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Liu X, Gilbert RG. Normal and abnormal glycogen structure - A review. Carbohydr Polym 2024; 338:122195. [PMID: 38763710 DOI: 10.1016/j.carbpol.2024.122195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 04/18/2024] [Accepted: 04/20/2024] [Indexed: 05/21/2024]
Abstract
Glycogen, a complex branched glucose polymer, is found in animals and bacteria, where it serves as an energy storage molecule. It has linear (1 → 4)-α glycosidic bonds between anhydroglucose monomer units, with branch points connected by (1 → 6)-α bonds. Individual glycogen molecules are referred to as β particles. In organs like the liver and heart, these β particles can bind into larger aggregate α particles, which exhibit a rosette-like morphology. The mechanisms and bonding underlying the aggregation process are not fully understood. For example, mammalian liver glycogen has been observed to be molecularly fragile under certain conditions, such as glycogen from diabetic livers fragmenting when exposed to dimethyl sulfoxide (DMSO), while glycogen from healthy livers is much less fragile; this indicates some difference, as yet unknown, in the bonding between β particles in healthy and diabetic glycogen. This fragility may have implications for blood sugar regulation, especially in pathological conditions such as diabetes.
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Affiliation(s)
- Xin Liu
- Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Zhongshan Biological Breeding Laboratory, and Jiangsu Key Laboratory of Crop Genetics and Physiology, College of Agriculture, Yangzhou University, Yangzhou 225009, China; Centre for Nutrition & Food Sciences, Queensland Alliance for Agriculture & Food Innovations (QAAFI), The University of Queensland, QLD 4072, Australia
| | - Robert G Gilbert
- Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Zhongshan Biological Breeding Laboratory, and Jiangsu Key Laboratory of Crop Genetics and Physiology, College of Agriculture, Yangzhou University, Yangzhou 225009, China; Centre for Nutrition & Food Sciences, Queensland Alliance for Agriculture & Food Innovations (QAAFI), The University of Queensland, QLD 4072, Australia.
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2
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Skurat AV, Segvich DM, Contreras CJ, Hu YC, Hurley TD, DePaoli-Roach AA, Roach PJ. Impaired malin expression and interaction with partner proteins in Lafora disease. J Biol Chem 2024; 300:107271. [PMID: 38588813 PMCID: PMC11063907 DOI: 10.1016/j.jbc.2024.107271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 03/25/2024] [Accepted: 03/27/2024] [Indexed: 04/10/2024] Open
Abstract
Lafora disease (LD) is an autosomal recessive myoclonus epilepsy with onset in the teenage years leading to death within a decade of onset. LD is characterized by the overaccumulation of hyperphosphorylated, poorly branched, insoluble, glycogen-like polymers called Lafora bodies. The disease is caused by mutations in either EPM2A, encoding laforin, a dual specificity phosphatase that dephosphorylates glycogen, or EMP2B, encoding malin, an E3-ubiquitin ligase. While glycogen is a widely accepted laforin substrate, substrates for malin have been difficult to identify partly due to the lack of malin antibodies able to detect malin in vivo. Here we describe a mouse model in which the malin gene is modified at the C-terminus to contain the c-myc tag sequence, making an expression of malin-myc readily detectable. Mass spectrometry analyses of immunoprecipitates using c-myc tag antibodies demonstrate that malin interacts with laforin and several glycogen-metabolizing enzymes. To investigate the role of laforin in these interactions we analyzed two additional mouse models: malin-myc/laforin knockout and malin-myc/LaforinCS, where laforin was either absent or the catalytic Cys was genomically mutated to Ser, respectively. The interaction of malin with partner proteins requires laforin but is not dependent on its catalytic activity or the presence of glycogen. Overall, the results demonstrate that laforin and malin form a complex in vivo, which stabilizes malin and enhances interaction with partner proteins to facilitate normal glycogen metabolism. They also provide insights into the development of LD and the rescue of the disease by the catalytically inactive phosphatase.
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Affiliation(s)
- Alexander V Skurat
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Lafora Epilepsy Cure Initiative, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Dyann M Segvich
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Lafora Epilepsy Cure Initiative, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Christopher J Contreras
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Lafora Epilepsy Cure Initiative, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Yueh-Chiang Hu
- Division of Developmental Biology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Thomas D Hurley
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Lafora Epilepsy Cure Initiative, University of Kentucky College of Medicine, Lexington, Kentucky, USA.
| | - Anna A DePaoli-Roach
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Lafora Epilepsy Cure Initiative, University of Kentucky College of Medicine, Lexington, Kentucky, USA.
| | - Peter J Roach
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Lafora Epilepsy Cure Initiative, University of Kentucky College of Medicine, Lexington, Kentucky, USA
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3
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Jose M, Fasaludeen A, Pavuluri H, Rudrabhatla PK, Chandrasekharan SV, Jose J, Banerjee M, Sundaram S, Radhakrishnan A, Menon RN. Metabolic causes of pediatric developmental & epileptic encephalopathies (DEE)- genetic variant analysis in a south Indian cohort. Seizure 2024; 115:20-27. [PMID: 38183824 DOI: 10.1016/j.seizure.2023.12.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 12/12/2023] [Accepted: 12/25/2023] [Indexed: 01/08/2024] Open
Abstract
PURPOSE Drug-resistant epilepsy is seen in patients with inborn errors of metabolism and metabolic dysfunction in neurons is crucial to brain disorders associated with psychomotor impairment. Diagnostic rates of metabolic causes of developmental and epileptic encephalopathy (DEE) using next generation sequencing have been rarely studied in literature. METHODS A prospective hospital study was carried out in 384 children with DEE, who underwent genetic testing. Metabolic disorders were evaluated with biochemical blood/urine assays and when required CSF estimations performed. RESULTS A total of 154 pathogenic/likely pathogenic variants in 384 children were identified. Out of 384 children, 89 were clinically suspected to have probable or possible metabolic disorders. Pathogenic/likely pathogenic variants in metabolic genes were identified in 39 out of 89 (43.8 %) and promising VUS in 28 (31.4 %). These included variants for progressive myoclonus epilepsies (21; 53.8 %), DEE with focal/multifocal seizures (8; 20.5 %), generalized epilepsy (5;12.8 %), early myoclonic encephalopathy (2; 5.1 %), LGS (1; 2.6 %) and West syndrome (2; 5.1 %). CONCLUSION Our cohort demonstrates for the first time from the Indian subcontinent that identification of metabolic variants can guide investigations and has therapeutic implications in patients with variable DEE phenotypes. A high utility is noted with regard to diagnosis and prognostication, given the low yield of available biochemical tests, indicating cost-effectiveness of this approach.
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Affiliation(s)
- Manna Jose
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
| | - Alfiya Fasaludeen
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
| | - Harini Pavuluri
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
| | - Pavan Kumar Rudrabhatla
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
| | - Soumya V Chandrasekharan
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
| | - Jithu Jose
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
| | - Moinak Banerjee
- Human Molecular Genetics Laboratory, Rajiv Gandhi Centre for Biotechnology, Trivandrum, Kerala, India
| | - Soumya Sundaram
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
| | - Ashalatha Radhakrishnan
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
| | - Ramshekhar N Menon
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India.
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4
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Bernardi S, Gemignani F, Marchese M. The involvement of Purkinje cells in progressive myoclonic epilepsy: Focus on neuronal ceroid lipofuscinosis. Neurobiol Dis 2023; 185:106258. [PMID: 37573956 PMCID: PMC10480493 DOI: 10.1016/j.nbd.2023.106258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 08/01/2023] [Accepted: 08/11/2023] [Indexed: 08/15/2023] Open
Abstract
The progressive myoclonic epilepsies (PMEs) are a group of rare neurodegenerative diseases characterized by myoclonus, epileptic seizures, and progressive neurological deterioration with cerebellar involvement. They include storage diseases like Gaucher disease, Lafora disease, and forms of neuronal ceroid lipofuscinosis (NCL). To date, 13 NCLs have been reported (CLN1-CLN8, CLN10-CLN14), associated with mutations in different genes. These forms, which affect both children and adults, are characterized by seizures, cognitive and motor impairments, and in most cases visual loss. In NCLs, as in other PMEs, central nervous system (CNS) neurodegeneration is widespread and involves different subpopulations of neurons. One of the most affected regions is the cerebellar cortex, where motor and non-motor information is processed and transmitted to deep cerebellar nuclei through the axons of Purkinje cells (PCs). PCs, being GABAergic, have an inhibitory effect on their target neurons, and provide the only inhibitory output of the cerebellum. Degeneration of PCs has been linked to motor impairments and epileptic seizures. Seizures occur when some insult upsets the normal balance in the CNS between excitatory and inhibitory impulses, causing hyperexcitability. Here we review the role of PCs in epilepsy onset and progression following their PME-related loss. In particular, we focus on the involvement of PCs in seizure phenotype in NCLs, highlighting findings from case reports and studies of animal models in which epilepsy can be linked to PC loss.
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Affiliation(s)
- Sara Bernardi
- Department Neurobiology and Molecular Medicine, IRCCS Fondazione Stella Maris, 56128 Pisa, Italy; Department of Biology, University of Pisa, Pisa, Italy
| | | | - Maria Marchese
- Department Neurobiology and Molecular Medicine, IRCCS Fondazione Stella Maris, 56128 Pisa, Italy.
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5
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Franceschetti S, Visani E, Panzica F, Coppola A, Striano P, Canafoglia L. Cortico-muscular coherence and brain networks in familial adult myoclonic epilepsy and progressive myoclonic epilepsy. Clin Neurophysiol 2023; 151:74-82. [PMID: 37216715 DOI: 10.1016/j.clinph.2023.04.009] [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: 01/25/2023] [Revised: 03/12/2023] [Accepted: 04/24/2023] [Indexed: 05/24/2023]
Abstract
OBJECTIVE Familial Adult Myoclonic Epilepsy (FAME) presents with action-activated myoclonus, often associated with epilepsy, sharing various features with Progressive Myoclonic Epilepsy (PMEs), but with slower course and limited motor disability. We aimed our study to identify measures suitable to explain the different severity of FAME2 compared to EPM1, the most common PME, and to detect the signature of the distinctive brain networks. METHODS We analyzed the EEG-EMG coherence (CMC) during segmental motor activity and indexes of connectivity in the two patient groups, and in healthy subjects (HS). We also investigated the regional and global properties of the network. RESULTS In FAME2, differently from EPM1, we found a well-localized distribution of beta-CMC and increased betweenness-centrality (BC) on the sensorimotor region contralateral to the activated hand. In both patient groups, compared to HS, there was a decline in the network connectivity indexes in the beta and gamma band, which was more obvious in FAME2. CONCLUSIONS In FAME2, better localized CMC and increased BC in comparison with EPM1 patients could counteract the severity and the spreading of the myoclonus. Decreased indexes of cortical integration were more severe in FAME2. SIGNIFICANCE Our measures correlated with different motor disabilities and identified distinctive brain network impairments.
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Affiliation(s)
- Silvana Franceschetti
- Neurophysiopathology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.
| | - Elisa Visani
- Bioengineering Unit, Dept. of Diagnostic and Technology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.
| | - Ferruccio Panzica
- Clinical Engineering, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.
| | - Antonietta Coppola
- Department of Neuroscience, Odontostomatology and Reproductive Sciences, Federico II, University of Naples, Napoli, Italy
| | - Pasquale Striano
- IRCCS Istituto "Giannina Gaslini", Genova, Italy; Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Genova, Italy
| | - Laura Canafoglia
- Integrated Diagnostics for Epilepsy, Dept of Diagnostic and Technology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.
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6
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Younger DS. Neurogenetic motor disorders. HANDBOOK OF CLINICAL NEUROLOGY 2023; 195:183-250. [PMID: 37562870 DOI: 10.1016/b978-0-323-98818-6.00003-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Advances in the field of neurogenetics have practical applications in rapid diagnosis on blood and body fluids to extract DNA, obviating the need for invasive investigations. The ability to obtain a presymptomatic diagnosis through genetic screening and biomarkers can be a guide to life-saving disease-modifying therapy or enzyme replacement therapy to compensate for the deficient disease-causing enzyme. The benefits of a comprehensive neurogenetic evaluation extend to family members in whom identification of the causal gene defect ensures carrier detection and at-risk counseling for future generations. This chapter explores the many facets of the neurogenetic evaluation in adult and pediatric motor disorders as a primer for later chapters in this volume and a roadmap for the future applications of genetics in neurology.
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Affiliation(s)
- David S Younger
- Department of Clinical Medicine and Neuroscience, CUNY School of Medicine, New York, NY, United States; Department of Medicine, Section of Internal Medicine and Neurology, White Plains Hospital, White Plains, NY, United States.
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7
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Progressive myoclonic epilepsies—English Version. ZEITSCHRIFT FÜR EPILEPTOLOGIE 2022. [DOI: 10.1007/s10309-022-00546-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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8
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Farajzadeh Valilou S, Karimzad Hagh J, Salimi Asl M, Abdi Rad I, Edizadeh M, Pooladi A. A novel biallelic LMNB2 variant in a patient with progressive myoclonus epilepsy and ataxia: A case of laminopathy. Clin Case Rep 2021; 9:e04520. [PMID: 34466237 PMCID: PMC8381754 DOI: 10.1002/ccr3.4520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 05/20/2021] [Accepted: 05/30/2021] [Indexed: 12/26/2022] Open
Abstract
The report of LMNB2-related progressive myoclonus epilepsy and ataxia due to missense homozygous c.473G>T variant.
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Affiliation(s)
- Saeed Farajzadeh Valilou
- Department of Medical Genetics and Sarem Cell Research Center (SCRC)Sarem Womens' HospitalTehranIran
- Medical Genetics Network (MeGeNe)Universal Scientific Education and Research Network (USERN)TehranIran
| | - Javad Karimzad Hagh
- Department of Medical Genetics and Sarem Cell Research Center (SCRC)Sarem Womens' HospitalTehranIran
- IVF CenterCuypers & Cuypers Fertility Center Heinsberger HöfeHeinsbergGermany
| | - Mohammad Salimi Asl
- Department of Medical Genetics and Sarem Cell Research Center (SCRC)Sarem Womens' HospitalTehranIran
| | - Isa Abdi Rad
- Departament of Medical GeneticsSchool of MedicineUrmia University of Medical SciencesUrmiaIran
| | - Masoud Edizadeh
- Biotechnology DepartmentSchool of MedicineLorestan University of Medical SciencesKhorramabadLorestanIran
| | - Arash Pooladi
- Cancer and Immunology Research CenterResearch Institute for Health DevelopmentKurdistan University of Medical SciencesSanandajIran
- Department of Medical GeneticsFaculty of MedicineKurdistan University of Medical SciencesSanandajIran
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9
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Mizuguchi T, Toyota T, Miyatake S, Mitsuhashi S, Doi H, Kudo Y, Kishida H, Hayashi N, Tsuburaya RS, Kinoshita M, Fukuyama T, Fukuda H, Koshimizu E, Tsuchida N, Uchiyama Y, Fujita A, Takata A, Miyake N, Kato M, Tanaka F, Adachi H, Matsumoto N. Complete sequencing of expanded SAMD12 repeats by long-read sequencing and Cas9-mediated enrichment. Brain 2021; 144:1103-1117. [PMID: 33791773 DOI: 10.1093/brain/awab021] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 11/02/2020] [Accepted: 11/17/2020] [Indexed: 11/14/2022] Open
Abstract
A pentanucleotide TTTCA repeat insertion into a polymorphic TTTTA repeat element in SAMD12 causes benign adult familial myoclonic epilepsy. Although the precise determination of the entire SAMD12 repeat sequence is important for molecular diagnosis and research, obtaining this sequence remains challenging when using conventional genomic/genetic methods, and even short-read and long-read next-generation sequencing technologies have been insufficient. Incomplete information regarding expanded repeat sequences may hamper our understanding of the pathogenic roles played by varying numbers of repeat units, genotype-phenotype correlations, and mutational mechanisms. Here, we report a new approach for the precise determination of the entire expanded repeat sequence and present a workflow designed to improve the diagnostic rates in various repeat expansion diseases. We examined 34 clinically diagnosed benign adult familial myoclonic epilepsy patients, from 29 families using repeat-primed PCR, Southern blot, and long-read sequencing with Cas9-mediated enrichment. Two cases with questionable results from repeat-primed PCR and/or Southern blot were confirmed as pathogenic using long-read sequencing with Cas9-mediated enrichment, resulting in the identification of pathogenic SAMD12 repeat expansions in 76% of examined families (22/29). Importantly, long-read sequencing with Cas9-mediated enrichment was able to provide detailed information regarding the sizes, configurations, and compositions of the expanded repeats. The inserted TTTCA repeat size and the proportion of TTTCA sequences among the overall repeat sequences were highly variable, and a novel repeat configuration was identified. A genotype-phenotype correlation study suggested that the insertion of even short (TTTCA)14 repeats contributed to the development of benign adult familial myoclonic epilepsy. However, the sizes of the overall TTTTA and TTTCA repeat units are also likely to be involved in the pathology of benign adult familial myoclonic epilepsy. Seven unsolved SAMD12-negative cases were investigated using whole-genome long-read sequencing, and infrequent, disease-associated, repeat expansions were identified in two cases. The strategic workflow resolved two questionable SAMD12-positive cases and two previously SAMD12-negative cases, increasing the diagnostic yield from 69% (20/29 families) to 83% (24/29 families). This study indicates the significant utility of long-read sequencing technologies to explore the pathogenic contributions made by various repeat units in complex repeat expansions and to improve the overall diagnostic rate.
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Affiliation(s)
- Takeshi Mizuguchi
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Tomoko Toyota
- Department of Neurology, University of Occupational and Environmental Health School of Medicine, Kitakyushu 807-8555, Japan
| | - Satoko Miyatake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan.,Clinical Genetics Department, Yokohama City University Hospital, Yokohama 236-0004, Japan
| | - Satomi Mitsuhashi
- Department of Genomic Function and Diversity, Medical Research Institute Tokyo Medical and Dental University, Tokyo 113-8510, Japan
| | - Hiroshi Doi
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Yosuke Kudo
- Department of Neurology, Yokohama Brain and Spine Center, Yokohama 235-0012, Japan
| | - Hitaru Kishida
- Department of Neurology, Yokohama City University Medical Center, Yokohama 232-0024, Japan
| | - Noriko Hayashi
- Department of Neurology, Yamato Municipal Hospital, Yamato 242-8602, Japan
| | - Rie S Tsuburaya
- Department of Pediatric Neurology, National Hospital Organization Utano National Hospital, Kyoto 616-8255, Japan
| | - Masako Kinoshita
- Department of Neurology, National Hospital Organization Utano National Hospital, Kyoto 616-8255, Japan
| | - Tetsuhiro Fukuyama
- Department of Pediatrics, Shinshu University School of Medicine, Matsumoto 390-8621, Japan
| | - Hiromi Fukuda
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan.,Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Eriko Koshimizu
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Naomi Tsuchida
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Yuri Uchiyama
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Atsushi Fujita
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Atsushi Takata
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Noriko Miyake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Mitsuhiro Kato
- Department of Pediatrics, Showa University School of Medicine, Tokyo 142-8666, Japan
| | - Fumiaki Tanaka
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Hiroaki Adachi
- Department of Neurology, University of Occupational and Environmental Health School of Medicine, Kitakyushu 807-8555, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
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10
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Courage C, Oliver KL, Park EJ, Cameron JM, Grabińska KA, Muona M, Canafoglia L, Gambardella A, Said E, Afawi Z, Baykan B, Brandt C, di Bonaventura C, Chew HB, Criscuolo C, Dibbens LM, Castellotti B, Riguzzi P, Labate A, Filla A, Giallonardo AT, Berecki G, Jackson CB, Joensuu T, Damiano JA, Kivity S, Korczyn A, Palotie A, Striano P, Uccellini D, Giuliano L, Andermann E, Scheffer IE, Michelucci R, Bahlo M, Franceschetti S, Sessa WC, Berkovic SF, Lehesjoki AE. Progressive myoclonus epilepsies-Residual unsolved cases have marked genetic heterogeneity including dolichol-dependent protein glycosylation pathway genes. Am J Hum Genet 2021; 108:722-738. [PMID: 33798445 DOI: 10.1016/j.ajhg.2021.03.013] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 03/05/2021] [Indexed: 02/04/2023] Open
Abstract
Progressive myoclonus epilepsies (PMEs) comprise a group of clinically and genetically heterogeneous rare diseases. Over 70% of PME cases can now be molecularly solved. Known PME genes encode a variety of proteins, many involved in lysosomal and endosomal function. We performed whole-exome sequencing (WES) in 84 (78 unrelated) unsolved PME-affected individuals, with or without additional family members, to discover novel causes. We identified likely disease-causing variants in 24 out of 78 (31%) unrelated individuals, despite previous genetic analyses. The diagnostic yield was significantly higher for individuals studied as trios or families (14/28) versus singletons (10/50) (OR = 3.9, p value = 0.01, Fisher's exact test). The 24 likely solved cases of PME involved 18 genes. First, we found and functionally validated five heterozygous variants in NUS1 and DHDDS and a homozygous variant in ALG10, with no previous disease associations. All three genes are involved in dolichol-dependent protein glycosylation, a pathway not previously implicated in PME. Second, we independently validate SEMA6B as a dominant PME gene in two unrelated individuals. Third, in five families, we identified variants in established PME genes; three with intronic or copy-number changes (CLN6, GBA, NEU1) and two very rare causes (ASAH1, CERS1). Fourth, we found a group of genes usually associated with developmental and epileptic encephalopathies, but here, remarkably, presenting as PME, with or without prior developmental delay. Our systematic analysis of these cases suggests that the small residuum of unsolved cases will most likely be a collection of very rare, genetically heterogeneous etiologies.
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Affiliation(s)
- Carolina Courage
- Folkhälsan Research Center, Helsinki 00290, Finland; Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki 00290, Finland
| | - Karen L Oliver
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg 3084, Victoria, Australia; Population Health and Immunity Division, the Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; Department of Medical Biology, the University of Melbourne, Melbourne, VIC 3010, Australia
| | - Eon Joo Park
- Department of Pharmacology and Vascular Biology and Therapeutics Program, Yale University School of Medicine, 10 Amistad Street, New Haven, CT 06520, USA
| | - Jillian M Cameron
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg 3084, Victoria, Australia
| | - Kariona A Grabińska
- Department of Pharmacology and Vascular Biology and Therapeutics Program, Yale University School of Medicine, 10 Amistad Street, New Haven, CT 06520, USA
| | - Mikko Muona
- Folkhälsan Research Center, Helsinki 00290, Finland; Blueprint Genetics, Espoo 02150, Finland
| | - Laura Canafoglia
- Neurophysiopathology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan 20133, Italy
| | | | - Edith Said
- Section of Medical Genetics, Mater dei Hospital, Msida MSD2090, Malta; Department of Anatomy and Cell Biology, University of Malta, Msida MSD2090, Malta
| | - Zaid Afawi
- Center for Neuroscience, Ben-Gurion University of the Negev, Be'er Sheva 8410402, Israel
| | - Betul Baykan
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul 34452, Turkey
| | | | - Carlo di Bonaventura
- Department of Human Neurosciences, Sapienza University of Rome, Viale dell'Università, 30, 00185 Rome, Italy
| | - Hui Bein Chew
- Genetics Department, Kuala Lumpur Hospital, Ministry of Health Malaysia, Jalan Pahang, 50586 Kuala Lumpur, Malaysia
| | - Chiara Criscuolo
- Department of Neuroscience, Reproductive, and Odontostomatological Sciences, University of Naples Federico II, Naples 80138, Italy
| | - Leanne M Dibbens
- Epilepsy Research Group, Australian Centre for Precision Health, UniSA Clinical and Health Sciences, University of South Australia, Adelaide, SA 5000, Australia
| | - Barbara Castellotti
- Unit of Genetics of Neurodegenerative and Metabolic Diseases, IRCCS Istituto Neurologico Carlo Besta Milan 20133, Italy
| | - Patrizia Riguzzi
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Unit of Neurology, Bellaria Hospital, Bologna 40139, Italy
| | - Angelo Labate
- Institute of Neurology, University Magna Græcia, Catanzaro 88100, Italy
| | - Alessandro Filla
- Department of Neuroscience, Reproductive, and Odontostomatological Sciences, University of Naples Federico II, Naples 80138, Italy
| | - Anna T Giallonardo
- Neurology Unit, Human Neurosciences Department, Sapienza University, Rome 00185, Italy
| | - Geza Berecki
- Ion Channels and Disease Group, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC 3052, Australia
| | - Christopher B Jackson
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
| | | | - John A Damiano
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg 3084, Victoria, Australia
| | - Sara Kivity
- Epilepsy Unit, Schneider Children's Medical Center of Israel, Petah Tiqvah 4922297, Israel
| | - Amos Korczyn
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 60198, Israel
| | - Aarno Palotie
- Institute for Molecular Medicine Finland (FIMM), HiLIFE, University of Helsinki, Helsinki 00290, Finland; Analytic and Translational Genetics Unit, Department of Medicine, Department of Neurology and Department of Psychiatry Massachusetts General Hospital, Boston, MA 02114, USA; The Stanley Center for Psychiatric Research and Program in Medical and Population Genetics, The Broad Institute of MIT and Harvard, Cambridge, Boston, MA 02142, USA
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto "G. Gaslini," Genova 16147, Italy
| | - Davide Uccellini
- Neurology - Neurophysiology Unit, ASST dei Sette Laghi, Galmarini Tradate Hospital, Tradate 21049, Italy
| | - Loretta Giuliano
- Dipartimento "G.F. Ingrassia," Università degli Studi di Catania, Catania 95131, Italy
| | - Eva Andermann
- Neurogenetics Unit and Epilepsy Research Group, Montreal Neurological Hospital and Institute, Montreal, QC H3A 2B4, Canada; Departments of Neurology & Neurosurgery and Human Genetics, McGill University, Montreal, QC H3A 0G4, Canada
| | - Ingrid E Scheffer
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg 3084, Victoria, Australia; Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC 3052, Australia; Department of Paediatrics, The University of Melbourne, Royal Children's Hospital, Parkville, VIC 3052, Australia; The Florey Institute, Parkville, VIC 3052, Australia
| | - Roberto Michelucci
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Unit of Neurology, Bellaria Hospital, Bologna 40139, Italy
| | - Melanie Bahlo
- Population Health and Immunity Division, the Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; Department of Medical Biology, the University of Melbourne, Melbourne, VIC 3010, Australia
| | - Silvana Franceschetti
- Neurophysiopathology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan 20133, Italy
| | - William C Sessa
- Department of Pharmacology and Vascular Biology and Therapeutics Program, Yale University School of Medicine, 10 Amistad Street, New Haven, CT 06520, USA
| | - Samuel F Berkovic
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg 3084, Victoria, Australia.
| | - Anna-Elina Lehesjoki
- Folkhälsan Research Center, Helsinki 00290, Finland; Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki 00290, Finland.
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11
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Dudipala SC, M P, Chennadi AK. A Novel Mutation in KCDT7 Gene in an Indian Girl With Progressive Myoclonus Epilepsy. Cureus 2021; 13:e13447. [PMID: 33767931 PMCID: PMC7982382 DOI: 10.7759/cureus.13447] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The progressive myoclonus epilepsy (PME) is a rare group of clinically and genetically heterogeneous disorders characterized by myoclonus, drug refractory epilepsy, and neurological deterioration. Here, we report a three-year-old female patient with neuroregression after a period of normal development and uncontrollable myoclonic seizures, which fulfill the criteria of PME. Next-generation sequencing revealed a novel homozygous mutation of variant c.173G>C in exon 2 of the KCDT7 (potassium channel tetramerization domain containing protein 7) gene that was compatible with the diagnosis of progressive myoclonic epilepsy 3 (PME3) with or without intracellular inclusions. This is a rare report of KCTD7 mutations causing PME in the Indian population. Our findings supported the important role of KCTD7 in PME and broadened the mutation spectrum.
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Affiliation(s)
- Sai Chandar Dudipala
- Pediatric Neurology, Star Women & Children Hospital, Karimnagar, IND.,Pediatrics, Prathima Institute of Medical Sciences, Karimnagar, IND
| | - Prashanthi M
- Pediatrics, Prathima Institute of Medical Sciences, Karimnagar, IND
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12
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Hirose S, Tanaka Y, Shibata M, Kimura Y, Ishikawa M, Higurashi N, Yamamoto T, Ichise E, Chiyonobu T, Ishii A. Application of induced pluripotent stem cells in epilepsy. Mol Cell Neurosci 2020; 108:103535. [DOI: 10.1016/j.mcn.2020.103535] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 07/10/2020] [Accepted: 07/31/2020] [Indexed: 02/06/2023] Open
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13
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Poeta L, Drongitis D, Verrillo L, Miano MG. DNA Hypermethylation and Unstable Repeat Diseases: A Paradigm of Transcriptional Silencing to Decipher the Basis of Pathogenic Mechanisms. Genes (Basel) 2020; 11:E684. [PMID: 32580525 PMCID: PMC7348995 DOI: 10.3390/genes11060684] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 06/18/2020] [Accepted: 06/19/2020] [Indexed: 12/12/2022] Open
Abstract
Unstable repeat disorders comprise a variable group of incurable human neurological and neuromuscular diseases caused by an increase in the copy number of tandem repeats located in various regions of their resident genes. It has become clear that dense DNA methylation in hyperexpanded non-coding repeats induces transcriptional silencing and, subsequently, insufficient protein synthesis. However, the ramifications of this paradigm reveal a far more profound role in disease pathogenesis. This review will summarize the significant progress made in a subset of non-coding repeat diseases demonstrating the role of dense landscapes of 5-methylcytosine (5mC) as a common disease modifier. However, the emerging findings suggest context-dependent models of 5mC-mediated silencing with distinct effects of excessive DNA methylation. An in-depth understanding of the molecular mechanisms underlying this peculiar group of human diseases constitutes a prerequisite that could help to discover novel pathogenic repeat loci, as well as to determine potential therapeutic targets. In this regard, we report on a brief description of advanced strategies in DNA methylation profiling for the identification of unstable Guanine-Cytosine (GC)-rich regions and on promising examples of molecular targeted therapies for Fragile X disease (FXS) and Friedrich ataxia (FRDA) that could pave the way for the application of this technique in other hypermethylated expansion disorders.
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Affiliation(s)
- Loredana Poeta
- Institute of Genetics and Biophysics “Adriano Buzzati-Traverso”, CNR, 80131 Naples, Italy; (L.P.); (D.D.); (L.V.)
| | - Denise Drongitis
- Institute of Genetics and Biophysics “Adriano Buzzati-Traverso”, CNR, 80131 Naples, Italy; (L.P.); (D.D.); (L.V.)
| | - Lucia Verrillo
- Institute of Genetics and Biophysics “Adriano Buzzati-Traverso”, CNR, 80131 Naples, Italy; (L.P.); (D.D.); (L.V.)
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, 81100 Caserta, Italy
| | - Maria Giuseppina Miano
- Institute of Genetics and Biophysics “Adriano Buzzati-Traverso”, CNR, 80131 Naples, Italy; (L.P.); (D.D.); (L.V.)
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14
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Exome sequencing identifies compound heterozygous KCTD7 mutations in a girl with progressivemyoclonus epilepsy. Clin Chim Acta 2019; 493:87-91. [DOI: 10.1016/j.cca.2019.02.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 02/13/2019] [Accepted: 02/27/2019] [Indexed: 12/31/2022]
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15
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Arntsen V, Strandheim J, Helland IB, Sand T, Brodtkorb E. Epileptological aspects of juvenile neuronal ceroid lipofuscinosis (CLN3 disease) through the lifespan. Epilepsy Behav 2019; 94:59-64. [PMID: 30884409 DOI: 10.1016/j.yebeh.2019.02.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 02/22/2019] [Accepted: 02/22/2019] [Indexed: 02/06/2023]
Abstract
PURPOSE Juvenile neuronal ceroid lipofuscinosis (CLN3 disease) is the most common neurodegenerative disorder in childhood with survival until young adult age. Visual loss is followed by epilepsy, cognitive, neuropsychiatric, and motor symptoms. We have studied the evolution of electroencephalographic (EEG) and seizure characteristics. METHODS Twenty-four patients were recruited via the Norwegian CLN3 disease parent association. Parents were interviewed. Medical records and EEG reports/recordings were collected. Electroencephalographic elements were classified according to Standardized computer-based organized reporting of EEG (SCORE). The evolution of EEG features along with seizure types was assessed by testing the difference in proportions with standardized normal deviate comparing findings below and above 15 years of age. RESULTS Mean age at study or death (n = 12) was 21.2 (10-39) years. Twenty-two patients had experienced seizures; the first was usually bilateral tonic-clonic (TC). Later, focal motor seizures frequently occurred, often with increasing multifocal and polymorphic features. Paroxysmal nonepileptic motor and autonomous symptoms were also suspected in several patients. Distinct myoclonic seizures were uncommon. In four patients, we identified episodes of bradycardia/sinus arrest. Electroencephalography showed progressive slowing of the background activity (p = 0.029). Focal epileptiform discharges were rare and mainly seen at age <10. Combined multifocal and bilateral epileptiform discharges increased in adolescence (p = 0.002). CONCLUSION Seizure and EEG characteristics change with time in CLN3 disease. Tonic-clonic seizures are common at onset, and multifocal motor seizures increase with age. In contrast, focal epileptiform abnormalities are more common in childhood, compared to later multifocal and bilateral discharges. This seizure disorder belongs to the combined generalized and focal epilepsies. Paucity of myoclonic seizures does not warrant classification as a classic progressive myoclonic epilepsy. When attacks with only behavior arrest occur, cardiac conduction abnormalities should be considered.
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Affiliation(s)
- Vibeke Arntsen
- Department of Neurology and Clinical Neurophysiology, St. Olav's University Hospital, Trondheim, Norway.
| | - John Strandheim
- Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway; Hemne Health Centre, Kyrksæterøra, Norway
| | - Ingrid B Helland
- Department of Clinical Neurosciences for Children, Rikshospitalet, Oslo University Hospital, Norway
| | - Trond Sand
- Department of Neurology and Clinical Neurophysiology, St. Olav's University Hospital, Trondheim, Norway; Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Eylert Brodtkorb
- Department of Neurology and Clinical Neurophysiology, St. Olav's University Hospital, Trondheim, Norway; Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
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16
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Hor CHH, Tang BL. Beta-propeller protein-associated neurodegeneration (BPAN) as a genetically simple model of multifaceted neuropathology resulting from defects in autophagy. Rev Neurosci 2019; 30:261-277. [DOI: 10.1515/revneuro-2018-0045] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 07/07/2018] [Indexed: 12/13/2022]
Abstract
AbstractAutophagy is an essential and conserved cellular homeostatic process. Defects in the core and accessory components of the autophagic machinery would most severely impact terminally differentiated cells, such as neurons. The neurodevelopmental/neurodegenerative disorder β-propeller protein-associated neurodegeneration (BPAN) resulted from heterozygous or hemizygous germline mutations/pathogenic variant of the X chromosome geneWDR45, encoding WD40 repeat protein interacting with phosphoinositides 4 (WIPI4). This most recently identified subtype of the spectrum of neurodegeneration with brain iron accumulation diseases is characterized by a biphasic mode of disease manifestation and progression. The first phase involves early-onset of epileptic seizures, global developmental delay, intellectual disability and autistic syndrome. Subsequently, Parkinsonism and dystonia, as well as dementia, emerge in a subacute manner in adolescence or early adulthood. BPAN disease phenotypes are thus complex and linked to a wide range of other neuropathological disorders. WIPI4/WDR45 has an essential role in autophagy, acting as a phosphatidylinositol 3-phosphate binding effector that participates in autophagosome biogenesis and size control. Here, we discuss recent updates on WIPI4’s mechanistic role in autophagy and link the neuropathological manifestations of BPAN’s biphasic infantile onset (epilepsy, autism) and adolescent onset (dystonic, Parkinsonism, dementia) phenotypes to neurological consequences of autophagy impairment that are now known or emerging in many other neurodevelopmental and neurodegenerative disorders. As monogenicWDR45mutations in BPAN result in a large spectrum of disease phenotypes that stem from autophagic dysfunctions, it could potentially serve as a simple and unique genetic model to investigate disease pathology and therapeutics for a wider range of neuropathological conditions with autophagy defects.
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Jepson JEC, Praschberger R, Krishnakumar SS. Mechanisms of Neurological Dysfunction in GOSR2 Progressive Myoclonus Epilepsy, a Golgi SNAREopathy. Neuroscience 2019; 420:41-49. [PMID: 30954670 DOI: 10.1016/j.neuroscience.2019.03.057] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 03/22/2019] [Accepted: 03/26/2019] [Indexed: 10/27/2022]
Abstract
Successive fusion events between transport vesicles and their target membranes mediate trafficking of secreted, membrane- and organelle-localised proteins. During the initial steps of this process, termed the secretory pathway, COPII vesicles bud from the endoplasmic reticulum (ER) and fuse with the cis-Golgi membrane, thus depositing their cargo. This fusion step is driven by a quartet of SNARE proteins that includes the cis-Golgi t-SNARE Membrin, encoded by the GOSR2 gene. Mis-sense mutations in GOSR2 result in Progressive Myoclonus Epilepsy (PME), a severe neurological disorder characterised by ataxia, myoclonus and seizures in the absence of significant cognitive impairment. However, given the ubiquitous and essential function of ER-to-Golgi transport, why GOSR2 mutations cause neurological dysfunction and not lethality or a broader range of developmental defects has remained an enigma. Here we highlight new work that has shed light on this issue and incorporate insights into canonical and non-canonical secretory trafficking pathways in neurons to speculate as to the cellular and molecular mechanisms underlying GOSR2 PME. This article is part of a Special Issue entitled: SNARE proteins: a long journey of science in brain physiology and pathology: from molecular.
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Affiliation(s)
- James E C Jepson
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK.
| | - Roman Praschberger
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK
| | - Shyam S Krishnakumar
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK; Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
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18
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A 12-kb structural variation in progressive myoclonic epilepsy was newly identified by long-read whole-genome sequencing. J Hum Genet 2019; 64:359-368. [PMID: 30760880 DOI: 10.1038/s10038-019-0569-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 01/22/2019] [Accepted: 01/22/2019] [Indexed: 12/20/2022]
Abstract
We report a family with progressive myoclonic epilepsy who underwent whole-exome sequencing but was negative for pathogenic variants. Similar clinical courses of a devastating neurodegenerative phenotype of two affected siblings were highly suggestive of a genetic etiology, which indicates that the survey of genetic variation by whole-exome sequencing was not comprehensive. To investigate the presence of a variant that remained unrecognized by standard genetic testing, PacBio long-read sequencing was performed. Structural variant (SV) detection using low-coverage (6×) whole-genome sequencing called 17,165 SVs (7,216 deletions and 9,949 insertions). Our SV selection narrowed down potential candidates to only five SVs (two deletions and three insertions) on the genes tagged with autosomal recessive phenotypes. Among them, a 12.4-kb deletion involving the CLN6 gene was the top candidate because its homozygous abnormalities cause neuronal ceroid lipofuscinosis. This deletion included the initiation codon and was found in a GC-rich region containing multiple repetitive elements. These results indicate the presence of a causal variant in a difficult-to-sequence region and suggest that such variants that remain enigmatic after the application of current whole-exome sequencing technology could be uncovered by unbiased application of long-read whole-genome sequencing.
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19
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Kanungo S, Wells K, Tribett T, El-Gharbawy A. Glycogen metabolism and glycogen storage disorders. ANNALS OF TRANSLATIONAL MEDICINE 2018; 6:474. [PMID: 30740405 DOI: 10.21037/atm.2018.10.59] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Glucose is the main energy fuel for the human brain. Maintenance of glucose homeostasis is therefore, crucial to meet cellular energy demands in both - normal physiological states and during stress or increased demands. Glucose is stored as glycogen primarily in the liver and skeletal muscle with a small amount stored in the brain. Liver glycogen primarily maintains blood glucose levels, while skeletal muscle glycogen is utilized during high-intensity exertion, and brain glycogen is an emergency cerebral energy source. Glycogen and glucose transform into one another through glycogen synthesis and degradation pathways. Thus, enzymatic defects along these pathways are associated with altered glucose metabolism and breakdown leading to hypoglycemia ± hepatomegaly and or liver disease in hepatic forms of glycogen storage disorder (GSD) and skeletal ± cardiac myopathy, depending on the site of the enzyme defects. Overall, defects in glycogen metabolism mainly present as GSDs and are a heterogenous group of inborn errors of carbohydrate metabolism. In this article we review the genetics, epidemiology, clinical and metabolic findings of various types of GSD, and glycolysis defects emphasizing current treatment and implications for future directions.
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Affiliation(s)
- Shibani Kanungo
- Department of Pediatric and Adolescent Medicine, Western Michigan University Homer Stryker MD School of Medicine, Kalamazoo, MI, USA
| | - Kimberly Wells
- Department of Pediatric and Adolescent Medicine, Western Michigan University Homer Stryker MD School of Medicine, Kalamazoo, MI, USA
| | - Taylor Tribett
- Department of Pediatric and Adolescent Medicine, Western Michigan University Homer Stryker MD School of Medicine, Kalamazoo, MI, USA
| | - Areeg El-Gharbawy
- Department of Pediatrics, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
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21
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Skurat AV, Segvich DM, DePaoli-Roach AA, Roach PJ. Novel method for detection of glycogen in cells. Glycobiology 2017; 27:416-424. [PMID: 28077463 PMCID: PMC5444244 DOI: 10.1093/glycob/cwx005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 01/09/2017] [Indexed: 12/11/2022] Open
Abstract
y Glycogen, a branched polymer of glucose, functions as an energy reserve in many living organisms. Abnormalities in glycogen metabolism, usually excessive accumulation, can be caused genetically, most often through mutation of the enzymes directly involved in synthesis and degradation of the polymer leading to a variety of glycogen storage diseases (GSDs). Microscopic visualization of glycogen deposits in cells and tissues is important for the study of normal glycogen metabolism as well as diagnosis of GSDs. Here, we describe a method for the detection of glycogen using a renewable, recombinant protein which contains the carbohydrate-binding module (CBM) from starch-binding domain containing protein 1 (Stbd1). We generated a fusion protein containing g lutathione S-transferase, a cM c eptitope and the tbd1 BM (GYSC) for use as a glycogen-binding probe, which can be detected with secondary antibodies against glutathione S-transferase or cMyc. By enzyme-linked immunosorbent assay, we demonstrate that GYSC binds glycogen and two other polymers of glucose, amylopectin and amylose. Immunofluorescence staining of cultured cells indicate a GYSC-specific signal that is co-localized with signals obtained with anti-glycogen or anti-glycogen synthase antibodies. GYSC-positive staining inside of lysosomes is observed in individual muscle fibers isolated from mice deficient in lysosomal enzyme acid alpha-glucosidase, a well-characterized model of GSD II (Pompe disease). Co-localized GYSC and glycogen signals are also found in muscle fibers isolated from mice deficient in malin, a model for Lafora disease. These data indicate that GYSC is a novel probe that can be used to study glycogen metabolism under normal and pathological conditions.
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Affiliation(s)
- Alexander V Skurat
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Dyann M Segvich
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Anna A DePaoli-Roach
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Peter J Roach
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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22
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Ostergaard JR. Juvenile neuronal ceroid lipofuscinosis (Batten disease): current insights. Degener Neurol Neuromuscul Dis 2016; 6:73-83. [PMID: 30050370 PMCID: PMC6053093 DOI: 10.2147/dnnd.s111967] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The present review is focused on juvenile neuronal ceroid lipofuscinosis (JNCL; Batten disease) due to a mutation in CLN3. Functional vision impairment occurring around 5-6 years of age is the first symptom in more than 80% of patients. Approximately 2 years later (though sometimes simultaneously), obvious signs of cognitive impairment appear. Behavior problems can occur in advance, especially in boys. These include anxious and depressed mood, aggressive behavior, and hallucinations, and even psychotic symptoms. Following the teens, severe dementia is present, including loss of memory, attention, and general reasoning abilities, as well as loss of independent adaptive skills such as mobility, feeding, and communicating. Sleep abnormalities, such as settling problems, nocturnal awakenings, and nightmares, are reported in more than half of patients. The vast majority, if not all, patients develop seizures, starting at approximately 10 years of age. Generalized tonic-clonic seizure occurs as the only type of seizure in approximately half of patients, and in combination with partial seizures in a third of patients. There seems to be no difference in seizure severity according to sex or genotype, and there is great variation in seizure activity among patients. Soon after diagnosis, patients begin to have slight ataxic symptoms, and at adolescence extrapyramidal symptoms (rigidity, bradykinesia, slow steps with flexion in hips and knees) occur with increasing frequency. Chewing and swallowing difficulties emerge as well, and food intake is hampered in the late teens. Disabling periodically involuntary movements may occur as well. A progressive cardiac involvement with repolarization disturbances, ventricular hypertrophy, and sinus-node dysfunction, ultimately leading to severe bradycardia and/or other conduction abnormalities, starts in the mid-teens. Patients are usually bedridden at 20 years of age, and death usually occurs in the third decade of life.
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Affiliation(s)
- John R Ostergaard
- Department of Paediatrics, Aarhus University Hospital, Centre for Rare Diseases, Aarhus, Denmark,
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23
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Roach PJ. Glycogen phosphorylation and Lafora disease. Mol Aspects Med 2015; 46:78-84. [PMID: 26278984 DOI: 10.1016/j.mam.2015.08.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 08/04/2015] [Indexed: 01/21/2023]
Abstract
Covalent phosphorylation of glycogen, first described 35 years ago, was put on firm ground through the work of the Whelan laboratory in the 1990s. But glycogen phosphorylation lay fallow until interest was rekindled in the mid 2000s by the finding that it could be removed by a glycogen-binding phosphatase, laforin, and that mutations in laforin cause a fatal teenage-onset epilepsy, called Lafora disease. Glycogen phosphorylation is due to phosphomonoesters at C2, C3 and C6 of glucose residues. Phosphate is rare, ranging from 1:500 to 1:5000 phosphates/glucose depending on the glycogen source. The mechanisms of glycogen phosphorylation remain under investigation but one hypothesis to explain C2 and perhaps C3 phosphate is that it results from a rare side reaction of the normal synthetic enzyme glycogen synthase. Lafora disease is likely caused by over-accumulation of abnormal glycogen in insoluble deposits termed Lafora bodies in neurons. The abnormality in the glycogen correlates with elevated phosphorylation (at C2, C3 and C6), reduced branching, insolubility and an enhanced tendency to aggregate and become insoluble. Hyperphosphorylation of glycogen is emerging as an important feature of this deadly childhood disease.
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Affiliation(s)
- Peter J Roach
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, IN 46202, USA.
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24
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Lesca G, Depienne C. Epilepsy genetics: the ongoing revolution. Rev Neurol (Paris) 2015; 171:539-57. [PMID: 26003806 DOI: 10.1016/j.neurol.2015.01.569] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 12/24/2014] [Accepted: 01/20/2015] [Indexed: 01/04/2023]
Abstract
Epilepsies have long remained refractory to gene identification due to several obstacles, including a highly variable inter- and intrafamilial expressivity of the phenotypes, a high frequency of phenocopies, and a huge genetic heterogeneity. Recent technological breakthroughs, such as array comparative genomic hybridization and next generation sequencing, have been leading, in the past few years, to the identification of an increasing number of genomic regions and genes in which mutations or copy-number variations cause various epileptic disorders, revealing an enormous diversity of pathophysiological mechanisms. The field that has undergone the most striking revolution is that of epileptic encephalopathies, for which most of causing genes have been discovered since the year 2012. Some examples are the continuous spike-and-waves during slow-wave sleep and Landau-Kleffner syndromes for which the recent discovery of the role of GRIN2A mutations has finally confirmed the genetic bases. These new technologies begin to be used for diagnostic applications, and the main challenge now resides in the interpretation of the huge mass of variants detected by these methods. The identification of causative mutations in epilepsies provides definitive confirmation of the clinical diagnosis, allows accurate genetic counselling, and sometimes permits the development of new appropriate and specific antiepileptic therapies. Future challenges include the identification of the genetic or environmental factors that modify the epileptic phenotypes caused by mutations in a given gene and the understanding of the role of somatic mutations in sporadic epilepsies.
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Affiliation(s)
- G Lesca
- Service de génétique, groupement hospitalier Est, hospices civils de Lyon, 59, boulevard Pinel, 69677 Bron, France; Université Claude-Bernard Lyon 1, 43, boulevard du 11-Novembre-1918, 69100 Villeurbanne, France; CRNL, CNRS UMR 5292, Inserm U1028, bâtiment IMBL, 11, avenue Jean-Capelle, 69621 Villeurbanne cedex, France.
| | - C Depienne
- Département de génétique et cytogénétique, hôpital Pitié-Salpêtrière, AP-HP, 47-83, boulevard de l'Hôpital, 75651 Paris cedex 13, France; Sorbonne universités, UPMC université Paris 06, 4, place Jussieu, 75005 Paris, France; ICM, CNRS UMR 7225, Inserm U1127, 47, boulevard de l'Hôpital, 75651 Paris cedex 13, France
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25
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Neverman NJ, Best HL, Hofmann SL, Hughes SM. Experimental therapies in the neuronal ceroid lipofuscinoses. Biochim Biophys Acta Mol Basis Dis 2015; 1852:2292-300. [PMID: 25957554 DOI: 10.1016/j.bbadis.2015.04.026] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 04/23/2015] [Accepted: 04/24/2015] [Indexed: 12/11/2022]
Abstract
The neuronal ceroid lipofuscinoses represent a group of severe childhood lysosomal storage diseases. With at least 13 identified variants they are the most common cause of inherited neurodegeneration in children. These diseases share common pathological characteristics including motor problems, vision loss, seizures, and cognitive decline, culminating in premature death. Currently, no form of the disease can be treated or cured, with only palliative care to minimise discomfort. This review focuses on current and potentially ground-breaking clinical trials, including small molecule, enzyme replacement, stem cell, and gene therapies, in the development of effective treatments for the various disease subtypes. This article is part of a Special Issue entitled: "Current Research on the Neuronal Ceroid Lipofuscinoses (Batten Disease)".
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Affiliation(s)
- Nicole J Neverman
- Department of Biochemistry, and Brain Health Research Centre, University of Otago, Dunedin, New Zealand; Batten Animal Research Network (BARN), New Zealand
| | - Hannah L Best
- Department of Biochemistry, and Brain Health Research Centre, University of Otago, Dunedin, New Zealand; Batten Animal Research Network (BARN), New Zealand
| | - Sandra L Hofmann
- University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Stephanie M Hughes
- Department of Biochemistry, and Brain Health Research Centre, University of Otago, Dunedin, New Zealand; Batten Animal Research Network (BARN), New Zealand.
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Augustine EF, Adams HR, Beck CA, Vierhile A, Kwon J, Rothberg PG, Marshall F, Block R, Dolan J, Mink JW. Standardized assessment of seizures in patients with juvenile neuronal ceroid lipofuscinosis. Dev Med Child Neurol 2015; 57:366-71. [PMID: 25387857 PMCID: PMC4610252 DOI: 10.1111/dmcn.12634] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/24/2014] [Indexed: 11/30/2022]
Abstract
AIM To evaluate seizure phenomenology, treatment, and course in individuals with juvenile neuronal ceroid lipofuscinosis (JNCL). METHOD Data from an ongoing natural history study of JNCL were analyzed using cross-sectional and longitudinal methods. Seizures were evaluated with the Unified Batten Disease Rating Scale, a disease-specific quantitative assessment tool. RESULTS Eighty-six children (44 males, 42 females) with JNCL were assessed at an average of three annual visits (range 1-11). Eighty-six percent (n=74) experienced at least one seizure, most commonly generalized tonic-clonic, with mean age at onset of 9 years 7 months (SD 2y 10mo). Seizures were infrequent, typically occurring less often than once every 3 months, and were managed with one to two medications for most participants. Valproate (49%, n=36) and levetiracetam (41%, n=30) were the most commonly used seizure medications. Myoclonic seizures occurred infrequently (16%, n=14). Seizure severity did not vary by sex or genotype. Seizures showed mild worsening with increasing age. INTERPRETATION The neuronal ceroid lipofuscinoses (NCLs) represent a group of disorders unified by neurodegeneration and symptoms of blindness, seizures, motor impairment, and dementia. While NCLs are considered in the differential diagnosis of progressive myoclonus epilepsy, we show that myoclonic seizures are infrequent in JNCL. This highlights the NCLs as consisting of genetically distinct disorders with differing natural history.
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Affiliation(s)
- Erika F Augustine
- Department of Neurology, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Heather R Adams
- Department of Neurology, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Christopher A Beck
- Department of Biostatistics and Computational Biology, University of Rochester, Rochester, New York
| | - Amy Vierhile
- Department of Neurology, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Jennifer Kwon
- Department of Neurology, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Paul G Rothberg
- Department of Pathology and Laboratory Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Frederick Marshall
- Department of Neurology, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Robert Block
- Department of Public Health Sciences, University of Rochester Medical Center, Rochester, New York, USA
| | - James Dolan
- Department of Public Health Sciences, University of Rochester Medical Center, Rochester, New York, USA
| | - Jonathan W Mink
- Department of Neurology, University of Rochester School of Medicine and Dentistry, Rochester, New York
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Muona M, Berkovic SF, Dibbens LM, Oliver KL, Maljevic S, Bayly MA, Joensuu T, Canafoglia L, Franceschetti S, Michelucci R, Markkinen S, Heron SE, Hildebrand MS, Andermann E, Andermann F, Gambardella A, Tinuper P, Licchetta L, Scheffer IE, Criscuolo C, Filla A, Ferlazzo E, Ahmad J, Ahmad A, Baykan B, Said E, Topcu M, Riguzzi P, King MD, Ozkara C, Andrade DM, Engelsen BA, Crespel A, Lindenau M, Lohmann E, Saletti V, Massano J, Privitera M, Espay AJ, Kauffmann B, Duchowny M, Møller RS, Straussberg R, Afawi Z, Ben-Zeev B, Samocha KE, Daly MJ, Petrou S, Lerche H, Palotie A, Lehesjoki AE. A recurrent de novo mutation in KCNC1 causes progressive myoclonus epilepsy. Nat Genet 2014; 47:39-46. [PMID: 25401298 DOI: 10.1038/ng.3144] [Citation(s) in RCA: 212] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 10/16/2014] [Indexed: 12/14/2022]
Abstract
Progressive myoclonus epilepsies (PMEs) are a group of rare, inherited disorders manifesting with action myoclonus, tonic-clonic seizures and ataxia. We sequenced the exomes of 84 unrelated individuals with PME of unknown cause and molecularly solved 26 cases (31%). Remarkably, a recurrent de novo mutation, c.959G>A (p.Arg320His), in KCNC1 was identified as a new major cause for PME. Eleven unrelated exome-sequenced (13%) and two affected individuals in a secondary cohort (7%) had this mutation. KCNC1 encodes KV3.1, a subunit of the KV3 voltage-gated potassium ion channels, which are major determinants of high-frequency neuronal firing. Functional analysis of the Arg320His mutant channel showed a dominant-negative loss-of-function effect. Ten cases had pathogenic mutations in known PME-associated genes (NEU1, NHLRC1, AFG3L2, EPM2A, CLN6 and SERPINI1). Identification of mutations in PRNP, SACS and TBC1D24 expand their phenotypic spectra to PME. These findings provide insights into the molecular genetic basis of PME and show the role of de novo mutations in this disease entity.
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Affiliation(s)
- Mikko Muona
- 1] Institute for Molecular Medicine Finland, University of Helsinki, Helsinki, Finland. [2] Folkhälsan Institute of Genetics, Helsinki, Finland. [3] Neuroscience Center, University of Helsinki, Helsinki, Finland. [4] Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
| | - Samuel F Berkovic
- Epilepsy Research Center, Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victoria, Australia
| | - Leanne M Dibbens
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Karen L Oliver
- Epilepsy Research Center, Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victoria, Australia
| | - Snezana Maljevic
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Marta A Bayly
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Tarja Joensuu
- 1] Folkhälsan Institute of Genetics, Helsinki, Finland. [2] Neuroscience Center, University of Helsinki, Helsinki, Finland. [3] Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
| | - Laura Canafoglia
- Department of Neurophysiopathology, C. Besta Foundation Neurological Institute, Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS), Milan, Italy
| | - Silvana Franceschetti
- Department of Neurophysiopathology, C. Besta Foundation Neurological Institute, Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS), Milan, Italy
| | - Roberto Michelucci
- Neurology Unit, IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy
| | - Salla Markkinen
- 1] Folkhälsan Institute of Genetics, Helsinki, Finland. [2] Neuroscience Center, University of Helsinki, Helsinki, Finland. [3] Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
| | - Sarah E Heron
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Michael S Hildebrand
- Epilepsy Research Center, Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victoria, Australia
| | - Eva Andermann
- Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Frederick Andermann
- Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | | | - Paolo Tinuper
- 1] Neurology Unit, IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy. [2] Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Laura Licchetta
- 1] Neurology Unit, IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy. [2] Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Ingrid E Scheffer
- 1] Epilepsy Research Center, Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victoria, Australia. [2] Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia. [3] Department of Pediatrics, Royal Children's Hospital, University of Melbourne, Melbourne, Victoria, Australia
| | - Chiara Criscuolo
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, Federico II University, Naples, Italy
| | - Alessandro Filla
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, Federico II University, Naples, Italy
| | - Edoardo Ferlazzo
- 1] Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro, Italy. [2] Regional Epilepsy Center, Bianchi-Melacrino-Morelli Hospital, Reggio Calabria, Italy
| | - Jamil Ahmad
- Department of Biotechnology and Informatics, Balochistan University of Information Technology, Engineering and Management Sciences, Quetta, Pakistan
| | - Adeel Ahmad
- Department of Medicine, Mayo Hospital, Lahore, Pakistan
| | - Betul Baykan
- 1] Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey. [2] Epilepsy Center (EPIMER), Istanbul University, Istanbul, Turkey
| | - Edith Said
- 1] Department of Anatomy and Cell Biology, University of Malta, Msida, Malta. [2] Section of Medical Genetics, Mater dei Hospital, Msida, Malta
| | - Meral Topcu
- Division of Pediatric Neurology, Department of Pediatrics, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Patrizia Riguzzi
- Neurology Unit, IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy
| | - Mary D King
- 1] Department of Neurology, Temple Street Children's University Hospital, Dublin, Ireland. [2] Academic Centre on Rare Diseases, School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Cigdem Ozkara
- Department of Neurology, Cerrahpasa Medical Faculty, Istanbul University, Istanbul, Turkey
| | - Danielle M Andrade
- Division of Neurology, Department of Medicine, University of Toronto, Toronto Western Hospital, Krembil Neurosciences Program, Toronto, Ontario, Canada
| | - Bernt A Engelsen
- 1] Department of Clinical Medicine, University of Bergen, Bergen, Norway. [2] Department of Neurology, Haukeland University Hospital, Bergen, Norway
| | | | - Matthias Lindenau
- Department of Neurology and Epileptology, Epilepsy Center Hamburg-Alsterdorf, Hamburg, Germany
| | - Ebba Lohmann
- 1] Department of Neurology and Epileptology, Epilepsy Center Hamburg-Alsterdorf, Hamburg, Germany. [2] Department of Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany. [3] German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Veronica Saletti
- Developmental Neurology Unit, C. Besta Foundation Neurological Institute, IRCCS, Milan, Italy
| | - João Massano
- 1] Department of Neurology, Centro Hospitalar São João, Porto, Portugal. [2] Department of Clinical Neurosciences and Mental Health, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Michael Privitera
- Epilepsy Center, University of Cincinnati Neuroscience Institute, Cincinnati, Ohio, USA
| | - Alberto J Espay
- Gardner Center for Parkinson Disease and Movement Disorders, University of Cincinnati, Cincinnati, Ohio, USA
| | | | - Michael Duchowny
- 1] Brain Institute, Miami Children's Hospital, Miami, Florida, USA. [2] Department of Neurology, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Rikke S Møller
- 1] Danish Epilepsy Centre, Dianalund, Denmark. [2] Institute of Regional Health Services Research, University of Southern Denmark, Odense, Denmark
| | - Rachel Straussberg
- 1] Neurogenetic Clinic, Child Neurology Institute, Schneider Children's Medical Center of Israel, Petah Tiqvah, Israel. [2] Sackler School of Medicine, Tel-Aviv University, Ramat Aviv, Israel
| | - Zaid Afawi
- 1] Sackler School of Medicine, Tel-Aviv University, Ramat Aviv, Israel. [2] Zlotowski Center for Neuroscience, Ben-Gurion University, Beer-Sheva, Israel
| | - Bruria Ben-Zeev
- 1] Sackler School of Medicine, Tel-Aviv University, Ramat Aviv, Israel. [2] Pediatric Neurology Unit, Edmond and Lilly Safra Children's Hospital, Sheba Medical Center, Ramat-Gan, Israel
| | - Kaitlin E Samocha
- 1] Analytic and Translational Genetics Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA. [2] Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, Massachusetts, USA. [3] Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, Massachusetts, USA. [4] Program in Genetics and Genomics, Biological and Biomedical Sciences, Harvard Medical School, Boston, Massachusetts, USA
| | - Mark J Daly
- 1] Analytic and Translational Genetics Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA. [2] Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, Massachusetts, USA. [3] Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, Massachusetts, USA. [4] Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, Massachusetts, USA
| | - Steven Petrou
- 1] Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia. [2] Centre for Neural Engineering, University of Melbourne, Melbourne, Victoria, Australia
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Aarno Palotie
- 1] Institute for Molecular Medicine Finland, University of Helsinki, Helsinki, Finland. [2] Analytic and Translational Genetics Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA. [3] Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, Massachusetts, USA. [4] Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, Massachusetts, USA. [5] Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK. [6] Psychiatric and Neurodevelopmental Genetics Unit, Department of Psychiatry, Massachusetts General Hospital, Boston, Massachusetts, USA. [7] Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Anna-Elina Lehesjoki
- 1] Folkhälsan Institute of Genetics, Helsinki, Finland. [2] Neuroscience Center, University of Helsinki, Helsinki, Finland. [3] Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
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Giorgi FS, Biagioni F, Lenzi P, Frati A, Fornai F. The role of autophagy in epileptogenesis and in epilepsy-induced neuronal alterations. J Neural Transm (Vienna) 2014; 122:849-62. [DOI: 10.1007/s00702-014-1312-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 09/09/2014] [Indexed: 12/12/2022]
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Olson HE, Poduri A, Pearl PL. Genetic forms of epilepsies and other paroxysmal disorders. Semin Neurol 2014; 34:266-79. [PMID: 25192505 DOI: 10.1055/s-0034-1386765] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Genetic mechanisms explain the pathophysiology of many forms of epilepsy and other paroxysmal disorders, such as alternating hemiplegia of childhood, familial hemiplegic migraine, and paroxysmal dyskinesias. Epilepsy is a key feature of well-defined genetic syndromes including tuberous sclerosis complex, Rett syndrome, Angelman syndrome, and others. There is an increasing number of single-gene causes or susceptibility factors associated with several epilepsy syndromes, including the early-onset epileptic encephalopathies, benign neonatal/infantile seizures, progressive myoclonus epilepsies, genetic generalized and benign focal epilepsies, epileptic aphasias, and familial focal epilepsies. Molecular mechanisms are diverse, and a single gene can be associated with a broad range of phenotypes. Additional features, such as dysmorphisms, head size, movement disorders, and family history may provide clues to a genetic diagnosis. Genetic testing can impact medical care and counseling. We discuss genetic mechanisms of epilepsy and other paroxysmal disorders, tools and indications for genetic testing, known genotype-phenotype associations, the importance of genetic counseling, and a look toward the future of epilepsy genetics.
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Affiliation(s)
- Heather E Olson
- Division of Epilepsy, Department of Neurology, Boston Children's Hospital, Boston, Massachusetts
| | - Annapurna Poduri
- Division of Epilepsy, Department of Neurology, Boston Children's Hospital, Boston, Massachusetts
| | - Phillip L Pearl
- Division of Epilepsy, Department of Neurology, Boston Children's Hospital, Boston, Massachusetts
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Gain in toxic function of stefin B EPM1 mutants aggregates: Correlation between cell death, aggregate number/size and oxidative stress. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:2089-99. [DOI: 10.1016/j.bbamcr.2014.05.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 05/28/2014] [Accepted: 05/29/2014] [Indexed: 11/19/2022]
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Fu YJ, Aida I, Tada M, Tada M, Toyoshima Y, Takeda S, Nakajima T, Naito H, Nishizawa M, Onodera O, Kakita A, Takahashi H. Progressive myoclonus epilepsy: extraneuronal brown pigment deposition and system neurodegeneration in the brains of Japanese patients with novel SCARB2 mutations. Neuropathol Appl Neurobiol 2014; 40:551-63. [PMID: 23659519 DOI: 10.1111/nan.12057] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2012] [Accepted: 04/30/2013] [Indexed: 11/29/2022]
Abstract
AIMS Mutations in the SCARB2 gene cause a rare autosomal recessive disease, progressive myoclonus epilepsy (PME) with or without renal failure, the former also being designated action myoclonus-renal failure syndrome. Although reported cases have been accumulating, only a few have described its neuropathology. We studied two Japanese patients with PME without renal failure, in whom the ages at onset and disease durations were 45 and 20 years, and 14 and 8.5 years respectively. METHODS Sequencing and restriction analysis of the SCARB2 gene and neuropathological examination with immunohistochemistry were performed. RESULTS Gene analyses revealed novel homozygous frameshift and nonsense mutations in the SCARB2 gene. Both cases exhibited deposition of brown pigment in the brain, especially the cerebellar and cerebral cortices. Ultrastructurally, the pigment granules were localized in astrocytes. Neuronal loss and gliosis were also evident in the brain, including the pallidoluysian and cerebello-olivary systems. The spinal cord was also affected. Such changes were less severe in one patient with late-onset disease than in the other patient with early-onset disease. In brain and kidney sections, immunostaining with an antibody against the C-terminus of human SCARB2 revealed decreased levels and no expression of the protein respectively. CONCLUSIONS The frameshift mutation detected in the patient with late-onset disease is a hitherto undescribed, unique type of SCARB2 gene mutation. The present two patients are the first reported to have clearly demonstrated both extraneuronal brown pigment deposition and system neurodegeneration as neuropathological features of PME with SCARB2 mutations.
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Affiliation(s)
- Yong-Juan Fu
- Department of Pathology, Brain Research Institute, University of Niigata, Niigata, Japan
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Vanni N, Fruscione F, Ferlazzo E, Striano P, Robbiano A, Traverso M, Sander T, Falace A, Gazzerro E, Bramanti P, Bielawski J, Fassio A, Minetti C, Genton P, Zara F. Impairment of ceramide synthesis causes a novel progressive myoclonus epilepsy. Ann Neurol 2014; 76:206-12. [PMID: 24782409 DOI: 10.1002/ana.24170] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 04/28/2014] [Accepted: 04/28/2014] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Alterations of sphingolipid metabolism are implicated in the pathogenesis of many neurodegenerative disorders. METHODS We identified a homozygous nonsynonymous mutation in CERS1, the gene encoding ceramide synthase 1, in 4 siblings affected by a progressive disorder with myoclonic epilepsy and dementia. CerS1, a transmembrane protein of the endoplasmic reticulum (ER), catalyzes the biosynthesis of C18-ceramides. RESULTS We demonstrated that the mutation decreases C18-ceramide levels. In addition, we showed that downregulation of CerS1 in a neuroblastoma cell line triggers ER stress response and induces proapoptotic pathways. INTERPRETATION This study demonstrates that impairment of ceramide biosynthesis underlies neurodegeneration in humans.
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Affiliation(s)
- Nicola Vanni
- Department of Neuroscience, Institute G. Gaslini, Genoa, Italy
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Abstract
PURPOSE OF REVIEW Myoclonus remains a challenging movement phenotype to characterize, evaluate, and treat. A systematic assessment of the temporal sequence, phenomenology, and distribution of movements can assist in the rational approach to diagnosis and management. RECENT FINDINGS Cortical forms of myoclonus are increasingly recognized as primarily cerebellar disorders. A syndrome of orthostatic myoclonus has been recognized by electrophysiology in patients with neurodegenerative disorders, mainly in Alzheimer disease, accounting for impairments in gait and balance previously mischaracterized as normal pressure hydrocephalus or orthostatic tremor. Tyrosine hydroxylase deficiency and Silver-Russell syndrome (uniparental disomy of chromosome 7) have been established as two novel causes of the myoclonus-dystonia syndrome. Mutations in the glycine receptor (GlyR) α1-subunit gene (GLRA1) explain the major expression of hyperekplexia, an inherited excessive startle disorder, butnewly identified mutations in GlyR β-subunit (GLRB) and glycine transporter 2 (GlyT2) genes (SLC6A5) account for "minor" forms of this disorder manifested as excessive startle and hypnic jerks. The entity previously known as palatal myoclonus has been reclassified as palatal tremor in recognition of its clinical and electromyographic features and no longer enters the differential diagnosis of myoclonic disorders. Increasing documentation of psychogenic features in patients previously characterized as having propriospinal myoclonus has cast doubts on the existence of this distinctive disorder. SUMMARY Myoclonus can be a prominent manifestation of a wide range of disorders. Electrophysiologic testing aids in distinguishing myoclonus from other mimics and classifying them according to cortical, subcortical, or spinal origin, which assists the choice of treatment. Despite the lack of randomized clinical trials, levetiracetam appears most effective in patients with cortical myoclonus, whereas clonazepam remains the only first-line therapeutic option in subcortical and spinal myoclonus.
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Ganos C, Biskup S, Krüger S, Meyer-Osores A, Hodecker S, Hagel C, Schöls L, Bhatia KP, Münchau A. Dystonia with aphonia, slow horizontal saccades, epilepsy and photic myoclonus: a novel syndrome? Parkinsonism Relat Disord 2013; 20:328-31. [PMID: 24359844 DOI: 10.1016/j.parkreldis.2013.11.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 11/05/2013] [Accepted: 11/15/2013] [Indexed: 11/29/2022]
Abstract
BACKGROUND Dystonia with anarthria and/or aphonia is a rare syndromic association. Here we present two cases with slowly progressive, severe generalized dystonia and aphonia, slow horizontal saccades, epilepsy and photic myoclonus. METHODS Detailed clinical data were collected over two decades in the female (index) patient and for nine years in her similarly affected son. Sanger sequencing followed by exome sequencing was performed. RESULTS Both patients had leg onset generalized dystonia with gradual rostral spread including prominent facial and oro-mandibular involvement. The index patient was anarthric, her son aphonic. Both had saccadic slowing, more marked for the horizontal plane, and subclinical epileptic activity. The index patient also had photic myoclonus and a combined axonal and demyelinating neuropathy. Known genetic causes of similar syndromes were not identified. CONCLUSION These cases with caudo-rostrally spreading generalized dystonia with prominent facial and oro-mandibular involvement, severe speech impairment, marked slowing of horizontal saccades, and photic myoclonus likely represent a novel entity.
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Affiliation(s)
- Christos Ganos
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, United Kingdom; Department of Neurology, University Medical Centre Hamburg-Eppendorf (UKE), Hamburg, Germany; Department of Paediatric and Adult Movement Disorders and Neuropsychiatry, Institute of Neurogenetics, University of Lübeck, Lübeck, Germany.
| | - Saskia Biskup
- Department of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; German Center for Neurogenerative Diseases, Tübingen, Germany; CeGaT GmbH, Tübingen, Germany
| | - Stefanie Krüger
- Department of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; German Center for Neurogenerative Diseases, Tübingen, Germany; CeGaT GmbH, Tübingen, Germany
| | - Aracelli Meyer-Osores
- Clinic for Degenerative Brain Diseases, Department of Pediatrics, University Medical, Center Hamburg-Eppendorf (UKE), 20246 Hamburg, Germany
| | - Sibylle Hodecker
- Department of Neurology, University Medical Centre Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Christian Hagel
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf (UKE), 20246 Hamburg, Germany
| | - Ludger Schöls
- Department of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; German Center for Neurogenerative Diseases, Tübingen, Germany
| | - Kailash P Bhatia
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, United Kingdom
| | - Alexander Münchau
- Department of Paediatric and Adult Movement Disorders and Neuropsychiatry, Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
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Schorlemmer K, Bauer S, Belke M, Hermsen A, Klein KM, Reif PS, Oertel WH, Kunz WS, Knake S, Rosenow F, Strzelczyk A. Sustained seizure remission on perampanel in progressive myoclonic epilepsy (Lafora disease). EPILEPSY & BEHAVIOR CASE REPORTS 2013; 1:118-21. [PMID: 25667843 PMCID: PMC4150630 DOI: 10.1016/j.ebcr.2013.07.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 07/13/2013] [Accepted: 07/16/2013] [Indexed: 12/18/2022]
Abstract
AIM The aim of this report is to provide initial evidence that add-on treatment with perampanel might be highly effective in progressive myoclonic epilepsy such as Lafora disease. CASE REPORT We report on a 21-year-old woman suffering from persistent myoclonus and generalized tonic-clonic seizures for more than seven years. Additionally, ataxia, a disturbance in speech and gait, as well as a cognitive decline were rapidly progressing. Subsequently, the diagnosis of Lafora disease was confirmed by the identification of a novel homozygous missense mutation in exon 3 of the EPM2A gene (c.538C>G; p.L180V). Adjunctive therapy with perampanel was started in this patient with advanced Lafora disease and was titrated up to 8 mg/day. A sustained and reproducible remission of myoclonus and GTCS could be achieved for a follow-up of three months. After dosage reduction to 6 mg/day, seizures recurred; however, on increasing the daily dose to 10 mg, seizures stopped for another three months. The patient also regained her ability to walk with help and the aid of a walker. CONCLUSIONS Perampanel is a selective, noncompetitive antagonist of AMPA-type glutamate receptors and recently licensed as adjunctive therapy for the treatment of refractory focal onset seizures. There is evidence for its effectiveness in generalized epilepsies, and phase III studies for this indication are on the way. Our case illustrates the possibility that perampanel might be a valuable option for treatment in PME. Considering its impressive efficacy in this case, we suggest a prospective, multicenter study evaluating perampanel in PME.
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Affiliation(s)
- Kathrin Schorlemmer
- Department of Neurology and Epilepsy Center Hessen, Philipps-University, Marburg, Germany
| | - Sebastian Bauer
- Department of Neurology and Epilepsy Center Hessen, Philipps-University, Marburg, Germany
| | - Marcus Belke
- Department of Neurology and Epilepsy Center Hessen, Philipps-University, Marburg, Germany
| | - Anke Hermsen
- Department of Neurology and Epilepsy Center Hessen, Philipps-University, Marburg, Germany
| | - Karl Martin Klein
- Department of Neurology and Epilepsy Center Hessen, Philipps-University, Marburg, Germany
| | - Philipp S Reif
- Department of Neurology and Epilepsy Center Hessen, Philipps-University, Marburg, Germany
| | - Wolfgang H Oertel
- Department of Neurology and Epilepsy Center Hessen, Philipps-University, Marburg, Germany
| | | | - Susanne Knake
- Department of Neurology and Epilepsy Center Hessen, Philipps-University, Marburg, Germany
| | - Felix Rosenow
- Department of Neurology and Epilepsy Center Hessen, Philipps-University, Marburg, Germany
| | - Adam Strzelczyk
- Department of Neurology and Epilepsy Center Hessen, Philipps-University, Marburg, Germany
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37
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Abstract
Many neurologic diseases cause discrete episodic impairment in contrast with progressive deterioration. The symptoms of these episodic disorders exhibit striking variety. Herein we review what is known of the phenotypes, genetics, and pathophysiology of episodic neurologic disorders. Of these, most are genetically complex, with unknown or polygenic inheritance. In contrast, a fascinating panoply of episodic disorders exhibit Mendelian inheritance. We classify episodic Mendelian disorders according to the primary neuroanatomical location affected: skeletal muscle, cardiac muscle, neuromuscular junction, peripheral nerve, or central nervous system (CNS). Most known Mendelian mutations alter genes that encode membrane-bound ion channels. These mutations cause ion channel dysfunction, which ultimately leads to altered membrane excitability as manifested by episodic disease. Other Mendelian disease genes encode proteins essential for ion channel trafficking or stability. These observations have cemented the channelopathy paradigm, in which episodic disorders are conceptualized as disorders of ion channels. However, we expand on this paradigm to propose that dysfunction at the synaptic and neuronal circuit levels may underlie some episodic neurologic entities.
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Affiliation(s)
- Jonathan F Russell
- Department of Neurology, Howard Hughes Medical Institute, School of Medicine, University of California-San Francisco, CA 94158, USA.
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38
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Hendriks WJAJ, Pulido R. Protein tyrosine phosphatase variants in human hereditary disorders and disease susceptibilities. Biochim Biophys Acta Mol Basis Dis 2013; 1832:1673-96. [PMID: 23707412 DOI: 10.1016/j.bbadis.2013.05.022] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 05/14/2013] [Accepted: 05/16/2013] [Indexed: 12/18/2022]
Abstract
Reversible tyrosine phosphorylation of proteins is a key regulatory mechanism to steer normal development and physiological functioning of multicellular organisms. Phosphotyrosine dephosphorylation is exerted by members of the super-family of protein tyrosine phosphatase (PTP) enzymes and many play such essential roles that a wide variety of hereditary disorders and disease susceptibilities in man are caused by PTP alleles. More than two decades of PTP research has resulted in a collection of PTP genetic variants with corresponding consequences at the molecular, cellular and physiological level. Here we present a comprehensive overview of these PTP gene variants that have been linked to disease states in man. Although the findings have direct bearing for disease diagnostics and for research on disease etiology, more work is necessary to translate this into therapies that alleviate the burden of these hereditary disorders and disease susceptibilities in man.
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Affiliation(s)
- Wiljan J A J Hendriks
- Department of Cell Biology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
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39
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Potschka H, Fischer A, von Rüden EL, Hülsmeyer V, Baumgärtner W. Canine epilepsy as a translational model? Epilepsia 2013; 54:571-9. [PMID: 23506100 DOI: 10.1111/epi.12138] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/29/2013] [Indexed: 01/01/2023]
Abstract
Dogs with spontaneous diseases can exhibit a striking similarity in etiology, clinical manifestation, and disease course when compared to human patients. Therefore, dogs are intensely discussed as a translational model of human disease. In particular, genetic studies in selected dog breeds serve as an excellent tool to identify epilepsy disease genes. In addition, canine epilepsy is discussed as a translational platform for drug testing. On one hand, epileptic dogs might serve as an interesting model by allowing the evaluation of drug efficacy and potency under clinical conditions with a focus on chronic seizures resistant to standard medication, preventive strategies, or status epilepticus. On the other hand, several limitations need to be considered including owner-based seizure monitoring, species differences in pharmacokinetics and drug interactions, as well as cost-intensiveness. The review gives an overview on the current state of knowledge regarding the etiology, clinical manifestation, pathology, and drug response of canine epilepsy, also pointing out the urgent need for further research on specific aspects. Moreover, the putative advantages, the disadvantages, and limitations of antiepileptic drug testing in canine epilepsy are critically discussed.
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Affiliation(s)
- Heidrun Potschka
- Institute of Pharmacology, Toxicology and Pharmacy, Ludwig-Maximilians-University, Munich, Germany.
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40
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Kousi M, Anttila V, Schulz A, Calafato S, Jakkula E, Riesch E, Myllykangas L, Kalimo H, Topçu M, Gökben S, Alehan F, Lemke JR, Alber M, Palotie A, Kopra O, Lehesjoki AE. Novel mutations consolidate KCTD7 as a progressive myoclonus epilepsy gene. J Med Genet 2013; 49:391-9. [PMID: 22693283 DOI: 10.1136/jmedgenet-2012-100859] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND The progressive myoclonus epilepsies (PMEs) comprise a group of clinically and genetically heterogeneous disorders characterised by myoclonus, epilepsy, and neurological deterioration. This study aimed to identify the underlying gene(s) in childhood onset PME patients with unknown molecular genetic background. METHODS Homozygosity mapping was applied on genome-wide single nucleotide polymorphism data of 18 Turkish patients. The potassium channel tetramerisation domain-containing 7 (KCTD7) gene, previously associated with PME in a single inbred family, was screened for mutations. The spatiotemporal expression of KCTD7 was assessed in cellular cultures and mouse brain tissue. RESULTS Overlapping homozygosity in 8/18 patients defined a 1.5 Mb segment on 7q11.21 as the major candidate locus. Screening of the positional candidate gene KCTD7 revealed homozygous missense mutations in two of the eight cases. Screening of KCTD7 in a further 132 PME patients revealed four additional mutations (two missense, one in-frame deletion, and one frameshift-causing) in five families. Eight patients presented with myoclonus and epilepsy and one with ataxia, the mean age of onset being 19 months. Within 2 years after onset, progressive loss of mental and motor skills ensued leading to severe dementia and motor handicap. KCTD7 showed cytosolic localisation and predominant neuronal expression, with widespread expression throughout the brain. None of three polypeptides carrying patient missense mutations affected the subcellular distribution of KCTD7. DISCUSSION These data confirm the causality of KCTD7 defects in PME, and imply that KCTD7 mutation screening should be considered in PME patients with onset around 2 years of age followed by rapid mental and motor deterioration.
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Affiliation(s)
- Maria Kousi
- Folkhälsan Institute of Genetics, Biomedicum Helsinki, PO Box 63, Haartmaninkatu 8, University of Helsinki, FIN-00014 Helsinki, Finland
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41
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Abstract
Seizures may be the first and the major presenting feature of an inborn error of metabolism (IEM), for example in a neonate with pyridoxine-dependent epilepsy. In other IEMs, seizures may be preceded by other major symptoms: by a reduced level of consciousness in a child with an organic acidaemia or urea cycle defect; or by loss of skills, progressive weakness, ataxia, and upper motor signs in a child with a lysosomal storage disorder or peroxisomal leukodystrophy. This review concentrates on those IEMs for which specific treatment is available. The common metabolic causes of seizures vary according to the age at presentation. Features from the history, examination, imaging, and first line biochemical investigations can all provide clues to an inborn error. This review attempts to delineate these and to provide a guide to the specific tests that can be used to make the diagnosis of disorders with specific treatment.
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Affiliation(s)
- Shamima Rahman
- Clinical and Molecular Genetics and Neurosciences Units, University College London Institute of Child Health, London and Metabolic and Neurosciences Units, Great Ormond Street Hospital for Children NHS Trust, London, UK.
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42
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Identification of COL6A2 mutations in progressive myoclonus epilepsy syndrome. Hum Genet 2012; 132:275-83. [DOI: 10.1007/s00439-012-1248-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 10/30/2012] [Indexed: 02/02/2023]
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43
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Michelucci R, Pasini E, Riguzzi P, Volpi L, Dazzo E, Nobile C. Genetics of epilepsy and relevance to current practice. Curr Neurol Neurosci Rep 2012; 12:445-55. [PMID: 22618127 DOI: 10.1007/s11910-012-0281-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Genetic factors are likely to play a major role in many epileptic conditions, spanning from classical idiopathic (genetic) generalized epilepsies to epileptic encephalopathies and focal epilepsies. In this review we describe the genetic advances in progressive myoclonus epilepsies, which are strictly monogenic disorders, genetic generalized epilepsies, mostly exhibiting complex genetic inheritance, and SCN1A-related phenotypes, namely genetic generalized epilepsy with febrile seizure plus and Dravet syndrome. Particular attention is devoted to a form of familial focal epilepsies, autosomal-dominant lateral temporal epilepsy, which is a model of non-ion genetic epilepsies. This condition is associated with mutations of the LGI1 gene, whose protein is secreted from the neurons and exerts its action on a number of targets, influencing cortical development and neuronal maturation.
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Affiliation(s)
- Roberto Michelucci
- Unit of Neurology, IRCCS Institute of Neurological Sciences, Bellaria Hospital, Via Altura 3, 40139, Bologna, Italy.
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44
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Singh S, Singh PK, Bhadauriya P, Ganesh S. Lafora disease E3 ubiquitin ligase malin is recruited to the processing bodies and regulates the microRNA-mediated gene silencing process via the decapping enzyme Dcp1a. RNA Biol 2012; 9:1440-9. [PMID: 23131811 DOI: 10.4161/rna.22708] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Intracellular transport, processing and stability of mRNA play critical roles in the functional physiology of the cell and defects in these processes are thought to underlie the pathogenesis in a number of neurodegenerative disorders. One of the cellular sites that regulate the mRNA half-life is the processing bodies, the dynamic cytoplasmic structures that represent the non-translating mRNA and the ribonucleoprotein complex that also control the decapping and translation of mRNA. In the present study we explored the possible role of malin E3 ubiquitin ligase in the mRNA decay pathway via the processing bodies. Defects in malin are associated with Lafora disease (LD)-a neurodegenerative disorder characterized by myoclonus seizures. We show here that malin is recruited to the processing bodies and that malin regulates the recruitment of mRNA decapping enzyme Dcp1a by promoting its degradation via the ubiquitin proteasome system. Depletion of malin results in elevated levels of Dcp1a and an altered microRNA-mediated gene silencing activity. Our study suggests that malin is one of the critical regulators of processing bodies and that defects in the mRNA processing might underlie some of the disease symptoms in LD.
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Affiliation(s)
- Sweta Singh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India
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45
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Andrade DM, Paton T, Turnbull J, Marshall CR, Scherer SW, Minassian BA. Mutation of the CLN6 gene in teenage-onset progressive myoclonus epilepsy. Pediatr Neurol 2012; 47:205-8. [PMID: 22883287 DOI: 10.1016/j.pediatrneurol.2012.05.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 05/10/2012] [Indexed: 11/19/2022]
Abstract
Progressive myoclonus epilepsies are severe, intractable, and neurodegenerative. They afflict patients of all ages, but more commonly adolescents, and comprise the main differential diagnosis of common juvenile myoclonic epilepsy. Genetic or minimally invasive pathologic diagnoses are available for many but not all teenage-onset progressive myoclonus epilepsies. We describe a multiplex family with autosomal recessive teenage-onset progressive myoclonus epilepsy that had remained undiagnosed despite extensive genetic and pathologic testing. We describe whole exome sequencing combined with homozygosity mapping to identify the disease gene directly and diagnose the family. The affected gene is CLN6, previously known to underlie variant late-infantile and adult-onset neuronal ceroid lipofuscinoses. Combined with other recent work, our results add CLN6 to the genetic mutations causing teenage-onset progressive myoclonus epilepsy, expand the group of teenage-onset progressive myoclonus epilepsy patients who can be diagnosed by genetic testing, and extend the clinical spectrum of CLN6 mutations to include teenage-onset progressive myoclonus epilepsy. This work also exemplifies the potentiality of next-generation sequencing in the genetic identification and diagnosis of patients with neurologic diseases of unknown cause.
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Affiliation(s)
- Danielle M Andrade
- Division of Neurology, Krembil Neuroscience Centre, University of Toronto, Toronto Western Hospital, 399 Bathurst Street, Toronto, Ontario, Canada.
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46
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Polajnar M, Ceru S, Kopitar-Jerala N, Zerovnik E. Human stefin B normal and patho-physiological role: molecular and cellular aspects of amyloid-type aggregation of certain EPM1 mutants. Front Mol Neurosci 2012; 5:88. [PMID: 22936898 PMCID: PMC3426797 DOI: 10.3389/fnmol.2012.00088] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2012] [Accepted: 08/03/2012] [Indexed: 11/24/2022] Open
Abstract
Epilepsies are characterized by abnormal electrophysiological activity of the brain. Among various types of inherited epilepsies different epilepsy syndromes, among them progressive myoclonus epilepsies with features of ataxia and neurodegeneration, are counted. The progressive myoclonus epilepsy of type 1 (EPM1), also known as Unverricht-Lundborg disease presents with features of cerebellar atrophy and increased oxidative stress. It has been found that EPM1 is caused by mutations in human cystatin B gene (human stefin B). We first describe the role of protein aggregation in other neurodegenerative conditions. Protein aggregates appear intraneurally but are also excreted, such as is the case with senile plaques of amyloid-β (Aβ) that accumulate in the brain parenchyma and vessel walls. A common characteristic of such diseases is the change of the protein conformation toward β secondary structure that accounts for the strong tendency of such proteins to aggregate and form amyloid fibrils. Second, we describe the patho-physiology of EPM1 and the normal and aberrant roles of stefin B in a mouse model of the disease. Furthermore, we discuss how the increased protein aggregation observed with some of the mutants of human stefin B may relate to the neurodegeneration that occurs in rare EPM1 patients. Our hypothesis (Ceru et al., 2005) states that some of the EPM1 mutants of human stefin B may undergo aggregation in neural cells, thus gaining additional toxic function (apart from loss of normal function). Our in vitro experiments thus far have confirmed that four mutants undergo increased aggregation relative to the wild-type protein. It has been shown that the R68X mutant forms amyloid-fibrils very rapidly, even at neutral pH and forms perinuclear inclusions, whereas the G4R mutant exhibits a prolonged lag phase, during which the toxic prefibrillar aggregates accumulate and are scattered more diffusely over the cytoplasm. Initial experiments on the G50E and Q71P missense EPM1 mutants are described.
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Affiliation(s)
- Mira Polajnar
- Department of Biochemistry and Molecular and Structural Biology, Jožef Stefan Institute Ljubljana, Slovenia
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47
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Lalonde R, Strazielle C. Brain regions and genes affecting myoclonus in animals. Neurosci Res 2012; 74:69-79. [PMID: 22824643 DOI: 10.1016/j.neures.2012.07.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 06/02/2012] [Accepted: 07/12/2012] [Indexed: 01/26/2023]
Abstract
Myoclonus is defined as large-amplitude rhythmic movements. Brain regions underlying myoclonic jerks include brainstem, cerebellum, and cortex. Gamma-aminobutyric acid (GABA) appears to be the main neurotransmitter involved in myoclonus, possibly interacting with biogenic amines, opiates, acetylcholine, and glycine. Myoclonic jumping is a specific subtype seen in rodents, comprising rearing and hopping continuously against a wall. Myoclonic jumping can be seen in normal mouse strains, possibly as a result of simply being put inside a cage. Like other types, it is also triggered by changes in GABA, 5HT, and dopamine neurotransmission. Implicated brain regions include hippocampus and dorsal striatum, possibly with respect to D(1) dopamine, NMDA, and δ opioid receptors. There is reason to suspect that myoclonic jumping is underreported due to insufficient observations into mouse cages.
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Affiliation(s)
- R Lalonde
- Université de Rouen, UFR des Sciences Humaines et Sociales, Laboratoire de Psychologie et Neurosciences: Intégration COgnitive du NEurone à la Société (ICONES), 76821 Mont Saint-Aignan Cedex, France.
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48
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A compound heterozygous missense mutation and a large deletion in the KCTD7 gene presenting as an opsoclonus-myoclonus ataxia-like syndrome. J Neurol 2012; 259:2590-8. [DOI: 10.1007/s00415-012-6545-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 05/01/2012] [Accepted: 05/03/2012] [Indexed: 12/14/2022]
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49
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Phenotype variations in Lafora progressive myoclonus epilepsy: possible involvement of genetic modifiers? J Hum Genet 2012; 57:283-5. [PMID: 22456482 DOI: 10.1038/jhg.2012.29] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Lafora progressive myoclonus epilepsy, also known as Lafora disease (LD), is the most severe and fatal form of progressive myoclonus epilepsy with its typical onset during the late childhood or early adolescence. LD is characterized by recurrent epileptic seizures and progressive decline in intellectual function. LD can be caused by defects in any of the two known genes and the clinical features of these two genetic groups are almost identical. The past one decade has witnessed considerable success in identifying the LD genes, their mutations, the cellular functions of gene products and on molecular basis of LD. Here, we briefly review the current literature on the phenotype variations, on possible presence of genetic modifiers, and candidate modifiers as targets for therapeutic interventions in LD.
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50
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Abstract
Glycogen is a branched polymer of glucose that acts as a store of energy in times of nutritional sufficiency for utilization in times of need. Its metabolism has been the subject of extensive investigation and much is known about its regulation by hormones such as insulin, glucagon and adrenaline (epinephrine). There has been debate over the relative importance of allosteric compared with covalent control of the key biosynthetic enzyme, glycogen synthase, as well as the relative importance of glucose entry into cells compared with glycogen synthase regulation in determining glycogen accumulation. Significant new developments in eukaryotic glycogen metabolism over the last decade or so include: (i) three-dimensional structures of the biosynthetic enzymes glycogenin and glycogen synthase, with associated implications for mechanism and control; (ii) analyses of several genetically engineered mice with altered glycogen metabolism that shed light on the mechanism of control; (iii) greater appreciation of the spatial aspects of glycogen metabolism, including more focus on the lysosomal degradation of glycogen; and (iv) glycogen phosphorylation and advances in the study of Lafora disease, which is emerging as a glycogen storage disease.
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