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Vincent A, Ahmed K, Hussein R, Berberovic Z, Tumber A, Zhao X, Minassian BA. Retinal Phenotyping of a Murine Model of Lafora Disease. Genes (Basel) 2023; 14:genes14040854. [PMID: 37107612 PMCID: PMC10137594 DOI: 10.3390/genes14040854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/24/2023] [Accepted: 03/27/2023] [Indexed: 04/05/2023] Open
Abstract
Lafora disease (LD) is a progressive neurologic disorder caused by biallelic pathogenic variants in EPM2A or EPM2B, leading to tissue accumulation of polyglucosan aggregates termed Lafora bodies (LBs). This study aimed to characterize the retinal phenotype in Epm2a−/− mice by examining knockout (KO; Epm2a−/−) and control (WT) littermates at two time points (10 and 14 months, respectively). In vivo exams included electroretinogram (ERG) testing, optical coherence tomography (OCT) and retinal photography. Ex vivo retinal testing included Periodic acid Schiff Diastase (PASD) staining, followed by imaging to assess and quantify LB deposition. There was no significant difference in any dark-adapted or light-adapted ERG parameters between KO and WT mice. The total retinal thickness was cFigure mparable between the groups and the retinal appearance was normal in both groups. On PASD staining, LBs were observed in KO mice within the inner and outer plexiform layers and in the inner nuclear layer. The average number of LBs within the inner plexiform layer in KO mice were 1743 ± 533 and 2615 ± 915 per mm2, at 10 and 14 months, respectively. This is the first study to characterize the retinal phenotype in an Epm2a−/− mouse model, demonstrating significant LB deposition in the bipolar cell nuclear layer and its synapses. This finding may be used to monitor the efficacy of experimental treatments in mouse models.
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Affiliation(s)
- Ajoy Vincent
- Department of Ophthalmology and Vision Sciences, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON M5T 3A9, Canada
| | - Kashif Ahmed
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Rowaida Hussein
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | | | - Anupreet Tumber
- Department of Ophthalmology and Vision Sciences, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Xiaochu Zhao
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Berge A. Minassian
- Division of Neurology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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Neurophysiology of Juvenile and Progressive Myoclonic Epilepsy. J Clin Neurophysiol 2023; 40:100-108. [PMID: 36735458 DOI: 10.1097/wnp.0000000000000913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
SUMMARY Myoclonus can be epileptic or nonepileptic. Epileptic myoclonus has been defined in clinical, neurophysiological, and neuroanatomical terms. Juvenile myoclonic epilepsy (JME) is typically considered to be an adolescent-onset idiopathic generalized epilepsy with a combination of myoclonic, generalized tonic-clonic, and absence seizures and normal cognitive status that responds well to anti-seizure medications but requires lifelong treatment. EEG shows generalized epileptiform discharges and photosensitivity. Recent observations indicate that the clinical picture of JME is heterogeneous and a number of neuropsychological and imaging studies have shown structural and functional abnormalities in the frontal lobes and thalamus. Advances in neurophysiology and imaging suggest that JME may not be a truly generalized epilepsy, in that restricted cortical and subcortical networks appear to be involved rather than the entire brain. Some patients with JME may be refractory to anti-seizure medications and attempts have been made to identify neurophysiological biomarkers predicting resistance. Progressive myoclonic epilepsy is a syndrome with multiple specific causes. It is distinct from JME because of the occurrence of progressive neurologic dysfunction in addition to myoclonus and generalized tonic-clonic seizures but may sometimes be difficult to distinguish from JME or misdiagnosed as drug-resistant JME. This article provides an overview of progressive myoclonic epilepsy and focuses on the clinical and neurophysiological findings in the two most commonly recognized forms of progressive myoclonic epilepsy-Unverricht-Lundborg disease (EPM1) and Lafora disease (EPM2). A variety of neurophysiological tests can be used to distinguish between JME and progressive myoclonic epilepsy and between EPM1 and EPM2.
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Della Vecchia S, Marchese M, Santorelli FM. Glial Contributions to Lafora Disease: A Systematic Review. Biomedicines 2022; 10:biomedicines10123103. [PMID: 36551859 PMCID: PMC9776290 DOI: 10.3390/biomedicines10123103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 11/25/2022] [Accepted: 11/28/2022] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND Lafora disease (LD) is a neurodegenerative condition characterized by the accumulation of polyglucosan bodies (PBs) throughout the brain. Alongside metabolic and molecular alterations, neuroinflammation has emerged as another key histopathological feature of LD. METHODS To investigate the role of astrocytes and microglia in LD, we performed a systematic review according to the PRISMA statement. PubMed, Scopus, and Web-of-Science database searches were performed independently by two reviewers. RESULTS Thirty-five studies analyzing the relationship of astrocytes and microglia with LD and/or the effects of anti-inflammatory treatments in LD animal models were identified and included in the review. Although LD has long been dominated by a neuronocentric view, a growing body of evidence suggests a role of glial cells in the disease, starting with the finding that these cells accumulate PBs. We discuss the potential meaning of glial PB accumulations, the likely factors activating glial cells, and the possible contribution of glial cells to LD neurodegeneration and epilepsy. CONCLUSIONS Given the evidence for the role of neuroinflammation in LD, future studies should consider glial cells as a potential therapeutic target for modifying/delaying LD progression; however, it should be kept in mind that these cells can potentially assume multiple reactive phenotypes, which could influence the therapeutic response.
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Affiliation(s)
- Stefania Della Vecchia
- Molecular Medicine and Neurogenetics, IRCCS Stella Maris Foundation, Calambrone, 56128 Pisa, Italy
- Correspondence: (S.D.V.); (F.M.S.)
| | - Maria Marchese
- Neurobiology, IRCCS Stella Maris Foundation, Calambrone, 56128 Pisa, Italy
| | - Filippo Maria Santorelli
- Molecular Medicine and Neurogenetics, IRCCS Stella Maris Foundation, Calambrone, 56128 Pisa, Italy
- Neurobiology, IRCCS Stella Maris Foundation, Calambrone, 56128 Pisa, Italy
- Correspondence: (S.D.V.); (F.M.S.)
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Demeny H, Florea B, Tabaran F, Danciu CG, Ognean L. EEG Patterns Orienting to Lafora Disease Diagnosis-A Case Report in Two Beagles. Front Vet Sci 2020; 7:589430. [PMID: 33251270 PMCID: PMC7674959 DOI: 10.3389/fvets.2020.589430] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 10/08/2020] [Indexed: 11/21/2022] Open
Abstract
Lafora Disease (LD) is a rare, fatal, late-onset, progressive form of myoclonic epilepsy, occurring in humans and dogs. Clinical manifestations of LD usually include seizures, spontaneous and reflex myoclonus with contractions of the neck and limb muscles. We studied the electroencephalogram (EEG) patterns of two beagles in whom LD was subsequently confirmed by genetic testing. In both cases, the EEG recordings, accompanied by electromyography (EMG), have shown similar uncommon patterns. The hypovoltaged background rhythm was interrupted by waxing “crescendo” polyspikes-slow wave complexes appearing 80–250 ms after the start of intermittent photic stimulation, followed by myoclonic jerks after 80–150 ms. This study highlights the value of EEG in establishing a presumptive diagnosis of LD in dogs.
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Affiliation(s)
- Helga Demeny
- Department of Preclinical and Clinical Sciences, Faculty of Veterinary Medicine, University of Agricultural Sciences and Veterinary Medicine, Cluj-Napoca, Romania
| | - Bogdan Florea
- Epilepsy and EEG Monitoring Center, Cluj-Napoca, Romania
| | - Flaviu Tabaran
- Department of Preclinical and Clinical Sciences, Faculty of Veterinary Medicine, University of Agricultural Sciences and Veterinary Medicine, Cluj-Napoca, Romania
| | - Cecilia Gabriella Danciu
- Department of Preclinical and Clinical Sciences, Faculty of Veterinary Medicine, University of Agricultural Sciences and Veterinary Medicine, Cluj-Napoca, Romania
| | - Laurent Ognean
- Department of Preclinical and Clinical Sciences, Faculty of Veterinary Medicine, University of Agricultural Sciences and Veterinary Medicine, Cluj-Napoca, Romania
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Farah BL, Yen PM, Koeberl DD. Links between autophagy and disorders of glycogen metabolism - Perspectives on pathogenesis and possible treatments. Mol Genet Metab 2020; 129:3-12. [PMID: 31787497 PMCID: PMC7836271 DOI: 10.1016/j.ymgme.2019.11.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 11/18/2019] [Accepted: 11/19/2019] [Indexed: 01/17/2023]
Abstract
The glycogen storage diseases are a group of inherited metabolic disorders that are characterized by specific enzymatic defects involving the synthesis or degradation of glycogen. Each disorder presents with a set of symptoms that are due to the underlying enzyme deficiency and the particular tissues that are affected. Autophagy is a process by which cells degrade and recycle unneeded or damaged intracellular components such as lipids, glycogen, and damaged mitochondria. Recent studies showed that several of the glycogen storage disorders have abnormal autophagy which can disturb normal cellular metabolism and/or mitochondrial function. Here, we provide a clinical overview of the glycogen storage disorders, a brief description of autophagy, and the known links between specific glycogen storage disorders and autophagy.
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Affiliation(s)
- Benjamin L Farah
- Department of Pathology, Singapore General Hospital, Singapore, Singapore.
| | - Paul M Yen
- Cardiovascular and Metabolic Disorders Program, Duke-NUS Medical School, Singapore, Singapore; Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, NC, USA
| | - Dwight D Koeberl
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical School, Durham, NC, USA; Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA..
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Sathiah P, Gochhait D, Dehuri P, Subramanian H. Diagnosis of Lafora Disease by Skin Biopsy. J Clin Diagn Res 2017; 11:EJ01-EJ02. [PMID: 29207724 DOI: 10.7860/jcdr/2017/28570.10552] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 05/30/2017] [Indexed: 11/24/2022]
Affiliation(s)
- Prasath Sathiah
- Senior Resident, Department of Pathology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Debasis Gochhait
- Assistant Professor, Department of Pathology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Priyadarshini Dehuri
- Senior Resident, Department of Pathology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Hema Subramanian
- Senior Resident, Department of Pathology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
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Chandramouli C, Varma U, Stevens EM, Xiao RP, Stapleton DI, Mellor KM, Delbridge LMD. Myocardial glycogen dynamics: New perspectives on disease mechanisms. Clin Exp Pharmacol Physiol 2015; 42:415-25. [DOI: 10.1111/1440-1681.12370] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 12/29/2014] [Accepted: 01/06/2015] [Indexed: 11/26/2022]
Affiliation(s)
| | - Upasna Varma
- Department of Physiology; University of Melbourne; Melbourne Vic. Australia
| | - Ellie M Stevens
- Department of Physiology; University of Auckland; Auckland New Zealand
| | - Rui-Ping Xiao
- Institute of Molecular Medicine; Peking University; Beijing China
| | - David I Stapleton
- Department of Physiology; University of Melbourne; Melbourne Vic. Australia
- The Florey Institute of Neuroscience; Melbourne Vic. Australia
| | - Kimberley M Mellor
- Department of Physiology; University of Melbourne; Melbourne Vic. Australia
- Department of Physiology; University of Auckland; Auckland New Zealand
| | - Lea MD Delbridge
- Department of Physiology; University of Melbourne; Melbourne Vic. Australia
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Santhosh NS, Sinha S, Satishchandra P. Epilepsy: Indian perspective. Ann Indian Acad Neurol 2014; 17:S3-S11. [PMID: 24791085 PMCID: PMC4001222 DOI: 10.4103/0972-2327.128643] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 02/17/2014] [Accepted: 02/17/2014] [Indexed: 12/05/2022] Open
Abstract
There are 50 million people living with epilepsy worldwide, and most of them reside in developing countries. About 10 million persons with epilepsy are there in India. Many people with active epilepsy do not receive appropriate treatment for their condition, leading to large treatment gap. The lack of knowledge of antiepileptic drugs, poverty, cultural beliefs, stigma, poor health infrastructure, and shortage of trained professionals contribute for the treatment gap. Infectious diseases play an important role in seizures and long-term burden causing both new-onset epilepsy and status epilepticus. Proper education and appropriate health care services can make tremendous change in a country like India. There have been many original researches in various aspects of epilepsy across India. Some of the geographically specific epilepsies occur only in certain regions of our country which have been highlighted by authors. Even the pre-surgical evaluation and epilepsy surgery in patients with drug-resistant epilepsy is available in many centers in our country. This article attempts to provide a complete preview of epilepsy in India.
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Affiliation(s)
| | - Sanjib Sinha
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India
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9
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[Lafora disease: histopathological study of axillary cutaneous biopsy]. Ann Pathol 2013; 33:84-6. [PMID: 23582833 DOI: 10.1016/j.annpat.2013.02.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 11/07/2011] [Accepted: 02/11/2013] [Indexed: 11/21/2022]
Abstract
Lafora body disease is a common and severe form of progressive myoclonic epilepsy. It is an autosomal recessive disorder with a gene locus recently mapped to chromosome 6q23-27. The disease presents between the age of 10 and 18 years with generalised seizures followed by myoclunus. Intellectual deterioration occurs early and progresses to dementia. The diagnosis must be usually confirmed by demonstrating Lafora bodies. The practical procedure is the axillary skin biopsy that shows PAS positive inclusion in the cells of the sweet ducts. We present a case of Lafora disease discovered in a 26-year-old man. Moreover, we emphasize on the diagnosis difficulties of this disease.
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10
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Sharma J, Mukherjee D, Rao SNR, Iyengar S, Shankar SK, Satishchandra P, Jana NR. Neuronatin-mediated aberrant calcium signaling and endoplasmic reticulum stress underlie neuropathology in Lafora disease. J Biol Chem 2013; 288:9482-90. [PMID: 23408434 DOI: 10.1074/jbc.m112.416180] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Lafora disease (LD) is a teenage-onset inherited progressive myoclonus epilepsy characterized by the accumulations of intracellular inclusions called Lafora bodies and caused by mutations in protein phosphatase laforin or ubiquitin ligase malin. But how the loss of function of either laforin or malin causes disease pathogenesis is poorly understood. Recently, neuronatin was identified as a novel substrate of malin that regulates glycogen synthesis. Here we demonstrate that the level of neuronatin is significantly up-regulated in the skin biopsy sample of LD patients having mutations in both malin and laforin. Neuronatin is highly expressed in human fetal brain with gradual decrease in expression in developing and adult brain. However, in adult brain, neuronatin is predominantly expressed in parvalbumin-positive GABAergic interneurons and localized in their processes. The level of neuronatin is increased and accumulated as insoluble aggregates in the cortical area of LD brain biopsy samples, and there is also a dramatic loss of parvalbumin-positive GABAergic interneurons. Ectopic expression of neuronatin in cultured neuronal cells results in increased intracellular Ca(2+), endoplasmic reticulum stress, proteasomal dysfunction, and cell death that can be partially rescued by malin. These findings suggest that the neuronatin-induced aberrant Ca(2+) signaling and endoplasmic reticulum stress might underlie LD pathogenesis.
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Affiliation(s)
- Jaiprakash Sharma
- Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar, Gurgaon 122 050, India
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11
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Sharma J, Mulherkar S, Mukherjee D, Jana NR. Malin regulates Wnt signaling pathway through degradation of dishevelled2. J Biol Chem 2012; 287:6830-9. [PMID: 22223637 DOI: 10.1074/jbc.m111.315135] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Using yeast-two hybrid screening followed by co-immunoprecipitation assay, we have found that the Lafora disease ubiquitin ligase malin interacts with dishevelled2, a key mediator of Wnt signaling pathway. Overexpression of malin enhances the degradation of dishevelled2 and inhibits Wnt signaling, which is evident from the down-regulation of β-catenin target genes and the decrease in β-catenin-mediated transcriptional activity. Partial knockdown of malin significantly increases the level of dishevelled2 and up-regulates Wnt signaling. Several malin mutants are found to be ineffective in degrading dishevelled2 and regulating the Wnt pathway. We have also found that malin enhances K48- and K63-linked ubiquitination of dishevelled2 that could lead to its degradation through both proteasome and autophagy. Altogether, our results indicate that malin regulates Wnt signaling pathway through the degradation of dishevelled2 and suggest possible deregulation of Wnt signaling in Lafora disease.
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Affiliation(s)
- Jaiprakash Sharma
- Cellular and Molecular Neuroscience Laboratory, National Brain Research Centre, Manesar, Gurgaon 122 050, India
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12
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Sharma J, Rao SNR, Shankar SK, Satishchandra P, Jana NR. Lafora disease ubiquitin ligase malin promotes proteasomal degradation of neuronatin and regulates glycogen synthesis. Neurobiol Dis 2011; 44:133-41. [PMID: 21742036 DOI: 10.1016/j.nbd.2011.06.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 05/27/2011] [Accepted: 06/16/2011] [Indexed: 01/01/2023] Open
Abstract
Lafora disease (LD) is the inherited progressive myoclonus epilepsy caused by mutations in either EPM2A gene, encoding the protein phosphatase laforin or the NHLRC1 gene, encoding the ubiquitin ligase malin. Since malin is an ubiquitin ligase and its mutations cause LD, it is hypothesized that improper clearance of its substrates might lead to LD pathogenesis. Here, we demonstrate for the first time that neuronatin is a novel substrate of malin. Malin interacts with neuronatin and enhances its degradation through proteasome. Interestingly, neuronatin is an aggregate prone protein, forms aggresome upon inhibition of cellular proteasome function and malin recruited to those aggresomes. Neuronatin is found to stimulate the glycogen synthesis through the activation of glycogen synthase and malin prevents neuronatin-induced glycogen synthesis. Several LD-associated mutants of malin are ineffective in the degradation of neuronatin and suppression of neuronatin-induced glycogen synthesis. Finally, we demonstrate the increased levels of neuronatin in the skin biopsy sample of LD patients. Overall, our results indicate that malin negatively regulates neuronatin and its loss of function in LD results in increased accumulation of neuronatin, which might be implicated in the formation of Lafora body or other aspect of disease pathogenesis.
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Affiliation(s)
- Jaiprakash Sharma
- Cellular and Molecular Neuroscience Laboratory, National Brain Research Centre, Manesar, Gurgaon-122 050, India
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Rao SN, Maity R, Sharma J, Dey P, Shankar SK, Satishchandra P, Jana NR. Sequestration of chaperones and proteasome into Lafora bodies and proteasomal dysfunction induced by Lafora disease-associated mutations of malin. Hum Mol Genet 2010; 19:4726-34. [DOI: 10.1093/hmg/ddq407] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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Abstract
Lafora disease is a rare, fatal, autosomal recessive, progressive myoclonic epilepsy. It may also be considered as a disorder of carbohydrate metabolism because of the formation of polyglucosan inclusion bodies in neural and other tissues due to abnormalities of the proteins laforin or malin. The condition is characterized by epilepsy, myoclonus and dementia. Diagnostic findings on MRI and neurophysiological testing are not definitive and biopsy or genetic studies may be required. Therapy in Lafora disease is currently limited to symptomatic management of the epilepsy, myoclonus and intercurrent complications. With a greater understanding of the pathophysiological processes involved, there is justified hope for future therapies.
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Affiliation(s)
- Thomas S Monaghan
- Department of Neurology and Neuroscience, Beaumont Hospital and Royal College of Surgeons in Ireland, Dublin 9, Ireland
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Rao SNR, Sharma J, Maity R, Jana NR. Co-chaperone CHIP stabilizes aggregate-prone malin, a ubiquitin ligase mutated in Lafora disease. J Biol Chem 2010; 285:1404-13. [PMID: 19892702 PMCID: PMC2801266 DOI: 10.1074/jbc.m109.006312] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2009] [Revised: 11/04/2009] [Indexed: 01/21/2023] Open
Abstract
Lafora disease (LD) is an autosomal recessive neurodegenerative disorder caused by mutation in either the dual specificity phosphatase laforin or ubiquitin ligase malin. A pathological hallmark of LD is the accumulation of cytoplasmic polyglucosan inclusions commonly known as Lafora bodies in both neuronal and non-neuronal tissues. How mutations in these two proteins cause disease pathogenesis is not well understood. Malin interacts with laforin and recruits to aggresomes upon proteasome inhibition and was shown to degrade misfolded proteins. Here we report that malin is spontaneously misfolded and tends to be aggregated, degraded by proteasomes, and forms not only aggresomes but also other cytoplasmic and nuclear aggregates in all transfected cells upon proteasomal inhibition. Malin also interacts with Hsp70. Several disease-causing mutants of malin are comparatively more unstable than wild type and form aggregates in most transfected cells even without the inhibition of proteasome function. These cytoplasmic and nuclear aggregates are immunoreactive to ubiquitin and 20 S proteasome. Interestingly, progressive proteasomal dysfunction and cell death is also most frequently observed in the mutant malin-overexpressed cells compared with the wild-type counterpart. Finally, we demonstrate that the co-chaperone carboxyl terminus of the Hsc70-interacting protein (CHIP) stabilizes malin by modulating the activity of Hsp70. All together, our results suggest that malin is unstable, and the aggregate-prone protein and co-chaperone CHIP can modulate its stability.
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Affiliation(s)
- Sudheendra N. R. Rao
- From the Cellular and Molecular Neuroscience Laboratory, National Brain Research Centre, Manesar, Gurgaon-122 050, India
| | - Jaiprakash Sharma
- From the Cellular and Molecular Neuroscience Laboratory, National Brain Research Centre, Manesar, Gurgaon-122 050, India
| | - Ranjan Maity
- From the Cellular and Molecular Neuroscience Laboratory, National Brain Research Centre, Manesar, Gurgaon-122 050, India
| | - Nihar Ranjan Jana
- From the Cellular and Molecular Neuroscience Laboratory, National Brain Research Centre, Manesar, Gurgaon-122 050, India
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Egawa K, Takahashi Y, Kubota Y, Kubota H, Inoue Y, Fujiwara T, Onodera O. Electroclinical features of epilepsy in patients with juvenile type dentatorubral-pallidoluysian atrophy. Epilepsia 2008; 49:2041-9. [DOI: 10.1111/j.1528-1167.2008.01701.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
Abstract Lafora progressive myoclonus epilepsy is an autosomal recessive, fatal, generalized polyglucosan storage disorder that occurs in childhood or adolescence with stimulus sensitive epilepsy (resting and action myoclonias, grand mal, and absence), dementia, ataxia and rapid neurologic deterioration. Mutations in EPM2A/laforin cause 58% of cases and mutations in EPM2B/malin cause 35% of cases. Accumulating evidence points to Lafora disease as primarily a disorder of cell death with impaired clearance of misfolded proteins, as shown by ubiquitin-positive aggresomes in HeLa cells transfected with mutated laforin, ubiquitin-positive polyglucosan inclusion bodies, and malin/E3 ubiquitin ligase polyubiquitination of laforin. How polyglucosan inclusion bodies accumulate is still a mystery. Polyglucosan accumulates hypothetically because of an overactive polyglucosan biosynthetic pathway or a breakdown in polyglucosan degradation. Five separate laboratories are looking for the biochemical pathways that connect laforin and malin to polyglucosan synthesis or degradation. A curative therapy for human Lafora disease with laforin replacement therapy using neutral pegylated immunoliposomes is being investigated.
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Affiliation(s)
- Antonio V Delgado-Escueta
- Comprehensive Epilepsy Program, Epilepsy Genetics/Genomics Laboratories, VA Greater Los Angeles Healthcare System, 11301 Wilshire Boulevard, West Los Angeles, CA 90073, USA.
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Abstract
Lafora's disease (LD) is a comparatively frequent and particularly severe type of progressive myoclonus epilepsy. Prevalence varies, LD is seen everywhere but is more common in geographic isolates and areas with high degree of inbreeding. Onset occurs during adolescence, with generalized tonic-clonic, clonic-tonic-clonic seizures, action and resting myoclonus, negative myoclonus, and focal occipital seizures with transient amaurosis. The course is marked by prominent cognitive deterioration, which can precede seizures and myoclonus, and by the progressive, relentless increase of seizures and myoclonus. Transmission is autosomal recessive. LD is genetically heterogeneous. Mutations/deletions of the EPM2A gene, localized in 1995 on 6q24, are found in 80p.cent (product: laforin), the less common EPM2B variant is on 6p22 (product: malin), but these two localizations do not account for all cases of LD. The diagnosis of LD may be suspected on the basis of the family history, age at onset, typical appearance of symptoms, rapid worsening of cognitive function, evaluation of fairly typical EEG aspects, and can easily be confirmed by axillar skin biopsy with proof of Lafora bodies (polyglucosan aggregates) in the sweat duct cells. Other biopsies, like brain biopsy, are generally not necessary. Genetic testing is useful for diagnosis but the genetic heterogeneity cannot rule out LD when none of the known mutations are detected. Genetic counselling and prenatal diagnosis are theoretically possible when the genetic anomaly has been documented in an affected member of the family. The treatment of LD remains purely symptomatic. Drugs that may aggravate myoclonus must be avoided. Psychological and social management is of utmost importance in LD. Death occurs 4 to 10 years after onset in typical forms.
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Affiliation(s)
- P Genton
- Centre Saint Paul - H. Gastaut, Marseille.
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Sinha S, Satishchandra P, Gayathri N, Yasha TC, Shankar SK. Progressive myoclonic epilepsy: A clinical, electrophysiological and pathological study from South India. J Neurol Sci 2007; 252:16-23. [PMID: 17166519 DOI: 10.1016/j.jns.2006.09.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Revised: 08/18/2006] [Accepted: 09/27/2006] [Indexed: 11/18/2022]
Abstract
Progressive myoclonic epilepsy (PME) is a syndrome complex encompassing different diagnostic entities and often cause problems in diagnosis. We describe the clinical, electrophysiological and pathological features of 97 patients with the diagnosis of PME evaluated over 25 years. Case records of confirmed patients of Neuronal ceroid lipofuscinosis (NCL = 40), Lafora body disease (LBD = 38), Myoclonic epilepsy with ragged red fibers (MERRF = 10), and probable Unverricht-Lundberg disease (ULD = 9) were reviewed. The mean age at onset in patients with NCL (n = 40) was 5.9+/-9.1 years (M:F:: 28:12). Subtypes of NCL were: late infantile (n = 19), infantile (n = 8), juvenile (n = 11) and adult (n = 2) NCL. EEG (n = 37) showed varying degree of diffuse slowing of background activity in 94.6% and epileptiform discharges in 81.1% of patients. Slow frequency photic stimulation evoked photo-convulsive response in 5 patients only. Giant SSEP was demonstrated in 7 and VEP study revealed a prolonged P100 (2) and absent waveform (7). Electrophysiological features of neuropathy were present in 3 patients. Presence of PAS and Luxol Fast Blue (LFB) positive, auto fluorescent (AF) ceroid material in brain tissue (n = 12) and electron microscopy of brain (n = 5), skin (n = 28) and muscle (n = 1) samples showing curvilinear and lamellar bodies established the diagnosis. Patients of LBD (mean age of onset at 14.4+/-3.9 years, M:F:: 24:14) with triad of PME symptoms were evaluated. EEG (n = 37) showed variable slowing of background activity in 94.6% and epileptiform discharges in 97.4%. Photosensitivity with fast frequency was observed only in 5 patients. CT (n = 32) and MRI (n = 4) revealed diffuse cortical atrophy. Giant SSEP was demonstrated in 24 patients of LBD while VEP study revealed a prolonged P100 (4) and absent waveform (8). Electrophysiological features of neuropathy were present in one patient. Diagnosis was established by the presence of PAS positive diastase resistant, Lugol's Iodine labeled inclusions in sweat glands of axillary skin (n = 35), brain (n = 2) and liver (n = 1). Ten patients with MERRF (mean age at onset: 14.6+/-5.8 years; M: F:: 3:2) had triad of PME symptoms. Muscle biopsy revealed oxidative reaction product and classical ragged red fibers. In nine patients of PME without cognitive decline, probable diagnosis of ULD (mean age at onset: 13.8+/-9.5 years) was considered after biopsy of skin and/or muscle excluded other forms of PMEs. Neuronal ceroid lipofuscinosis and Lafora body diseases were the common causes of PME in the series from south India. This is one of the largest series from the Indian subcontinent to the best of our knowledge. Photosensitivity is notably less common in LBD/NCL in this series distinctly different from those reported in the literature. Further exploration is required to determine whether different genotype is responsible. Morphological changes were helpful in diagnosis and could be confirmed by biopsy of peripheral tissues like skin and muscle in majority (60%). Electron microscopy was helpful in the diagnosis NCL and MERRF.
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Affiliation(s)
- S Sinha
- Department of Neurology, National Institute of Mental Health and NeuroSciences (NIMHANS), Bangalore, India.
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Abstract
Progressive myoclonic epilepsies (PMEs) are a group of rare disorders characterized by the occurrence of seizures, myoclonus, and progressive neurological dysfunction. This article discusses epidemiology, genetics, pathology, clinical manifestations, EEG characteristics, methods of diagnosis and treatment of the most common causes of PME, including Unverricht-Lundborg Disease (Baltic Myoclonus), MERRF, neuronal ceroid lipofuscinosis, dentatorubropallidoluysan atrophy, Gaucher disease, Lafora disease, and sialidosis. The aim of this paper is to provide clinicians with useful clinical information in order to facilitate the diagnosis and treatment of these rare diseases.
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Affiliation(s)
- Mary L Zupanc
- Department of Neurology and Pediatrics, Children's Hospital of Wisconsin, Milwaukee, Wisconsin, USA
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Delgado-Escueta AV, Ganesh S, Yamakawa K. Advances in the genetics of progressive myoclonus epilepsy. AMERICAN JOURNAL OF MEDICAL GENETICS 2002; 106:129-38. [PMID: 11579433 DOI: 10.1002/ajmg.1575] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The genetic progressive myoclonus epilepsies (PMEs) are clinically characterized by the triad of stimulus sensitive myoclonus (segmental lightning like muscular jerks), epilepsy (grand mal and absences) and progressive neurologic deterioration (dementia, ataxia, and various neurologic signs depending on the cause). Etiologically heterogenous, PMEs are rare and mostly autosomal recessive disorders, with the exception of autosomal dominant dentatorubral-pallidoluysian atrophy and mitochondrial encephalomyopathy with ragged red fibers (MERRF). In the last five years, specific mutations have been defined in Lafora disease (gene for laforin or dual specificity phosphatase in 6q24), Unverricht-Lundborg disease (cystatin B in 21q22.3), Jansky-Bielschowsky ceroid lipofuscinoses (CLN2 gene for tripeptidyl peptidase 1 in 11q15), Finnish variant of late infantile ceroid lipofuscinoses (CLN5 gene in 13q21-32 encodes 407 amino acids with two transmembrane helices of unknown function), juvenile ceroid lipofuscinoses or Batten disease (CLN3 gene in 16p encodes 438 amino acid protein of unknown function), a subtype of Batten disease and infantile ceroid lipofuscinoses of the Haltia-Santavuori type (both are caused by mutations in palmitoyl-protein thiosterase gene at 1p32), dentadorubropallidoluysian atrophy (CAG repeats in a gene in 12p13.31) and the mitochondrial syndrome MERRF (tRNA Lys mutation in mitochondrial DNA). In this review, we cover mainly these rapid advances.
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Affiliation(s)
- A V Delgado-Escueta
- Comprehensive Epilepsy Program, Epilepsy Genetics/Genomics Laboratories, VA GLAHS-West Los Angeles Medical Center, University of California, 90095-1769, USA.
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Ganesh S, Shoda K, Amano K, Uchiyama A, Kumada S, Moriyama N, Hirose S, Yamakawa K. Mutation screening for Japanese Lafora's disease patients: identification of novel sequence variants in the coding and upstream regulatory regions of EPM2A gene. Mol Cell Probes 2001; 15:281-9. [PMID: 11735300 DOI: 10.1006/mcpr.2001.0371] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The progressive myoclonus epilepsy of Lafora type (LD) is an autosomal recessive disorder caused by mutations in the EPM2A gene. We demonstrated recently that EPM2A encodes a dual-specificity phosphatase that is primarily associated with polyribosomes. In the present study, we screened for mutations in the EPM2A gene in 4 Japanese LD families and identified a novel mis-sense mutation, Ala46Pro (136G-->C), in heterozygous condition in one patient. In addition, sequence analyses in the patient and control DNA samples identified 4 single nucleotide polymorphisms (SNPs) (75G/A, 120G/T, 159C/G, 171C/T) in the coding region and a novel insertion/deletion polymorphic site (-483[T](11/10)[A](2/3)) and a SNP (-547A/G) in the putative regulatory region of the EPM2A gene. None of the sequence variants, however, co-segregated with the LD phenotype. Haplotype analysis for the 6q24 region in the affected families revealed lack of homozygosity at the EPM2A locus. Our studies suggest that EPM2A is not involved in the disease phenotype of the 4 families studied and that locus heterogeneity for LD may exist in Japanese population also. A simple test described for the detection of Ala46Pro mutation present heterozygously in Japanese population (allele frequency 0.026) can be used for screening this novel allele in a larger sample size.
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Affiliation(s)
- S Ganesh
- Laboratory for Neurogenetics, RIKEN Brain Science Institute, 2-1, Hirosawa, Wako-shi, Saitama 351-0198, Japan
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de Quadros A, Sá DS, Kowacs PA, Teive HA, Werneck LC. [Lafora's disease and movement disorders: report of 2 cases]. ARQUIVOS DE NEURO-PSIQUIATRIA 2000; 58:720-3. [PMID: 10973115 DOI: 10.1590/s0004-282x2000000400019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Two cases of Lafora's disease with prominent movement disorders portraying rare initial manifestations are reported. In both patients, the first manifestations were cerebellar ataxia, dysartria and startle phenomenon. These symptoms occurred before seizures, myoclonic and progressive dementia, which are more well known as manifestations of Lafora's disease. The diagnosis was confirmed by the identification of PAS positive inclusion bodies in deep skin biopsy samples. Our patients presented an unexpected slow progression of the disease, with longer survival. Lafora's disease should be remembered among diseases causing slowly progressive ataxia associated with epileptic seizures.
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Affiliation(s)
- A de Quadros
- Departamento de Clínica Médica, Hospital de Clínicas, Universidade Federal do Paraná
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Abstract
Lafora disease is a fatal neurometabolic disorder characterized by progressive myoclonic epilepsy. Diagnosis relies upon the discovery of specific inclusion bodies in any of several organs. Dermatologists and dermatopathologists should be familiar with this condition because axillary skin biopsy is useful to diagnose this disorder. We present a case of Lafora disease diagnosed by axillary skin biopsy and review the condition's clinical, histologic, and ultrastructural features.
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Affiliation(s)
- D Karimipour
- Department of Dermatology, University of Michigan Medical Center and University of Michigan Comprehensive Cancer Center, Ann Arbor 48109-0314, USA
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Minassian BA, Lee JR, Herbrick JA, Huizenga J, Soder S, Mungall AJ, Dunham I, Gardner R, Fong CY, Carpenter S, Jardim L, Satishchandra P, Andermann E, Snead OC, Lopes-Cendes I, Tsui LC, Delgado-Escueta AV, Rouleau GA, Scherer SW. Mutations in a gene encoding a novel protein tyrosine phosphatase cause progressive myoclonus epilepsy. Nat Genet 1998; 20:171-4. [PMID: 9771710 DOI: 10.1038/2470] [Citation(s) in RCA: 329] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Lafora's disease (LD; OMIM 254780) is an autosomal recessive form of progressive myoclonus epilepsy characterized by seizures and cumulative neurological deterioration. Onset occurs during late childhood and usually results in death within ten years of the first symptoms. With few exceptions, patients follow a homogeneous clinical course despite the existence of genetic heterogeneity. Biopsy of various tissues, including brain, revealed characteristic polyglucosan inclusions called Lafora bodies, which suggested LD might be a generalized storage disease. Using a positional cloning approach, we have identified at chromosome 6q24 a novel gene, EPM2A, that encodes a protein with consensus amino acid sequence indicative of a protein tyrosine phosphatase (PTP). mRNA transcripts representing alternatively spliced forms of EPM2A were found in every tissue examined, including brain. Six distinct DNA sequence variations in EPM2A in nine families, and one homozygous microdeletion in another family, have been found to cosegregate with LD. These mutations are predicted to cause deleterious effects in the putative protein product, named laforin, resulting in LD.
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Affiliation(s)
- B A Minassian
- Department of Genetics, The Hospital for Sick Children, University of Toronto, Ontario, Canada
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Hirvasniemi A, Herrala P, Leisti J. Northern epilepsy syndrome: clinical course and the effect of medication on seizures. Epilepsia 1995; 36:792-7. [PMID: 7635097 DOI: 10.1111/j.1528-1157.1995.tb01616.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We describe the clinical course and treatment of 19 patients with the Northern epilepsy syndrome, an autosomal recessively inherited epilepsy with associated mental deterioration. The clinical course could be divided into three successive stages. The first stage continued from the onset of epilepsy until puberty. Seizures began at a mean age of 6.6 years and consisted predominantly of generalized tonic-clonic convulsions (GTC) and, transiently, also of complex partial seizures (CPS). Until puberty, seizure frequency increased in most patients from one attack in 1-2 months to one to two attacks weekly. Seizures did not respond to phenytoin (PHT) or carbamazepine (CBZ), were transiently controlled by valproate (VPA) and phenobarbital (PB), but were effectively treated only by clonazepam (CZP). Mental deterioration began 2-5 years after the onset of epilepsy and was most rapid before adulthood, a time when the seizures were also most frequent. The second stage is marked by fewer seizures, further mental deterioration, and less rapid progression. All patients were demented (I.Q. < 70) by age of 30 years. The first signs of motor clumsiness also appeared then. The third stage was one of permanent disability and usually began in middle age. Seizures were few, but the patients were clumsy and had marked equilibrium difficulties.
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Affiliation(s)
- A Hirvasniemi
- Department of Pediatrics, Kainuu Central Hospital, Kajaani, Finland
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Acharya JN, Satishchandra P, Shankar SK. Familial progressive myoclonus epilepsy: clinical and electrophysiologic observations. Epilepsia 1995; 36:429-34. [PMID: 7614918 DOI: 10.1111/j.1528-1157.1995.tb00482.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Progressive myoclonus epilepsy (PME) is a syndrome complex encompassing different diagnostic entities. Among the 30 cases of PME studied during 1982 and 1992 at the National Institute of Mental Health and Neurosciences, Bangalore, South India, the specific diagnoses included Lafora disease (LD), neuronal ceroid lipofuscinosis (NCL). Unverricht-Lundborg disease (ULD), and myoclonus epilepsy and ragged-red fibres (MERRF). We discuss the familial nature of PME and the clinical and electrophysiological abnormalities in asymptomatic siblings. Eight cases of LD were in three different families with 3 affected siblings in two families (L1, L2) and 2 siblings in the third family (L3). Occipital seizures and behavioral changes occurred in all 3 members of L1 but were absent in the other two families. Age of onset was similar in two families (L1, 11 years; L2, 14.5 years), but not in the third. Presymptomatic EEG abnormalities were observed as long as 6 years before onset in L2. ULD occurred in 2 sisters in one family. Both had identical clinical features and normal somatosensory evoked potentials (SSEPs). The asymptomatic sister of the patient MERRF had abnormal EEG and giant SSEPs for the past 2 years. Thus, although all variations are evident in the overall clinical pattern in each of the PME, affected member of individuals families tend to be similar. Once an index case is identified, electrophysiologic tests (EEG and SSEP) may be useful in identifying other affected siblings in the presymptomatic stage.
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Affiliation(s)
- J N Acharya
- Department of Neurology, National Institute of Mental Health and Neuro Sciences (NIMHANS), Bangalore, India
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