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Yoshioka W, Nishino I, Noguchi S. Recent advances in establishing a cure for GNE myopathy. Curr Opin Neurol 2022; 35:629-636. [PMID: 35959526 DOI: 10.1097/wco.0000000000001090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW GNE myopathy is a rare autosomal recessive disease caused by biallelic variants in the GNE gene, which encodes an enzyme involved in sialic acid biosynthesis. No drugs are approved for the treatment of GNE myopathy. Following proof-of-concept of sialic acid supplementation efficacy in mouse models, multiple clinical trials have been conducted. Here, we review clinical trials of sialic acid supplementation therapies and provide new insights into the additional clinical features of GNE myopathy. RECENT FINDINGS Clinical trials of sialic acid supplementation have been conducted in Europe, the USA, Japan, and South Korea. Some clinical trials of NeuAc-extended release tablets demonstrated amelioration of decline in upper extremity muscle strength; however, no significant improvement was observed in phase 3 trials in Europe and USA. A phase 2 trial of ManNAc showed slowed decline of both upper and lower extremity strength. GNE myopathy patient registries have been established in Europe and Japan, and have provided information on extramuscular manifestations such as thrombocytopenia, respiratory dysfunction, and sleep apnea syndrome. Sensitive and reliable biomarkers, and a disease-specific functional activity scale, have also been investigated. SUMMARY We discuss recent advances in establishing a GNE myopathy cure, and discuss other prospective therapeutic options, including gene therapy.
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Affiliation(s)
- Wakako Yoshioka
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Ogawa-Higashi, Kodaira
- Department of Clinical Genome Analysis, Medical Genome Center, NCNP, Tokyo, Japan
| | - Ichizo Nishino
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Ogawa-Higashi, Kodaira
- Department of Clinical Genome Analysis, Medical Genome Center, NCNP, Tokyo, Japan
| | - Satoru Noguchi
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Ogawa-Higashi, Kodaira
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Guo X, Zhao Z, Shen H, Bing Q, Li N, Chen J, Hu J. Gene analysis and clinical features of 22 GNE myopathy patients. Neurol Sci 2022; 43:5049-5056. [PMID: 35438352 DOI: 10.1007/s10072-022-06023-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 03/18/2022] [Indexed: 01/02/2023]
Abstract
INTRODUCTION GNE myopathy is an autosomal recessive distal myopathy caused by a biallelic mutation in UDP-N-acetylglucosamine 2-epomerase/N-acetylmannosamine kinase. In this study, we discuss the clinical features, pathological characteristics, genetic profiles, and atypical clinical manifestations of 22 Chinese GNE patients. MATERIALS AND METHODS Retrospective analysis was performed for GNE myopathy patients at our institute between 2005 and 2021. Histopathological analysis and gene testing were done according to standard protocols. RESULTS Molecular analysis revealed 14-reported and 7 novel mutations, including c.125G > A (p.P42Q), c.226G > A (p.V76I), c.970C > G (p.H324D), c.155A > G (p.D52G), c.1055G > A (p.R352H), c.1064G > A (p.G355E), and c.491 T > C (p.I164T) in GNE. D207V was the most frequent mutation showing an allele frequency of 25%. A total of 21 patients presented classic clinical manifestation, and only 1 patient had signs of proximal muscle weakness. A patient containing p.V603L and p.R160X mutations showed idiopathic thrombocytopenia and distal weakness. There were 4 female patients who experienced rapid deterioration after pregnancy. DISCUSSION Our study revealed 7 novel mutations in GNE, where p.D207V was shown as a potential hotspot mutation in Chinese patients. Idiopathic thrombocytopenia should be a concern in GNE myopathy patients. Twenty-seven percent of female patients experienced rapid deterioration during pregnancy or after delivery.
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Affiliation(s)
- Xuan Guo
- Department of Neuromuscular Disorders, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, People's Republic of China
| | - Zhe Zhao
- Department of Neuromuscular Disorders, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, People's Republic of China
| | - Hongrui Shen
- Department of Neuromuscular Disorders, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, People's Republic of China
| | - Qi Bing
- Department of Neuromuscular Disorders, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, People's Republic of China
| | - Nan Li
- Department of Neuromuscular Disorders, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, People's Republic of China
| | - Jiannan Chen
- Department of Neuromuscular Disorders, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, People's Republic of China
| | - Jing Hu
- Department of Neuromuscular Disorders, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, People's Republic of China.
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Yoshioka W, Miyasaka N, Okubo R, Shimizu R, Takahashi Y, Oda Y, Nishino I, Nakamura H, Mori-Yoshimura M. Pregnancy in GNE myopathy patients: a nationwide repository survey in Japan. Orphanet J Rare Dis 2020; 15:245. [PMID: 32917266 PMCID: PMC7488253 DOI: 10.1186/s13023-020-01487-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 08/02/2020] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND GNE myopathy is an autosomal recessive adult-onset distal myopathy. While a few case reports have described the progression of GNE myopathy during pregnancy, to our knowledge, none have examined disease progression after delivery or obstetric complications. OBJECTIVE This study aimed to reveal maternal complications, newborn complications, and the impact of pregnancy on disease progression in GNE myopathy patients. METHODS We conducted a questionnaire survey on pregnancy, delivery, and newborns involving female GNE myopathy patients who are currently registered in a national registry in Japan. RESULTS The response rate for the questionnaire survey was 60.0% (72/120). Of the 72 respondents, 44 (61.1%) had pregnancy experience (average, 1.8 pregnancies; 53 pregnancies before onset and 28 after onset). The incidence of threatened abortion was 26.9% among post-onset pregnancies, which was higher compared to those of the general Japanese population (p = 0.03). No other maternal or infant complications were commonly observed. Over 80% were unaware of changes in disease progression during pregnancy (mean age, 32.8 ± 3.5 years) or after delivery (32.9 ± 3.8 years), while 19.0% experienced disease exacerbation within a year after delivery (30.0 ± 1.0 years). Six patients developed myopathy within a year after delivery (29.7 ± 4.6 years), while none developed myopathy during pregnancy. CONCLUSIONS There were no serious maternal or newborn complications, and subjective progression did not differ during or after delivery in the majority of GNE myopathy patients. However, our findings suggest the importance of considering the possibility of threatened abortion and disease progression after delivery.
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Affiliation(s)
- Wakako Yoshioka
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), 4-1-1 Ogawa-higashi-cho, Kodaira, Tokyo, Japan.,Institute of Medical Genetics, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, Japan
| | - Naoyuki Miyasaka
- Comprehensive Reproductive Medicine, Graduate School of Medical and Dental Sciences (Medicine), Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, Japan
| | - Ryo Okubo
- Department of Clinical Epidemiology, Translational Medical Center, NCNP, Tokyo, Japan
| | - Reiko Shimizu
- Department of Clinical Research Promotion, Translational Medical Center, NCNP, Tokyo, Japan
| | - Yuji Takahashi
- Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry (NCNP), 4-1-1 Ogawa-Higashi, Kodaira, Tokyo, 187-8502, Japan
| | - Yuriko Oda
- Patient Association for Distal Myopathies, 2-2-15 Hamamatsucho, Minato-ku, Tokyo, Japan
| | - Ichizo Nishino
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), 4-1-1 Ogawa-higashi-cho, Kodaira, Tokyo, Japan
| | - Harumasa Nakamura
- Department of Clinical Research Promotion, Translational Medical Center, NCNP, Tokyo, Japan
| | - Madoka Mori-Yoshimura
- Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry (NCNP), 4-1-1 Ogawa-Higashi, Kodaira, Tokyo, 187-8502, Japan.
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4
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Soule T, Phan C, White C, Resch L, Lacson A, Martens K, Pfeffer G. GNE Myopathy With Novel Mutations and Pronounced Paraspinal Muscle Atrophy. Front Neurol 2018; 9:942. [PMID: 30467490 PMCID: PMC6236015 DOI: 10.3389/fneur.2018.00942] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 10/17/2018] [Indexed: 11/13/2022] Open
Abstract
GNE myopathy is characterized by distal muscle weakness, and caused by recessive mutations in GNE. Its onset is characteristically in young adulthood, although a broad spectrum of onset age is known to exist. A large number of mutations in GNE are pathogenic and this clinical phenotype can be difficult to differentiate clinically from other late-onset myopathies. We describe two families with novel mutations in GNE, and describe their clinical and MRI features. We also describe the presence of striking paraspinal muscle involvement on MRI of the lumbar spine, which is an under-recognized feature of GNE myopathy.
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Affiliation(s)
- Tyler Soule
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Cecile Phan
- Department of Medicine, University of Alberta, Edmonton, AB, Canada
| | - Chris White
- Department of Clinical Neurosciences, University of Calgary, Calgary, AB, Canada
| | - Lothar Resch
- Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, AB, Canada
| | - Atilano Lacson
- Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB, Canada
| | - Kristina Martens
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Gerald Pfeffer
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.,Department of Clinical Neurosciences, University of Calgary, Calgary, AB, Canada
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Chamova T, Guergueltcheva V, Gospodinova M, Krause S, Cirak S, Kaprelyan A, Angelova L, Mihaylova V, Bichev S, Chandler D, Naydenov E, Grudkova M, Djukmedzhiev P, Voit T, Pogoryelova O, Lochmüller H, Goebel HH, Bahlo M, Kalaydjieva L, Tournev I. GNE myopathy in Roma patients homozygous for the p.I618T founder mutation. Neuromuscul Disord 2015; 25:713-8. [DOI: 10.1016/j.nmd.2015.07.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Revised: 06/07/2015] [Accepted: 07/07/2015] [Indexed: 02/02/2023]
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6
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Zhao J, Wang Z, Hong D, Lv H, Zhang W, Chen J, Yuan Y. Mutational spectrum and clinical features in 35 unrelated mainland Chinese patients with GNE myopathy. J Neurol Sci 2015; 354:21-6. [DOI: 10.1016/j.jns.2015.04.028] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 04/18/2015] [Accepted: 04/20/2015] [Indexed: 02/07/2023]
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7
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Haghighi A, Nafissi S, Qurashi A, Tan Z, Shamshiri H, Nilipour Y, Haghighi A, Desnick RJ, Kornreich R. Genetics of GNE myopathy in the non-Jewish Persian population. Eur J Hum Genet 2015; 24:243-51. [PMID: 25966635 DOI: 10.1038/ejhg.2015.78] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Revised: 12/27/2014] [Accepted: 01/07/2015] [Indexed: 12/31/2022] Open
Abstract
GNE myopathy is an autosomal recessive adult-onset disorder characterized by progressive muscle atrophy and weakness, initially involving the distal muscles, while often sparing the quadriceps. It is caused by variants in the GNE gene that encodes a key bifunctional enzyme in the sialic acid biosynthetic pathway. We investigated the clinical and molecular characteristics of 18 non-Jewish Persian patients from 11 unrelated GNE myopathy families. In addition, we reviewed the previously reported cases and suggest genotype-phenotype correlations for the identified variants. Comprehensive clinical and laboratory evaluations were carried out. Sequencing of the GNE gene was performed using genomic DNA from the patients. Screening of the identified variants was performed in all relevant family members. Molecular analyses identified three causative homozygous GNE variants in 11 families: c.2228T>C (p. M743T) in 7, c.830G>A (p.R277Q) in 2, and one novel variation (c.804G>A) in 2 families that results in a synonymous codon change (p.L268=) and likely creates a novel splice site affecting the protein function. This study confirms that c.2228T>C (p.M743T) is the most prevalent disease-causing variant in the non-Jewish Persian population, but other GNE variants can cause GNE myopathy in this population. The patients with all three different variants had similar ages of onset. The youngest patient was an 18-year-old girl in whom the c.830G>A (p.R277Q) variant was identified, whereas the oldest onset age (31 years) was seen in a male patient with c.804G>A (p.L268=). The results of this investigation expand our knowledge about the genotype-phenotype correlations in GNE myopathy and aid in clinical management and therapeutic interventions.
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Affiliation(s)
- Alireza Haghighi
- Department of Genetics, Harvard Medical School, Boston, MA, USA.,Department of Medicine and the Howard Hughes Medical Institute, Brigham and Women's Hospital, Boston, MA, USA.,Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Shahriar Nafissi
- Department of Neurology, Iranian Center of Neurological Research, Tehran University of Medical Sciences, Shariati Hospital, Tehran, Iran
| | - Abrar Qurashi
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Zheng Tan
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Hosein Shamshiri
- Department of Neurology, Iranian Center of Neurological Research, Tehran University of Medical Sciences, Shariati Hospital, Tehran, Iran
| | - Yalda Nilipour
- Department of Pathology, Pediatric Pathology Research Center, Mofid Children Hospital, Shahid Beheshti Medical University, Tehran, Iran
| | | | - Robert J Desnick
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Ruth Kornreich
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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8
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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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9
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Sim JE, Hong JM, Suh GI, Cho H, Park KS, Sohn EH, Choi YC. A Case of GNE Myopathy Presenting a Rapid Deterioration during Pregnancy. J Clin Neurol 2013; 9:280-2. [PMID: 24285971 PMCID: PMC3840140 DOI: 10.3988/jcn.2013.9.4.280] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Revised: 07/10/2012] [Accepted: 07/10/2012] [Indexed: 02/01/2023] Open
Abstract
Background GNE myopathy is characterized by early-adult-onset distal myopathy sparing quadriceps caused by mutations in the GNE gene encoding UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase, an enzyme in the sialic-acid synthesis pathway. Case Report A 27-year-old Korean woman presented a rapid deterioration in strength of the distal lower limbs during her first pregnancy. She was diagnosed with GNE myopathy and carrying the compound heterozygous mutations of the GNE gene (D208N/M29T). Conclusions This is a representative case implying that an increased requirement of sialic acid during pregnancy might trigger a clinical worsening of GNE myopathy.
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Affiliation(s)
- Jae Eun Sim
- Department of Neurology, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
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10
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Miryounesi M, Soltanzadeh P, Modarressi MH. Hereditary inclusion body myopathy in Persian Jews: a case report from Iran. Clin Genet 2013; 85:595-7. [PMID: 23841835 DOI: 10.1111/cge.12220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 06/19/2013] [Accepted: 06/19/2013] [Indexed: 11/28/2022]
Affiliation(s)
- M Miryounesi
- Department of Medical Genetics, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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11
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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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12
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Lu X, Pu C, Huang X, Liu J, Mao Y. Distal myopathy with rimmed vacuoles: clinical and muscle morphological characteristics and spectrum of GNE gene mutations in 53 Chinese patients. Neurol Res 2012; 33:1025-31. [PMID: 22196754 DOI: 10.1179/1743132811y.0000000070] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVES Distal myopathy with rimmed vacuoles (DMRV) is a typical autosomal recessive hereditary inclusion body myopathy, characterized by slowly progressive distal muscle weakness with relative sparing of the quadriceps. This study aimed to investigate the variability of clinical and morphological presentation and the spectrum of Glucosamine (UDP-N-acetyl)-2-epimerase/N-acetylmannosamine kinase (GNE) mutations in Chinese DMRV patients. METHODS We retrospectively reviewed the medical records of 37 patients with DMRV in PLA General Hospital from 1986 to 2011, and further conducted a review of 16 reported Chinese DMRV patients from other hospitals. We systematically analyzed the clinical, muscle morphological features and GNE gene mutation status of all DMRV patients. RESULTS A total of 53 DMRV patients were studied. Fourteen cases had family history and other 39 cases were sporadic. Fifteen cases showed atypical pathological presentation as mononuclear cell invasion into necrotic or non-necrotic muscle fibers. Rare initial symptom, earlier age of onset and more dysmorphic presentations were shown in sporadic patients. Eighteen mutations in GNE gene were identified. c.317T>C (p.I106T) was a novel GNE gene mutation. c.1892C>T (p.A631V), c.527A>T (p.D176V) and c.1523T>C (p.L508S) were the common GNE mutations in Chinese DMRV patients. DISCUSSION The clinical, pathological and genetic characteristics of DMRV are distinct in Chinese patients.
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Affiliation(s)
- Xianghui Lu
- Chinese PLA General Hospital, Beijing, China
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13
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Dilated cardiomyopathy and inclusion body myositis. Neurol Sci 2011; 33:367-70. [DOI: 10.1007/s10072-011-0766-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Accepted: 08/30/2011] [Indexed: 10/17/2022]
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14
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Boyden SE, Duncan AR, Estrella EA, Lidov HGW, Mahoney LJ, Katz JS, Kunkel LM, Kang PB. Molecular diagnosis of hereditary inclusion body myopathy by linkage analysis and identification of a novel splice site mutation in GNE. BMC MEDICAL GENETICS 2011; 12:87. [PMID: 21708040 PMCID: PMC3141630 DOI: 10.1186/1471-2350-12-87] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Accepted: 06/28/2011] [Indexed: 11/13/2022]
Abstract
Background Many myopathies share clinical features in common, and diagnosis often requires genetic testing. We ascertained a family in which five siblings presented with distal muscle weakness of unknown etiology. Methods We performed high-density genomewide linkage analysis and mutation screening of candidate genes to identify the genetic defect in the family. Preserved clinical biopsy material was reviewed to confirm the diagnosis, and reverse transcriptase PCR was used to determine the molecular effect of a splice site mutation. Results The linkage scan excluded the majority of known myopathy genes, but one linkage peak included the gene GNE, in which mutations cause autosomal recessive hereditary inclusion body myopathy type 2 (HIBM2). Muscle biopsy tissue from a patient showed myopathic features, including small basophilic fibers with vacuoles. Sequence analysis of GNE revealed affected individuals were compound heterozygous for a novel mutation in the 5' splice donor site of intron 10 (c.1816+5G>A) and a previously reported missense mutation (c.2086G>A, p.V696M), confirming the diagnosis as HIBM2. The splice site mutation correlated with exclusion of exon 10 from the transcript, which is predicted to produce an in-frame deletion (p.G545_D605del) of 61 amino acids in the kinase domain of the GNE protein. The father of the proband was heterozygous for the splice site mutation and exhibited mild distal weakness late in life. Conclusions Our study expands on the extensive allelic heterogeneity of HIBM2 and demonstrates the value of linkage analysis in resolving ambiguous clinical findings to achieve a molecular diagnosis.
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Affiliation(s)
- Steven E Boyden
- Division of Genetics, Children's Hospital Boston, Boston, MA 02115, USA
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