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Safwat S, Flannery KP, El Beheiry AA, Mokhtar MM, Abdalla E, Manzini MC. Genetic blueprint of congenital muscular dystrophies with brain malformations in Egypt: A report of 11 families. Neurogenetics 2024; 25:93-102. [PMID: 38296890 PMCID: PMC11076401 DOI: 10.1007/s10048-024-00745-z] [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: 12/07/2023] [Accepted: 01/12/2024] [Indexed: 02/02/2024]
Abstract
Congenital muscular dystrophies (CMDs) are a group of rare muscle disorders characterized by early onset hypotonia and motor developmental delay associated with brain malformations with or without eye anomalies in the most severe cases. In this study, we aimed to uncover the genetic basis of severe CMD in Egypt and to determine the efficacy of whole exome sequencing (WES)-based genetic diagnosis in this population. We recruited twelve individuals from eleven families with a clinical diagnosis of CMD with brain malformations that fell into two groups: seven patients with suspected dystroglycanopathy and five patients with suspected merosin-deficient CMD. WES was analyzed by variant filtering using multiple approaches including splicing and copy number variant (CNV) analysis. We identified likely pathogenic variants in FKRP in two cases and variants in POMT1, POMK, and B3GALNT2 in three individuals. All individuals with merosin-deficient CMD had truncating variants in LAMA2. Further analysis in one of the two unsolved cases showed a homozygous protein-truncating variant in Feline Leukemia Virus subgroup C Receptor 1 (FLVCR1). FLVCR1 loss of function has never been previously reported. Yet, loss of function of its paralog, FLVCR2, causes lethal hydranencephaly-hydrocephaly syndrome (Fowler Syndrome) which should be considered in the differential diagnosis for dystroglycanopathy. Overall, we reached a diagnostic rate of 86% (6/7) for dystroglycanopathies and 100% (5/5) for merosinopathy. In conclusion, our results provide further evidence that WES is an important diagnostic method in CMD in developing countries to improve the diagnostic rate, management plan, and genetic counseling for these disorders.
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Affiliation(s)
- Sylvia Safwat
- Department of Neuroscience and Cell Biology, Child Health Institute of New Jersey, Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ, USA
- Department of Human Genetics, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Kyle P Flannery
- Department of Neuroscience and Cell Biology, Child Health Institute of New Jersey, Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Ahmed A El Beheiry
- Department of Radiodiagnosis and Interventional Radiology, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Mohamed M Mokhtar
- Department of Radiodiagnosis and Interventional Radiology, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Ebtesam Abdalla
- Department of Human Genetics, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - M Chiara Manzini
- Department of Neuroscience and Cell Biology, Child Health Institute of New Jersey, Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ, USA.
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Salih MA. The Meryon Lecture at the 24th annual meeting of the Meryon Society, St. Anne's College, Oxford, UK, 15th July 2022: Neuromuscular diseases in the Arab population. Neuromuscul Disord 2023; 33:792-799. [PMID: 37679229 DOI: 10.1016/j.nmd.2023.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/09/2023]
Affiliation(s)
- Mustafa A Salih
- Consultant Pediatric Neurologist, Health Sector, King Abdulaziz City for Science and Technology, Riyadh 11442, Saudi Arabia.
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3
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Arockiaraj AI, Johnson MA, Munir A, Ekambaram P, Lucas PC, McAllister-Lucas LM, Kemaladewi DU. CRISPRa-induced upregulation of human LAMA1 compensates for LAMA2-deficiency in Merosin-deficient congenital muscular dystrophy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.06.531347. [PMID: 36945402 PMCID: PMC10028808 DOI: 10.1101/2023.03.06.531347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
Merosin-deficient congenital muscular dystrophy (MDC1A) is an autosomal recessive disorder caused by mutations in the LAMA2 gene, resulting in a defective form of the extracellular matrix protein laminin-α2 (LAMA2). Individuals diagnosed with MDC1A exhibit progressive muscle wasting and declining neuromuscular functions. No treatments for this disorder are currently available. We previously showed that postnatal Lama1 upregulation, achieved through CRISPR activation (CRISPRa), compensates for Lama2 deficiency and prevents neuromuscular pathophysiology in a mouse model of MDC1A. In this study, we assessed the feasibility of upregulating human LAMA1 as a potential therapeutic strategy for individuals with MDC1A, regardless of their mutations. We hypothesized that CRISPRa-mediated upregulation of human LAMA1 would compensate for the lack of LAMA2 and rescue cellular abnormalities in MDC1A fibroblasts. Global transcriptomic and pathway enrichment analyses of fibroblasts collected from individuals carrying pathogenic LAMA2 mutations, compared with healthy controls, indicated higher expression of transcripts encoding proteins that contribute to wound healing, including Transforming Growth Factor-β (TGF-β) and Fibroblast Growth Factor (FGF). These findings were supported by wound-healing assays indicating that MDC1A fibroblasts migrated significantly more rapidly than the controls. Subsequently, we treated the MDC1A fibroblasts with SadCas9-2XVP64 and sgRNAs targeting the LAMA1 promoter. We observed robust LAMA1 expression, which was accompanied by significant decreases in cell migration and expression of FGFR2, TGF-β2, and ACTA2, which are involved in the wound-healing mechanism in MDC1A fibroblasts. Collectively, our data suggest that CRISPRa-mediated LAMA1 upregulation may be a feasible mutation-independent therapeutic approach for MDC1A. This strategy might be adapted to address other neuromuscular diseases and inherited conditions in which strong compensatory mechanisms have been identified.
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Affiliation(s)
- Annie I. Arockiaraj
- Department of Human Genetics, School of Public Health, University of Pittsburgh, Pittsburgh, USA
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, USA
| | - Marie A. Johnson
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, USA
| | - Anushe Munir
- Department of Human Genetics, School of Public Health, University of Pittsburgh, Pittsburgh, USA
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, USA
| | - Prasanna Ekambaram
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, USA
| | - Peter C. Lucas
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, USA
| | | | - Dwi U. Kemaladewi
- Department of Human Genetics, School of Public Health, University of Pittsburgh, Pittsburgh, USA
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, USA
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4
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Inherited myopathies in the Middle East and North Africa. GENE REPORTS 2022. [DOI: 10.1016/j.genrep.2022.101674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Guo L, Tang WM, Song YZ. [Clinical features and LAMA2 mutations of patients with congenital muscular dystrophy type 1A: a case report and literature review]. ZHONGGUO DANG DAI ER KE ZA ZHI = CHINESE JOURNAL OF CONTEMPORARY PEDIATRICS 2020; 22:608-613. [PMID: 32571460 PMCID: PMC7390210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 05/11/2020] [Indexed: 03/30/2024]
Abstract
Biallelic pathogenic mutations of the LAMA2 gene result in congenital muscular dystrophy type 1A (CMD1A). The patient in this study was a boy aged 19 months, with the clinical manifestations of motor development delay and increases in the serum levels of creatine kinase, aminotransferases, and lactate dehydrogenase. Genetic analysis showed that the patient had compound heterozygous mutations in the LAMA2 gene, among which c.7147C>T (p.Ala2383Ter) from his mother was a known nonsense mutation, and c.8551_8552insAA (p.Ile2852ArgfsTer2) from his father was a frameshift mutation which had never been reported before and was identified as a pathogenic mutation based on the ACMG guideline. The boy was confirmed with CMD1A. A literature review of related articles in China and overseas revealed that most children with CMD1A have disease onset within 6 months after birth, with the features of motor developmental delay, elevated serum creatine kinase, and white matter impairment on imaging examination. The mutations of the LAMA2 gene have remarkable heterogeneity, the majority of which are null mutations. There are no specific treatment methods for CMD1A currently, and children with CMD1A usually have a poor long-term prognosis.
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Affiliation(s)
- Li Guo
- Department of Pediatrics, First Affiliated Hospital, Jinan University, Guangzhou 510630, China.
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Guo L, Tang WM, Song YZ. [Clinical features and LAMA2 mutations of patients with congenital muscular dystrophy type 1A: a case report and literature review]. ZHONGGUO DANG DAI ER KE ZA ZHI = CHINESE JOURNAL OF CONTEMPORARY PEDIATRICS 2020; 22:608-613. [PMID: 32571460 PMCID: PMC7390210 DOI: 10.7499/j.issn.1008-8830.2001102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 05/11/2020] [Indexed: 06/11/2023]
Abstract
Biallelic pathogenic mutations of the LAMA2 gene result in congenital muscular dystrophy type 1A (CMD1A). The patient in this study was a boy aged 19 months, with the clinical manifestations of motor development delay and increases in the serum levels of creatine kinase, aminotransferases, and lactate dehydrogenase. Genetic analysis showed that the patient had compound heterozygous mutations in the LAMA2 gene, among which c.7147C>T (p.Ala2383Ter) from his mother was a known nonsense mutation, and c.8551_8552insAA (p.Ile2852ArgfsTer2) from his father was a frameshift mutation which had never been reported before and was identified as a pathogenic mutation based on the ACMG guideline. The boy was confirmed with CMD1A. A literature review of related articles in China and overseas revealed that most children with CMD1A have disease onset within 6 months after birth, with the features of motor developmental delay, elevated serum creatine kinase, and white matter impairment on imaging examination. The mutations of the LAMA2 gene have remarkable heterogeneity, the majority of which are null mutations. There are no specific treatment methods for CMD1A currently, and children with CMD1A usually have a poor long-term prognosis.
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Affiliation(s)
- Li Guo
- Department of Pediatrics, First Affiliated Hospital, Jinan University, Guangzhou 510630, China.
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AMIN MUTAZ, BAKHIT YOUSUF, KOKO MAHMOUD, IBRAHIM MOHAMEDOSAMAMIRGAHNI, SALIH MA, IBRAHIM MUNTASER, SEIDI OSHEIKA. Rare variant in LAMA2 gene causing congenital muscular dystrophy in a Sudanese family. A case report. ACTA MYOLOGICA : MYOPATHIES AND CARDIOMYOPATHIES : OFFICIAL JOURNAL OF THE MEDITERRANEAN SOCIETY OF MYOLOGY 2019; 38:21-24. [PMID: 31309178 PMCID: PMC6598405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Congenital muscular dystrophies (CMD) are a heterogeneous group of disorders caused by mutations in musculoskeletal proteins. The most common type of CMD in Europe is Merosin-deficient CMD caused by mutations in laminin-α2 protein. Very few studies reported pathogenic variants underlying these disorders especially from Africa. In this study we report a rare variant (p.Arg148Trp, rs752485547) in LAMA2 gene causing a mild form of Merosin-deficient CMD in a Sudanese family. The family consisted of two patients diagnosed clinically with congenital muscular dystrophy since childhood and five healthy siblings born to consanguineous parents. Whole exome sequencing was performed for the two patients and a healthy sibling. A rare missense variant (p.Arg148Trp, rs752485547) in LAMA2 gene was discovered and verified using Sanger sequencing. The segregation pattern was consistent with autosomal recessive inheritance. The pathogenicity of this variant was predicted using bioinformatics tools. More studies are needed to explore the whole spectrum of mutations in CMD in patients from Sudan and other parts of the world.
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Affiliation(s)
- MUTAZ AMIN
- Department of Biochemistry, Faculty of Medicine, University of Khartoum, Sudan,Address for correspondence: Mutaz Amin, Department of Biochemistry, Faculty of Medicine, University of Khartoum, Sudan, Qasr street, Khartoum, Sudan. E-mail:
| | - YOUSUF BAKHIT
- Department of Basic Medical sciences, Faculty of Dentistry, University of Khartoum, Sudan
| | - MAHMOUD KOKO
- Department of Molecular biology, Institute of Endemic Diseases, University of Khartoum, Sudan, Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, Tuebingen, Germany
| | | | - MA SALIH
- Department of Bioinformatics, Africa city of technology, Sudan
| | - MUNTASER IBRAHIM
- Department of Molecular biology, Institute of Endemic Diseases, University of Khartoum, Sudan
| | - OSHEIK A SEIDI
- Department of Medicine, Faculty of Medicine, University of Khartoum, Sudan
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Saha M, Reddy HM, Salih MA, Estrella E, Jones MD, Mitsuhashi S, Cho KA, Suzuki-Hatano S, Rizzo SA, Hamad MH, Mukhtar MM, Hamed AA, Elseed MA, Lek M, Valkanas E, MacArthur DG, Kunkel LM, Pacak CA, Draper I, Kang PB. Impact of PYROXD1 deficiency on cellular respiration and correlations with genetic analyses of limb-girdle muscular dystrophy in Saudi Arabia and Sudan. Physiol Genomics 2018; 50:929-939. [PMID: 30345904 DOI: 10.1152/physiolgenomics.00036.2018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Next-generation sequencing is commonly used to screen for pathogenic mutations in families with Mendelian disorders, but due to the pace of discoveries, gaps have widened for some diseases between genetic and pathophysiological knowledge. We recruited and analyzed 16 families with limb-girdle muscular dystrophy (LGMD) of Arab descent from Saudi Arabia and Sudan who did not have confirmed genetic diagnoses. The analysis included both traditional and next-generation sequencing approaches. Cellular and metabolic studies were performed on Pyroxd1 siRNA C2C12 myoblasts and controls. Pathogenic mutations were identified in eight of the 16 families. One Sudanese family of Arab descent residing in Saudi Arabia harbored a homozygous c.464A>G, p.Asn155Ser mutation in PYROXD1, a gene recently reported in association with myofibrillar myopathy and whose protein product reduces thiol residues. Pyroxd1 deficiency in murine C2C12 myoblasts yielded evidence for impairments of cellular proliferation, migration, and differentiation, while CG10721 (Pyroxd1 fly homolog) knockdown in Drosophila yielded a lethal phenotype. Further investigations indicated that Pyroxd1 does not localize to mitochondria, yet Pyroxd1 deficiency is associated with decreased cellular respiration. This study identified pathogenic mutations in half of the LGMD families from the cohort, including one in PYROXD1. Developmental impairments were demonstrated in vitro for Pyroxd1 deficiency and in vivo for CG10721 deficiency, with reduced metabolic activity in vitro for Pyroxd1 deficiency.
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Affiliation(s)
- Madhurima Saha
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine , Gainesville, Florida
| | - Hemakumar M Reddy
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine , Gainesville, Florida
| | - Mustafa A Salih
- Division of Neurology, Department of Pediatrics, King Saud University , Riyadh , Saudi Arabia
| | - Elicia Estrella
- Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School , Boston, Massachusetts
| | - Michael D Jones
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine , Gainesville, Florida
| | - Satomi Mitsuhashi
- Department of Neurology, Boston Children's Hospital and Harvard Medical School , Boston, Massachusetts
| | - Kyung-Ah Cho
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine , Gainesville, Florida
| | - Silveli Suzuki-Hatano
- Department of Pediatrics, University of Florida College of Medicine , Gainesville, Florida
| | - Skylar A Rizzo
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine , Gainesville, Florida
| | - Muddathir H Hamad
- Division of Neurology, Department of Pediatrics, King Saud University , Riyadh , Saudi Arabia
| | - Maowia M Mukhtar
- The Institute of Endemic Diseases, University of Khartoum , Khartoum , Sudan
| | - Ahlam A Hamed
- Department of Paediatrics and Child Health, Faculty of Medicine, University of Khartoum , Khartoum , Sudan
| | - Maha A Elseed
- Department of Paediatrics and Child Health, Faculty of Medicine, University of Khartoum , Khartoum , Sudan
| | - Monkol Lek
- Analytic and Translational Genetics Unit, Massachusetts General Hospital and Harvard Medical School , Boston, Massachusetts.,Broad Institute of the Massachusetts Institute of Technology and Harvard University , Cambridge, Massachusetts
| | - Elise Valkanas
- Analytic and Translational Genetics Unit, Massachusetts General Hospital and Harvard Medical School , Boston, Massachusetts.,Broad Institute of the Massachusetts Institute of Technology and Harvard University , Cambridge, Massachusetts
| | - Daniel G MacArthur
- Analytic and Translational Genetics Unit, Massachusetts General Hospital and Harvard Medical School , Boston, Massachusetts.,Broad Institute of the Massachusetts Institute of Technology and Harvard University , Cambridge, Massachusetts
| | - Louis M Kunkel
- Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School , Boston, Massachusetts
| | - Christina A Pacak
- Department of Pediatrics, University of Florida College of Medicine , Gainesville, Florida
| | - Isabelle Draper
- Molecular Cardiology Research Institute, Tufts Medical Center , Boston, Massachusetts
| | - Peter B Kang
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine , Gainesville, Florida.,Department of Neurology and Department of Molecular Genetics and Microbiology, University of Florida College of Medicine , Gainesville, Florida.,Genetics Institute and Myology Institute, University of Florida , Gainesville, Florida
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Incecik F, Herguner OM, Ceylaner S, Altunbasak S. Merosin-negative congenital muscular dystrophy: Report of five cases. J Pediatr Neurosci 2016; 10:346-9. [PMID: 26962340 PMCID: PMC4770646 DOI: 10.4103/1817-1745.174432] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Context: Congenital muscular dystrophy type 1A (MDC1A) is caused by mutations in the laminin α-2 gene encoding laminin-a2. Aims: The purpose of this study is to determine clinical and genetic results in five Turkish patients with MDC1A. Setting and Designs: Five children with MDC1A were retrospectively analyzed. Results: Three (60%) were boys, and 2 (40%) were girls. Parental consanguinity was found in all the families. In all the patients, hypotonia, weakness, delayed motor milestones, markedly elevated creatine phosphokinase (CPK) concentration, and brain white matter abnormalities on magnetic resonance imaging were detected. Mutation analysis was performed in all the patients, and 3 different mutations were detected. However, a mutation in patient 1 and 2 has not been previously described in the literature. Conclusions: When a patient presents with severe congenital hypotonia, muscle weakness, high serum CPK levels, and white matter abnormalities, should be suspected as MDC1A.
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Affiliation(s)
- Faruk Incecik
- Department of Pediatrics, Division of Pediatric Neurology, Faculty of Medicine, Cukurova University, Adana, Turkey
| | - Ozlem M Herguner
- Department of Pediatrics, Division of Pediatric Neurology, Faculty of Medicine, Cukurova University, Adana, Turkey
| | | | - Sakir Altunbasak
- Department of Pediatrics, Division of Pediatric Neurology, Faculty of Medicine, Cukurova University, Adana, Turkey
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Løkken N, Born AP, Duno M, Vissing J. LAMA2-related myopathy: Frequency among congenital and limb-girdle muscular dystrophies. Muscle Nerve 2015; 52:547-53. [PMID: 25663498 DOI: 10.1002/mus.24588] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/25/2015] [Indexed: 01/06/2023]
Abstract
INTRODUCTION Muscular dystrophy caused by LAMA2-gene mutations is an autosomal recessive disease typically presenting as a severe, early-onset congenital muscular dystrophy (CMD). However, milder cases with a limb-girdle type muscular dystrophy (LGMD) have been described. METHODS In this study, we assessed the frequency and phenotypic spectrum of LAMA2-related muscular dystrophy in CMD (n = 18) and LGMD2 (n = 128) cohorts identified in the last 15 years in eastern Denmark. The medical history, brain-MRI, muscle pathology, muscle laminin-α2 expression, and genetic analyses were assessed. RESULTS Molecular genetics revealed 2 pathogenic LAMA2 mutations in 5 of 18 CMD and 3 of 128 LGMD patients, corresponding to a LAMA2-mutation frequency of 28% in the CMD and 2.3% in the LGMD cohorts, respectively. CONCLUSIONS This study demonstrates a wide clinical spectrum of LAMA2-related muscular dystrophy and its prevalence in an LGMD2 cohort, which indicates that LAMA2 muscular dystrophy should be included in the LGMD2 nomenclature.
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Affiliation(s)
- Nicoline Løkken
- Copenhagen Neuromuscular Center, section 3342, Righospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark
| | - Alfred Peter Born
- Department of Pediatrics, Rigshospitalet, University of Copenhagen, Denmark
| | - Morten Duno
- Department of Clinical Genetics, Rigshospitalet, University of Copenhagen, Denmark
| | - John Vissing
- Copenhagen Neuromuscular Center, section 3342, Righospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark
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Gupta VA, Kawahara G, Myers JA, Chen AT, Hall TE, Manzini MC, Currie PD, Zhou Y, Zon LI, Kunkel LM, Beggs AH. A splice site mutation in laminin-α2 results in a severe muscular dystrophy and growth abnormalities in zebrafish. PLoS One 2012; 7:e43794. [PMID: 22952766 PMCID: PMC3428294 DOI: 10.1371/journal.pone.0043794] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 07/24/2012] [Indexed: 11/18/2022] Open
Abstract
Congenital muscular dystrophy (CMD) is a clinically and genetically heterogeneous group of inherited muscle disorders. In patients, muscle weakness is usually present at or shortly after birth and is progressive in nature. Merosin deficient congenital muscular dystrophy (MDC1A) is a form of CMD caused by a defect in the laminin-α2 gene (LAMA2). Laminin-α2 is an extracellular matrix protein that interacts with the dystrophin-dystroglycan (DGC) complex in membranes providing stability to muscle fibers. In an N-ethyl-N-nitrosourea mutagenesis screen to develop zebrafish models of neuromuscular diseases, we identified a mutant fish that exhibits severe muscular dystrophy early in development. Genetic mapping identified a splice site mutation in the lama2 gene. This splice site is highly conserved in humans and this mutation results in mis-splicing of RNA and a loss of protein function. Homozygous lama2 mutant zebrafish, designated lama2cl501/cl501, exhibited reduced motor function and progressive degeneration of skeletal muscles and died at 8–15 days post fertilization. The skeletal muscles exhibited damaged myosepta and detachment of myofibers in the affected fish. Laminin-α2 deficiency also resulted in growth defects in the brain and eye of the mutant fish. This laminin-α2 deficient mutant fish represents a novel disease model to develop therapies for modulating splicing defects in congenital muscular dystrophies and to restore the muscle function in human patients with CMD.
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Affiliation(s)
- Vandana A. Gupta
- Genomics Program and Division of Genetics, Boston Children’s Hospital, Harvard Medical School, The Manton Center for Orphan Disease Research, Boston, Massachusetts, United States of America
| | - Genri Kawahara
- Genomics Program and Division of Genetics, Boston Children’s Hospital, Harvard Medical School, The Manton Center for Orphan Disease Research, Boston, Massachusetts, United States of America
| | - Jennifer A. Myers
- Genomics Program and Division of Genetics, Boston Children’s Hospital, Harvard Medical School, The Manton Center for Orphan Disease Research, Boston, Massachusetts, United States of America
| | - Aye T. Chen
- Stem Cell Program and Pediatric Hematology/Oncology, Boston Children’s Hospital and Dana Farber Cancer Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Thomas E. Hall
- Australian Regenerative Medicine Institute, Monash University, Clayton Campus, Victoria, Australia
| | - M. Chiara Manzini
- Genomics Program and Division of Genetics, Boston Children’s Hospital, Harvard Medical School, The Manton Center for Orphan Disease Research, Boston, Massachusetts, United States of America
| | - Peter D. Currie
- Australian Regenerative Medicine Institute, Monash University, Clayton Campus, Victoria, Australia
| | - Yi Zhou
- Stem Cell Program and Pediatric Hematology/Oncology, Boston Children’s Hospital and Dana Farber Cancer Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Leonard I. Zon
- Stem Cell Program and Pediatric Hematology/Oncology, Boston Children’s Hospital and Dana Farber Cancer Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, Massachusetts, United States of America
- Howard Hughes Medical Institute, San Francisco, California, United States of America
| | - Louis M. Kunkel
- Genomics Program and Division of Genetics, Boston Children’s Hospital, Harvard Medical School, The Manton Center for Orphan Disease Research, Boston, Massachusetts, United States of America
| | - Alan H. Beggs
- Genomics Program and Division of Genetics, Boston Children’s Hospital, Harvard Medical School, The Manton Center for Orphan Disease Research, Boston, Massachusetts, United States of America
- * E-mail:
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