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Grajales-Reyes JG, García-González A, María-Ríos JC, Grajales-Reyes GE, Delgado-Vélez M, Báez-Pagán CA, Quesada O, Gómez CM, Lasalde-Dominicci JA. A Panel of Slow-Channel Syndrome Mice Reveals a Unique Locomotor Behavioral Signature. J Neuromuscul Dis 2019; 4:341-347. [PMID: 29036836 DOI: 10.3233/jnd-170226] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Muscle nicotinic acetylcholine receptor (nAChR) mutations can lead to altered channel kinetics and neuromuscular junction degeneration, a neurodegenerative disorder collectively known as slow-channel syndrome (SCS). A multivariate analysis using running wheels was used to generate activity profiles for a variety of SCS models, uncovering unique locomotor patterns for the different nAChR mutants. Particularly, the αL251T and ɛL269F mutations exhibit decreased event distance, duration, and velocity over a period of 24 hours. Our approach suggests a robust relationship between the pathophysiology of SCS and locomotor activity.
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Affiliation(s)
- José G Grajales-Reyes
- Department of Biology, University of Puerto Rico, Río Piedras Campus, San Juan, PR, USA
| | | | - José C María-Ríos
- Department of Biology, University of Puerto Rico, Río Piedras Campus, San Juan, PR, USA
| | - Gary E Grajales-Reyes
- Department of Biology, University of Puerto Rico, Río Piedras Campus, San Juan, PR, USA
| | - Manuel Delgado-Vélez
- Department of Biology, University of Puerto Rico, Río Piedras Campus, San Juan, PR, USA
| | - Carlos A Báez-Pagán
- Department of Biology, University of Puerto Rico, Río Piedras Campus, San Juan, PR, USA
| | - Orestes Quesada
- Department of Physical Sciences, University of Puerto Rico, Río Piedras Campus, San Juan, PR, USA
| | | | - José A Lasalde-Dominicci
- Department of Biology, University of Puerto Rico, Río Piedras Campus, San Juan, PR, USA.,Department of Chemistry, University of Puerto Rico, Río Piedras Campus, San Juan, PR, USA
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Natera-de Benito D, Domínguez-Carral J, Muelas N, Nascimento A, Ortez C, Jaijo T, Arteaga R, Colomer J, Vilchez JJ. Phenotypic heterogeneity in two large Roma families with a congenital myasthenic syndrome due to CHRNE 1267delG mutation. A long-term follow-up. Neuromuscul Disord 2016; 26:789-795. [PMID: 27634344 DOI: 10.1016/j.nmd.2016.08.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 07/22/2016] [Accepted: 08/10/2016] [Indexed: 11/29/2022]
Abstract
Congenital myasthenic syndromes (CMS) are a heterogeneous group of genetic disorders. Mutations in CHRNE are one of the most common cause of them and the ɛ1267delG frameshifting mutation is described to be present on at least one allele of 60% of patients with CHRNE mutations. We present a comprehensive description of the heterogeneous clinical features of the CMS caused by the homozygous 1267delG mutation in the AChR Ɛ subunit in nine members of two large Gipsy kindreds. Our observations indicate that founder Roma mutation 1267delG leads to a phenotype further characterized by ophthalmoplegia, bilateral ptosis, and good response to pyridostigmine and 3,4-DAP; but also by facial weakness, bulbar symptoms, neck muscle weakness, and proximal limb weakness that sometimes entails the loss of ambulation. Interestingly, we found in our series a remarkable proportion of patients with a progressive or fluctuating course of the disease. This finding is in some contrast with previous idea that considered this form of CMS as benign, non progressive, and with a low impact on the capacity of ambulation.
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Affiliation(s)
- D Natera-de Benito
- Department of Pediatrics, Hospital Universitario de Fuenlabrada, Madrid, Spain.
| | - J Domínguez-Carral
- Department of Pediatrics, Hospital Universitario Marqués de Valdecilla, Santander, Spain
| | - N Muelas
- Department of Neurology, Hospital Universitari La Fe, Valencia, Spain
| | - A Nascimento
- Department of Neuromuscular Diseases, Hospital Sant Joan de Déu, Barcelona, Spain
| | - C Ortez
- Department of Neuromuscular Diseases, Hospital Sant Joan de Déu, Barcelona, Spain
| | - T Jaijo
- Department of Neurology, Hospital Universitari La Fe, Valencia, Spain
| | - R Arteaga
- Department of Pediatrics, Hospital Universitario Marqués de Valdecilla, Santander, Spain
| | - J Colomer
- Department of Neuromuscular Diseases, Hospital Sant Joan de Déu, Barcelona, Spain
| | - J J Vilchez
- Department of Neurology, Hospital Universitari La Fe, Valencia, Spain
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Natera-de Benito D, Bestué M, Vilchez JJ, Evangelista T, Töpf A, García-Ribes A, Trujillo-Tiebas MJ, García-Hoyos M, Ortez C, Camacho A, Jiménez E, Dusl M, Abicht A, Lochmüller H, Colomer J, Nascimento A. Long-term follow-up in patients with congenital myasthenic syndrome due to RAPSN mutations. Neuromuscul Disord 2015; 26:153-9. [PMID: 26782015 DOI: 10.1016/j.nmd.2015.10.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 10/27/2015] [Accepted: 10/29/2015] [Indexed: 11/19/2022]
Abstract
Rapsyn (RAPSN) mutations are a common cause of postsynaptic congenital myasthenic syndromes. We present a comprehensive description of the clinical and molecular findings of ten patients with CMS due to mutations in RAPSN, mostly with a long-term follow-up. Two patients were homozygous and eight were heterozygous for the common p.Asn88Lys mutation. In three of the heterozygous patients we have identified three novel mutations (c.869T > C; p.Leu290Pro, c.1185delG; p.Thr396Profs*12, and c.358delC; p.Gln120Serfs*8). In our cohort, the RAPSN mutations lead to a relatively homogeneous phenotype, characterized by fluctuating ptosis, occasional bulbar symptoms, neck muscle weakness, and mild proximal muscle weakness with exacerbations precipitated by minor infections. Interestingly, episodic exacerbations continue to occur during adulthood. These were characterized by proximal limb girdle weakness and ptosis, and not so much by respiratory insufficiency after age 6. All patients presented during neonatal period and responded to cholinergic agonists. In most of the affected patients, additional use of 3,4-diaminopyridine resulted in significant clinical benefit. The disease course is stable except for intermittent worsening.
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Affiliation(s)
- D Natera-de Benito
- Department of Pediatrics, Hospital Universitario de Fuenlabrada, Madrid, Spain.
| | - M Bestué
- Department of Neurology, Hospital General San Jorge, Huesca, Spain
| | - J J Vilchez
- Department of Neurology, Hospital Universitari La Fe, Valencia, Spain
| | - T Evangelista
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - A Töpf
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - A García-Ribes
- Department of Pediatrics, Hospital Universitario Cruces, Bilbao, Spain
| | - M J Trujillo-Tiebas
- Department of Genetics, Hospital Universitario Fundación Jiménez Díaz, Madrid, Spain
| | - M García-Hoyos
- Department of Genetics, Instituto de Medicina Genómica, Valencia, Spain
| | - C Ortez
- Department of Neuromuscular Diseases, Hospital Sant Joan de Déu, Barcelona, Spain
| | - A Camacho
- Department of Pediatric Neurology, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - E Jiménez
- Department of Pediatrics, Hospital Universitario Rey Juan Carlos, Madrid, Spain
| | - M Dusl
- Friedrich-Baur-Institute, Ludwig-Maximilians-University Munich, Munich 80336,Germany
| | - A Abicht
- Friedrich-Baur-Institute, Ludwig-Maximilians-University Munich, Munich 80336,Germany; Medical Genetics Center, Munich, Germany
| | - H Lochmüller
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - J Colomer
- Department of Neuromuscular Diseases, Hospital Sant Joan de Déu, Barcelona, Spain
| | - A Nascimento
- Department of Neuromuscular Diseases, Hospital Sant Joan de Déu, Barcelona, Spain
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Guo Y, Menezes MJ, Menezes MP, Liang J, Li D, Riley LG, Clarke NF, Andrews PI, Tian L, Webster R, Wang F, Liu X, Shen Y, Thorburn DR, Keating BJ, Engel A, Hakonarson H, Christodoulou J, Xu X. Delayed diagnosis of congenital myasthenia due to associated mitochondrial enzyme defect. Neuromuscul Disord 2014; 25:257-61. [PMID: 25557462 DOI: 10.1016/j.nmd.2014.11.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 11/15/2014] [Accepted: 11/24/2014] [Indexed: 11/18/2022]
Abstract
Clinical phenotypes of congenital myasthenic syndromes and primary mitochondrial disorders share significant overlap in their clinical presentations, leading to challenges in making the correct diagnosis. Next generation sequencing is transforming molecular diagnosis of inherited neuromuscular disorders by identifying novel disease genes and by identifying previously known genes in undiagnosed patients. This is evident in two patients who were initially suspected to have a mitochondrial myopathy, but in whom a clear diagnosis of congenital myasthenic syndromes was made through whole exome sequencing. In patient 1, whole exome sequencing revealed compound heterozygous mutations c.1228C > T (p.Arg410Trp) and c.679C > T (p.Arg227*) in collagen-like tail subunit (single strand of homotrimer) of asymmetric acetylcholinesterase (COLQ). In patient 2, in whom a deletion of exon 52 in Dystrophin gene was previously detected by multiplex ligation-dependent probe amplification, Sanger sequencing revealed an additional homozygous mutation c.1511_1513delCTT (p.Pro504Argfs*183) in docking protein7 (DOK7). These case reports highlight the need for careful diagnosis of clinically heterogeneous syndromes like congenital myasthenic syndromes, which are treatable, and for which delayed diagnosis is likely to have implications for patient health. The report also demonstrates that whole exome sequencing is an effective diagnostic tool in providing molecular diagnosis in patients with complex phenotypes.
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Affiliation(s)
- Yiran Guo
- The Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Minal J Menezes
- Genetic Metabolic Disorders Research Unit, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, NSW, Australia; Discipline of Paediatrics & Child Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Manoj P Menezes
- Discipline of Paediatrics & Child Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia; Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, NSW, Australia
| | | | - Dong Li
- The Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Lisa G Riley
- Genetic Metabolic Disorders Research Unit, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, NSW, Australia
| | - Nigel F Clarke
- Discipline of Paediatrics & Child Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia; Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, NSW, Australia
| | - P Ian Andrews
- Department of Neurology, Sydney Children's Hospital, Randwick, NSW, Australia
| | - Lifeng Tian
- The Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Richard Webster
- Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, NSW, Australia
| | - Fengxiang Wang
- The Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | | | | | - David R Thorburn
- Murdoch Childrens Research Institute and Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, VIC, Australia; Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Brendan J Keating
- The Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States; Department of Pediatrics, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States; Department of Human Genetics Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, United States
| | - Andrew Engel
- Department of Neurology, Mayo Clinic, Rochester, MN, United States
| | - Hakon Hakonarson
- The Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States; Department of Pediatrics, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States; Department of Human Genetics Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, United States
| | - John Christodoulou
- Genetic Metabolic Disorders Research Unit, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, NSW, Australia; Discipline of Paediatrics & Child Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia; Discipline of Genetic Medicine, Sydney Medical School, University of Sydney, Sydney, NSW, Australia.
| | - Xun Xu
- BGI-Shenzhen, Shenzhen 518083, China; The Guangdong Enterprise Key Laboratory of Human Disease Genomics, BGI-Shenzhen, Shenzhen, China
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Klein A, Robb S, Rushing E, Liu WW, Belaya K, Beeson D. Congenital myasthenic syndrome caused by mutations in DPAGT. Neuromuscul Disord 2014; 25:253-6. [PMID: 25500013 DOI: 10.1016/j.nmd.2014.11.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 11/19/2014] [Accepted: 11/20/2014] [Indexed: 11/28/2022]
Abstract
Congenital myasthenic syndromes with prominent limb girdle involvement are an important differential diagnosis for congenital myopathies because of the therapeutic considerations. We present a case where accurate diagnosis was delayed for many years. Fluctuations of weakness were misinterpreted as effects of alternative treatments. Weakness was generalised, most prominently in the arms. Fatigability was more prominent in less affected muscles revealed by a positive Simpson test. Stimulation single fibre electromyography confirmed the suspected neuromuscular transmission defect. The marked response to pyridostigmine and cognitive impairment pointed to a myasthenic syndrome due to impaired glycosylation. Two mutations in trans were found in DPAGT1, the gene coding for dolichyl-phosphate N-acetylglucosaminephosphotransferase, one novel, the other previously reported in a rare form of congenital disorder of glycosylation. Gene expression studies revealed that both mutations reduce DPAGT1 expression. Phenotypic features not previously described for DPAGT1 CMS included restricted ocular abduction and long finger flexor contractures.
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Affiliation(s)
- Andrea Klein
- Department of Paediatric Neurology, University Children's Hospital Zürich, Zürich, Switzerland.
| | - Stephanie Robb
- Dubowitz Neuromuscular Centre, Institute of Child Health, Great Ormond Street Hospital, London, United Kingdom
| | - Elisabeth Rushing
- Department of Neuropathology, University Hospital Zürich, Zürich, Switzerland
| | - Wei-Wei Liu
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom
| | - Kasiaryna Belaya
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom
| | - David Beeson
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom
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Webster RG, Cossins J, Lashley D, Maxwell S, Liu WW, Wickens JR, Martinez-Martinez P, de Baets M, Beeson D. A mouse model of the slow channel myasthenic syndrome: Neuromuscular physiology and effects of ephedrine treatment. Exp Neurol 2013; 248:286-98. [PMID: 23797154 DOI: 10.1016/j.expneurol.2013.06.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 05/10/2013] [Accepted: 06/14/2013] [Indexed: 02/04/2023]
Abstract
In the slow channel congenital myasthenic syndrome mutations in genes encoding the muscle acetylcholine receptor give rise to prolonged ion channel activations. The resulting cation overload in the postsynaptic region leads to damage of synaptic structures, impaired neuromuscular transmission and fatigable muscle weakness. Previously we identified and characterised in detail the properties of the slow channel syndrome mutation εL221F. Here, using this mutation, we generate a transgenic mouse model for the slow channel syndrome that expresses mutant human ε-subunits harbouring an EGFP tag within the M3-M4 cytoplasmic region, driven by a ~1500 bp region of the CHRNB promoter. Fluorescent mutant acetylcholine receptors are assembled, cluster at the motor endplates and give rise to a disease model that mirrors the human condition. Mice demonstrate mild fatigable muscle weakness, prolonged endplate and miniature endplate potentials, and variable degeneration of the postsynaptic membrane. We use our model to investigate ephedrine as a potential treatment. Mice were assessed before and after six weeks on oral ephedrine (serum ephedrine concentration 89 ± 3 ng/ml) using an inverted screen test and in vivo electromyography. Treated mice demonstrated modest benefit for screen hang time, and in measures of compound muscle action potentials and mean jitter that did not reach statistical significance. Ephedrine and salbutamol show clear benefit when used in the treatment of DOK7 or COLQ congenital myasthenic syndromes. Our results highlight only a modest potential benefit of these β2-adrenergic receptor agonists for the treatment of the slow channel syndrome.
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Affiliation(s)
- R G Webster
- Neurosciences Group, Nuffield Dept. of Clinical Neurosciences, University of Oxford, Oxford, UK
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