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Carrera-García L, Natera-de Benito D, Dieterich K, de la Banda MGG, Felter A, Inarejos E, Codina A, Jou C, Roldan M, Palau F, Hoenicka J, Pijuan J, Ortez C, Expósito-Escudero J, Durand C, Nugues F, Jimenez-Mallebrera C, Colomer J, Carlier RY, Lochmüller H, Quijano-Roy S, Nascimento A. CHRNG-related nonlethal multiple pterygium syndrome: Muscle imaging pattern and clinical, histopathological, and molecular genetic findings. Am J Med Genet A 2019; 179:915-926. [PMID: 30868735 DOI: 10.1002/ajmg.a.61122] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 02/05/2019] [Accepted: 02/06/2019] [Indexed: 12/15/2022]
Abstract
Mutations in the CHRNG gene cause autosomal recessive multiple pterygium syndrome (MPS). Herein we present a long-term follow-up of seven patients with CHRNG-related nonlethal MPS and we compare them with the 57 previously published patients. The objective is defining not only the clinical, histopathological, and molecular genetic characteristics, but also the type and degree of muscle involvement on whole-body magnetic resonance imaging (WBMRI). CHRNG mutations lead to a distinctive phenotype characterized by multiple congenital contractures, pterygium, and facial dysmorphism, with a stable clinical course over the years. Postnatal abnormalities at the neuromuscular junction were observed in the muscle biopsy of these patients. WBMRI showed distinctive features different from other arthrogryposis multiple congenita. A marked muscle bulk reduction is the predominant finding, mostly affecting the spinal erector muscles and gluteus maximus. Fatty infiltration was only observed in deep paravertebral muscles and distal lower limbs. Mutations in CHRNG are mainly located at the extracellular domain of the protein. Our study contributes to further define the phenotypic spectrum of CHRNG-related nonlethal MPS, including muscle imaging features, which may be useful in distinguishing it from other diffuse arthrogryposis entities.
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Affiliation(s)
- Laura Carrera-García
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Universitari Sant Joan de Deu, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Barcelona, Spain
| | - Daniel Natera-de Benito
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Universitari Sant Joan de Deu, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Barcelona, Spain
| | - Klaus Dieterich
- Département de Génétique et Procréation, CHU de Grenoble Alpes, Grenoble Cedex 9, France
| | - Marta G G de la Banda
- Neuromuscular Unit, Department of Pediatric Neurology, Intensive Care and Rehabilitation, Raymond Poincaré University Hospital (AP-HP; UVSQ Paris Saclay), Garches, France
| | - Adrien Felter
- Department of Medical Radiology, Raymond Poincaré University Hospital (AP-HP; UVSQ Paris Saclay), Garches, France
| | - Emili Inarejos
- Department of Radiology, Hospital Universitari Sant Joan de Deu, Barcelona, Spain
| | - Anna Codina
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Universitari Sant Joan de Deu, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Barcelona, Spain
| | - Cristina Jou
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Universitari Sant Joan de Deu, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Barcelona, Spain.,Department of Pathology, Hospital Sant Joan de Deu, Barcelona, Spain
| | - Monica Roldan
- Confocal Microscopy Unit, Department of Pathology, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Francesc Palau
- Department of Genetic and Molecular Medicine, Hospital Sant Joan de Déu, Barcelona, Spain.,Laboratory of Neurogenetics and Molecular Medicine, Institut de Recerca Sant Joan de Déu, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Barcelona, Spain.,Division of Pediatrics, University of Barcelona School of Medicine, Barcelona, Spain
| | - Janet Hoenicka
- Laboratory of Neurogenetics and Molecular Medicine, Institut de Recerca Sant Joan de Déu, Barcelona, Spain.,Centro de Investigación Biomédica en Salud Mental (CIBERSAM), Barcelona, Spain
| | - Jordi Pijuan
- Laboratory of Neurogenetics and Molecular Medicine, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
| | - Carlos Ortez
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Universitari Sant Joan de Deu, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Barcelona, Spain
| | - Jessica Expósito-Escudero
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Universitari Sant Joan de Deu, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Barcelona, Spain
| | - Chantal Durand
- Department of Radiology, CHU de Grenoble Alpes, Grenoble, France
| | | | - Cecilia Jimenez-Mallebrera
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Universitari Sant Joan de Deu, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Barcelona, Spain
| | - Jaume Colomer
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Universitari Sant Joan de Deu, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Barcelona, Spain
| | - Robert Y Carlier
- Department of Medical Radiology, Raymond Poincaré University Hospital (AP-HP; UVSQ Paris Saclay), Garches, France
| | - Hanns Lochmüller
- Department of Neuropediatrics and Muscle Disorders, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany.,Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.,Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada and Division of Neurology, Department of Medicine, The Ottawa Hospital, Ottawa, Ontario, Canada
| | - Susana Quijano-Roy
- Neuromuscular Unit, Department of Pediatric Neurology, Intensive Care and Rehabilitation, Raymond Poincaré University Hospital (AP-HP; UVSQ Paris Saclay), Garches, France
| | - Andres Nascimento
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Universitari Sant Joan de Deu, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Barcelona, Spain
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Zisimopoulou P, Brenner T, Trakas N, Tzartos SJ. Serological diagnostics in myasthenia gravis based on novel assays and recently identified antigens. Autoimmun Rev 2013; 12:924-30. [PMID: 23537507 DOI: 10.1016/j.autrev.2013.03.002] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2013] [Indexed: 10/27/2022]
Abstract
Myasthenia gravis (MG) is the most common immune-mediated disorder of the neuromuscular junction with a prevalence of 200-300/million population and its study has established paradigms for exploring other antibody-mediated diseases. Most MG patients (~85%) have autoantibodies against the muscle acetylcholine receptor (AChR-MG), whereas about 6% of MG patients have autoantibodies against the muscle specific kinase (MuSK-MG). Until recently no autoantibodies could be detected in the remaining patients (seronegative MG). Probably, the most sensitive assays for the detection of the autoantibodies in MG sera have been the radioimmunoprecipitation assays (RIPA) for both types of MG. However, with recent novel methods, not yet used routinely, it has been shown that the "seronegative" MG group includes patients with low levels of autoantibodies or of low affinity, against the known autoantigens, or even with antibodies to recently identified autoantigens. Since MG is heterogeneous in terms of pathophysiology, depending on the autoantigen targeted and on other factors (e.g. presence of thymoma), the serological tests are crucial in verifying the initial clinical diagnosis, whereas frequent measurement of autoantibody levels is important in monitoring the course of the disease and the efficacy of treatment. In addition, in AChR-MG, autoantibodies against the muscle proteins titin and ryanodin receptor have been identified; these antibodies are useful for the classification of MG, indicating the concomitant presence of thymoma, and as prognostic markers.
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Stergiou C, Zisimopoulou P, Tzartos SJ. Expression of water-soluble, ligand-binding concatameric extracellular domains of the human neuronal nicotinic receptor alpha4 and beta2 subunits in the yeast Pichia pastoris: glycosylation is not required for ligand binding. J Biol Chem 2011; 286:8884-92. [PMID: 21252231 DOI: 10.1074/jbc.m110.171645] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) are ligand-gated cation channels that are responsible for cell communication via the neurotransmitter acetylcholine. The predominant nAChR subtype in the mammalian brain with a high affinity for nicotine is composed of α4 and β2 subunits. This nAChR subtype is responsible for addiction to nicotine and is thought to be implicated in Alzheimer and Parkinson diseases and therefore presents an important target for drug design. In an effort to obtain water-soluble, ligand-binding domains of the human α4β2 nAChR for structural studies, we expressed the extracellular domains (ECDs) of these subunits in the eukaryotic expression system Pichia pastoris. The wild-type ECDs and their mutants containing the more hydrophilic Cys-loop from the snail acetylcholine-binding protein (individually expressed or coexpressed) did not demonstrate any specific interaction with ligands. We then linked the mutated ECDs with the 24-amino acid peptide (AGS)(8) and observed that the β2-24-α4 ECD concatamer, but not the α4-24-β2 one, exhibited very satisfactory water solubility and ligand binding properties. The (125)I-epibatidine and [(3)H]nicotine bound to β2-24-α4 with dissociation constants (K(d)) of 0.38 and 19 nm, respectively, close to the published values for the intact α4β2 AChR. In addition, (125)I-epibatidine binding was blocked by nicotine, cytisine, acetylcholine, and carbamylcholine with inhibition constants (K(i)) of 20.64, 3.24, 242, and 2,254 nm, respectively. Interestingly, deglycosylation of the concatamer did not affect its ligand binding properties. Furthermore, the deglycosylated β2-24-α4 ECD existed mainly in monomeric form, thus forming an appropriate material for structural studies and possibly for pharmacological evaluation of novel α4β2 nAChR-specific agonists.
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Affiliation(s)
- Christos Stergiou
- Department of Biochemistry, Hellenic Pasteur Institute, GR11521 Athens, Greece
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Zouridakis M, Zisimopoulou P, Poulas K, Tzartos SJ. Recent advances in understanding the structure of nicotinic acetylcholine receptors. IUBMB Life 2009; 61:407-23. [PMID: 19319967 DOI: 10.1002/iub.170] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Nicotinic acetylcholine receptors (nAChRs), members of the Cys-loop ligand-gated ion channels (LGICs) superfamily, are involved in signal transduction upon binding of the neurotransmitter acetylcholine or exogenous ligands, such as nicotine. nAChRs are pentameric assemblies of homologous subunits surrounding a central pore that gates cation flux, and are expressed at the neuromuscular junction and in the nervous system and several nonneuronal cell types. The 17 known nAChR subunits assemble into a variety of pharmacologically distinct receptor subtypes. nAChRs are implicated in a range of physiological functions and pathophysiological conditions related to muscle contraction, learning and memory, reward, motor control, arousal, and analgesia, and therefore present an important target for drug research. Such studies would be greatly facilitated by knowledge of the high-resolution structure of the nAChR. Although this information is far from complete, important progress has been made mainly based on electron microscopy studies of Torpedo nAChR and the high-resolution X-ray crystal structures of the homologous molluscan acetylcholine-binding proteins, the extracellular domain of the mouse nAChR alpha1 subunit, and two prokaryotic pentameric LGICs. Here, we review some of the latest advances in our understanding of nAChR structure and gating.
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Affiliation(s)
- Marios Zouridakis
- Department of Biochemistry, Hellenic Pasteur Institute, Athens, Greece
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