurology, Zhejiang Hospital, Hangzhou, Zhejiang, China
| | - Zhiyuan Ouyang
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Hongwei Wu
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Department of Neurology, Lishui People's Hospital, Lishui, Zhejiang, China
| | - Si Chen
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Cancer Institute, Key Laboratory of Cancer Prevention and Intervention, China National Ministry of Education, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Houmin Yin
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xia Qiu
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Shuang Wang
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Meiping Ding
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yelei Tang
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Feng Yu
- Genesky Diagnostics Inc, Biobay, SIP, Suzhou, Jiangsu, China
| | - Caihua Li
- Genesky Biotechnologies Inc., Shanghai, China
| | - Tao Wang
- Genesky Biotechnologies Inc., Shanghai, China
| | - Hiroyuki Ishiura
- Department of Neurology, Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Shoji Tsuji
- Department of Molecular Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,Institute of Medical Genomics, International University of Health and Welfare, Chiba, Japan
| | - Chuan Jiao
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Chunyu Liu
- Department of Psychiatry, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Jianfeng Xiao
- Department of Neurology, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Wei Luo
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
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12
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Ji Y, Li Y, Shi C, Gao Y, Yang J, Liang D, Yang Z, Xu Y. Identification of a novel mutation in PLA2G6 gene and phenotypic heterogeneity analysis of PLA2G6-related neurodegeneration. Parkinsonism Relat Disord 2019; 65:159-164. [PMID: 31196701 DOI: 10.1016/j.parkreldis.2019.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 03/30/2019] [Accepted: 04/01/2019] [Indexed: 10/27/2022]
Abstract
INTRODUCTION This study reports a novel mutation site of the phospholipase A2 group VI (PLA2G6) gene, and analyzes the information of 67 previously published cases to elucidate PLA2G6 phenotype-genotype variations. METHODS We collected clinical data and examined gene mutation sites from one Chinese patient with adult-onset ataxia and her family. Next-generation sequencing (NGS) and Sanger sequencing were used to verify possible mutations. PolyPhen-2, SIFT, and MutationTaster were used to predict their pathogenicity. For analyzing the distribution frequency of the mutation, 597 healthy controls were recruited. We also analyzed the clinical and genetic information of 67 cases from 23 studies in Pubmed database. RESULTS A novel compound heterozygous mutation of the PLA2G6 gene, c.1648delC and c.991G > T, was found in the Chinese patient, and classified as pathogenic. The c.1648delC variation was absent in ExAC, 1000G, dbSNP databases and the 597 healthy controls. Of the 67 cases, 29 presented ataxia. The signs of cerebellar atrophy appeared in the MRIs of most patients, while signs of iron accumulation were absent in older-aged patients with a compound heterozygous mutation. Thirty-eight patients showed no ataxia. A negative or mild extrapyramidal symptom accompanied by a low age, a homogenous mutation, while moderate or severe extrapyramidal symptoms were associated with an old age and a compound heterozygous mutation. CONCLUSION A novel compound heterozygous mutation of the PLA2G6 gene, c.1648delC and c.991G > T, is associated with adult onset ataxia. Phenotype-genotype variations of PLA2G6 are predicted to be caused by the loss of protein or enzyme activity of phospholipase-2.
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Affiliation(s)
- Yan Ji
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, 450052, China
| | - Yusheng Li
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, 450052, China
| | - Changhe Shi
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, 450052, China
| | - Yuan Gao
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, 450052, China
| | - Jing Yang
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, 450052, China
| | - Dongyi Liang
- The Medical College of ZhengZhou University, Zhengzhou, Henan, 450050, China
| | - Zhihua Yang
- The Medical College of ZhengZhou University, Zhengzhou, Henan, 450050, China
| | - Yuming Xu
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, 450052, China.
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13
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Lin H, Hu N, Zhang Y, Wang Y, Macdonald RL. Whole exome sequencing reveals novel NOV and DCAF13 variants in a Chinese pedigree with familial cortical myoclonic tremor with epilepsy. Neurosci Lett 2018; 684:115-120. [PMID: 30003937 DOI: 10.1016/j.neulet.2018.07.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 07/06/2018] [Accepted: 07/07/2018] [Indexed: 11/18/2022]
Abstract
OBJECTIVE We report a large new family of familial cortical myoclonic tremor with epilepsy(FCMTE) from China and identify the possible causative gene(s) for the family. METHOD Whole exome sequencing of blood genomic DNA from 4 patients and 2 unaffected family members were performed. Detected variants and their cosegregation were confirmed by Sanger sequencing. RESULTS We identified c.20 G > C variant in the DCAF13 gene and c.983 T > C variant in the NOV gene cosegregating in the family. There was no additional cross-over in the family to narrow to one gene. The two DCAF13 and NOV gene variants are located on 8q23.3 and 8q24.12, which is consistent with the location 8q23.3-q24.13 reported previously for a group of Japanese families. The DCAF13 variant is located in alternative transcription start site(TSS) and the function of alternative TSS is unknown. The missense NOV variant is near the C terminus in a site that is highly conserved across species. It was predicted to be deleterious on protein function. CONCLUSIONS In this study, we identify two novel variants in the DCAF13 and NOV genes associated with FCMTE in Asian populations. The interval between two variants is 15.6Mb, which is very close to each other. Future studies of additional families with this phenotype are warranted to confirm whether it is rare bigenic or monogenic inheritance.
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Affiliation(s)
- Hua Lin
- Department of Neurology, XuanWu Hospital, Capital Medical University, Beijing, China.
| | - Ningning Hu
- Departments of Neurology, Vanderbilt University Medical Center, Nashville, TN USA
| | - Yanfeng Zhang
- Division of Epidemiology, Departments of Medicine, Vanderbilt University Medical Center Nashville, TN USA; HudsonAlpha Institute for Biotechnology, Huntsville, AL USA
| | - Yuping Wang
- Department of Neurology, XuanWu Hospital, Capital Medical University, Beijing, China.
| | - Robert L Macdonald
- Departments of Neurology, Vanderbilt University Medical Center, Nashville, TN USA; Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN USA; Pharmacology, Vanderbilt University Medical Center, Nashville, TN USA.
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14
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van den Ende T, Sharifi S, van der Salm SMA, van Rootselaar AF. Familial Cortical Myoclonic Tremor and Epilepsy, an Enigmatic Disorder: From Phenotypes to Pathophysiology and Genetics. A Systematic Review. Tremor Other Hyperkinet Mov (N Y) 2018; 8:503. [PMID: 29416935 PMCID: PMC5801339 DOI: 10.7916/d85155wj] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 01/02/2018] [Indexed: 02/06/2023] Open
Abstract
Background Autosomal dominant familial cortical myoclonic tremor and epilepsy (FCMTE) is characterized by distal tremulous myoclonus, generalized seizures, and signs of cortical reflex myoclonus. FCMTE has been described in over 100 pedigrees worldwide, under several different names and acronyms. Pathological changes have been located in the cerebellum. This systematic review discusses the clinical spectrum, treatment, pathophysiology, and genetic findings. Methods We carried out a PubMed search, using a combination of the following search terms: cortical tremor, myoclonus, epilepsy, benign course, adult onset, familial, and autosomal dominant; this resulted in a total of 77 studies (761 patients; 126 pedigrees) fulfilling the inclusion and exclusion criteria. Results Phenotypic differences across pedigrees exist, possibly related to underlying genetic differences. A "benign" phenotype has been described in several Japanese families and pedigrees linked to 8q (FCMTE1). French patients (5p linkage; FCMTE3) exhibit more severe progression, and in Japanese/Chinese pedigrees (with unknown linkage) anticipation has been suggested. Preferred treatment is with valproate (mind teratogenicity), levetiracetam, and/or clonazepam. Several genes have been identified, which differ in potential pathogenicity. Discussion Based on the core features (above), the syndrome can be considered a distinct clinical entity. Clinical features may also include proximal myoclonus and mild progression with aging. Valproate or levetiracetam, with or without clonazepam, reduces symptoms. FCMTE is a heterogeneous disorder, and likely to include a variety of different conditions with mutations of different genes. Distinct phenotypic traits might reflect different genetic mutations. Genes involved in Purkinje cell outgrowth or those encoding for ion channels or neurotransmitters seem good candidate genes.
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Affiliation(s)
- Tom van den Ende
- Department of Neurology and Clinical Neurophysiology, Amsterdam Neuroscience, Academic Medical Center, Amsterdam, The Netherlands
| | - Sarvi Sharifi
- Department of Neurology and Clinical Neurophysiology, Amsterdam Neuroscience, Academic Medical Center, Amsterdam, The Netherlands
| | - Sandra M. A. van der Salm
- Brain Center Rudolf Magnus, Department of Neurology and Neurosurgery, University Medical Center, Utrecht, The Netherlands
- Stichting Epilepsie Instellingen Nederland (SEIN), Zwolle, The Netherlands
| | - Anne-Fleur van Rootselaar
- Department of Neurology and Clinical Neurophysiology, Amsterdam Neuroscience, Academic Medical Center, Amsterdam, The Netherlands
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