1
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Cameron JM, Ellis CA, Berkovic SF. ILAE Genetics Literacy series: Progressive myoclonus epilepsies. Epileptic Disord 2023; 25:670-680. [PMID: 37616028 PMCID: PMC10947580 DOI: 10.1002/epd2.20152] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 07/21/2023] [Accepted: 08/19/2023] [Indexed: 08/25/2023]
Abstract
Progressive Myoclonus Epilepsy (PME) is a rare epilepsy syndrome characterized by the development of progressively worsening myoclonus, ataxia, and seizures. A molecular diagnosis can now be established in approximately 80% of individuals with PME. Almost fifty genetic causes of PME have now been established, although some remain extremely rare. Herein, we provide a review of clinical phenotypes and genotypes of the more commonly encountered PMEs. Using an illustrative case example, we describe appropriate clinical investigation and therapeutic strategies to guide the management of this often relentlessly progressive and devastating epilepsy syndrome. This manuscript in the Genetic Literacy series maps to Learning Objective 1.2 of the ILAE Curriculum for Epileptology (Epileptic Disord. 2019;21:129).
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Affiliation(s)
- Jillian M. Cameron
- Epilepsy Research Centre, Department of MedicineUniversity of MelbourneAustin HealthMelbourneVictoriaAustralia
| | - Colin A. Ellis
- Department of NeurologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvaniaUSA
| | - Samuel F. Berkovic
- Epilepsy Research Centre, Department of MedicineUniversity of MelbourneAustin HealthMelbourneVictoriaAustralia
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2
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Hyppönen J, Paanila V, Äikiä M, Koskenkorva P, Könönen M, Vanninen R, Mervaala E, Kälviäinen R, Hakumäki J. Progressive myoclonic epilepsy type 1 (EPM1) patients present with abnormal 1H MRS brain metabolic profiles associated with cognitive function. Neuroimage Clin 2023; 39:103459. [PMID: 37541097 PMCID: PMC10412857 DOI: 10.1016/j.nicl.2023.103459] [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: 04/12/2023] [Revised: 06/14/2023] [Accepted: 06/20/2023] [Indexed: 08/06/2023]
Abstract
PURPOSE Progressive myoclonic epilepsy, type 1A (EPM1, Unverricht-Lundborg disease), is a rare neurodegenerative autosomal recessive disorder characterized by stimulus-sensitive and action myoclonus and tonic-clonic epileptic seizures. Patients develop neurological symptoms, including ataxia, intention tremor, and dysarthria, over time, with relatively limited and nonspecific MRI atrophy findings. The effects of the disease on brain metabolism are largely unknown. METHOD Eighteen EPM1 patients (9 M, 9F) underwent clinical evaluation and neuropsychological testing, which included the assessment of intellectual ability, verbal memory, and psychomotor and executive functions. Magnetic resonance spectroscopy (MRS) and imaging (MRI) were performed on a 1.5 T MRI system. 2D MRS chemical shift imaging (CSI) maps (TE = 270) were obtained from the following regions of the brain: basal ganglia, thalamus, insula, splenium, and occipital white and gray matter, and N-acetyl-aspartate (NAA)-, choline (Cho)-, and lactate (Lac)-to-creatine (Cr) ratios were analyzed. Ten healthy age-and sex-matched subjects (5M, 5F) were used as controls for MRS. RESULTS We found significant brain metabolic changes involving lactate, NAA, and choline, which are widespread in the basal ganglia, thalamic nuclei, insula, and occipital areas of EPM1 patients. Changes, especially in the right insula, basal ganglia, and thalamus, were associated with intellectual abilities and impairment of the psychomotor and executive functions of EPM1 patients. CONCLUSION Multiple brain metabolic alterations suggest the presence of neurodegeneration associated with EPM1 progression. The changes in metabolite ratios are associated with the neurocognitive dysfunction caused by the disease. However, the role of MRS findings in understanding pathophysiology of EPM1 warrants further studies.
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Affiliation(s)
- Jelena Hyppönen
- Department of Clinical Neurophysiology, Epilepsy Center, Diagnostic Imaging Center, Kuopio University Hospital, Full Member of ERN EpiCARE, Kuopio, Finland; Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Vili Paanila
- Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland; Department of Clinical Radiology, Diagnostic Imaging Center, Kuopio University Hospital, Full Member of ERN EpiCARE, Kuopio, Finland
| | - Marja Äikiä
- Epilepsy Center, Neurocenter, Kuopio University Hospital, Full Member of ERN EpiCARE, Kuopio, Finland
| | - Päivi Koskenkorva
- Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland; Department of Clinical Radiology, Diagnostic Imaging Center, Kuopio University Hospital, Full Member of ERN EpiCARE, Kuopio, Finland
| | - Mervi Könönen
- Department of Clinical Radiology, Diagnostic Imaging Center, Kuopio University Hospital, Full Member of ERN EpiCARE, Kuopio, Finland
| | - Ritva Vanninen
- Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland; Department of Clinical Radiology, Diagnostic Imaging Center, Kuopio University Hospital, Full Member of ERN EpiCARE, Kuopio, Finland
| | - Esa Mervaala
- Department of Clinical Neurophysiology, Epilepsy Center, Diagnostic Imaging Center, Kuopio University Hospital, Full Member of ERN EpiCARE, Kuopio, Finland; Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Reetta Kälviäinen
- Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland; Epilepsy Center, Neurocenter, Kuopio University Hospital, Full Member of ERN EpiCARE, Kuopio, Finland
| | - Juhana Hakumäki
- Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland; Department of Clinical Radiology, Diagnostic Imaging Center, Kuopio University Hospital, Full Member of ERN EpiCARE, Kuopio, Finland.
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3
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Gorski K, Jackson CB, Nyman TA, Rezov V, Battersby BJ, Lehesjoki AE. Progressive mitochondrial dysfunction in cerebellar synaptosomes of cystatin B-deficient mice. Front Mol Neurosci 2023; 16:1175851. [PMID: 37251643 PMCID: PMC10213208 DOI: 10.3389/fnmol.2023.1175851] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 04/25/2023] [Indexed: 05/31/2023] Open
Abstract
The involvement of mitochondrial dysfunction in cystatin B (CSTB) deficiency has been suggested, but its role in the onset of neurodegeneration, myoclonus, and ataxia in the CSTB-deficient mouse model (Cstb-/-) is yet unknown. CSTB is an inhibitor of lysosomal and nuclear cysteine cathepsins. In humans, partial loss-of-function mutations cause the progressive myoclonus epilepsy neurodegenerative disorder, EPM1. Here we applied proteome analysis and respirometry on cerebellar synaptosomes from early symptomatic (Cstb-/-) mice to identify the molecular mechanisms involved in the onset of CSTB-deficiency associated neural pathogenesis. Proteome analysis showed that CSTB deficiency is associated with differential expression of mitochondrial and synaptic proteins, and respirometry revealed a progressive impairment in mitochondrial function coinciding with the onset of myoclonus and neurodegeneration in (Cstb-/-) mice. This mitochondrial dysfunction was not associated with alterations in mitochondrial DNA copy number or membrane ultrastructure. Collectively, our results show that CSTB deficiency generates a defect in synaptic mitochondrial bioenergetics that coincides with the onset and progression of the clinical phenotypes, and thus is likely a contributor to the pathogenesis of EPM1.
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Affiliation(s)
- Katarin Gorski
- Folkhälsan Research Center, Helsinki, Finland
- Medicum, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Christopher B. Jackson
- Department of Biochemistry and Developmental Biology, Medicum, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Tuula A. Nyman
- Department of Immunology, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Veronika Rezov
- Folkhälsan Research Center, Helsinki, Finland
- Medicum, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | | | - Anna-Elina Lehesjoki
- Folkhälsan Research Center, Helsinki, Finland
- Medicum, Faculty of Medicine, University of Helsinki, Helsinki, Finland
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Daura E, Tegelberg S, Hakala P, Lehesjoki AE, Joensuu T. Cystatin B deficiency results in sustained histone H3 tail cleavage in postnatal mouse brain mediated by increased chromatin-associated cathepsin L activity. Front Mol Neurosci 2022; 15:1069122. [DOI: 10.3389/fnmol.2022.1069122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 11/14/2022] [Indexed: 12/05/2022] Open
Abstract
Cystatin B (CSTB) is a cysteine cathepsin inhibitor whose biallelic loss-of-function mutations in human result in defects in brain development and in neurodegeneration. The physiological function of CSTB is largely unknown, and the mechanisms underlying the human brain diseases remain poorly understood. We previously showed that CSTB modulates the proteolysis of the N-terminal tail of histone H3 (H3cs1) during in vitro neurogenesis. Here we investigated the significance of this mechanism in postnatal mouse brain. Spatiotemporal analysis of H3cs1 intensity showed that while H3cs1 in wild-type (wt) mice was found at varying levels during the first postnatal month, it was virtually absent in adult brain. We further showed that the high level of H3cs1 coincides with chromatin association of de novo synthesized cathepsin L suggesting a role for nuclear cathepsin L in brain development and maturation. On the contrary, the brains of Cstb–/– mice showed sustained H3cs1 proteolysis to adulthood with increased chromatin-associated cathepsin L activity, implying that CSTB regulates chromatin-associated cathepsin L activity in the postnatal mouse brain. As H3 tail proteolysis has been linked to cellular senescence in vitro, we explored the presence of several cellular senescence markers in the maturing Cstb–/– cerebellum, where we see increased levels of H3cs1. While several markers showed alterations in Cstb–/– mice, the results remained inconclusive regarding the association of deficient CSTB function with H3cs1-induced senescence. Together, we identify a molecular role for CSTB in brain with implications for brain development and disease.
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5
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Žerovnik E. Human stefin B: from its structure, folding, and aggregation to its function in health and disease. Front Mol Neurosci 2022; 15:1009976. [PMID: 36340691 PMCID: PMC9634419 DOI: 10.3389/fnmol.2022.1009976] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 09/01/2022] [Indexed: 01/11/2024] Open
Abstract
Mutations in the gene for human stefin B (cystatin B) cause progressive myoclonic epilepsy type 1 (EPM1), a neurodegenerative disorder. The most common change is dodecamer repeats in the promoter region of the gene, though missense and frameshift mutations also appear. Human stefin B primarily acts as a cysteine cathepsin inhibitor, and it also exhibits alternative functions. It plays a protective role against oxidative stress, likely via reducing mitochondrial damage and thus generating fewer mitochondrial reactive oxygen species (ROS). Accordingly, lack of stefin B results in increased inflammation and NLRP3 inflammasome activation, producing more ROS. The protein is cytosolic but also has an important role in the nucleus, where it prevents cleavage of the N terminal part of histone 3 by inhibiting cathepsins L and B and thus regulates transcription and cell cycle. Furthermore, it has been shown that stefin B is oligomeric in cells and that it has a specific role in the physiology of the synapse and in vesicular transport. On the basis of my research team's data on the structure, folding, and aggregation of stefin B, we have proposed that it might regulate proteostasis, possessing a chaperone-like function. In this review, I synthesize these observations and derive some conclusions on possible sources of EPM1 pathology. The interaction partners of stefin B and other gene mutations leading to EPM1-like pathology are discussed and common pathways are pinpointed.
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Affiliation(s)
- Eva Žerovnik
- Department of Biochemistry and Molecular and Structural Biology, Jožef Stefan Institute, Ljubljana, Slovenia
- Jožef Stefan International Postgraduate School, Ljubljana, Slovenia
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Daura E, Tegelberg S, Yoshihara M, Jackson C, Simonetti F, Aksentjeff K, Ezer S, Hakala P, Katayama S, Kere J, Lehesjoki AE, Joensuu T. Cystatin B-deficiency triggers ectopic histone H3 tail cleavage during neurogenesis. Neurobiol Dis 2021; 156:105418. [PMID: 34102276 DOI: 10.1016/j.nbd.2021.105418] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/30/2021] [Accepted: 06/04/2021] [Indexed: 12/29/2022] Open
Abstract
Cystatin B (CSTB) acts as an inhibitor of cysteine proteases of the cathepsin family and loss-of-function mutations result in human brain diseases with a genotype-phenotype correlation. In the most severe case, CSTB-deficiency disrupts brain development, and yet the molecular basis of this mechanism is missing. Here, we establish CSTB as a regulator of chromatin structure during neural stem cell renewal and differentiation. Murine neural precursor cells (NPCs) undergo transient proteolytic cleavage of the N-terminal histone H3 tail by cathepsins B and L upon induction of differentiation into neurons and glia. In contrast, CSTB-deficiency triggers premature H3 tail cleavage in undifferentiated self-renewing NPCs and sustained H3 tail proteolysis in differentiating neural cells. This leads to significant transcriptional changes in NPCs, particularly of nuclear-encoded mitochondrial genes. In turn, these transcriptional alterations impair the enhanced mitochondrial respiration that is induced upon neural stem cell differentiation. Collectively, our findings reveal the basis of epigenetic regulation in the molecular pathogenesis of CSTB deficiency.
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Affiliation(s)
- Eduard Daura
- Folkhälsan Research Center, 00290 Helsinki, Finland; Medicum, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
| | - Saara Tegelberg
- Folkhälsan Research Center, 00290 Helsinki, Finland; Medicum, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
| | - Masahito Yoshihara
- Department of Biosciences and Nutrition, Karolinska Institutet, 141 83 Stockholm, Sweden
| | - Christopher Jackson
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland; Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
| | - Francesca Simonetti
- Folkhälsan Research Center, 00290 Helsinki, Finland; Medicum, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
| | - Katri Aksentjeff
- Folkhälsan Research Center, 00290 Helsinki, Finland; Medicum, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
| | - Sini Ezer
- Folkhälsan Research Center, 00290 Helsinki, Finland; Medicum, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
| | - Paula Hakala
- Folkhälsan Research Center, 00290 Helsinki, Finland; Medicum, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
| | - Shintaro Katayama
- Folkhälsan Research Center, 00290 Helsinki, Finland; Medicum, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland; Department of Biosciences and Nutrition, Karolinska Institutet, 141 83 Stockholm, Sweden
| | - Juha Kere
- Folkhälsan Research Center, 00290 Helsinki, Finland; Department of Biosciences and Nutrition, Karolinska Institutet, 141 83 Stockholm, Sweden; Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
| | - Anna-Elina Lehesjoki
- Folkhälsan Research Center, 00290 Helsinki, Finland; Medicum, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland.
| | - Tarja Joensuu
- Folkhälsan Research Center, 00290 Helsinki, Finland; Medicum, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
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7
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Gorski K, Spoljaric A, Nyman TA, Kaila K, Battersby BJ, Lehesjoki AE. Quantitative Changes in the Mitochondrial Proteome of Cerebellar Synaptosomes From Preclinical Cystatin B-Deficient Mice. Front Mol Neurosci 2020; 13:570640. [PMID: 33281550 PMCID: PMC7691638 DOI: 10.3389/fnmol.2020.570640] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 10/21/2020] [Indexed: 12/04/2022] Open
Abstract
Progressive myoclonus epilepsy of Unverricht-Lundborg type (EPM1) is a neurodegenerative disorder caused by loss-of-function mutations in the cystatin B (CSTB) gene. Progression of the clinical symptoms in EPM1 patients, including stimulus-sensitive myoclonus, tonic-clonic seizures, and ataxia, are well described. However, the cellular dysfunction during the presymptomatic phase that precedes the disease onset is not understood. CSTB deficiency leads to alterations in GABAergic signaling, and causes early neuroinflammation followed by progressive neurodegeneration in brains of a mouse model, manifesting as progressive myoclonus and ataxia. Here, we report the first proteome atlas from cerebellar synaptosomes of presymptomatic Cstb-deficient mice, and propose that early mitochondrial dysfunction is important to the pathogenesis of altered synaptic function in EPM1. A decreased sodium- and chloride dependent GABA transporter 1 (GAT-1) abundance was noted in synaptosomes with CSTB deficiency, but no functional difference was seen between the two genotypes in electrophysiological experiments with pharmacological block of GAT-1. Collectively, our findings provide novel insights into the early onset and pathogenesis of CSTB deficiency, and reveal greater complexity to the molecular pathogenesis of EPM1.
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Affiliation(s)
- Katarin Gorski
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Albert Spoljaric
- Molecular and Integrative Biosciences, and Neuroscience Center (HiLIFE), Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Tuula A Nyman
- Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - Kai Kaila
- Molecular and Integrative Biosciences, and Neuroscience Center (HiLIFE), Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | | | - Anna-Elina Lehesjoki
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland
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8
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Bosak M, Sułek A, Łukasik M, Żak A, Słowik A, Lasek-Bal A. Genetic testing and the phenotype of Polish patients with Unverricht-Lundborg disease (EPM1) - A cohort study. Epilepsy Behav 2020; 112:107439. [PMID: 32920378 DOI: 10.1016/j.yebeh.2020.107439] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 08/21/2020] [Accepted: 08/21/2020] [Indexed: 11/17/2022]
Abstract
AIM OF THE STUDY The aim of this study was to explore genetic findings and the phenotype in Polish patients with Unverricht-Lundborg disease (ULD). MATERIALS AND METHODS We retrospectively evaluated mutations in the cystatin B (CSTB) gene and clinical presentation in a cohort of patients with ULD. The study population consisted of 19 (14 males) patients with genetically confirmed disease. RESULTS Sixteen patients were homozygous for the expanded dodecamer repeat mutation alleles, one subject was compound heterozygous for the dodecamer repeat expansion and other mutation, in two, the type of mutation has not yet been established. The numbers of repeats in the CSTB gene varied from 60 to 81. Clinical information was available for 16 subjects. The disease course was progressive in all patients, leading to severe disability, mainly due to myoclonus, in nine. CONCLUSIONS AND CLINICAL IMPLICATIONS Genetic findings and the clinical picture of our patients with ULD were in accordance with available studies. The most common genetic defect underlying ULD was homozygosity for an unstable expansion of a dodecamer repeat in the CSTB gene. Patients with action or/and stimulus sensitive myoclonus or intractable myoclonus epilepsy, especially with onset in late childhood/adolescence should be screened for ULD.
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Affiliation(s)
- Magdalena Bosak
- Jagiellonian University Medical College, Faculty of Medicine, Department of Neurology, Jakubowskiego 2, 30-688 Kraków, Poland.
| | - Anna Sułek
- Department of Genetics, Institute of Psychiatry and Neurology, Sobieskiego 9, 02-957 Warszawa, Poland
| | - Maria Łukasik
- Laboratory of Flow Cytometry and Vascular Biology, Department of Neurology, University of Medical Sciences, Przybyszewskiego 49, 60-355 Poznań, Poland
| | - Amadeusz Żak
- Department of Neurology, School of Health Sciences, Medical University of Silesia, Ziołowa 45/47, 40-635 Katowice, Poland
| | - Agnieszka Słowik
- Jagiellonian University Medical College, Faculty of Medicine, Department of Neurology, Jakubowskiego 2, 30-688 Kraków, Poland
| | - Anetta Lasek-Bal
- Department of Neurology, School of Health Sciences, Medical University of Silesia, Ziołowa 45/47, 40-635 Katowice, Poland
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9
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Correction of a Splicing Mutation Affecting an Unverricht-Lundborg Disease Patient by Antisense Therapy. Genes (Basel) 2018; 9:genes9090455. [PMID: 30208654 PMCID: PMC6162617 DOI: 10.3390/genes9090455] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 08/31/2018] [Accepted: 09/05/2018] [Indexed: 01/16/2023] Open
Abstract
Unverricht-Lundborg disease (ULD) is a common form of progressive myoclonic epilepsy caused by mutations in the cystatin B gene (CSTB) that encodes an inhibitor of several lysosomal cathepsins. Presently, only pharmacological treatment and psychosocial support are available for ULD patients. To overcome the pathogenic effect of the ULD splicing mutation c.66G>A (exon 1), we investigated whether an antisense oligonucleotide therapeutic strategy could correct the defect in patient cells. A specific locked nucleic acid (LNA) antisense oligonucleotide was designed to block a cryptic 5′ss in intron 1. Overall, this approach allowed the restoration of the normal splicing pattern. Furthermore, the recovery was both sequence and dose-specific. In general, this work provides a proof of principle on the correction of a CSTB gene defect causing ULD through a mutation-specific antisense therapy. It adds evidence to the feasibility of this approach, joining the many studies that are paving the way for translating antisense technology into the clinical practice. The insights detailed herein make mutation-based therapy a clear candidate for personalized treatment of ULD patients, encouraging similar investigations into other genetic diseases.
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Bhat S, Ganesh S. New discoveries in progressive myoclonus epilepsies: a clinical outlook. Expert Rev Neurother 2018; 18:649-667. [DOI: 10.1080/14737175.2018.1503949] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Shweta Bhat
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India
| | - Subramaniam Ganesh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India
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11
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Severe neurodegeneration, progressive cerebral volume loss and diffuse hypomyelination associated with a homozygous frameshift mutation in CSTB. Eur J Hum Genet 2017; 25:775-778. [PMID: 28378817 DOI: 10.1038/ejhg.2017.39] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 01/11/2017] [Accepted: 02/17/2017] [Indexed: 11/08/2022] Open
Abstract
Mutations of the cystatin B gene (CSTB; OMIM 601145) are known to cause Unverricht-Lundborg disease or progressive myoclonic epilepsy-1A (EPM1A, MIM #254800). Most patients are homozygous for an expanded (>30) dodecamer repeat in the promoter region of CSTB, or are compound heterozygotes for the dodecamer repeat and a point mutation. We report two adolescent sisters born to consanguineous parents of Sri Lankan descent who presented with profound global developmental delay, microcephaly, cortical blindness and axial hypotonia with appendicular hypertonia. Neither sibling ever developed head control, independent sitting or ambulation, and never developed speech. The elder sister had a seizure disorder. Both sisters had profound microcephaly and distinct facial features. On serial brain imaging, they had progressive atrophy of the corpus callosum and supratentorial brain, and diffuse hypomyelination with progressive loss of myelin signal. Exome sequencing revealed both siblings to be homozygous for a c.218dupT (p.His75Serfs*2) mutation in exon 3 of CSTB. The neuroimaging features of our patients are consistent with those observed in Cstb-knockout mice, which supports the hypothesis that disease severity is inversely correlated with the amount of residual functional cystatin B protein.
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12
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Assenza G, Benvenga A, Gennaro E, Tombini M, Campana C, Assenza F, Di Pino G, Di Lazzaro V. A novel c132-134del mutation in Unverricht-Lundborg disease and the review of literature of heterozygous compound patients. Epilepsia 2016; 58:e31-e35. [PMID: 27888502 DOI: 10.1111/epi.13626] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/02/2016] [Indexed: 11/29/2022]
Abstract
Unverricht-Lundborg disease or progressive myoclonic epilepsy type 1 (EPM1) is an autosomal recessive disease caused by mutation of the cystatin B gene (CSTB), located on chromosome 21q22.3. The most common mutation is an expansion of unstable dodecamer repetition (CCCCGCCCCGCG), whereas other types of mutations are rare. Among these, heterozygous compound mutations are described to induce a more severe phenotype than that of homozygous dodecameric repetition. We report two siblings affected by heterozygous compound mutations carrying a novel mutation of the deletion of three nucleotides in exon 2 of the gene in position 132-134 of the coding sequence (c.132-134del) in the allele not including the dodecamer repetition. This mutation results in the loss of two amino acid residues and insertion of an asparagine in position 44 (p.Lys44_Ser45delinsAsn). Our patients presented a very different clinical picture. The male patient had a severe myoclonus, drug-resistant epilepsy and psychiatric comorbidity, while his affected sister had only very rare seizures and sporadic myoclonic jerks at awakening. The revision of literature about heterozygous compound EPM1 patients confirms this gender phenotypic expressivity, with female patients carrying less severe symptoms than male patients. These data lead to the hypothesis of complex gender-specific factors interacting with CSTB expressivity in EPM1 patients.
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Affiliation(s)
- Giovanni Assenza
- Clinical Neurology, Campus Biomedico University of Rome, Rome, Italy
| | | | - Elena Gennaro
- Genetic Laboratory, E.O. Ospedali Galliera, Genova, Italy
| | - Mario Tombini
- Clinical Neurology, Campus Biomedico University of Rome, Rome, Italy
| | - Chiara Campana
- Clinical Neurology, Campus Biomedico University of Rome, Rome, Italy
| | - Federica Assenza
- Clinical Neurology, Campus Biomedico University of Rome, Rome, Italy
| | - Giovanni Di Pino
- Clinical Neurology, Campus Biomedico University of Rome, Rome, Italy
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13
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Žerovnik E. Putative alternative functions of human stefin B (cystatin B): binding to amyloid-beta, membranes, and copper. J Mol Recognit 2016; 30. [PMID: 27577977 DOI: 10.1002/jmr.2562] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 07/25/2016] [Accepted: 07/26/2016] [Indexed: 12/17/2022]
Abstract
We describe studies performed thus far on stefin B from the family of cystatins as a model protein for folding and amyloid fibril formation studies. We also briefly mention our studies on aggregation of some of the missense EPM1 mutants of stefin B in cells, which mimic additional pathological traits (gain in toxic function) in selected patients with EPM1 disease. We collected data on the reported interactors of stefin B and discuss several hypotheses of possible cytosolic alternative functions.
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Affiliation(s)
- Eva Žerovnik
- Department of Biochemistry and Molecular and Structural Biology, Jožef Stefan Institute, Ljubljana, Slovenia.,CipKeBip-Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins, Ljubljana, Slovenia
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Mancini GM, Schot R, de Wit MCY, de Coo RF, Oostenbrink R, Bindels-de Heus K, Berger LP, Lequin MH, de Vries FA, Wilke M, van Slegtenhorst MA. CSTBnull mutation associated with microcephaly, early developmental delay, and severe dyskinesia. Neurology 2016; 86:877-8. [DOI: 10.1212/wnl.0000000000002422] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 10/29/2015] [Indexed: 11/15/2022] Open
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Kopra O, Joensuu T, Lehesjoki AE. Mouse Model of Unverricht-Lundborg Disease. Mov Disord 2015. [DOI: 10.1016/b978-0-12-405195-9.00041-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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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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Franceschetti S, Michelucci R, Canafoglia L, Striano P, Gambardella A, Magaudda A, Tinuper P, La Neve A, Ferlazzo E, Gobbi G, Giallonardo AT, Capovilla G, Visani E, Panzica F, Avanzini G, Tassinari CA, Bianchi A, Zara F. Progressive myoclonic epilepsies: definitive and still undetermined causes. Neurology 2014; 82:405-11. [PMID: 24384641 DOI: 10.1212/wnl.0000000000000077] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To define the clinical spectrum and etiology of progressive myoclonic epilepsies (PMEs) in Italy using a database developed by the Genetics Commission of the Italian League against Epilepsy. METHODS We collected clinical and laboratory data from patients referred to 25 Italian epilepsy centers regardless of whether a positive causative factor was identified. PMEs of undetermined origins were grouped using 2-step cluster analysis. RESULTS We collected clinical data from 204 patients, including 77 with a diagnosis of Unverricht-Lundborg disease and 37 with a diagnosis of Lafora body disease; 31 patients had PMEs due to rarer genetic causes, mainly neuronal ceroid lipofuscinoses. Two more patients had celiac disease. Despite extensive investigation, we found no definitive etiology for 57 patients. Cluster analysis indicated that these patients could be grouped into 2 clusters defined by age at disease onset, age at myoclonus onset, previous psychomotor delay, seizure characteristics, photosensitivity, associated signs other than those included in the cardinal definition of PME, and pathologic MRI findings. CONCLUSIONS Information concerning the distribution of different genetic causes of PMEs may provide a framework for an updated diagnostic workup. Phenotypes of the patients with PME of undetermined cause varied widely. The presence of separate clusters suggests that novel forms of PME are yet to be clinically and genetically characterized.
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Affiliation(s)
- Silvana Franceschetti
- From the Department of Neurophysiopathology and Epilepsy Centre (S.F., L.C., E.V., F.P., G.A.), IRCCS Foundation C. Besta Neurological Institute, Milan; Unit of Neurology (R.M.), IRCCS Institute of Neurological Sciences, Bellaria Hospital, Bologna; Pediatric Neurology and Muscular Diseases Unit (P.S.), DINOGMI-Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, G. Gaslini Institute; Department of Medical and Surgical Sciences (A.G., E.F.), Magna Graecia University, Catanzaro; Institute of Neurological Sciences (A.G.), National Research Council, Mangone, Cosenza; Epilepsy Centre (A.M.), Department of Neuroscience, University of Messina; IRCCS Institute of Neurological Sciences and Department of Biomedical and Neuromotor Sciences (P.T.), University of Bologna; Epilepsy Centre (A.L.N.), Azienda Ospedaliero Universitaria Consorziale, Dipartimento di Scienze Mediche di Base, Neuroscienze ed Organi di Senso, Policlinico, Bari; Child Neurology Unit (G.G.), IRCCS delle Scienze Neurologiche, Bologna; Department of Neurology and Psychiatry (A.T.G.), Neurology Unit, La Sapienza University, Rome; Epilepsy Center (G.C.), Department of Child Neuropsychiatry, C. Poma Hospital, Mantua; University of Bologna (C.A.T.); Department of Neurology and Epilepsy Centre (A.B.), San Donato Hospital, Arezzo; and Istituto Gaslini (F.Z.), Laboratory of Neurogenetics, Genoa, Italy. Coinvestigators are listed on the Neurology® Web site at www.neurology.org
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Canafoglia L, Gennaro E, Capovilla G, Gobbi G, Boni A, Beccaria F, Viri M, Michelucci R, Agazzi P, Assereto S, Coviello DA, Di Stefano M, Rossi Sebastiano D, Franceschetti S, Zara F. Electroclinical presentation and genotype-phenotype relationships in patients with Unverricht-Lundborg disease carrying compound heterozygousCSTBpoint and indel mutations. Epilepsia 2012. [DOI: 10.1111/j.1528-1167.2012.03718.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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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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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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