1
|
Barbeau S, Semprez F, Dobbertin A, Merriadec L, Roussange F, Eymard B, Sternberg D, Fournier E, Karasoy H, Martinat C, Legay C. Molecular Analysis of a Congenital Myasthenic Syndrome Due to a Pathogenic Variant Affecting the C-Terminus of ColQ. Int J Mol Sci 2023; 24:16217. [PMID: 38003406 PMCID: PMC10671321 DOI: 10.3390/ijms242216217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/04/2023] [Accepted: 11/04/2023] [Indexed: 11/26/2023] Open
Abstract
Congenital Myasthenic Syndromes (CMSs) are rare inherited diseases of the neuromuscular junction characterized by muscle weakness. CMSs with acetylcholinesterase deficiency are due to pathogenic variants in COLQ, a collagen that anchors the enzyme at the synapse. The two COLQ N-terminal domains have been characterized as being biochemical and functional. They are responsible for the structure of the protein in the triple helix and the association of COLQ with acetylcholinesterase. To deepen the analysis of the distal C-terminal peptide properties and understand the CMSs associated to pathogenic variants in this domain, we have analyzed the case of a 32 year old male patient bearing a homozygote splice site variant c.1281 C > T that changes the sequence of the last 28 aa in COLQ. Using COS cell and mouse muscle cell expression, we show that the COLQ variant does not impair the formation of the collagen triple helix in these cells, nor its association with acetylcholinesterase, and that the hetero-oligomers are secreted. However, the interaction of COLQ variant with LRP4, a signaling hub at the neuromuscular junction, is decreased by 44% as demonstrated by in vitro biochemical methods. In addition, an increase in all acetylcholine receptor subunit mRNA levels is observed in muscle cells derived from the patient iPSC. All these approaches point to pathophysiological mechanisms essentially characterized by a decrease in signaling and the presence of immature acetylcholine receptors.
Collapse
Affiliation(s)
- Susie Barbeau
- CNRS, Saint Pères Paris Institute for the Neurosciences (SPPIN), Université Paris Cité, 75270 Paris, France
| | - Fannie Semprez
- CNRS, Saint Pères Paris Institute for the Neurosciences (SPPIN), Université Paris Cité, 75270 Paris, France
| | - Alexandre Dobbertin
- CNRS, Saint Pères Paris Institute for the Neurosciences (SPPIN), Université Paris Cité, 75270 Paris, France
| | - Laurine Merriadec
- INSERM/UEPS UMR 861, Université Paris Saclay, I-STEM, 91100 Corbeil-Essonnes, France
| | - Florine Roussange
- INSERM/UEPS UMR 861, Université Paris Saclay, I-STEM, 91100 Corbeil-Essonnes, France
| | - Bruno Eymard
- Inserm U 1127, CNRS UMR 7225, Sorbonne Université Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle Épinière, ICM, Sorbonne Université, 75013 Paris, France
- AP-HP, Hôpital Pitié-Salpêtrière, 75013 Paris, France
| | - Damien Sternberg
- Inserm U 1127, CNRS UMR 7225, Sorbonne Université Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle Épinière, ICM, Sorbonne Université, 75013 Paris, France
- AP-HP, Hôpital Pitié-Salpêtrière, 75013 Paris, France
| | - Emmanuel Fournier
- Department of Physiology, Faculté de Médecine Pitié-Salpêtrière, Sorbonne Université, 75006 Paris, France
| | - Hanice Karasoy
- Department of Neurology, Faculty of Medicine, Ege University, Izmir 35100, Turkey
| | - Cécile Martinat
- INSERM/UEPS UMR 861, Université Paris Saclay, I-STEM, 91100 Corbeil-Essonnes, France
| | - Claire Legay
- CNRS, Saint Pères Paris Institute for the Neurosciences (SPPIN), Université Paris Cité, 75270 Paris, France
| |
Collapse
|
2
|
Uyen Dao TM, Barbeau S, Messéant J, Della-Gaspera B, Bouceba T, Semprez F, Legay C, Dobbertin A. The collagen ColQ binds to LRP4 and regulates the activation of the Muscle-Specific Kinase-LRP4 receptor complex by agrin at the neuromuscular junction. J Biol Chem 2023; 299:104962. [PMID: 37356721 PMCID: PMC10382678 DOI: 10.1016/j.jbc.2023.104962] [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: 04/20/2022] [Revised: 06/09/2023] [Accepted: 06/13/2023] [Indexed: 06/27/2023] Open
Abstract
Collagen Q (ColQ) is a nonfibrillar collagen that plays a crucial role at the vertebrate neuromuscular junction (NMJ) by anchoring acetylcholinesterase to the synapse. ColQ also functions in signaling, as it regulates acetylcholine receptor clustering and synaptic gene expression, in a manner dependent on muscle-specific kinase (MuSK), a key protein in NMJ formation and maintenance. MuSK forms a complex with low-density lipoprotein receptor-related protein 4 (LRP4), its coreceptor for the proteoglycan agrin at the NMJ. Previous studies suggested that ColQ also interacts with MuSK. However, the molecular mechanisms underlying ColQ functions and ColQ-MuSK interaction have not been fully elucidated. Here, we investigated whether ColQ binds directly to MuSK and/or LRP4 and whether it modulates agrin-mediated MuSK-LRP4 activation. Using coimmunoprecipitation, pull-down, plate-binding assays, and surface plasmon resonance, we show that ColQ binds directly to LRP4 but not to MuSK and that ColQ interacts indirectly with MuSK through LRP4. In addition, we show that the LRP4 N-terminal region, which contains the agrin-binding sites, is also crucial for ColQ binding to LRP4. Moreover, ColQ-LRP4 interaction was reduced in the presence of agrin, suggesting that agrin and ColQ compete for binding to LRP4. Strikingly, we reveal ColQ has two opposing effects on agrin-induced MuSK-LRP4 signaling: it constitutively reduces MuSK phosphorylation levels in agrin-stimulated myotubes but concomitantly increases MuSK accumulation at the muscle cell surface. Our results identify LRP4 as a major receptor of ColQ and provide new insights into mechanisms of ColQ signaling and acetylcholinesterase anchoring at the NMJ.
Collapse
Affiliation(s)
- Thi Minh Uyen Dao
- Université Paris Cité, CNRS, Saints-Pères Paris Institute for the Neurosciences, Paris, France
| | - Susie Barbeau
- Université Paris Cité, CNRS, Saints-Pères Paris Institute for the Neurosciences, Paris, France
| | - Julien Messéant
- Université Paris Cité, CNRS, Saints-Pères Paris Institute for the Neurosciences, Paris, France
| | | | - Tahar Bouceba
- Sorbonne Université, CNRS, IBPS, Protein Engineering Platform, Paris, France
| | - Fannie Semprez
- Université Paris Cité, CNRS, Saints-Pères Paris Institute for the Neurosciences, Paris, France
| | - Claire Legay
- Université Paris Cité, CNRS, Saints-Pères Paris Institute for the Neurosciences, Paris, France
| | - Alexandre Dobbertin
- Université Paris Cité, CNRS, Saints-Pères Paris Institute for the Neurosciences, Paris, France.
| |
Collapse
|
3
|
Eshaghian T, Rabbani B, Badv RS, Mikaeeli S, Gharib B, Iyadurai S, Mahdieh N. COLQ-related congenital myasthenic syndrome: An integrative view. Neurogenetics 2023; 24:189-200. [PMID: 37231228 DOI: 10.1007/s10048-023-00719-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 05/15/2023] [Indexed: 05/27/2023]
Abstract
Congenital myasthenic syndromes are inherited disorders caused by mutation in components of the neuromuscular junction and manifest early in life. Mutations in COLQ gene result in congenital myasthenic syndrome. Here, we present the analysis of data from 209 patients from 195 unrelated families highlighting genotype-phenotype correlation. In addition, we describe a COLQ homozygous variant a new patient and discuss it utilizing the Phyre2 and I-TASSER programs. Clinical, molecular genetics, imaging (MRI), and electrodiagnostic (EEG, EMG/NCS) evaluations were performed. Our data showed 89 pathogenic/likely pathogenic variants including 35 missenses, 21 indels, 14 nonsense, 14 splicing, and 5 large deletions variants. Eight common variants were responsible for 48.46% of those. Weakness in proximal muscles, hypotonia, and generalized weakness were detected in all individuals tested. Apart from the weakness, extensive clinical heterogeneity was noted among patients with COLQ-related patients based on their genotypes-those with variants affecting the splice site exhibited more severe clinical features while those with missense variants displayed milder phenotypes, suggesting the role of differential splice variants in multiple functions within the muscle. Analyses and descriptions of these COLQ variants may be helpful in clinical trial readiness and potential development of novel therapies in the setting of established structure-function relationships.
Collapse
Affiliation(s)
- Tina Eshaghian
- Growth and Development Research, Tehran University of Medical Sciences, Tehran, Iran
| | - Bahareh Rabbani
- Growth and Development Research, Tehran University of Medical Sciences, Tehran, Iran
| | - Reza Shervin Badv
- Growth and Development Research, Tehran University of Medical Sciences, Tehran, Iran
- Children's Hospital Center, Pediatric Center of Excellence, Tehran University of Medical Center, Tehran, Iran
| | - Sahar Mikaeeli
- Growth and Development Research, Tehran University of Medical Sciences, Tehran, Iran
| | - Behdad Gharib
- Children's Hospital Center, Pediatric Center of Excellence, Tehran University of Medical Center, Tehran, Iran
| | - Stanley Iyadurai
- Johns Hopkins All Children's Hospital, Division of Neurology, 601 5th Street S, St. Petersburg, FL, 33701, USA
| | - Nejat Mahdieh
- Growth and Development Research, Tehran University of Medical Sciences, Tehran, Iran.
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Niayesh-Vali asr Intersection, Tehran, Iran.
| |
Collapse
|
4
|
Ohno K, Ohkawara B, Shen XM, Selcen D, Engel AG. Clinical and Pathologic Features of Congenital Myasthenic Syndromes Caused by 35 Genes-A Comprehensive Review. Int J Mol Sci 2023; 24:ijms24043730. [PMID: 36835142 PMCID: PMC9961056 DOI: 10.3390/ijms24043730] [Citation(s) in RCA: 36] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 02/09/2023] [Accepted: 02/09/2023] [Indexed: 02/16/2023] Open
Abstract
Congenital myasthenic syndromes (CMS) are a heterogeneous group of disorders characterized by impaired neuromuscular signal transmission due to germline pathogenic variants in genes expressed at the neuromuscular junction (NMJ). A total of 35 genes have been reported in CMS (AGRN, ALG14, ALG2, CHAT, CHD8, CHRNA1, CHRNB1, CHRND, CHRNE, CHRNG, COL13A1, COLQ, DOK7, DPAGT1, GFPT1, GMPPB, LAMA5, LAMB2, LRP4, MUSK, MYO9A, PLEC, PREPL, PURA, RAPSN, RPH3A, SCN4A, SLC18A3, SLC25A1, SLC5A7, SNAP25, SYT2, TOR1AIP1, UNC13A, VAMP1). The 35 genes can be classified into 14 groups according to the pathomechanical, clinical, and therapeutic features of CMS patients. Measurement of compound muscle action potentials elicited by repetitive nerve stimulation is required to diagnose CMS. Clinical and electrophysiological features are not sufficient to identify a defective molecule, and genetic studies are always required for accurate diagnosis. From a pharmacological point of view, cholinesterase inhibitors are effective in most groups of CMS, but are contraindicated in some groups of CMS. Similarly, ephedrine, salbutamol (albuterol), amifampridine are effective in most but not all groups of CMS. This review extensively covers pathomechanical and clinical features of CMS by citing 442 relevant articles.
Collapse
Affiliation(s)
- Kinji Ohno
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
- Correspondence: (K.O.); (A.G.E.)
| | - Bisei Ohkawara
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Xin-Ming Shen
- Department of Neurology and Neuromuscular Research Laboratory, Mayo Clinic, Rochester, MN 55905, USA
| | - Duygu Selcen
- Department of Neurology and Neuromuscular Research Laboratory, Mayo Clinic, Rochester, MN 55905, USA
| | - Andrew G. Engel
- Department of Neurology and Neuromuscular Research Laboratory, Mayo Clinic, Rochester, MN 55905, USA
- Correspondence: (K.O.); (A.G.E.)
| |
Collapse
|
5
|
Zhang Q, Sha Q, Qiao K, Liu X, Gong X, Du A. Two patients with congenital myasthenic syndrome caused by COLQ gene mutations and the consequent ColQ protein defect. Heliyon 2023; 9:e13272. [PMID: 36798769 PMCID: PMC9925971 DOI: 10.1016/j.heliyon.2023.e13272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 12/12/2022] [Accepted: 01/24/2023] [Indexed: 01/27/2023] Open
Abstract
Objective To report two cases of congenital myasthenic syndromes (CMS) in a Chinese family with mutations in the COLQ gene and to prove the consequence defect of the ColQ protein. Method Clinical characteristics of the two children from the same family were described. Next-generation sequencing (NGS) and sanger sequencing was performed on the proband and family members. The consequence of the mutation was predicted by 3D protein structure prediction using I-TASSER. The wild type and mutant were transfected to 293T cells, and ColQ protein was detected by Western Blot. Results The diagnosis of CMS was based on a symptom combination of fatigable muscle weakness, ptosis, scoliosis, and hypotonia, aggravation of muscle weakness after the neostigmine test, and a 46% decrement in repetitive nerve stimulation. A muscle biopsy was performed on the proband, revealing mild variation in the myofiber size. NGS data revealed two compound heterozygous mutations at c.173delC (p.Pro58Hisfs*22) and c.C706T (p.R236X) in the COLQ gene, where the former was a novel mutation. A 3D structure prediction showed two truncated ColQ proteins with 78aa and 235aa, respectively. The truncated ColQ protein was proved in 293T cells transfected with c.173delC or c.C706T mutants by Western Blot. Conclusions The mutations of c.173delC and c.C706T in the COLQ gene led to truncated ColQ protein and contributed to the pathogenesis of CMS in this Chinese family.
Collapse
Affiliation(s)
- Qiting Zhang
- Department of Neurology, Tongren Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, 200336, China
| | - Qianqian Sha
- Department of Neurology, Tongren Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, 200336, China
| | - Kai Qiao
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, 200040, China
| | - Xiaoli Liu
- Department of Neurology, Shanghai Fengxian District Central Hospital, Shanghai Jiao Tong University Affiliated Sixth People's Hospital South Campus, Shanghai, 201406, China
| | - Xiaohui Gong
- Department of Neonatology, Shanghai Children's Hospital, Shanghai, 200062, China
- Corresponding author.
| | - Ailian Du
- Department of Neurology, Tongren Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, 200336, China
- Corresponding author.
| |
Collapse
|
6
|
Shao S, Shi G, Bi FF, Huang K. Pharmacological Treatments for Congenital Myasthenic Syndromes Caused by COLQ Mutations. Curr Neuropharmacol 2023; 21:1594-1605. [PMID: 36703579 PMCID: PMC10472815 DOI: 10.2174/1570159x21666230126145652] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 09/30/2022] [Accepted: 11/18/2022] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Congenital myasthenic syndromes (CMS) refer to a series of inherited disorders caused by defects in various proteins. Mutation in the collagen-like tail subunit of asymmetric acetylcholinesterase (COLQ) is the second-most common cause of CMS. However, data on pharmacological treatments are limited. OBJECTIVE In this study, we reviewed related reports to determine the most appropriate pharmacological strategy for CMS caused by COLQ mutations. A literature review and meta-analysis were also performed. PubMed, MEDLINE, Web of Science, and Cochrane Library databases were searched to identify studies published in English before July 22, 2022. RESULTS A total of 42 studies including 164 patients with CMS due to 72 different COLQ mutations were selected for evaluation. Most studies were case reports, and none were randomized clinical trials. Our meta-analysis revealed evidence that β-adrenergic agonists, including salbutamol and ephedrine, can be used as first-line pharmacological treatments for CMS patients with COLQ mutations, as 98.7% of patients (74/75) treated with β-adrenergic agonists showed positive effects. In addition, AChEIs should be avoided in CMS patients with COLQ mutations, as 90.5% (105/116) of patients treated with AChEIs showed either no or negative effects. CONCLUSION (1) β-adrenergic agonist therapy is the first pharmacological strategy for treating CMS with COLQ mutations. (2) AChEIs should be avoided in patients with CMS with COLQ mutations.
Collapse
Affiliation(s)
- Shuai Shao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
- Xiangya School of Medicine, Central South University, Changsha, Hunan province, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
| | - Guanzhong Shi
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
- Xiangya School of Medicine, Central South University, Changsha, Hunan province, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
| | - Fang-Fang Bi
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
| | - Kun Huang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
| |
Collapse
|
7
|
Hayes AJ, Farrugia BL, Biose IJ, Bix GJ, Melrose J. Perlecan, A Multi-Functional, Cell-Instructive, Matrix-Stabilizing Proteoglycan With Roles in Tissue Development Has Relevance to Connective Tissue Repair and Regeneration. Front Cell Dev Biol 2022; 10:856261. [PMID: 35433700 PMCID: PMC9010944 DOI: 10.3389/fcell.2022.856261] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 02/28/2022] [Indexed: 12/19/2022] Open
Abstract
This review highlights the multifunctional properties of perlecan (HSPG2) and its potential roles in repair biology. Perlecan is ubiquitous, occurring in vascular, cartilaginous, adipose, lymphoreticular, bone and bone marrow stroma and in neural tissues. Perlecan has roles in angiogenesis, tissue development and extracellular matrix stabilization in mature weight bearing and tensional tissues. Perlecan contributes to mechanosensory properties in cartilage through pericellular interactions with fibrillin-1, type IV, V, VI and XI collagen and elastin. Perlecan domain I - FGF, PDGF, VEGF and BMP interactions promote embryonic cellular proliferation, differentiation, and tissue development. Perlecan domain II, an LDLR-like domain interacts with lipids, Wnt and Hedgehog morphogens. Perlecan domain III binds FGF-7 and 18 and has roles in the secretion of perlecan. Perlecan domain IV, an immunoglobulin repeat domain, has cell attachment and matrix stabilizing properties. Perlecan domain V promotes tissue repair through interactions with VEGF, VEGF-R2 and α2β1 integrin. Perlecan domain-V LG1-LG2 and LG3 fragments antagonize these interactions. Perlecan domain V promotes reconstitution of the blood brain barrier damaged by ischemic stroke and is neurogenic and neuroprotective. Perlecan-VEGF-VEGFR2, perlecan-FGF-2 and perlecan-PDGF interactions promote angiogenesis and wound healing. Perlecan domain I, III and V interactions with platelet factor-4 and megakaryocyte and platelet inhibitory receptor promote adhesion of cells to implants and scaffolds in vascular repair. Perlecan localizes acetylcholinesterase in the neuromuscular junction and is of functional significance in neuromuscular control. Perlecan mutation leads to Schwartz-Jampel Syndrome, functional impairment of the biomechanical properties of the intervertebral disc, variable levels of chondroplasia and myotonia. A greater understanding of the functional working of the neuromuscular junction may be insightful in therapeutic approaches in the treatment of neuromuscular disorders. Tissue engineering of salivary glands has been undertaken using bioactive peptides (TWSKV) derived from perlecan domain IV. Perlecan TWSKV peptide induces differentiation of salivary gland cells into self-assembling acini-like structures that express salivary gland biomarkers and secrete α-amylase. Perlecan also promotes chondroprogenitor stem cell maturation and development of pluripotent migratory stem cell lineages, which participate in diarthrodial joint formation, and early cartilage development. Recent studies have also shown that perlecan is prominently expressed during repair of adult human articular cartilage. Perlecan also has roles in endochondral ossification and bone development. Perlecan domain I hydrogels been used in tissue engineering to establish heparin binding growth factor gradients that promote cell migration and cartilage repair. Perlecan domain I collagen I fibril scaffolds have also been used as an FGF-2 delivery system for tissue repair. With the availability of recombinant perlecan domains, the development of other tissue repair strategies should emerge in the near future. Perlecan co-localization with vascular elastin in the intima, acts as a blood shear-flow endothelial sensor that regulates blood volume and pressure and has a similar role to perlecan in canalicular fluid, regulating bone development and remodeling. This complements perlecan's roles in growth plate cartilage and in endochondral ossification to form the appendicular and axial skeleton. Perlecan is thus a ubiquitous, multifunctional, and pleomorphic molecule of considerable biological importance. A greater understanding of its diverse biological roles and functional repertoires during tissue development, growth and disease will yield valuable insights into how this impressive proteoglycan could be utilized successfully in repair biology.
Collapse
Affiliation(s)
- Anthony J. Hayes
- Bioimaging Research Hub, Cardiff School of Biosciences, Cardiff University, Wales, United Kingdom
| | - Brooke L. Farrugia
- Department of Biomedical Engineering, Melbourne School of Engineering, The University of Melbourne, Melbourne, VIC, Australia
| | - Ifechukwude J. Biose
- Departments of Neurosurgery and Neurology, Clinical Neuroscience Research Center, Tulane University School of Medicine, New Orleans, LA, United States
| | - Gregory J. Bix
- Departments of Neurosurgery and Neurology, Clinical Neuroscience Research Center, Tulane University School of Medicine, New Orleans, LA, United States
| | - James Melrose
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia
- Raymond Purves Bone and Joint Research Laboratories, Kolling Institute of Medical Research, Royal North Shore Hospital, The Faculty of Medicine and Health, The University of Sydney, St. Leonard’s, NSW, Australia
| |
Collapse
|
8
|
Luo X, Wang C, Lin L, Yuan F, Wang S, Wang Y, Wang A, Wang C, Wu S, Lan X, Xu Q, Yin R, Cheng H, Zhang Y, Xi J, Zhang J, Sun X, Yan J, Zeng F, Chen Y. Mechanisms of Congenital Myasthenia Caused by Three Mutations in the COLQ Gene. Front Pediatr 2021; 9:679342. [PMID: 34912755 PMCID: PMC8667818 DOI: 10.3389/fped.2021.679342] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 11/08/2021] [Indexed: 01/12/2023] Open
Abstract
The gene encoding collagen like tail subunit of asymmetric acetylcholinesterase (COLQ) is responsible for the transcription of three strands of collagen of acetylcholinesterase, which is attached to the endplate of neuromuscular junctions. Mutations in the COLQ gene are inherited in an autosomal-recessive manner and can lead to type V congenital myasthenia syndrome (CMS), which manifests as decreased muscle strength at birth or shortly after birth, respiratory failure, restricted eye movements, drooping of eyelids, and difficulty swallowing. Here we reported three variants within COLQ in two unrelated children with CMS. An intronic variant (c.393+1G>A) and a novel missense variant (p.Q381P) were identified as compound heterozygous in a 13-month-old boy, with the parents being carriers of each. An intragenic deletion including exons 14 and 15 was found in a homozygous state in a 12-year-old boy. We studied the relative expression of the COLQ and AChE gene in the probands' families, performed three-dimensional protein structural analysis, and analyzed the conservation of the missense mutation c.1142A>C (p.Q381P). The splicing mutation c.393+1G>A was found to affect the normal splicing of COLQ exon 5, resulting in a 27-bp deletion. The missense mutation c.1142A>C (p.Q381P) was located in a conserved position in different species. We found that homozygous deletion of COLQ exons 14-15 resulted in a 241-bp deletion, which decreased the number of amino acids and caused a frameshift translation. COLQ expression was significantly lower in the probands than in the probands' parents and siblings, while AChE expression was significantly higher. Moreover, the mutations were found to cause significant differences in the predicted three-dimensional structure of the protein. The splicing mutation c.393+1G>A, missense mutation c.1A>C (p.Q381P), and COLQ exon 14-15 deletion could cause CMS.
Collapse
Affiliation(s)
- Xiaona Luo
- Department of Neurology, Shanghai Children's Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Chunmei Wang
- Department of Neurology, Shanghai Children's Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Longlong Lin
- Department of Neurology, Shanghai Children's Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Fang Yuan
- Department of Neurology, Shanghai Children's Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Simei Wang
- Department of Neurology, Shanghai Children's Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Yilin Wang
- Department of Neurology, Shanghai Children's Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Anqi Wang
- Department of Neurology, Shanghai Children's Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Chao Wang
- Department of Neurology, Shanghai Children's Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Shengnan Wu
- Department of Neurology, Shanghai Children's Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Xiaoping Lan
- Department of Neurology, Shanghai Children's Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Quanmei Xu
- Department of Neurology, Shanghai Children's Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Rongrong Yin
- Department of Neurology, Shanghai Children's Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Hongyi Cheng
- Department of Neurology, Shanghai Children's Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Yuanfeng Zhang
- Department of Neurology, Shanghai Children's Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Jiaming Xi
- Department of Neurology, Shanghai Children's Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Jie Zhang
- Department of Neurology, Shanghai Children's Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Xiaomin Sun
- Department of Neurology, Shanghai Children's Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Jingbin Yan
- National Health Commission (NHC) Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology and Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai, China
| | - Fanyi Zeng
- National Health Commission (NHC) Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology and Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai, China
| | - Yucai Chen
- Department of Neurology, Shanghai Children's Hospital, Shanghai JiaoTong University, Shanghai, China.,National Health Commission (NHC) Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology and Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai, China
| |
Collapse
|
9
|
Laforgia N, De Cosmo L, Palumbo O, Ranieri C, Sesta M, Capodiferro D, Pantaleo A, Iapicca P, Lastella P, Capozza M, Schettini F, Bukvic N, Bagnulo R, Resta N. The First Case of Congenital Myasthenic Syndrome Caused by a Large Homozygous Deletion in the C-Terminal Region of COLQ (Collagen Like Tail Subunit of Asymmetric Acetylcholinesterase) Protein. Genes (Basel) 2020; 11:genes11121519. [PMID: 33353066 PMCID: PMC7765904 DOI: 10.3390/genes11121519] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/13/2020] [Accepted: 12/15/2020] [Indexed: 12/13/2022] Open
Abstract
Congenital myasthenic syndromes (CMSs) are caused by mutations in genes that encode proteins involved in the organization, maintenance, function, or modification of the neuromuscular junction. Among these, the collagenic tail of endplate acetylcholinesterase protein (COLQ; MIM 603033) has a crucial role in anchoring the enzyme into the synaptic basal lamina. Here, we report on the first case of a patient with a homozygous deletion affecting the last exons of the COLQ gene in a CMS patient born to consanguineous parents of Pakistani origin. Electromyography (EMG), electroencephalography (EEG), clinical exome sequencing (CES), and single nucleotide polymorphism (SNP) array analyses were performed. The subject was born at term after an uneventful pregnancy and developed significant hypotonia and dystonia, clinical pseudoseizures, and recurring respiratory insufficiency with a need for mechanical ventilation. CES analysis of the patient revealed a homozygous deletion of the COLQ gene located on the 3p25.1 chromosome region. The SNP-array confirmed the presence of deletion that extended from exon 11 to the last exon 17 with a size of 19.5 Kb. Our results add new insights about the underlying pathogenetic mechanisms expanding the spectrum of causative COLQ mutations. It is relevant, considering the therapeutic implications, to apply suitable molecular approaches so that no type of mutation is missed: “each lost mutation means a baby treated improperly”.
Collapse
Affiliation(s)
- Nicola Laforgia
- Section of Neonatology and Neonatal Intensive Care Unit, Department of Biomedical Science and Human Oncology (DIMO), University of Bari “Aldo Moro”, 70124 Bari, Italy; (N.L.); (L.D.C.); (D.C.); (M.C.); (F.S.)
| | - Lucrezia De Cosmo
- Section of Neonatology and Neonatal Intensive Care Unit, Department of Biomedical Science and Human Oncology (DIMO), University of Bari “Aldo Moro”, 70124 Bari, Italy; (N.L.); (L.D.C.); (D.C.); (M.C.); (F.S.)
| | - Orazio Palumbo
- Division of Medical Genetics, Fondazione IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy;
| | - Carlotta Ranieri
- Division of Medical Genetics, Department of Biomedical Sciences and Human Oncology (DIMO), University of Bari “Aldo Moro”, 70124 Bari, Italy; (C.R.); (A.P.); (R.B.)
| | - Michela Sesta
- Neurology Unit, University Hospital Consortium Corporation Polyclinic of Bari, 70124 Bari, Italy;
| | - Donatella Capodiferro
- Section of Neonatology and Neonatal Intensive Care Unit, Department of Biomedical Science and Human Oncology (DIMO), University of Bari “Aldo Moro”, 70124 Bari, Italy; (N.L.); (L.D.C.); (D.C.); (M.C.); (F.S.)
| | - Antonino Pantaleo
- Division of Medical Genetics, Department of Biomedical Sciences and Human Oncology (DIMO), University of Bari “Aldo Moro”, 70124 Bari, Italy; (C.R.); (A.P.); (R.B.)
| | | | - Patrizia Lastella
- Rare Diseases Centre—Internal Medicine Unit “C. Frugoni”, Polyclinic of Bari, 70124 Bari, Italy;
| | - Manuela Capozza
- Section of Neonatology and Neonatal Intensive Care Unit, Department of Biomedical Science and Human Oncology (DIMO), University of Bari “Aldo Moro”, 70124 Bari, Italy; (N.L.); (L.D.C.); (D.C.); (M.C.); (F.S.)
| | - Federico Schettini
- Section of Neonatology and Neonatal Intensive Care Unit, Department of Biomedical Science and Human Oncology (DIMO), University of Bari “Aldo Moro”, 70124 Bari, Italy; (N.L.); (L.D.C.); (D.C.); (M.C.); (F.S.)
| | - Nenad Bukvic
- Medical Genetics Section, University Hospital Consortium Corporation Polyclinic of Bari, 70124 Bari, Italy;
| | - Rosanna Bagnulo
- Division of Medical Genetics, Department of Biomedical Sciences and Human Oncology (DIMO), University of Bari “Aldo Moro”, 70124 Bari, Italy; (C.R.); (A.P.); (R.B.)
| | - Nicoletta Resta
- Division of Medical Genetics, Department of Biomedical Sciences and Human Oncology (DIMO), University of Bari “Aldo Moro”, 70124 Bari, Italy; (C.R.); (A.P.); (R.B.)
- Medical Genetics Section, University Hospital Consortium Corporation Polyclinic of Bari, 70124 Bari, Italy;
- Correspondence: ; Tel.: +39-0805593619
| |
Collapse
|
10
|
Pohanka M. Diagnoses of Pathological States Based on Acetylcholinesterase and Butyrylcholinesterase. Curr Med Chem 2020; 27:2994-3011. [PMID: 30706778 DOI: 10.2174/0929867326666190130161202] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 01/16/2019] [Accepted: 01/17/2019] [Indexed: 12/15/2022]
Abstract
Two cholinesterases exist: Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). While AChE plays a crucial role in neurotransmissions, BChE has no specific function apart from the detoxification of some drugs and secondary metabolites from plants. Thus, both AChE and BChE can serve as biochemical markers of various pathologies. Poisoning by nerve agents like sarin, soman, tabun, VX, novichok and overdosing by drugs used in some neurodegenerative disorders like Alzheimer´s disease and myasthenia gravis, as well as poisoning by organophosphorus pesticides are relevant to this issue. But it appears that changes in these enzymes take place in other processes including oxidative stress, inflammation, some types of cancer and genetically conditioned diseases. In this review, the cholinesterases are introduced, the mechanism of inhibitors action is explained and the relations between the cholinesterases and pathologies are explained.
Collapse
Affiliation(s)
- Miroslav Pohanka
- Faculty of Military Health Sciences, University of Defence, Trebesska 1575, 50001 Hradec Kralove, Czech Republic
| |
Collapse
|
11
|
Collagens at the vertebrate neuromuscular junction, from structure to pathologies. Neurosci Lett 2020; 735:135155. [PMID: 32534096 DOI: 10.1016/j.neulet.2020.135155] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 06/05/2020] [Accepted: 06/09/2020] [Indexed: 12/17/2022]
Abstract
The extracellular matrix at the neuromuscular junction is built upon components secreted by the motoneuron, the muscle cell and terminal Schwann cells, the cells constituting this specific synapse. This compartment contains glycoproteins, proteoglycans and collagens that form a dense and specialized layer, the synaptic basal lamina. A number of these molecules are known to play a crucial role in anterograde and retrograde signalings that are active in neuromuscular junction formation, maintenance and function. Here, we focus on the isoforms of collagens which are enriched at the synapse. We summarize what we know of their structure, their function and their interactions with transmembrane receptors and other components of the synaptic basal lamina. A number of neuromuscular diseases, congenital myastenic syndromes and myasthenia gravis are caused by human mutations and autoantibodies against these proteins. Analysis of these diseases and of the specific collagen knock-out mice highlights the roles of some of these collagens in promoting a functional synapse.
Collapse
|
12
|
Legay C. Congenital myasthenic syndromes with acetylcholinesterase deficiency, the pathophysiological mechanisms. Ann N Y Acad Sci 2019; 1413:104-110. [PMID: 29405353 DOI: 10.1111/nyas.13595] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 12/12/2017] [Accepted: 12/12/2017] [Indexed: 12/15/2022]
Abstract
The neuromuscular junction (NMJ) is a cholinergic synapse in vertebrates. This synapse connects motoneurons to muscles and is responsible for muscle contraction, a physiological process that is essential for survival. A key factor for the normal functioning of this synapse is the regulation of acetylcholine (ACh) levels in the synaptic cleft. This is ensured by acetylcholinesterase (AChE), which degrades ACh. A number of mutations in synaptic genes expressed in motoneurons or muscle cells have been identified and are causative for a class of neuromuscular diseases called congenital myasthenic syndromes (CMSs). One of these CMSs is due to deficiency in AChE, which is absent or diffuse in the synaptic cleft. Here, I focus on the origins of the syndrome. The role of ColQ, a collagen that anchors AChE in the synaptic cleft, is discussed in this context. Studies performed on patient biopsies, transgenic mice, and muscle cultures have provided a more comprehensive view of the connectome at the NMJ that should be useful for understanding the differences in the symptoms observed in specific CMSs due to mutated proteins in the synaptic cleft.
Collapse
Affiliation(s)
- Claire Legay
- CNRS 8119, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| |
Collapse
|
13
|
Abstract
OBJECTIVES Congenital myasthenic syndromes (CMSs) are a genotypically and phenotypically heterogeneous group of neuromuscular disorders, which have in common an impaired neuromuscular transmission. Since the field of CMSs is steadily expanding, the present review aimed at summarizing and discussing current knowledge and recent advances concerning the etiology, clinical presentation, diagnosis, and treatment of CMSs. METHODS Systematic literature review. RESULTS Currently, mutations in 32 genes are made responsible for autosomal dominant or autosomal recessive CMSs. These mutations concern 8 presynaptic, 4 synaptic, 15 post-synaptic, and 5 glycosilation proteins. These proteins function as ion-channels, enzymes, or structural, signalling, sensor, or transporter proteins. The most common causative genes are CHAT, COLQ, RAPSN, CHRNE, DOK7, and GFPT1. Phenotypically, these mutations manifest as abnormal fatigability or permanent or fluctuating weakness of extra-ocular, facial, bulbar, axial, respiratory, or limb muscles, hypotonia, or developmental delay. Cognitive disability, dysmorphism, neuropathy, or epilepsy are rare. Low- or high-frequency repetitive nerve stimulation may show an abnormal increment or decrement, and SF-EMG an increased jitter or blockings. Most CMSs respond favourably to acetylcholine-esterase inhibitors, 3,4-diamino-pyridine, salbutamol, albuterol, ephedrine, fluoxetine, or atracurium. CONCLUSIONS CMSs are an increasingly recognised group of genetically transmitted defects, which usually respond favorably to drugs enhancing the neuromuscular transmission. CMSs need to be differentiated from neuromuscular disorders due to muscle or nerve dysfunction.
Collapse
Affiliation(s)
- Josef Finsterer
- Krankenanstalt Rudolfstiftung, Messerli Institute, Veterinary University of Vienna, Postfach 20, 1180, Vienna, Austria.
| |
Collapse
|
14
|
Maguire LH, Handelman SK, Du X, Chen Y, Pers TH, Speliotes EK. Genome-wide association analyses identify 39 new susceptibility loci for diverticular disease. Nat Genet 2018; 50:1359-1365. [PMID: 30177863 PMCID: PMC6168378 DOI: 10.1038/s41588-018-0203-z] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 07/23/2018] [Indexed: 12/31/2022]
Abstract
Diverticular disease is common and has a high morbidity. Treatments are limited owing to the poor understanding of its pathophysiology. Here, to elucidate its etiology, we performed a genome-wide association study of diverticular disease (27,444 cases; 382,284 controls) from the UK Biobank and tested for replication in the Michigan Genomics Initiative (2,572 cases; 28,649 controls). We identified 42 loci associated with diverticular disease; 39 of these loci are novel. Using data-driven expression-prioritized integration for complex traits (DEPICT), we show that genes in these associated regions are significantly enriched for expression in mesenchymal stem cells and multiple connective tissue cell types and are co-expressed with genes that have a role in vascular and mesenchymal biology. Genes in these associated loci have roles in immunity, extracellular matrix biology, cell adhesion, membrane transport and intestinal motility. Phenome-wide association analysis of the 42 variants shows a common etiology of diverticular disease with obesity and hernia. These analyses shed light on the genomic landscape of diverticular disease.
Collapse
Affiliation(s)
- Lillias H Maguire
- Department of Surgery, Division of Colorectal Surgery, University of Michigan, Ann Arbor, MI, USA.
| | - Samuel K Handelman
- Department of Internal Medicine, Division of Gastroenterology, Ann Arbor, MI, USA
| | - Xiaomeng Du
- Department of Internal Medicine, Division of Gastroenterology, Ann Arbor, MI, USA
| | - Yanhua Chen
- Department of Internal Medicine, Division of Gastroenterology, Ann Arbor, MI, USA
| | - Tune H Pers
- The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark
| | - Elizabeth K Speliotes
- Department of Internal Medicine, Division of Gastroenterology, Ann Arbor, MI, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| |
Collapse
|
15
|
Maselli RA, Arredondo J, Vázquez J, Chong JX, Bamshad MJ, Nickerson DA, Lara M, Ng F, Lo VL, Pytel P, McDonald CM. A presynaptic congenital myasthenic syndrome attributed to a homozygous sequence variant in LAMA5. Ann N Y Acad Sci 2018; 1413:119-125. [PMID: 29377152 DOI: 10.1111/nyas.13585] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 11/18/2017] [Accepted: 11/27/2017] [Indexed: 12/23/2022]
Abstract
We report a severe defect of neuromuscular transmission in a consanguineous patient with a homozygous variant in the laminin α5 subunit gene (LAMA5). The variant c.8046C > T (p.Arg2659Trp) is rare and has a predicted deleterious effect. The affected individual, who also carries a rare homozygous sequence variant in LAMA1, had normal cognitive function, but magnetic resonance brain imaging showed mild volume loss and periventricular T2 prolongation. Repetitive nerve stimulation at 2 Hz showed 50% decrement of compound muscle action potential amplitudes but 250% facilitation immediately after exercise, similar to that seen in Lambert-Eaton myasthenic syndrome. Endplate studies demonstrated a profound reduction of the endplate potential quantal content but normal amplitudes of miniature endplate potentials. Electron microscopy showed endplates with increased postsynaptic folding that were denuded or only partially occupied by small nerve terminals. Expression studies revealed that p.Arg2659Trp caused decreased binding of laminin α5 to SV2A and impaired laminin-521 cell adhesion and cell projection support in primary neuronal cultures. In summary, this report describing severe neuromuscular transmission failure in a patient with a LAMA5 mutation expands the list of phenotypes associated with defects in genes encoding α-laminins.
Collapse
Affiliation(s)
- Ricardo A Maselli
- Department of Neurology, University of California Davis, Sacramento, California
| | - Juan Arredondo
- Department of Neurology, University of California Davis, Sacramento, California
| | - Jessica Vázquez
- Department of Neurology, University of California Davis, Sacramento, California
| | - Jessica X Chong
- Department of Pediatrics, University of Washington, Seattle, Washington
| | - Michael J Bamshad
- Department of Pediatrics, University of Washington, Seattle, Washington.,Department of Genome Sciences, University of Washington, Seattle, Washington.,Division of Genetic Medicine, Seattle Children's Hospital, Seattle, Washington
| | - Deborah A Nickerson
- Department of Genome Sciences, University of Washington, Seattle, Washington
| | - Marian Lara
- Department of Neurology, University of California Davis, Sacramento, California
| | - Fiona Ng
- Department of Neurology, University of California Davis, Sacramento, California
| | - Victoria Lee Lo
- Department of Neurology, University of California Davis, Sacramento, California
| | - Peter Pytel
- Department of Pathology, University of Chicago, Chicago, Illinois
| | - Craig M McDonald
- Department of Medicine and Rehabilitation, University of California Davis, Sacramento, California
| |
Collapse
|
16
|
Maselli RA, Arredondo J, Vázquez J, Chong JX, Bamshad MJ, Nickerson DA, Lara M, Ng F, Lo VL, Pytel P, McDonald CM. Presynaptic congenital myasthenic syndrome with a homozygous sequence variant in LAMA5 combines myopia, facial tics, and failure of neuromuscular transmission. Am J Med Genet A 2017; 173:2240-2245. [PMID: 28544784 DOI: 10.1002/ajmg.a.38291] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 04/03/2017] [Accepted: 04/24/2017] [Indexed: 12/13/2022]
Abstract
Defects in genes encoding the isoforms of the laminin alpha subunit have been linked to various phenotypic manifestations, including brain malformations, muscular dystrophy, ocular defects, cardiomyopathy, and skin abnormalities. We report here a severe defect of neuromuscular transmission in a consanguineous patient with a homozygous variant in the laminin alpha-5 subunit gene (LAMA5). The variant c.8046C>T (p.Arg2659Trp) is rare and has a predicted deleterious effect. The affected individual, who also carries a rare homozygous sequence variant in LAMA1, had muscle weakness, myopia, and facial tics. Magnetic resonance imaging of brain showed mild volume loss and periventricular T2 prolongation. Repetitive nerve stimulation revealed 50% decrement of compound muscle action potential amplitudes and 250% facilitation immediately after exercise, Endplate studies identified a profound reduction of the endplate potential quantal content and endplates with normal postsynaptic folding that were denuded or partially occupied by small nerve terminals. Expression studies revealed that p.Arg2659Trp caused decreased binding of laminin alpha-5 to SV2A and impaired laminin-521 cell-adhesion and cell projection support in primary neuronal cultures. In summary, this report describing severe neuromuscular transmission failure in a patient with a LAMA5 mutation expands the list of phenotypes associated with defects in genes encoding alpha-laminins.
Collapse
Affiliation(s)
- Ricardo A Maselli
- Department of Neurology, University of California Davis, Sacramento, California
| | - Juan Arredondo
- Department of Neurology, University of California Davis, Sacramento, California
| | - Jessica Vázquez
- Department of Neurology, University of California Davis, Sacramento, California
| | - Jessica X Chong
- Department of Pediatrics, University of Washington, Seattle, Washington
| | | | - Michael J Bamshad
- Department of Pediatrics, University of Washington, Seattle, Washington.,Department of Genome Sciences, University of Washington, Seattle, Washington.,Division of Genetic Medicine, Seattle Children's Hospital, Seattle, Washington
| | - Deborah A Nickerson
- Department of Genome Sciences, University of Washington, Seattle, Washington
| | - Marian Lara
- Department of Neurology, University of California Davis, Sacramento, California
| | - Fiona Ng
- Department of Neurology, University of California Davis, Sacramento, California
| | - Victoria L Lo
- Department of Neurology, University of California Davis, Sacramento, California
| | - Peter Pytel
- Department of Pathology, University of Chicago, Chicago, Illinois
| | - Craig M McDonald
- Department of Medicine and Rehabilitation, University of California Davis, Sacramento, California
| |
Collapse
|
17
|
Sigoillot SM, Bourgeois F, Karmouch J, Molgó J, Dobbertin A, Chevalier C, Houlgatte R, Léger J, Legay C. Neuromuscular junction immaturity and muscle atrophy are hallmarks of the ColQ-deficient mouse, a model of congenital myasthenic syndrome with acetylcholinesterase deficiency. FASEB J 2016; 30:2382-99. [PMID: 26993635 DOI: 10.1096/fj.201500162] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 02/26/2016] [Indexed: 12/13/2022]
Abstract
The collagen ColQ anchors acetylcholinesterase (AChE) in the synaptic cleft of the neuromuscular junction (NMJ). It also binds MuSK and perlecan/dystroglycan, 2 signaling platforms of the postsynaptic domain. Mutations in ColQ cause a congenital myasthenic syndrome (CMS) with AChE deficiency. Because the absence of AChE does not fully explain the complexity of the syndrome and there is no curative treatment for the disease, we explored additional potential targets of ColQ by conducting a large genetic screening of ColQ-deficient mice, a model for CMS with AChE deficiency, and analyzed their NMJ and muscle phenotypes. We demonstrated that ColQ controls the development and the maturation of the postsynaptic domain by regulating synaptic gene expression. Notably, ColQ deficiency leads to an up-regulation of the 5 subunits of the nicotinic acetylcholine receptor (AChR), leading to mixed mature and immature AChRs at the NMJ of adult mice. ColQ also regulates the expression of extracellular matrix (ECM) components. However, whereas the ECM mRNAs were down-regulated in vitro, compensation seemed to occur in vivo to maintain normal levels of these mRNAs. Finally, ColQ deficiency leads to a general atrophic phenotype and hypoplasia that affect fast muscles. This study points to new specific hallmarks for this CMS.-Sigoillot, S. M., Bourgeois, F., Karmouch, J., Molgó, J., Dobbertin, A., Chevalier, C., Houlgatte, R., Léger, J., Legay, C. Neuromuscular junction immaturity and muscle atrophy are hallmarks of the ColQ-deficient mouse, a model of congenital myasthenic syndrome with acetylcholinesterase deficiency.
Collapse
Affiliation(s)
- Séverine M Sigoillot
- Centre de Neurophysique, Physiologie et Pathologie, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 8119, Université Paris Descartes, Sorbonne Paris Cité, Paris France
| | - Francine Bourgeois
- Centre de Neurophysique, Physiologie et Pathologie, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 8119, Université Paris Descartes, Sorbonne Paris Cité, Paris France
| | - Jennifer Karmouch
- Centre de Neurophysique, Physiologie et Pathologie, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 8119, Université Paris Descartes, Sorbonne Paris Cité, Paris France
| | - Jordi Molgó
- Commissariat à l'énergie Atomique et aux Energies Alternatives, Institut de Biologie et Technologies de Saclay, Service d'Ingénierie Moléculaire des Protéines, Gif sur Yvette, France; Institut des Neurosciences Paris-Saclay, UMR 9197, CNRS/Université Paris-Sud, Paris, France; and
| | - Alexandre Dobbertin
- Centre de Neurophysique, Physiologie et Pathologie, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 8119, Université Paris Descartes, Sorbonne Paris Cité, Paris France
| | - Catherine Chevalier
- Institut de Recherche Thérapeutique de l'Université de Nantes, Plateforme Génomique Intégrative, Nantes, France
| | - Rémi Houlgatte
- Institut de Recherche Thérapeutique de l'Université de Nantes, Plateforme Génomique Intégrative, Nantes, France
| | - Jean Léger
- Institut de Recherche Thérapeutique de l'Université de Nantes, Plateforme Génomique Intégrative, Nantes, France
| | - Claire Legay
- Centre de Neurophysique, Physiologie et Pathologie, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 8119, Université Paris Descartes, Sorbonne Paris Cité, Paris France;
| |
Collapse
|
18
|
Roche DB, Brackenridge DA, McGuffin LJ. Proteins and Their Interacting Partners: An Introduction to Protein-Ligand Binding Site Prediction Methods. Int J Mol Sci 2015; 16:29829-42. [PMID: 26694353 PMCID: PMC4691145 DOI: 10.3390/ijms161226202] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Revised: 12/02/2015] [Accepted: 12/10/2015] [Indexed: 01/14/2023] Open
Abstract
Elucidating the biological and biochemical roles of proteins, and subsequently determining their interacting partners, can be difficult and time consuming using in vitro and/or in vivo methods, and consequently the majority of newly sequenced proteins will have unknown structures and functions. However, in silico methods for predicting protein-ligand binding sites and protein biochemical functions offer an alternative practical solution. The characterisation of protein-ligand binding sites is essential for investigating new functional roles, which can impact the major biological research spheres of health, food, and energy security. In this review we discuss the role in silico methods play in 3D modelling of protein-ligand binding sites, along with their role in predicting biochemical functionality. In addition, we describe in detail some of the key alternative in silico prediction approaches that are available, as well as discussing the Critical Assessment of Techniques for Protein Structure Prediction (CASP) and the Continuous Automated Model EvaluatiOn (CAMEO) projects, and their impact on developments in the field. Furthermore, we discuss the importance of protein function prediction methods for tackling 21st century problems.
Collapse
Affiliation(s)
- Daniel Barry Roche
- Institut de Biologie Computationnelle, LIRMM, CNRS, Université de Montpellier, Montpellier 34095, France.
- Centre de Recherche de Biochimie Macromoléculaire, CNRS-UMR 5237, Montpellier 34293, France.
| | | | | |
Collapse
|
19
|
Abitbol M, Hitte C, Bossé P, Blanchard-Gutton N, Thomas A, Martignat L, Blot S, Tiret L. A COLQ Missense Mutation in Sphynx and Devon Rex Cats with Congenital Myasthenic Syndrome. PLoS One 2015; 10:e0137019. [PMID: 26327126 PMCID: PMC4556666 DOI: 10.1371/journal.pone.0137019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 08/11/2015] [Indexed: 11/25/2022] Open
Abstract
An autosomal recessive neuromuscular disorder characterized by skeletal muscle weakness, fatigability and variable electromyographic or muscular histopathological features has been described in the two related Sphynx and Devon Rex cat breeds (Felis catus). Collection of data from two affected Sphynx cats and their relatives pointed out a single disease candidate region on feline chromosome C2, identified following a genome-wide SNP-based homozygosity mapping strategy. In that region, we further identified COLQ (collagen-like tail subunit of asymmetric acetylcholinesterase) as a good candidate gene, since COLQ mutations were identified in affected humans and dogs with endplate acetylcholinesterase deficiency leading to a synaptic form of congenital myasthenic syndrome (CMS). A homozygous c.1190G>A missense variant located in exon 15 of COLQ, leading to a C397Y substitution, was identified in the two affected cats. C397 is a highly-conserved residue from the C-terminal domain of the protein; its mutation was previously shown to produce CMS in humans, and here we confirmed in an affected Sphynx cat that it induces a loss of acetylcholinesterase clustering at the neuromuscular junction. Segregation of the c.1190G>A variant was 100% consistent with the autosomal recessive mode of inheritance of the disorder in our cat pedigree; in addition, an affected, unrelated Devon Rex cat recruited thereafter was also homozygous for the variant. Genotyping of a panel of 333 cats from 14 breeds failed to identify a single carrier in non-Sphynx and non-Devon Rex cats. Finally, the percentage of healthy carriers in a European subpanel of 81 genotyped Sphynx cats was estimated to be low (3.7%) and 14 control Devon Rex cats were genotyped as wild-type individuals. Altogether, these results strongly support that the neuromuscular disorder reported in Sphynx and Devon Rex breeds is a CMS caused by a unique c.1190G>A missense mutation, presumably transmitted through a founder effect, which strictly and slightly disseminated in these two breeds. The presently available DNA test will help owners avoid matings at risk.
Collapse
Affiliation(s)
- Marie Abitbol
- Inserm, IMRB U955-E10, 94000, Créteil, France
- Université Paris Est, Ecole nationale vétérinaire d'Alfort, 94700, Maisons-Alfort, & Faculté de médecine, 94000, Créteil, France
- Etablissement Français du Sang, 94017, Créteil, France
- APHP, Hôpitaux Universitaires Henri Mondor, DHU Pepsy & Centre de référence des maladies neuromusculaires GNMH, 94000 Créteil, France
- * E-mail:
| | - Christophe Hitte
- Institut de Génétique et Développement de Rennes IGDR, UMR6290 CNRS—Université de Rennes 1, Rennes, France
| | - Philippe Bossé
- Inserm, IMRB U955-E10, 94000, Créteil, France
- Université Paris Est, Ecole nationale vétérinaire d'Alfort, 94700, Maisons-Alfort, & Faculté de médecine, 94000, Créteil, France
- Etablissement Français du Sang, 94017, Créteil, France
- APHP, Hôpitaux Universitaires Henri Mondor, DHU Pepsy & Centre de référence des maladies neuromusculaires GNMH, 94000 Créteil, France
| | - Nicolas Blanchard-Gutton
- Inserm, IMRB U955-E10, 94000, Créteil, France
- Université Paris Est, Ecole nationale vétérinaire d'Alfort, 94700, Maisons-Alfort, & Faculté de médecine, 94000, Créteil, France
- Etablissement Français du Sang, 94017, Créteil, France
- APHP, Hôpitaux Universitaires Henri Mondor, DHU Pepsy & Centre de référence des maladies neuromusculaires GNMH, 94000 Créteil, France
| | - Anne Thomas
- Antagene, Animal Genetics Laboratory, La Tour de Salvagny, France
| | - Lionel Martignat
- ONIRIS, UP Sécurité Sanitaire en Biotechnologies de la Reproduction, Nantes, France
| | - Stéphane Blot
- Inserm, IMRB U955-E10, 94000, Créteil, France
- Université Paris Est, Ecole nationale vétérinaire d'Alfort, 94700, Maisons-Alfort, & Faculté de médecine, 94000, Créteil, France
- Etablissement Français du Sang, 94017, Créteil, France
- APHP, Hôpitaux Universitaires Henri Mondor, DHU Pepsy & Centre de référence des maladies neuromusculaires GNMH, 94000 Créteil, France
| | - Laurent Tiret
- Inserm, IMRB U955-E10, 94000, Créteil, France
- Université Paris Est, Ecole nationale vétérinaire d'Alfort, 94700, Maisons-Alfort, & Faculté de médecine, 94000, Créteil, France
- Etablissement Français du Sang, 94017, Créteil, France
- APHP, Hôpitaux Universitaires Henri Mondor, DHU Pepsy & Centre de référence des maladies neuromusculaires GNMH, 94000 Créteil, France
| |
Collapse
|
20
|
Nichols B, Takeda S, Yokota T. Nonmechanical Roles of Dystrophin and Associated Proteins in Exercise, Neuromuscular Junctions, and Brains. Brain Sci 2015; 5:275-98. [PMID: 26230713 PMCID: PMC4588140 DOI: 10.3390/brainsci5030275] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 06/29/2015] [Accepted: 07/21/2015] [Indexed: 02/06/2023] Open
Abstract
Dystrophin-glycoprotein complex (DGC) is an important structural unit in skeletal muscle that connects the cytoskeleton (f-actin) of a muscle fiber to the extracellular matrix (ECM). Several muscular dystrophies, such as Duchenne muscular dystrophy, Becker muscular dystrophy, congenital muscular dystrophies (dystroglycanopathies), and limb-girdle muscular dystrophies (sarcoglycanopathies), are caused by mutations in the different DGC components. Although many early studies indicated DGC plays a crucial mechanical role in maintaining the structural integrity of skeletal muscle, recent studies identified novel roles of DGC. Beyond a mechanical role, these DGC members play important signaling roles and act as a scaffold for various signaling pathways. For example, neuronal nitric oxide synthase (nNOS), which is localized at the muscle membrane by DGC members (dystrophin and syntrophins), plays an important role in the regulation of the blood flow during exercise. DGC also plays important roles at the neuromuscular junction (NMJ) and in the brain. In this review, we will focus on recently identified roles of DGC particularly in exercise and the brain.
Collapse
Affiliation(s)
- Bailey Nichols
- Department of Medical Genetics, University of Alberta Faculty of Medicine and Dentistry.
| | - Shin'ichi Takeda
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, Ogawa-higashi, Kodaira, Tokyo 187-8502, Japan.
| | - Toshifumi Yokota
- Department of Medical Genetics, University of Alberta Faculty of Medicine and Dentistry.
- Muscular Dystrophy Canada Research Chair, 8812-112 St, Edmonton, AB T6G 2H7, Canada.
| |
Collapse
|
21
|
Zoltowska Katarzyna M, Belaya K, Leite M, Patrick W, Vincent A, Beeson D. Collagen Q--a potential target for autoantibodies in myasthenia gravis. J Neurol Sci 2014; 348:241-4. [PMID: 25577314 DOI: 10.1016/j.jns.2014.12.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 12/08/2014] [Accepted: 12/11/2014] [Indexed: 01/11/2023]
Abstract
Myasthenia gravis (MG) is an autoimmune disorder caused by autoantibodies targeting proteins expressed at the neuromuscular junction (NMJ). In most cases the targets are acetylcholine receptor (AChR), muscle-specific tyrosine kinase (MuSK), or occasionally low-density lipoprotein receptor-related protein 4 (LRP4), but there is still a group of patients, often called seronegative MG (SNMG), with unknown antibody targets. One potential target is collagen Q (COLQ), which is restricted to the NMJ and is crucial for anchoring the NMJ-specific form of acetylcholinesterase (AChE). 415 serum samples with a clinical diagnosis of MG and 43 control samples were screened for the presence of COLQ autoantibodies using a cell-based assay (CBA) with HEK293 cells overexpressing COLQ at the cell surface. COLQ antibodies were detected in 12/415 MG sera and in one/43 control samples. Five of the COLQ-Ab+individuals were also positive for AChR-Abs and 2 for MuSK-Abs. Although the COLQ antibodies were only present at low frequency, and did not differ significantly from the small control cohort, further studies could address whether they modify the clinical presentation or the benefits of anti-cholinesterase therapy.
Collapse
Affiliation(s)
- Marta Zoltowska Katarzyna
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Weatherall Institute of Molecular Medicine, Neurosciences Group, OX3 9DS, Oxford, UK
| | - Katsiaryna Belaya
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Weatherall Institute of Molecular Medicine, Neurosciences Group, OX3 9DS, Oxford, UK
| | - Maria Leite
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Weatherall Institute of Molecular Medicine, Neurosciences Group, OX3 9DS, Oxford, UK
| | - Waters Patrick
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Weatherall Institute of Molecular Medicine, Neurosciences Group, OX3 9DS, Oxford, UK
| | - Angela Vincent
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Weatherall Institute of Molecular Medicine, Neurosciences Group, OX3 9DS, Oxford, UK
| | - David Beeson
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Weatherall Institute of Molecular Medicine, Neurosciences Group, OX3 9DS, Oxford, UK.
| |
Collapse
|
22
|
Inherited disorders of the neuromuscular junction: an update. J Neurol 2014; 261:2234-43. [PMID: 25305004 DOI: 10.1007/s00415-014-7520-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 09/23/2014] [Indexed: 10/24/2022]
Abstract
Congenital myasthenic syndromes (CMSs) are a group of heterogeneous inherited disorders caused by mutations in genes affecting the function and structure of the neuromuscular junction. This review updates the reader on established and novel subtypes of congenital myasthenia, and the treatment strategies for these increasingly heterogeneous disorders. The discovery of mutations associated with the N-glycosylation pathway and in the family of serine peptidases has shown that causative genes encoding ubiquitously expressed molecules can produce defects at the human neuromuscular junction. By contrast, mutations in lipoprotein-like receptor 4 (LRP4), a long-time candidate gene for congenital myasthenia, and a novel phenotype of myasthenia with distal weakness and atrophy due to mutations in AGRN have now been described. In addition, a pathogenic splicing mutation in a nonfunctional exon of CHRNA1 has been reported emphasizing the importance of analysing nonfunctional exons in genetic analysis. The benefit of salbutamol and ephedrine alone or combined with pyridostigmine or 3,4-DAP is increasingly being reported for particular subtypes of CMS.
Collapse
|
23
|
|
24
|
Rinz CJ, Levine J, Minor KM, Humphries HD, Lara R, Starr-Moss AN, Guo LT, Williams DC, Shelton GD, Clark LA. A COLQ missense mutation in Labrador Retrievers having congenital myasthenic syndrome. PLoS One 2014; 9:e106425. [PMID: 25166616 PMCID: PMC4148433 DOI: 10.1371/journal.pone.0106425] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 07/29/2014] [Indexed: 01/08/2023] Open
Abstract
Congenital myasthenic syndromes (CMSs) are heterogeneous neuromuscular disorders characterized by skeletal muscle weakness caused by disruption of signal transmission across the neuromuscular junction (NMJ). CMSs are rarely encountered in veterinary medicine, and causative mutations have only been identified in Old Danish Pointing Dogs and Brahman cattle to date. Herein, we characterize a novel CMS in 2 Labrador Retriever littermates with an early onset of marked generalized muscle weakness. Because the sire and dam share 2 recent common ancestors, CMS is likely the result of recessive alleles inherited identical by descent (IBD). Genome-wide SNP profiles generated from the Illumina HD array for 9 nuclear family members were used to determine genomic inheritance patterns in chromosomal regions encompassing 18 functional candidate genes. SNP haplotypes spanning 3 genes were consistent with autosomal recessive transmission, and microsatellite data showed that only the segment encompassing COLQ was inherited IBD. COLQ encodes the collagenous tail of acetylcholinesterase, the enzyme responsible for termination of signal transduction in the NMJ. Sequences from COLQ revealed a variant in exon 14 (c.1010T>C) that results in the substitution of a conserved amino acid (I337T) within the C-terminal domain. Both affected puppies were homozygous for this variant, and 16 relatives were heterozygous, while 288 unrelated Labrador Retrievers and 112 dogs of other breeds were wild-type. A recent study in which 2 human CMS patients were found to be homozygous for an identical COLQ mutation (c.1010T>C; I337T) provides further evidence that this mutation is pathogenic. This report describes the first COLQ mutation in canine CMS and demonstrates the utility of SNP profiles from nuclear family members for the identification of private mutations.
Collapse
Affiliation(s)
- Caitlin J. Rinz
- Department of Genetics and Biochemistry, College of Agriculture, Forestry, and Life Sciences, Clemson University, Clemson, South Carolina, United States of America
| | - Jonathan Levine
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States of America
| | - Katie M. Minor
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Hammon D. Humphries
- Department of Pathology, School of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Renee Lara
- Kingdom Animal Hospital, Bryan, Texas, United States of America
| | - Alison N. Starr-Moss
- Department of Genetics and Biochemistry, College of Agriculture, Forestry, and Life Sciences, Clemson University, Clemson, South Carolina, United States of America
| | - Ling T. Guo
- Department of Pathology, School of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - D. Colette Williams
- R. Prichard Veterinary Medical Teaching Hospital, University of California Davis, Davis, California, United States of America
| | - G. Diane Shelton
- Department of Pathology, School of Medicine, University of California San Diego, La Jolla, California, United States of America
- * E-mail: (GDS); (LAC)
| | - Leigh Anne Clark
- Department of Genetics and Biochemistry, College of Agriculture, Forestry, and Life Sciences, Clemson University, Clemson, South Carolina, United States of America
- * E-mail: (GDS); (LAC)
| |
Collapse
|
25
|
Clinical and molecular analysis of a novel COLQ missense mutation causing congenital myasthenic syndrome in a Syrian family. Pediatr Neurol 2014; 51:165-9. [PMID: 24938146 DOI: 10.1016/j.pediatrneurol.2014.03.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2014] [Revised: 03/12/2014] [Accepted: 03/15/2014] [Indexed: 02/08/2023]
Abstract
BACKGROUND Congenital myasthenic syndromes with end-plate acetylcholinesterase deficiency are rare autosomal recessive disorders characterized by onset of the disease in early childhood, general weakness exacerbated by exertion, ophthalmoplegia, and refractoriness to anticholinesterase drugs. To date, all reported cases have been attributed to mutations in 18 genes including the COLQ gene that encodes a specific collagen that anchors acetylcholinesterase at the basal lamina of the neuromuscular junction. We identified a Syrian family with two children of consanguineous parents from two branches affected with congenital myasthenic syndrome with end-plate acetylcholinesterase deficiency. METHOD The absence of acetylcholinesterase antibodies was demonstrated biochemically. Consequently, all the coding regions, exon-intron boundaries, and the 5' and 3' untranslated regions of the COLQ gene were amplified and sequenced using the Sanger sequencing method. RESULTS We observed that the severity of the phenotype in the two affected children differed. One child had mild symptoms that included difficulties in gait and feeding with mild respiratory insufficiency. Her sibling died in the first months of life because of severe respiratory failure. The second patient had severe symptoms from birth and has been mechanically ventilated. DNA sequencing revealed a novel homozygous single nucleotide substitution mutation (c.1010T>C) in the COLQ gene in both patients. This substitution leads to a missense amino acid substitution at position 337 of the protein (p.Ile337Thr). This mutation is likely to impair ColQ's trimeric organization and therefore its anchoring within the synaptic basal lamina. CONCLUSION We identified the molecular cause underlying congenital myasthenic syndrome in two patients. The marked phenotypic variation suggests that other factors including modifier genes may affect the severity of this disease.
Collapse
|