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Neu CT, Weilepp L, Bork K, Gesper A, Horstkorte R. GNE deficiency impairs Myogenesis in C2C12 cells and cannot be rescued by ManNAc supplementation. Glycobiology 2024; 34:cwae004. [PMID: 38224318 PMCID: PMC10987290 DOI: 10.1093/glycob/cwae004] [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: 08/08/2023] [Revised: 12/19/2023] [Accepted: 01/09/2024] [Indexed: 01/16/2024] Open
Abstract
GNE myopathy (GNEM) is a late-onset muscle atrophy, caused by mutations in the gene for the key enzyme of sialic acid biosynthesis, UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE). With an incidence of one to nine cases per million it is an ultra-rare, so far untreatable, autosomal recessive disease. Several attempts have been made to treat GNEM patients by oral supplementation with sialic acid precursors (e.g. N-acetylmannosamine, ManNAc) to restore sarcolemmal sialylation and muscle strength. In most studies, however, no significant improvement was observed. The lack of a suitable mouse model makes it difficult to understand the exact pathomechanism of GNEM and many years of research have failed to identify the role of GNE in skeletal muscle due to the lack of appropriate tools. We established a CRISPR/Cas9-mediated Gne-knockout cell line using murine C2C12 cells to gain insight into the actual role of the GNE enzyme and sialylation in a muscular context. The main aspect of this study was to evaluate the therapeutic potential of ManNAc and N-acetylneuraminic acid (Neu5Ac). Treatment of Gne-deficient C2C12 cells with Neu5Ac, but not with ManNAc, showed a restoration of the sialylation level back to wild type levels-albeit only with long-term treatment, which could explain the rather low therapeutic potential. We furthermore highlight the importance of sialic acids on myogenesis, for C2C12 Gne-knockout myoblasts lack the ability to differentiate into mature myotubes.
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Affiliation(s)
- Carolin T Neu
- Institute for Physiological Chemistry, Medical Faculty, Martin Luther University Halle-Wittenberg, 06114 Halle (Saale), Germany
| | - Linus Weilepp
- Institute for Physiological Chemistry, Medical Faculty, Martin Luther University Halle-Wittenberg, 06114 Halle (Saale), Germany
| | - Kaya Bork
- Institute for Physiological Chemistry, Medical Faculty, Martin Luther University Halle-Wittenberg, 06114 Halle (Saale), Germany
| | - Astrid Gesper
- Institute for Physiological Chemistry, Medical Faculty, Martin Luther University Halle-Wittenberg, 06114 Halle (Saale), Germany
| | - Rüdiger Horstkorte
- Institute for Physiological Chemistry, Medical Faculty, Martin Luther University Halle-Wittenberg, 06114 Halle (Saale), Germany
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Chakravorty S, Berger K, Arafat D, Nallamilli BRR, Subramanian HP, Joseph S, Anderson ME, Campbell KP, Glass J, Gibson G, Hegde M. Clinical utility of RNA sequencing to resolve unusual GNE myopathy with a novel promoter deletion. Muscle Nerve 2019; 60:98-103. [PMID: 30990900 DOI: 10.1002/mus.26486] [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: 06/01/2018] [Revised: 04/09/2019] [Accepted: 04/12/2019] [Indexed: 02/07/2023]
Abstract
INTRODUCTION UDP N-acetylglucosamine2-epimerase/N-acetylmannosamine-kinase (GNE) gene mutations can cause mostly autosomal-recessive myopathy with juvenile-onset known as hereditary inclusion-body myopathy (HIBM). METHODS We describe a family of a patient showing an unusual HIBM with both vacuolar myopathy and myositis without quadriceps-sparing, hindering diagnosis. We show how genetic testing with functional assays, clinical transcriptome sequencing (RNA-seq) in particular, helped facilitate both the diagnosis and a better understanding of the genotype-phenotype relationship. RESULTS We identified a novel 7.08 kb pathogenic deletion upstream of GNE using array comparative genomic hybridization (aCGH) and a common Val727Met variant. Using RNA-seq, we found only monoallelic (Val727Met-allele) expression, leading to ~50% GNE reduction in muscle. Importantly, α-dystroglycan is hypoglycosylated in the patient muscle, suggesting HIBM could be a "dystroglycanopathy." CONCLUSIONS Our study shows the importance of considering aCGH for GNE-myopathies, and the potential of RNA-seq for faster, definitive molecular diagnosis of unusual myopathies. Muscle Nerve, 2019.
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Affiliation(s)
- Samya Chakravorty
- Department of Human Genetics, Emory University School of Medicine, Whitehead Building Suite 301, 615 Michael Street NE, Georgia, USA
| | - Kiera Berger
- Center for Integrative Genomics, School of Biology, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Dalia Arafat
- Center for Integrative Genomics, School of Biology, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Babi Ramesh Reddy Nallamilli
- Department of Human Genetics, Emory University School of Medicine, Whitehead Building Suite 301, 615 Michael Street NE, Georgia, USA
| | - Hari Prasanna Subramanian
- Center for Integrative Genomics, School of Biology, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Soumya Joseph
- Howard Hughes Medical Institute, Department of Molecular Physiology and Biophysics, Department of Neurology, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, 52242, USA
| | - Mary E Anderson
- Howard Hughes Medical Institute, Department of Molecular Physiology and Biophysics, Department of Neurology, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, 52242, USA
| | - Kevin P Campbell
- Howard Hughes Medical Institute, Department of Molecular Physiology and Biophysics, Department of Neurology, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, 52242, USA
| | - Jonathan Glass
- Department of Neurology and Pathology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Greg Gibson
- Center for Integrative Genomics, School of Biology, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Madhuri Hegde
- Department of Human Genetics, Emory University School of Medicine, Whitehead Building Suite 301, 615 Michael Street NE, Georgia, USA.,Global Laboratory Services/Diagnostics, Perkin Elmer, Waltham, Massachusetts, USA
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Nakamura K, Hamaguchi T, Sakai K, Noto D, Ono K, Hayashi Y, Nishino I, Yamada M. Granuloma formation in a patient with GNE myopathy: A case report. Neuromuscul Disord 2016; 27:183-184. [PMID: 27919547 DOI: 10.1016/j.nmd.2016.11.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 11/13/2016] [Accepted: 11/13/2016] [Indexed: 11/25/2022]
Abstract
We report a patient with GNE myopathy with a homozygous mutation (c.1505-4G>A) in GNE gene. The patient recognized progressive weakness of extremities at age 60. Neurological examination at age 65 revealed severe weakness and atrophy in the tibialis anterior muscles and distal predominant moderate weakness in the extremities. Muscle biopsy performed at age 65 showed myopathic changes with rimmed vacuoles, and the noteworthy finding was non-caseating epithelioid cell granuloma formation surrounded by numerous inflammatory cells. Granuloma formation has never been reported in patients with GNE myopathy. We presume that aggregation of abnormal proteins and autophagy dysregulation in the myocytes of GNE myopathy could induce granuloma formation.
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Affiliation(s)
- Keiko Nakamura
- Department of Neurology and Neurobiology of Aging, Kanazawa University Graduate School of Medical Sciences, 13-1 Takara-machi, Kanazawa, Japan.
| | - Tsuyoshi Hamaguchi
- Department of Neurology and Neurobiology of Aging, Kanazawa University Graduate School of Medical Sciences, 13-1 Takara-machi, Kanazawa, Japan
| | - Kenji Sakai
- Department of Neurology and Neurobiology of Aging, Kanazawa University Graduate School of Medical Sciences, 13-1 Takara-machi, Kanazawa, Japan
| | - Daisuke Noto
- Department of Neurology and Neurobiology of Aging, Kanazawa University Graduate School of Medical Sciences, 13-1 Takara-machi, Kanazawa, Japan
| | - Kenjiro Ono
- Department of Neurology and Neurobiology of Aging, Kanazawa University Graduate School of Medical Sciences, 13-1 Takara-machi, Kanazawa, Japan; Department of Neurology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, Japan
| | - Yukiko Hayashi
- Department of Pathophysiology, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-ku, Tokyo, Japan
| | - Ichizo Nishino
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1 Ogawa-Higashi, Kodaira, Tokyo, Japan
| | - Masahito Yamada
- Department of Neurology and Neurobiology of Aging, Kanazawa University Graduate School of Medical Sciences, 13-1 Takara-machi, Kanazawa, Japan
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Kazamel M, Sorenson EJ, Milone M. Clinical and Electrophysiological Findings in Hereditary Inclusion Body Myopathy Compared With Sporadic Inclusion Body Myositis. J Clin Neuromuscul Dis 2016; 17:190-196. [PMID: 27224433 DOI: 10.1097/cnd.0000000000000113] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
OBJECTIVE To compare the clinical and electrophysiological findings in hereditary inclusion body myopathy (hIBM) and sporadic inclusion body myositis (sIBM) patients. METHODS We retrospectively identified 8 genetically proven hIBM patients and 1 DNAJB6 myopathy with pathological features of hIBM, and compared their clinical, electromyographic, and serological data with a group of 51 pathologically proven sIBM patients. RESULTS hIBM patients had a younger mean age of onset (36 vs. 60 years, P = 0.0001). Diagnostic delay was shorter in sIBM (6 vs. 15 years, P = 0.0003). Wrist flexors (P = 0.02), digit flexors (P = 0.01), digit extensors (P = 0.02), and quadriceps (P = 0.008) muscles were more frequently affected in sIBM. Fibrillation potentials were more common in sIBM patients (P = 0.03). Electrical myotonia was found in 4 hIBM patients, not significantly different from sIBM patients (P = 0.45). Creatinine kinase was higher in sIBM patients (799 vs 232, P = 0.03). CONCLUSIONS sIBM and hIBM seem to have similar electromyographic changes. The combination of clinical, serological, and histopathological findings can guide genetic testing to the final diagnosis.
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Willems AP, van Engelen BGM, Lefeber DJ. Genetic defects in the hexosamine and sialic acid biosynthesis pathway. Biochim Biophys Acta Gen Subj 2015; 1860:1640-54. [PMID: 26721333 DOI: 10.1016/j.bbagen.2015.12.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 12/18/2015] [Accepted: 12/19/2015] [Indexed: 01/10/2023]
Abstract
BACKGROUND Congenital disorders of glycosylation are caused by defects in the glycosylation of proteins and lipids. Classically, gene defects with multisystem disease have been identified in the ubiquitously expressed glycosyltransferases required for protein N-glycosylation. An increasing number of defects are being described in sugar supply pathways for protein glycosylation with tissue-restricted clinical symptoms. SCOPE OF REVIEW In this review, we address the hexosamine and sialic acid biosynthesis pathways in sugar metabolism. GFPT1, PGM3 and GNE are essential for synthesis of nucleotide sugars uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) and cytidine-5'-monophospho-N-acetylneuraminic acid (CMP-sialic acid) as precursors for various glycosylation pathways. Defects in these enzymes result in contrasting clinical phenotypes of congenital myasthenia, immunodeficiency or adult-onset myopathy, respectively. We therefore discuss the biochemical mechanisms of known genetic defects in the hexosamine and CMP-sialic acid synthesis pathway in relation to the clinical phenotypes. MAJOR CONCLUSIONS Both UDP-GlcNAc and CMP-sialic acid are important precursors for diverse protein glycosylation reactions and for conversion into other nucleotide-sugars. Defects in the synthesis of these nucleotide sugars might affect a wide range of protein glycosylation reactions. Involvement of multiple glycosylation pathways might contribute to disease phenotype, but the currently available biochemical information on sugar metabolism is insufficient to understand why defects in these pathways present with tissue-specific phenotypes. GENERAL SIGNIFICANCE Future research on the interplay between sugar metabolism and different glycosylation pathways in a tissue- and cell-specific manner will contribute to elucidation of disease mechanisms and will create new opportunities for therapeutic intervention. This article is part of a Special Issue entitled "Glycans in personalised medicine" Guest Editor: Professor Gordan Lauc.
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Affiliation(s)
- Anke P Willems
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Centre, Box 9101, 6500 HB Nijmegen, The Netherlands; Department of Laboratory Medicine, Translational Metabolic Laboratory, Radboudumc Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Baziel G M van Engelen
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Centre, Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Dirk J Lefeber
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Centre, Box 9101, 6500 HB Nijmegen, The Netherlands; Department of Laboratory Medicine, Translational Metabolic Laboratory, Radboudumc Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands.
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Celeste FV, Vilboux T, Ciccone C, de Dios JK, Malicdan MCV, Leoyklang P, McKew JC, Gahl WA, Carrillo-Carrasco N, Huizing M. Mutation update for GNE gene variants associated with GNE myopathy. Hum Mutat 2015; 35:915-26. [PMID: 24796702 DOI: 10.1002/humu.22583] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 04/23/2014] [Indexed: 12/31/2022]
Abstract
The GNE gene encodes the rate-limiting, bifunctional enzyme of sialic acid biosynthesis, uridine diphosphate-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE). Biallelic GNE mutations underlie GNE myopathy, an adult-onset progressive myopathy. GNE myopathy-associated GNE mutations are predominantly missense, resulting in reduced, but not absent, GNE enzyme activities. The exact pathomechanism of GNE myopathy remains unknown, but likely involves aberrant (muscle) sialylation. Here, we summarize 154 reported and novel GNE variants associated with GNE myopathy, including 122 missense, 11 nonsense, 14 insertion/deletions, and seven intronic variants. All variants were deposited in the online GNE variation database (http://www.dmd.nl/nmdb2/home.php?select_db=GNE). We report the predicted effects on protein function of all variants well as the predicted effects on epimerase and/or kinase enzymatic activities of selected variants. By analyzing exome sequence databases, we identified three frequently occurring, unreported GNE missense variants/polymorphisms, important for future sequence interpretations. Based on allele frequencies, we estimate the world-wide prevalence of GNE myopathy to be ∼4-21/1,000,000. This previously unrecognized high prevalence confirms suspicions that many patients may escape diagnosis. Awareness among physicians for GNE myopathy is essential for the identification of new patients, which is required for better understanding of the disorder's pathomechanism and for the success of ongoing treatment trials.
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Affiliation(s)
- Frank V Celeste
- Therapeutics for Rare and Neglected Diseases, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland
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Krause S. Insights into muscle degeneration from heritable inclusion body myopathies. Front Aging Neurosci 2015; 7:13. [PMID: 25729363 PMCID: PMC4325924 DOI: 10.3389/fnagi.2015.00013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 01/30/2015] [Indexed: 12/13/2022] Open
Abstract
Muscle mass and function are gradually lost in age-related, degenerative neuromuscular disorders, which also reflect the clinical hallmarks of sarcopenia. The consensus definition of sarcopenia includes a condition of age-related loss of muscle mass, quality, and strength. The most common acquired muscle disease affecting adults aged over 50 years is sporadic inclusion body myositis (sIBM). Besides inflammatory effects and immune-mediated muscle injury, degenerative myofiber changes are characteristic features of the disease. Although the earliest triggering events in sIBM remain elusive, a plethora of downstream mechanisms are implicated in the pathophysiology of muscle wasting. Although it remains controversial whether hereditary forms of inclusion body myopathy (IBM) may be considered as degenerative sIBM disease models, partial pathophysiological aspects can mimic the much more frequent sporadic condition, in particular the occurrence of inclusion bodies in skeletal muscle. Various clinical aspects in genetically determined skeletal muscle disorders reflect age-related alterations observed in sarcopenia. Several intriguing clues from monogenic defects in heritable IBMs contributing to the molecular basis of muscle loss will be discussed with special emphasis on inclusion body myopathy with Paget's disease of bone and frontotemporal dementia (IBMPFD) and GNE myopathy. Finally, also the recently identified dominant multisystem proteinopathy will be considered, which may rarely present as IBM.
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Affiliation(s)
- Sabine Krause
- Laboratory for Molecular Myology, Department of Neurology, Friedrich Baur Institute, Ludwig Maximilians University , Munich , Germany
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Subramony S, Moscovich M, Ashizawa T. Genetics and Clinical Features of Inherited Ataxias. Mov Disord 2015. [DOI: 10.1016/b978-0-12-405195-9.00062-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Abstract
In this article, distal myopathy syndromes are discussed. A discussion of the more traditional distal myopathies is followed by discussion of the myofibrillar myopathies. Other clinically and genetically distinctive distal myopathy syndromes usually based on single or smaller family cohorts are reviewed. Other neuromuscular disorders that are important to recognize are also considered, because they show prominent distal limb weakness.
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Affiliation(s)
- Mazen M Dimachkie
- Neuromuscular Section, Neurophysiology Division, Department of Neurology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Mail Stop 2012, Kansas City, KS 66160, USA.
| | - Richard J Barohn
- Department of Neurology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Mail Stop 2012, Kansas City, KS 66160, USA
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Tanboon J, Rongsa K, Pithukpakorn M, Boonyapisit K, Limwongse C, Sangruchi T. A Novel Mutation of the GNE Gene in Distal Myopathy with Rimmed Vacuoles: A Case with Inflammation. Case Rep Neurol 2014; 6:55-9. [PMID: 24707269 PMCID: PMC3975748 DOI: 10.1159/000360730] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Distal myopathy with rimmed vacuoles (DMRV) is an autosomal recessive or sporadic early adult-onset myopathy caused by mutations in the UDP-N-acetylglucosamine 2-epimerase and N-acetylmannosamine kinase (GNE) gene. Characteristic pathologic features of DMRV are rimmed vacuoles on muscle biopsy and tubulofilamentous inclusion in ultrastructural study. Presence of inflammation in DMRV is unusual. We report a sporadic case of DMRV in a 40-year-old Thai man who presented with slowly progressive distal muscle weakness. Gene analysis revealed a compound heterozygous mutation of the GNE gene including a novel mutation c.1057A>G (p.K353E) and a known mutation c.2086G>A (p.V696M). The latter is the most common mutation in Thai DMRV patients. The muscle pathology was compatible with DMRV except for focal inflammation.
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Affiliation(s)
- Jantima Tanboon
- Department of Pathology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand ; Siriraj Neurogenetic Network, Department of Research and Development, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Kanjana Rongsa
- Siriraj Neurogenetic Network, Department of Research and Development, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Manop Pithukpakorn
- Siriraj Neurogenetic Network, Department of Research and Development, Siriraj Hospital, Mahidol University, Bangkok, Thailand ; Department of Internal Medicine, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Kanokwan Boonyapisit
- Siriraj Neurogenetic Network, Department of Research and Development, Siriraj Hospital, Mahidol University, Bangkok, Thailand ; Department of Internal Medicine, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Chanin Limwongse
- Siriraj Neurogenetic Network, Department of Research and Development, Siriraj Hospital, Mahidol University, Bangkok, Thailand ; Department of Internal Medicine, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Tumtip Sangruchi
- Department of Pathology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand ; Siriraj Neurogenetic Network, Department of Research and Development, Siriraj Hospital, Mahidol University, Bangkok, Thailand
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Abstract
The distal myopathies are a heterogeneous group of genetic disorders defined by a predominant distal weakness at onset or throughout the evolution of the disease and by pathological data supporting a myopathic process. The number of genes associated with distal myopathies continues to increase. Fourteen distinct distal myopathies are currently defined by their gene and causative mutations, compared to just five entities delineated on clinical grounds two decades ago. The known proteins affected in the distal myopathies are of many types and include a significant number of sarcomeric proteins. The useful indicators for clinicians to direct towards a correct molecular diagnosis are the mode of inheritance, the age at onset, the pattern of muscle involvement, the serum creatine kinase level and the muscle pathology findings. This review gives an overview of the clinical and genetic characteristics of the currently identified distal myopathies with emphasis on some recent findings.
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Cai H, Yabe I, Shirai S, Nishimura H, Hirotani M, Kano T, Houzen H, Yoshida K, Sasaki H. Novel GNE compound heterozygous mutations in a GNE myopathy patient. Muscle Nerve 2013; 48:594-8. [PMID: 23558691 DOI: 10.1002/mus.23862] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/29/2013] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Molecular studies have revealed that some patients with myopathies with rimmed vacuoles have pathogenic mutations in the UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine kinase (GNE) and Z-band alternatively spliced PDZ motif-containing protein (ZASP) genes. METHODS We investigated a patient with distal myopathy with rimmed vacuoles by muscle biopsy and sequenced 6 candidate genes. RESULTS The patient carried GNE compound heterozygous missense mutations (p.V421A and p.N635K) and a ZASP variant (p.D673N). This patient also presented with distal weakness sparing the quadriceps muscles and had atypical results for Z-band-associated protein immunostaining. This finding indicates that the GNE mutations are pathogenic, and the diagnosis is compatible with GNE myopathy. CONCLUSIONS By combining pathological studies and candidate gene screening, we identified a patient with GNE myopathy due to novel GNE compound heterozygous mutations.
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Affiliation(s)
- Huaying Cai
- Department of Neurology, Hokkaido University Graduate School of Medicine, N15W7, Kita-ku, Sapporo, 060-8638, Japan
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Hinderlich S, Weidemann W, Yardeni T, Horstkorte R, Huizing M. UDP-GlcNAc 2-Epimerase/ManNAc Kinase (GNE): A Master Regulator of Sialic Acid Synthesis. Top Curr Chem (Cham) 2013; 366:97-137. [PMID: 23842869 DOI: 10.1007/128_2013_464] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase is the key enzyme of sialic acid biosynthesis in vertebrates. It catalyzes the first two steps of the cytosolic formation of CMP-N-acetylneuraminic acid from UDP-N-acetylglucosamine. In this review we give an overview of structure, biochemistry, and genetics of the bifunctional enzyme and its complex regulation. Furthermore, we will focus on diseases related to UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase.
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Affiliation(s)
- Stephan Hinderlich
- Department of Life Sciences and Technology, Beuth Hochschule für Technik Berlin, University of Applied Sciences, Berlin, Germany,
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15
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Abstract
Hereditary inclusion body myopathy is an autosomal recessive disorder that presents in early adulthood with slowly progressive weakness sparing the quadriceps. Muscle histopathology reveals rimmed vacuoles without inflammation. The disorder is caused by a mutation in the gene for UDP-N-acetylglucosamine 2-epimerase-N-acetylmannosamine kinase (GNE), a bifunctional enzyme involved in protein glycosylation. Over 40 mutations have been described to date. We present a case of a young woman with progressive lower extremity weakness. Clinical presentation, laboratory evaluation, electrodiagnostic testing, muscle pathology, and genetic sequencing are described. The patient was found to have heterozygous mutations in the GNE gene, confirming the diagnosis of hereditary inclusion body myopathy. The mutations she carried have not been described previously. We briefly review the clinical, histopathologic, and molecular genetic findings of this disorder.
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Mori-Yoshimura M, Monma K, Suzuki N, Aoki M, Kumamoto T, Tanaka K, Tomimitsu H, Nakano S, Sonoo M, Shimizu J, Sugie K, Nakamura H, Oya Y, Hayashi YK, Malicdan MCV, Noguchi S, Murata M, Nishino I. Heterozygous UDP-GlcNAc 2-epimerase and N-acetylmannosamine kinase domain mutations in the GNE gene result in a less severe GNE myopathy phenotype compared to homozygous N-acetylmannosamine kinase domain mutations. J Neurol Sci 2012; 318:100-5. [PMID: 22507750 DOI: 10.1016/j.jns.2012.03.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 03/20/2012] [Accepted: 03/21/2012] [Indexed: 10/28/2022]
Abstract
BACKGROUND Glucosamine (UDP-N-acetyl)-2-epimerase/N-acetylmannosamine kinase (GNE) myopathy, also called distal myopathy with rimmed vacuoles (DMRV) or hereditary inclusion body myopathy (HIBM), is a rare, progressive autosomal recessive disorder caused by mutations in the GNE gene. Here, we examined the relationship between genotype and clinical phenotype in participants with GNE myopathy. METHODS Participants with GNE myopathy were asked to complete a questionnaire regarding medical history and current symptoms. RESULTS A total of 71 participants with genetically confirmed GNE myopathy (27 males and 44 females; mean age, 43.1±13.0 (mean±SD) years) completed the questionnaire. Initial symptoms (e.g., foot drop and lower limb weakness) appeared at a mean age of 24.8±8.3 years. Among the 71 participants, 11 (15.5%) had the ability to walk, with a median time to loss of ambulation of 17.0±2.1 years after disease onset. Participants with a homozygous mutation (p.V572L) in the N-acetylmannosamine kinase domain (KD/KD participants) had an earlier disease onset compared to compound heterozygous participants with mutations in the uridine diphosphate-N-acetylglucosamine (UDP-GlcNAc) 2-epimerase and N-acetylmannosamine kinase domains (ED/KD participants; 26.3±7.3 vs. 21.2±11.1 years, respectively). KD/KD participants were more frequently non-ambulatory compared to ED/KD participants at the time of survey (80% vs. 50%). Data were verified using medical records available from 17 outpatient participants. CONCLUSIONS Homozygous KD/KD participants exhibited a more severe phenotype compared to heterozygous ED/KD participants.
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Affiliation(s)
- Madoka Mori-Yoshimura
- Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashi, Kodaira, Tokyo 187-8551, Japan.
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Dimitri D, Eymard B. Myopathies inflammatoires, myopathies nécrosantes auto-immunes, myopathies génétiques de l’adulte : frontières diagnostiques. Rev Med Interne 2012; 33:134-42. [DOI: 10.1016/j.revmed.2011.11.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2011] [Accepted: 11/26/2011] [Indexed: 10/14/2022]
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Clinical, pathological, and genetic mutation analysis of sporadic inclusion body myositis in Japanese people. J Neurol 2012; 259:1913-22. [PMID: 22349865 DOI: 10.1007/s00415-012-6439-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 12/17/2011] [Accepted: 01/24/2012] [Indexed: 12/13/2022]
Abstract
Previous studies have identified several genetic loci associated with the development of familial inclusion body myopathy. However, there have been few genetic analyses of sporadic inclusion body myositis (sIBM). In order to explore the molecular basis of sIBM and to investigate genotype-phenotype correlations, we performed a clinicopathological analysis of 21 sIBM patients and screened for mutations in the Desmin, GNE, MYHC2A, VCP, and ZASP genes. All coding exons of the five genes were sequenced directly. Definite IBM was confirmed in 14 cases, probable IBM in three cases, and possible IBM in four cases. No cases showed missense mutations in the Desmin, GNE, or VCP genes. Three patients carried the missense mutation c.2542T>C (p.V805A) in the MYHC2A gene; immunohistochemical staining for MYHC isoforms in these three cases showed atrophy or loss of muscle fibers expressing MYHC IIa or IIx. One patient harbored the missense mutation c.1719G>A (p.V566M) in the ZASP gene; immunohistochemical studies of Z-band-associated proteins revealed Z-band abnormalities. Both of the novel heterogeneous mutations were located in highly evolutionarily conserved domains of their respective genes. Cumulatively, these findings have expanded our understanding of the molecular background of sIBM. However, we advocate further clinicopathology and investigation of additional candidate genes in a larger cohort.
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Kurochkina N, Yardeni T, Huizing M. Molecular modeling of the bifunctional enzyme UDP-GlcNAc 2-epimerase/ManNAc kinase and predictions of structural effects of mutations associated with HIBM and sialuria. Glycobiology 2010; 20:322-37. [PMID: 19917666 PMCID: PMC2815652 DOI: 10.1093/glycob/cwp176] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 11/03/2009] [Accepted: 11/04/2009] [Indexed: 12/18/2022] Open
Abstract
The bifunctional enzyme UDP-GlcNAc 2-epimerase/ ManNAc kinase (GNE/MNK), encoded by the GNE gene, catalyzes the first two committed, rate-limiting steps in the biosynthesis of N-acetylneuraminic acid (sialic acid). GNE/MNK is feedback inhibited by binding of the downstream product, CMP-sialic acid in its allosteric site. GNE mutations can result in two human disorders, hereditary inclusion body myopathy (HIBM) or sialuria. So far, no active site geometry predictions or conformational transitions involved with function are available for mammalian GNE/MNK. The N-terminal GNE domain is homologous to various prokaryotic 2-epimerases, some of which have solved crystallographic structures. The C-terminal MNK domain belongs to the sugar kinases superfamily; its crystallographic structure is solved at 2.84 A and three-dimensional structures have also been reported for several other kinases. In this work, we employed available structural data of GNE/MNK homologs to model the active sites of human GNE/MNK and identify critical amino acid residues responsible for interactions with substrates. In addition, we modeled effects of GNE/MNK missense mutations associated with HIBM or sialuria on helix arrangement, substrate binding, and enzyme action. We found that all reported mutations are associated with the active sites or secondary structure interfaces of GNE/MNK. The Persian-Jewish HIBM founder mutation p.M712T is located at the interface alpha4alpha10 and likely affects GlcNAc, Mg2+, and ATP binding. This work contributes to further understanding of GNE/MNK function and ligand binding, which may assist future studies for therapeutic options that target misfolded GNE/MNK in HIBM and/or sialuria.
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Affiliation(s)
- Natalya Kurochkina
- Department of Biophysics, The School of Theoretical Modeling, Chevy Chase, MD 20825, USA.
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Hereditary inclusion body myopathy: a decade of progress. Biochim Biophys Acta Mol Basis Dis 2009; 1792:881-7. [PMID: 19596068 DOI: 10.1016/j.bbadis.2009.07.001] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 06/29/2009] [Accepted: 07/01/2009] [Indexed: 12/25/2022]
Abstract
Hereditary Inclusion Body Myopathy (HIBM) is an autosomal recessive, quadriceps sparing type commonly referred to as HIBM but also termed h-IBM or Inclusion Body Myopathy 2 (IBM2). The clinical manifestations begin with muscle weakness progressing over the next 10-20 years uniquely sparing the quadriceps until the most advanced stage of the disease. Histopathology of an HIBM muscle biopsy shows rimmed vacuoles on Gomori's trichrome stain, small fibers in groups and tubulofilaments without evidence of inflammation. In affected individuals distinct mutations have been identified in the GNE gene, which encodes the bifunctional enzyme uridine diphospho-N-acetylglucosamine (UDP-GlcNAc) 2-epimerase/N-acetyl-mannosamine (ManNAc) kinase (GNE/MNK). GNE/MNK catalyzes the first two committed steps in the biosynthesis of acetylneuraminic acid (Neu5Ac), an abundant and functionally important sugar. The generation of HIBM animal models has led to novel insights into both the disease and the role of GNE/MNK in pathophysiology. Recent advances in therapeutic approaches for HIBM, including administration of N-acetyl-mannosamine (ManNAc), a precursor of Neu5Ac will be discussed.
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21
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[Distal myopathy due to mutations of GNE gene: clinical spectrum and diagnosis]. Rev Neurol (Paris) 2008; 164:434-43. [PMID: 18555875 DOI: 10.1016/j.neurol.2008.02.040] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2007] [Revised: 02/08/2008] [Accepted: 02/20/2008] [Indexed: 11/23/2022]
Abstract
Distal myopathies are rare muscular disorders clinically characterized by a predominantly distal muscular involvement. Among recessive forms, the myopathy resulting from mutations in the UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine kinase (GNE) gene, often designated as Nonaka myopathy, primarily affect young adults and are characterized by muscle wasting and weakness predominating on the anterior compartment of the leg, a remarkable quadriceps sparing and a frequent evolution towards ambulation loss after a few years. Finding rimmed vacuoles on muscle biopsy is a further argument for the diagnosis. However, the presentation and course may vary and we describe four patients who illustrate the clinical spectrum of the disease: the first patient had a classical form with progressive weakness over several years, the second one a rapidly progressive myopathy leading to ambulation loss within three years from onset, the third one a very slow course with no ambulation loss after several decades, and the last one a progressive form with misleading neurogenic features on the EMG. One of our four patients harbored a homozygous mutation, and three others were compound heterozygous, two of them displaying an original mutation: one had a c.2036 T>G (p.Val679Gly) substitution, the c.829 C>T (p.Arg277Cys) substitution.
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Sadeh M, Dabby R. Steroid-responsive myopathy: immune-mediated necrotizing myopathy or polymyositis without inflammation? J Clin Neuromuscul Dis 2008; 9:341-344. [PMID: 18344715 DOI: 10.1097/cnd.0b013e31815e5d4a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
OBJECTIVE To describe the clinical course and steroid responsiveness of a patient with subacute proximal symmetric weakness, very high serum creatine kinase activity, and myopathic pattern with fibrillations in the electromyogram, whose muscle biopsy showed necrotizing myopathy, with practically no inflammation. DESIGN Case report. SETTING Academic research. RESULTS Diagnosis of muscular dystrophy was suggested; nevertheless, steroid treatment was initiated, and the patient recovered and gained normal strength. However, after a few years he stopped treatment, and all symptoms recurred. He developed severe proximal weakness of all limbs. Another biopsy showed similar findings, with no inflammation; still, he responded favorably to steroids and immunosuppressive medications. Currently on a low dose of prednisone and methotrexate, he has no neurological deficit. CONCLUSION The absence of inflammation in muscle biopsy may lead to misdiagnosis of muscular dystrophy; however, if the clinical impression is that of inflammatory myopathy, an immunomodulatory treatment should be initiated. During the past century, there has been much controversy about the diagnosis of polymyositis (PM). The debate is still ongoing. We present hereby a patient with typical course and clinical features of PM who underwent two muscle biopsies, several years apart, which showed necrotizing myopathy, practically without inflammation, leading to misdiagnosis of muscular dystrophy. This report brings up the dispute regarding the role of muscle biopsy in the diagnosis of PM.
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Affiliation(s)
- Menachem Sadeh
- Department of Neurology, Wolfson Medical Center, Holon, Israel; and Sackler Faculty of Medicine, Tel Aviv University, Tel-Aviv, Israel.
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23
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Abstract
Sporadic inclusion-body myositis (sIBM) is the most common acquired muscle disease in Caucasians over the age of 50 years. Pathologically it is marked by inflammatory, degenerative, and mitochondrial changes that interact in a yet-unknown way to cause progressive muscle degeneration and weakness. The cause of the disease is unknown, but it is thought to involve a complex interplay between environmental factors, genetic susceptibility, and aging. The strongest evidence for genetic susceptibility comes from studies of the major histocompatibility complex (MHC), where different combinations of alleles have been associated with sIBM in different ethnic groups. The rare occurrence of familial cases of inclusion-body myositis (fIBM) adds additional evidence for genetic susceptibility. Other candidate genes such as those encoding some of the proteins accumulating in muscle fibers have been investigated, with negative results. The increased understanding of related disorders, the hereditary inclusion-body myopathies (hIBM), may also provide clues to the underlying pathogenesis of sIBM, but to date there is no indication that the genes responsible for these conditions are involved in sIBM. This review summarizes current understanding of the contribution of genetic susceptibility factors to the development of sIBM.
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Affiliation(s)
- M Needham
- Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Level 4, A Block, Queen Elizabeth II Medical Centre, Nedlands, Western Australia 6009, Australia.
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Liewluck T, Pho-Iam T, Limwongse C, Thongnoppakhun W, Boonyapisit K, Raksadawan N, Murayama K, Hayashi YK, Nishino I, Sangruchi T. Mutation analysis of the GNE gene in distal myopathy with rimmed vacuoles (DMRV) patients in Thailand. Muscle Nerve 2007; 34:775-8. [PMID: 16810679 DOI: 10.1002/mus.20583] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Distal myopathy with rimmed vacuoles (DMRV) is an early-adult-onset, distal myopathy caused by a mutation of the UDP-N-acetylglucosamine 2 epimerase/N-acetylmannosamine kinase (GNE) gene. We herein report four Thai patients with DMRV who carried compound heterozygous mutations of the GNE gene including three novel (p.G89R, p.P511T, and p.I656N) and two known mutations (p.A524V and p.V696M). All patients shared p.V696M in one allele. Our study demonstrates the mutation spectrum of the GNE gene in Thai patients with DMRV.
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Affiliation(s)
- Teerin Liewluck
- Department of Pathology, Faculty of Medicine, Siriraj Hospital, Mahidol University, 2 Prannok Rd., Siriraj, Bangkok-Noi, Bangkok 10700, Thailand.
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Affiliation(s)
- Michael R Rose
- King's College Hospital, University of London, London UK
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26
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Abstract
PURPOSE OF REVIEW The distal myopathies are a heterogeneous group of disorders that pose a challenge to both the clinician and geneticist. This article summarizes the findings of recent clinical, genetic and molecular studies and the current diagnostic approach to this group of patients. RECENT FINDINGS Publications over the past 5 years describe a number of new clinical phenotypes and genetic loci and further emphasize the overlap in clinical phenotype between a number of these disorders and between the distal and limb girdle myopathies and hereditary inclusion body myopathies. Recent studies have led to the identification of the genes and mutations responsible for early onset (Laing) myopathy and tibial (Udd) myopathy, and for distal myopathy with rimmed vacuoles (Nonaka), which has been shown to be allelic with quadriceps sparing hereditary inclusion body myopathy (IBM2), and have elucidated the underlying pathogenetic mechanisms in these conditions. New diagnostic approaches using magnetic resonance imaging, and a blood-based assay for dysferlin deficiency, have also been reported. SUMMARY These findings have important implications for future genetic linkage and gene expression studies and for the diagnostic approach to patients with a distal myopathy phenotype. They also hold promise for the eventual development of therapies for this group of disorders.
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Affiliation(s)
- Frank L Mastaglia
- Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Perth, Western Australia, Australia.
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27
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Kim BJ, Ki CS, Kim JW, Sung DH, Choi YC, Kim SH. Mutation analysis of the GNE gene in Korean patients with distal myopathy with rimmed vacuoles. J Hum Genet 2005; 51:137-140. [PMID: 16372135 DOI: 10.1007/s10038-005-0338-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2005] [Accepted: 10/21/2005] [Indexed: 10/25/2022]
Abstract
Distal myopathy with rimmed vacuoles (DMRV; MIM 605820) is an autosomal recessive neuromuscular disorder characterized by weakness of the anterior compartment of the lower limbs, sparing the quadriceps muscles. Recently, mutations in the UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine kinase (GNE) gene have been identified as the genetic basis of DMRV. To investigate the mutation spectrum of the GNE gene in Korean patients with DMRV, we performed clinical and genetic analysis of nine unrelated patients suspected to have DMRV. Direct sequencing analysis revealed that eight out of nine patients (88.9%) were either homozygous or compound heterozygous for GNE gene mutations, including three known (C13S, R129Q, and V572L) and two novel mutations (M29T and A591T) [corrected] The allelic frequencies of the V572L and C13S mutations were 68.8% (11/16) and 12.5% (2/16), respectively. These results suggest that screening for GNE gene mutations in patients suspected to have DMRV would be helpful for molecular diagnosis of DMRV in the Korean population.
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Affiliation(s)
- Byoung Joon Kim
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Chang-Seok Ki
- Department of Laboratory Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Jong-Won Kim
- Department of Laboratory Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Duk Hyun Sung
- Department of Physical Medicine and Rehabilitation, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Young-Chul Choi
- Department of Neurology, Brain Korea 21 Project for Medicine, Yonsei University College of Medicine, Seoul, South Korea
| | - Seung Hyun Kim
- Department of Neurology, College of Medicine, Hanyang University, Seoul, South Korea
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Abstract
PURPOSE OF REVIEW The etiology and much about the pathogenesis of the inflammatory myopathies remain a mystery. In this review, we investigate recent research efforts to understand the pathogenesis of the diverse entities of polymyositis (PM), dermatomyositis (DM), and inclusion body myositis (IBM), diseases that result from interactions between environmental risk factors and genetic susceptibility. RECENT FINDINGS Over the past year, there has been considerable progress toward better understanding of IBM, with relatively few developments toward understanding PM and DM. Although these diseases may share some common clinical phenotypic and serologic components, they differ on a molecular and cellular level. SUMMARY The need for definitive, safer therapies in these diseases makes vital the search for defining detailed pathogenesis of inflammation and muscle fiber damage at the molecular level.
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Affiliation(s)
- Lisa Christopher-Stine
- Division of Rheumatology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Nonaka I, Noguchi S, Nishino I. Distal myopathy with rimmed vacuoles and hereditary inclusion body myopathy. Curr Neurol Neurosci Rep 2005; 5:61-5. [PMID: 15676110 DOI: 10.1007/s11910-005-0025-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Distal myopathy with rimmed vacuoles (DMRV) and hereditary inclusion body myopathy (hIBM) share similar clinical features, including onset in young adulthood with preferential involvement of the anterior compartment of the lower legs and sparing of the quadriceps femoris muscles. The most significant muscle pathology is the presence of rimmed vacuoles, which appear to play a major role in muscle atrophy and weakness. After the discovery of the gene locus in both DMRV and hIBM on chromosome 9 and mutations in the gene encoding the enzyme UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE), it became clear that they are allelic disorders. From gene analysis, it is evident that these diseases are not restricted to people of Japanese and Jewish ancestry, but that they are widely distributed throughout all ethnic groups. Although defective glycosylation to a muscle fiber has been suggested, the mechanism by which myofibrillar degeneration is followed by rimmed vacuole formation remains to be clarified.
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Affiliation(s)
- Ikuya Nonaka
- Division of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo 187-8502, Japan.
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Kalaydjieva L, Lochmüller H, Tournev I, Baas F, Beres J, Colomer J, Guergueltcheva V, Herrmann R, Karcagi V, King R, Miyata T, Müllner-Eidenböck A, Okuda T, Milic Rasic V, Santos M, Talim B, Vilchez J, Walter M, Urtizberea A, Merlini L. 125th ENMC International Workshop: Neuromuscular disorders in the Roma (Gypsy) population, 23-25 April 2004, Naarden, The Netherlands. Neuromuscul Disord 2004; 15:65-71. [PMID: 15639123 DOI: 10.1016/j.nmd.2004.09.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2004] [Indexed: 12/16/2022]
Affiliation(s)
- Luba Kalaydjieva
- Western Australian Institute for Medical Research and Centre for Medical Research, The University of Western Australia, Perth, Australia.
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Nirmalananthan N, Holton JL, Hanna MG. Is it really myositis? A consideration of the differential diagnosis. Curr Opin Rheumatol 2004; 16:684-91. [PMID: 15577605 DOI: 10.1097/01.bor.0000143441.27065.bc] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
PURPOSE OF REVIEW The idiopathic inflammatory myopathies are an important and treatable group of disorders. However, the potential toxicity associated with the immune therapeutic regimens used to treat these disorders may be significant; therefore, accurate diagnosis before such treatment is essential. The differential diagnosis is potentially large. Accurate diagnosis usually depends on a combination of careful clinical assessment in conjunction with detailed laboratory investigations. Muscle biopsy remains essential in achieving an accurate diagnosis that will then guide treatment. This review describes the diagnostic approach used. RECENT FINDINGS There has been debate over the requirements for an accurate diagnosis of inflammatory myopathy (i.e., polymyositis and dermatomyositis). It is increasingly recognized that there can be clinical and muscle histopathologic overlap between the features of inflammatory myopathies and those of other muscle disorders, in particular, the genetic muscular dystrophies. Pathologic findings of inflammation and major histocompatibility complex upregulation, although typical of inflammatory myopathies, have been shown to occur in some muscular dystrophies, complicating the diagnostic process. Inclusion body myositis is much less responsive to immunotherapy and is now recognized as the most common acquired muscle disease in those older than 50 years of age. It is likely that genetic muscular dystrophies and inclusion body myositis account for some cases of apparently "treatment-resistant" myositis. SUMMARY A thorough clinical assessment, including a detailed family history, complemented by electromyography and creatine kinase measurements, should be undertaken in any patient with presumed idiopathic inflammatory myopathy. In addition, a muscle biopsy remains essential in all cases. A precise tissue diagnosis confirming features of an active inflammatory process should be achieved before immunosuppressive treatment is commenced. An increasing array of immunocytochemical and histioenzymatic stains now allows a full analysis and will help to confirm or exclude virtually all the differential diagnostic possibilities considered in this review. Electron microscopy may also be valuable in selected cases. Close collaboration between clinicians and muscle pathologists is essential in allowing the most accurate interpretation of myopathologic findings in the clinical context.
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Affiliation(s)
- Niranjanan Nirmalananthan
- Neurogenetics Group, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
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