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Polet SS, de Koning TJ, Lambrechts RA, Tijssen MAJ, Sibon OCM, Gorter JA. Conventional and novel anti-seizure medications reveal a particular role for GABA A in a North Sea progressive myoclonus Epilepsy Drosophila model. Epilepsy Res 2024; 203:107380. [PMID: 38781737 DOI: 10.1016/j.eplepsyres.2024.107380] [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: 12/18/2023] [Revised: 04/01/2024] [Accepted: 05/06/2024] [Indexed: 05/25/2024]
Abstract
OBJECTIVE North Sea Progressive Myoclonus Epilepsy (NS-PME) is a rare genetic disorder characterized by ataxia, myoclonus and seizures with a progressive course. Although the cause of NS-PME is known, namely a homozygous mutation in the GOSR2 gene (c.430 G>T; p. Gly144Trp), sufficient treatment is lacking. Despite combinations of on average 3-5 anti-seizure medications (ASMs), debilitating myoclonus and seizures persist. Here we aimed to gain insight into the most effective anti-convulsive target in NS-PME by evaluating the individual effects of ASMs in a NS-PME Drosophila model. METHOD A previously generated Drosophila model for NS-PME was used displaying progressive heat-sensitive seizures. We used this model to test 1. a first-generation ASM (sodium barbital), 2. common ASMs used in NS-PME (clonazepam, valproic acid, levetiracetam, ethosuximide) and 3. a novel third-generation ASM (ganaxolone) with similar mode of action to sodium barbital. Compounds were administered by adding them to the food in a range of concentrations. After 7 days of treatment, the percentage of heat-induced seizures was determined and compared to non-treated but affected controls. RESULTS As previously reported in the NS-PME Drosophila model, sodium barbital resulted in significant seizure suppression, with increasing effect at higher dosages. Of the commonly prescribed ASMs, clonazepam and ethosuximide resulted in significant seizure suppression, whereas both valproic acid and levetiracetam did not show any changes in seizures. Interestingly, ganaxolone did result in seizure suppression as well. CONCLUSION Of the six drugs tested, three of the four that resulted in seizure suppression (sodium barbital, clonazepam, ganaxolone) are primary known for their direct effect on GABAA receptors. This suggests that GABAA could be a potentially important target in the treatment of NS-PME. Consequently, these findings add rationale to the exploration of the clinical effect of ganaxolone in NS-PME and other progressive myoclonus epilepsies.
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Affiliation(s)
- Sjoukje S Polet
- Department of Neurology, University Medical Center Groningen, University of Groningen, 30.001 AB51, Groningen 9700 RB, the Netherlands; Expertise Center Movement Disorders Groningen, University Medical Center Groningen, University of Groningen, 30.001 AB51, Groningen 9700 RB, the Netherlands.
| | - Tom J de Koning
- Expertise Center Movement Disorders Groningen, University Medical Center Groningen, University of Groningen, 30.001 AB51, Groningen 9700 RB, the Netherlands; Department of Neurology and Medical Genetics, University Medical Center Groningen, University of Groningen, 30.001 AB51, Groningen 9700 RB, the Netherlands; Department of Clinical Sciences, Pediatrics, Lund University, Lund BMC I12, 221 84, Sweden
| | - Roald A Lambrechts
- Expertise Center Movement Disorders Groningen, University Medical Center Groningen, University of Groningen, 30.001 AB51, Groningen 9700 RB, the Netherlands; Department of Neurology, University Medical Center Groningen, University of Groningen, 30.001 AB51, Groningen 9700 RB, the Netherlands
| | - Marina A J Tijssen
- Expertise Center Movement Disorders Groningen, University Medical Center Groningen, University of Groningen, 30.001 AB51, Groningen 9700 RB, the Netherlands; Department of Neurology, University Medical Center Groningen, University of Groningen, 30.001 AB51, Groningen 9700 RB, the Netherlands
| | - Ody C M Sibon
- Expertise Center Movement Disorders Groningen, University Medical Center Groningen, University of Groningen, 30.001 AB51, Groningen 9700 RB, the Netherlands; Department of Biomedical Sciences (BMS), University Medical Center Groningen, University of Groningen, 30.001 FB32, Groningen 9700 AD, the Netherlands
| | - Jenke A Gorter
- Expertise Center Movement Disorders Groningen, University Medical Center Groningen, University of Groningen, 30.001 AB51, Groningen 9700 RB, the Netherlands; Department of Biomedical Sciences (BMS), University Medical Center Groningen, University of Groningen, 30.001 FB32, Groningen 9700 AD, the Netherlands
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2
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van der Veen S, Eggink H, Elting JWJ, Sival D, Verschuuren-Bemelmans CC, de Koning TJ, Tijssen MAJ. The natural history of progressive myoclonus ataxia. Neurobiol Dis 2024; 199:106555. [PMID: 38844245 DOI: 10.1016/j.nbd.2024.106555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Revised: 05/22/2024] [Accepted: 06/03/2024] [Indexed: 06/16/2024] Open
Abstract
Progressive myoclonus ataxia (PMA) is a rare clinical syndrome characterized by the presence of progressive myoclonus and ataxia, and can be accompanied by mild cognitive impairment and infrequent epileptic seizures. This is the first study to describe the natural history of PMA and identify clinical, electrophysiological, and genetic features explaining the variability in disease progression. A Dutch cohort of consecutive patients meeting the criteria of the refined definition of PMA was included. The current phenotype was assessed during in-person consultation by movement disorders experts, and retrospective data was collected to describe disease presentation and progression, including brain imaging and therapy efficacy. Extensive genetic and electrophysiological tests were performed. The presence of cortical hyperexcitability was determined, by either the identification of a cortical correlate of myoclonic jerks with simultaneous electromyography-electroencephalography or a giant somatosensory evoked potential. We included 34 patients with PMA with a median disease duration of 15 years and a clear progressive course in most patients (76%). A molecular etiology was identified in 82% patients: ATM, CAMTA1, DHDDS, EBF3, GOSR2, ITPR1, KCNC3, NUS1, POLR1A, PRKCG, SEMA6B, SPTBN2, TPP1, ZMYND11, and a 12p13.32 deletion. The natural history is a rather homogenous onset of ataxia in the first two years of life followed by myoclonus in the first 5 years of life. Main accompanying neurological dysfunctions included cognitive impairment (62%), epilepsy (38%), autism spectrum disorder (27%), and behavioral problems (18%). Disease progression showed large variability ranging from an epilepsy free PMA phenotype (62%) to evolution towards a progressive myoclonus epilepsy (PME) phenotype (18%): the existence of a PMA-PME spectrum. Cortical hyperexcitability could be tested in 17 patients, and was present in 11 patients and supported cortical myoclonus. Interestingly, post-hoc analysis showed that an absence of cortical hyperexcitability, suggesting non-cortical myoclonus, was associated with the PMA-end of the spectrum with no epilepsy and milder myoclonus, independent of disease duration. An association between the underlying genetic defects and progression on the PMA-PME spectrum was observed. By describing the natural history of the largest cohort of published patients with PMA so far, we see a homogeneous onset with variable disease progression, in which phenotypic evolution to PME occurs in the minority. Genetic and electrophysiological features may be of prognostic value, especially the determination of cortical hyperexcitability. Furthermore, the identification of cortical and non-cortical myoclonus in PMA helps us gain insight in the underlying pathophysiology of myoclonus.
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Affiliation(s)
- Sterre van der Veen
- Department of Neurology, University of Groningen, University Medical Centre Groningen, 9700 RB, Groningen, the Netherlands; Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen, 9700 RB, Groningen, the Netherlands
| | - Hendriekje Eggink
- Department of Neurology, University of Groningen, University Medical Centre Groningen, 9700 RB, Groningen, the Netherlands; Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen, 9700 RB, Groningen, the Netherlands
| | - Jan Willem J Elting
- Department of Neurology, University of Groningen, University Medical Centre Groningen, 9700 RB, Groningen, the Netherlands; Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen, 9700 RB, Groningen, the Netherlands
| | - Deborah Sival
- Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen, 9700 RB, Groningen, the Netherlands; Department of Pediatrics, University of Groningen, University Medical Center Groningen, 9700 RB, Groningen, the Netherlands
| | - Corien C Verschuuren-Bemelmans
- Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen, 9700 RB, Groningen, the Netherlands; Department of Genetics, University of Groningen, University Medical Centre Groningen, 9700 RB, Groningen, the Netherlands
| | - Tom J de Koning
- Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen, 9700 RB, Groningen, the Netherlands; Department of Genetics, University of Groningen, University Medical Centre Groningen, 9700 RB, Groningen, the Netherlands; Pediatrics, department of Clinical Sciences, Lund University, 22185 Lund, Sweden
| | - Marina A J Tijssen
- Department of Neurology, University of Groningen, University Medical Centre Groningen, 9700 RB, Groningen, the Netherlands; Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen, 9700 RB, Groningen, the Netherlands.
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3
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Pollini L, van der Veen S, Elting JWJ, Tijssen MAJ. Negative Myoclonus: Neurophysiological Study and Clinical Impact in Progressive Myoclonus Ataxia. Mov Disord 2024; 39:674-683. [PMID: 38385661 DOI: 10.1002/mds.29741] [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: 09/23/2023] [Revised: 01/13/2024] [Accepted: 01/25/2024] [Indexed: 02/23/2024] Open
Abstract
INTRODUCTION Negative myoclonus (NM) is an involuntary movement caused by a sudden interruption of muscular activity, resulting in gait problems and falls. OBJECTIVE To establish frequency, clinical impact, and neurophysiology of NM in progressive myoclonus ataxia (PMA) patients. METHODS Clinical, neurophysiological, and genetic data of 14 PMA individuals from University Medical Centre Groningen (UMCG) Expertise Center Movement Disorder Groningen were retrospectively collected. Neurophysiological examination included video-electromyography-accelerometry assessment in all patients and electroencephalography (EEG) examination in 13 individuals. Jerk-locked (or silent period-locked) back-averaging and cortico-muscular coherence (CMC) analysis aided the classification of myoclonus. RESULTS NM was present in 6 (NM+) and absent in 8 (NM-) PMA patients. NM+ individuals have more frequent falls (100% vs. 37.5%) and higher scores on the Gross Motor Function Classification System (GMFCS) (4.3 ±0.74 vs. 2.5 ±1.2) than NM- individuals. Genetic background of NM+ included GOSR2 and SEMA6B, while that of NM- included ATM, KCNC3, NUS1, STPBN2, and GOSR2. NM was frequently preceded by positive myoclonus (PM) and silent-period length was between 88 and 194 ms. EEG epileptiform discharges were associated with NM in 2 cases. PM was classified as cortical in 5 NM+ and 2 NM- through EEG inspection, jerk-locked back-averaging, or CMC analysis. DISCUSSION Neurophysiological examination is crucial for detecting NM that could be missed on clinical examination due to a preceding PM. Evidence points to a cortical origin of NM, an association with more severe motor phenotype, and suggests the presence of genetic disorders causing either a PMA or progressive myoclonus epilepsy, rather than pure PMA phenotype. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Luca Pollini
- Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy
- Department of Neurology, University of Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
- Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
| | - Sterre van der Veen
- Department of Neurology, University of Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
- Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
| | - Jan Willem J Elting
- Department of Neurology, University of Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
- Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
- Department of Clinical Neurophysiology, University of Groningen, University Medical Center Groningen (UMCG), Groningen, The Netherlands
| | - Marina A J Tijssen
- Department of Neurology, University of Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
- Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
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4
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Van Der Veen S, Tijssen MAJ, Berkovic SF. The Muddle of Myoclonus: Many Guises, 2 Disciplines, Consensus Needed. Neurol Clin Pract 2023; 13:e200187. [PMID: 37664134 PMCID: PMC10473854 DOI: 10.1212/cpj.0000000000200187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 07/18/2023] [Indexed: 09/05/2023]
Abstract
Myoclonus is often approached in different ways by epileptologists and movement disorder specialists, leading to confusion in the literature. Multiplicity and inconsistency over the past 2 centuries resulted in a lack of precision and ambiguity of the terminology. We show that this is a current problem in which one phenomenon has been described with many terms and vice versa. Of more importance, we discuss the conceptualization of myoclonus from perspectives of both fields and focus on the borderland that exists, especially in the spectrum of cortical and epileptic myoclonus. By giving 2 examples, we illustrate the conundrum: the spectrum of progressive myoclonus epilepsies and progressive myoclonic ataxias and "cortical tremor" observed in familial cortical myoclonic tremor with epilepsy or familial adult myoclonic epilepsy. We attempt to facilitate to bridge these subspecialties and form the base for a uniform understanding to take this issue forward toward future classifications, discussions, and scientific research.
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Affiliation(s)
- Sterre Van Der Veen
- Department of Neurology (SVDV, MAJT), University of Groningen, University Medical Centre Groningen; Expertise Centre Movement Disorders Groningen (SVDV, MAJT), University Medical Centre Groningen; and Epilepsy Research Centre (SVDV, SFB), Department of Medicine, University of Melbourne, Austin Health
| | - Marina A J Tijssen
- Department of Neurology (SVDV, MAJT), University of Groningen, University Medical Centre Groningen; Expertise Centre Movement Disorders Groningen (SVDV, MAJT), University Medical Centre Groningen; and Epilepsy Research Centre (SVDV, SFB), Department of Medicine, University of Melbourne, Austin Health
| | - Samuel F Berkovic
- Department of Neurology (SVDV, MAJT), University of Groningen, University Medical Centre Groningen; Expertise Centre Movement Disorders Groningen (SVDV, MAJT), University Medical Centre Groningen; and Epilepsy Research Centre (SVDV, SFB), Department of Medicine, University of Melbourne, Austin Health
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5
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Hentrich L, Parnes M, Lotze TE, Coorg R, de Koning TJ, Nguyen KM, Yip CK, Jungbluth H, Koy A, Dafsari HS. Novel Genetic and Phenotypic Expansion in GOSR2-Related Progressive Myoclonus Epilepsy. Genes (Basel) 2023; 14:1860. [PMID: 37895210 PMCID: PMC10606070 DOI: 10.3390/genes14101860] [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: 09/03/2023] [Revised: 09/18/2023] [Accepted: 09/19/2023] [Indexed: 10/29/2023] Open
Abstract
Biallelic variants in the Golgi SNAP receptor complex member 2 gene (GOSR2) have been reported in progressive myoclonus epilepsy with neurodegeneration. Typical clinical features include ataxia and areflexia during early childhood, followed by seizures, scoliosis, dysarthria, and myoclonus. Here, we report two novel patients from unrelated families with a GOSR2-related disorder and novel genetic and clinical findings. The first patient, a male compound heterozygous for the GOSR2 splice site variant c.336+1G>A and the novel c.364G>A,p.Glu122Lys missense variant showed global developmental delay and seizures at the age of 2 years, followed by myoclonus at the age of 8 years with partial response to clonazepam. The second patient, a female homozygous for the GOSR2 founder variant p.Gly144Trp, showed only mild fine motor developmental delay and generalized tonic-clonic seizures triggered by infections during adolescence, with seizure remission on levetiracetam. The associated movement disorder progressed atypically slowly during adolescence compared to its usual speed, from initial intention tremor and myoclonus to ataxia, hyporeflexia, dysmetria, and dystonia. These findings expand the genotype-phenotype spectrum of GOSR2-related disorders and suggest that GOSR2 should be included in the consideration of monogenetic causes of dystonia, global developmental delay, and seizures.
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Affiliation(s)
- Lea Hentrich
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany; (L.H.)
- Max-Planck-Institute for Biology of Ageing, 50931 Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), 50931 Cologne, Germany
| | - Mered Parnes
- Division of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; (M.P.); (T.E.L.)
| | - Timothy Edward Lotze
- Division of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; (M.P.); (T.E.L.)
| | - Rohini Coorg
- Division of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; (M.P.); (T.E.L.)
| | - Tom J. de Koning
- Department of Genetics, University Medical Center Groningen, University of Groningen, 9713 GZ Groningen, The Netherlands
- Pediatrics, Department of Clinical Sciences, Lund University, 221 00 Lund, Sweden
| | - Kha M. Nguyen
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (K.M.N.); (C.K.Y.)
| | - Calvin K. Yip
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (K.M.N.); (C.K.Y.)
| | - Heinz Jungbluth
- Department of Paediatric Neurology, Evelina’s Children Hospital, Guy’s & St. Thomas’ Hospital NHS Foundation Trust, London SE1 7EH, UK
- Randall Division of Cell and Molecular Biophysics, Muscle Signaling Section, King’s College London, London WC2R 2LS, UK
| | - Anne Koy
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany; (L.H.)
- Center for Rare Diseases, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany
| | - Hormos Salimi Dafsari
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany; (L.H.)
- Max-Planck-Institute for Biology of Ageing, 50931 Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), 50931 Cologne, Germany
- Department of Paediatric Neurology, Evelina’s Children Hospital, Guy’s & St. Thomas’ Hospital NHS Foundation Trust, London SE1 7EH, UK
- Randall Division of Cell and Molecular Biophysics, Muscle Signaling Section, King’s College London, London WC2R 2LS, UK
- Center for Rare Diseases, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany
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6
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Aburayyan A, Carlson RJ, Rabie GN, Lee MK, Gulsuner S, Walsh T, Avraham KB, Kanaan MN, King MC. A paradoxical genotype-phenotype relationship: Low level of GOSR2 translation from a non-AUG start codon in a family with profound hearing loss. Hum Mol Genet 2023; 32:2265-2268. [PMID: 37074134 PMCID: PMC10321379 DOI: 10.1093/hmg/ddad066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 03/25/2023] [Accepted: 04/10/2023] [Indexed: 04/20/2023] Open
Affiliation(s)
- Amal Aburayyan
- Department of Genome Sciences and Department of Medicine, University of Washington, Seattle, WA, USA
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
- Hereditary Research Laboratory, Department of Biology, Bethlehem University, Bethlehem, Palestine
| | - Ryan J Carlson
- Department of Genome Sciences and Department of Medicine, University of Washington, Seattle, WA, USA
| | - Grace N Rabie
- Hereditary Research Laboratory, Department of Biology, Bethlehem University, Bethlehem, Palestine
| | - Ming K Lee
- Department of Genome Sciences and Department of Medicine, University of Washington, Seattle, WA, USA
| | - Suleyman Gulsuner
- Department of Genome Sciences and Department of Medicine, University of Washington, Seattle, WA, USA
| | - Tom Walsh
- Department of Genome Sciences and Department of Medicine, University of Washington, Seattle, WA, USA
| | - Karen B Avraham
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Moien N Kanaan
- Hereditary Research Laboratory, Department of Biology, Bethlehem University, Bethlehem, Palestine
| | - Mary-Claire King
- Department of Genome Sciences and Department of Medicine, University of Washington, Seattle, WA, USA
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7
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Stemmerik MG, Borch JDS, Dunø M, Krag T, Vissing J. Myopathy can be a key phenotype of membrin (GOSR2) deficiency. Hum Mutat 2021; 42:1101-1106. [PMID: 34167170 DOI: 10.1002/humu.24247] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 06/01/2021] [Accepted: 06/22/2021] [Indexed: 11/10/2022]
Abstract
T1-weighted, cross-sectional MR images showing shoulder girdle, abdominal, paraspinal, gluteal and thigh muscles almost completely replaced by fat, whereas lower leg muscles are almost unaffected i a patient who is compound heterozygous for pathogenic variants in GOSR2.
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Affiliation(s)
- Mads G Stemmerik
- Department of Neurology, Copenhagen Neuromuscular Center, University of Copenhagen, Copenhagen, Denmark
| | - Josefine de S Borch
- Department of Neurology, Copenhagen Neuromuscular Center, University of Copenhagen, Copenhagen, Denmark
| | - Morten Dunø
- Department of Clinical Genetics, Molecular Genetic Laboratory, University Hospital Copenhagen, Copenhagen, Denmark
| | - Thomas Krag
- Department of Neurology, Copenhagen Neuromuscular Center, University of Copenhagen, Copenhagen, Denmark
| | - John Vissing
- Department of Neurology, Copenhagen Neuromuscular Center, University of Copenhagen, Copenhagen, Denmark
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8
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Tang BL. Defects in early secretory pathway transport machinery components and neurodevelopmental disorders. Rev Neurosci 2021; 32:851-869. [PMID: 33781010 DOI: 10.1515/revneuro-2021-0020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 03/12/2021] [Indexed: 12/23/2022]
Abstract
The early secretory pathway, provisionally comprising of vesicular traffic between the endoplasmic reticulum (ER) and the Golgi apparatus, occurs constitutively in mammalian cells. Critical for a constant supply of secretory and plasma membrane (PM) materials, the pathway is presumably essential for general cellular function and survival. Neurons exhibit a high intensity in membrane dynamics and protein/lipid trafficking, with differential and polarized trafficking towards the somatodendritic and axonal PM domains. Mutations in genes encoding early secretory pathway membrane trafficking machinery components are known to result in neurodevelopmental or neurological disorders with disease manifestation in early life. Here, such rare disorders associated with autosomal recessive mutations in coat proteins, membrane tethering complexes and membrane fusion machineries responsible for trafficking in the early secretory pathway are summarily discussed. These mutations affected genes encoding subunits of coat protein complex I and II, subunits of transport protein particle (TRAPP) complexes, members of the YIP1 domain family (YIPF) and a SNAP receptor (SNARE) family member. Why the ubiquitously present and constitutively acting early secretory pathway machinery components could specifically affect neurodevelopment is addressed, with the plausible underlying disease etiologies and neuropathological mechanisms resulting from these mutations explored.
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Affiliation(s)
- Bor Luen Tang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, Singapore117597, Singapore
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9
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Henige H, Kaur S, Pappas K. Compound heterozygous variants in GOSR2 associated with congenital muscular dystrophy: A case report. Eur J Med Genet 2021; 64:104184. [PMID: 33639315 DOI: 10.1016/j.ejmg.2021.104184] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 12/29/2020] [Accepted: 02/20/2021] [Indexed: 11/30/2022]
Abstract
The homozygous missense variant in the GOSR2 gene (c.430G > T) is known to be associated with progressive myoclonic epilepsy (PME). The clinical presentation of GOSR2-related PME involves the development of ataxia, seizures, scoliosis, areflexia, and mildly elevated creatine kinase. Recently, it has been suggested that some compound heterozygous variants in GOSR2 are associated with a predominant muscular dystrophy phenotype. Here we report a case of a now 22 month old female who presented with congenital hypotonia and persistently elevated creatine kinase levels. Whole exome sequencing showed pathogenic compound heterozygous variants in GOSR2 (c.430G > T and c.82C > T). This case contributes to the expanding clinical spectrum of GOSR2 variants with PME representing the milder end and congenital muscular dystrophy representing the more severe end of the spectrum.
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Affiliation(s)
- Hannah Henige
- Division of Genetic, Genomic, and Metabolic Disorders, Children's Hospital of Michigan, Detroit, MI, USA.
| | - Shagun Kaur
- Division of Genetic, Genomic, and Metabolic Disorders, Children's Hospital of Michigan, Detroit, MI, USA
| | - Kara Pappas
- Division of Genetic, Genomic, and Metabolic Disorders, Children's Hospital of Michigan, Detroit, MI, USA; Department of Pediatrics, Central Michigan University, Mount Pleasant, MI, USA
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10
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Tang BL. SNAREs and developmental disorders. J Cell Physiol 2020; 236:2482-2504. [PMID: 32959907 DOI: 10.1002/jcp.30067] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/20/2020] [Accepted: 09/09/2020] [Indexed: 12/12/2022]
Abstract
Members of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) family mediate membrane fusion processes associated with vesicular trafficking and autophagy. SNAREs mediate core membrane fusion processes essential for all cells, but some SNAREs serve cell/tissue type-specific exocytic/endocytic functions, and are therefore critical for various aspects of embryonic development. Mutations or variants of their encoding genes could give rise to developmental disorders, such as those affecting the nervous system and immune system in humans. Mutations to components in the canonical synaptic vesicle fusion SNARE complex (VAMP2, STX1A/B, and SNAP25) and a key regulator of SNARE complex formation MUNC18-1, produce variant phenotypes of autism, intellectual disability, movement disorders, and epilepsy. STX11 and MUNC18-2 mutations underlie 2 subtypes of familial hemophagocytic lymphohistiocytosis. STX3 mutations contribute to variant microvillus inclusion disease. Chromosomal microdeletions involving STX16 play a role in pseudohypoparathyroidism type IB associated with abnormal imprinting of the GNAS complex locus. In this short review, I discuss these and other SNARE gene mutations and variants that are known to be associated with a variety developmental disorders, with a focus on their underlying cellular and molecular pathological basis deciphered through disease modeling. Possible pathogenic potentials of other SNAREs whose variants could be disease predisposing are also speculated upon.
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Affiliation(s)
- Bor L Tang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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