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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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Sarkozy A, Foley AR, Zambon AA, Bönnemann CG, Muntoni F. LAMA2-Related Dystrophies: Clinical Phenotypes, Disease Biomarkers, and Clinical Trial Readiness. Front Mol Neurosci 2020; 13:123. [PMID: 32848593 PMCID: PMC7419697 DOI: 10.3389/fnmol.2020.00123] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 06/17/2020] [Indexed: 12/19/2022] Open
Abstract
Mutations in the LAMA2 gene affect the production of the α2 subunit of laminin-211 (= merosin) and result in either partial or complete laminin-211 deficiency. Complete merosin deficiency is typically associated with a more severe congenital muscular dystrophy (CMD), clinically manifested by hypotonia and weakness at birth, the development of contractures of large joints, and progressive respiratory involvement. Muscle atrophy and severe weakness typically prevent independent ambulation. Partial merosin deficiency is mostly manifested by later onset limb-girdle weakness and joint contractures so that independent ambulation is typically achieved. Collectively, complete and partial merosin deficiency is referred to as LAMA2-related dystrophies (LAMA2-RDs) and represents one of the most common forms of congenital muscular dystrophies worldwide. LAMA2-RDs are classically characterized by both central and peripheral nervous system involvement with abnormal appearing white matter (WM) on brain MRI and dystrophic appearing muscle on muscle biopsy as well as creatine kinase (CK) levels commonly elevated to >1,000 IU/L. Next-generation sequencing (NGS) has greatly improved diagnostic abilities for LAMA2-RD, and the majority of patients with merosin deficiency carry recessive pathogenic variants in the LAMA2 gene. The existence of multiple animal models for LAMA2-RDs has helped to advance our understanding of laminin-211 and has been instrumental in preclinical research progress and translation to clinical trials. The first clinical trial for the LAMA2-RDs was a phase 1 pharmacokinetic and safety study of the anti-apoptotic compound omigapil, based on preclinical studies performed in the dy W/dy W and dy 2J/dy 2J mouse models. This phase 1 study enabled the collection of pulmonary and motor outcome measures and also provided the opportunity for investigating exploratory outcome measures including muscle ultrasound, muscle MRI and serum, and urine biomarker collection. Natural history studies, including a five-year prospective natural history and comparative outcome measures study in patients with LAMA2-RD, have helped to better delineate the natural history and identify viable outcome measures. Plans for further clinical trials for LAMA2-RDs are presently in progress, highlighting the necessity of identifying adequate, disease-relevant biomarkers, capable of reflecting potential therapeutic changes, in addition to refining the clinical outcome measures and time-to-event trajectory analysis of affected patients.
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Affiliation(s)
- Anna Sarkozy
- Dubowitz Neuromuscular Centre, Institute of Child Health, Great Ormond Street Hospital for Children, London, United Kingdom
| | - A Reghan Foley
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Alberto A Zambon
- Dubowitz Neuromuscular Centre, Institute of Child Health, Great Ormond Street Hospital for Children, London, United Kingdom
| | - Carsten G Bönnemann
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, Institute of Child Health, Great Ormond Street Hospital for Children, London, United Kingdom.,National Institute for Health Research Great Ormond Street Hospital Biomedical Research Centre, London, United Kingdom
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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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Oliveira J, Gruber A, Cardoso M, Taipa R, Fineza I, Gonçalves A, Laner A, Winder TL, Schroeder J, Rath J, Oliveira ME, Vieira E, Sousa AP, Vieira JP, Lourenço T, Almendra L, Negrão L, Santos M, Melo-Pires M, Coelho T, den Dunnen JT, Santos R, Sousa M. LAMA2 gene mutation update: Toward a more comprehensive picture of the laminin-α2 variome and its related phenotypes. Hum Mutat 2018; 39:1314-1337. [PMID: 30055037 DOI: 10.1002/humu.23599] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Revised: 07/05/2018] [Accepted: 07/25/2018] [Indexed: 12/15/2022]
Abstract
Congenital muscular dystrophy type 1A (MDC1A) is one of the main subtypes of early-onset muscle disease, caused by disease-associated variants in the laminin-α2 (LAMA2) gene. MDC1A usually presents as a severe neonatal hypotonia and failure to thrive. Muscle weakness compromises normal motor development, leading to the inability to sit unsupported or to walk independently. The phenotype associated with LAMA2 defects has been expanded to include milder and atypical cases, being now collectively known as LAMA2-related muscular dystrophies (LAMA2-MD). Through an international multicenter collaborative effort, 61 new LAMA2 disease-associated variants were identified in 86 patients, representing the largest number of patients and new disease-causing variants in a single report. The collaborative variant collection was supported by the LOVD-powered LAMA2 gene variant database (https://www.LOVD.nl/LAMA2), updated as part of this work. As of December 2017, the database contains 486 unique LAMA2 variants (309 disease-associated), obtained from direct submissions and literature reports. Database content was systematically reviewed and further insights concerning LAMA2-MD are presented. We focus on the impact of missense changes, especially the c.2461A > C (p.Thr821Pro) variant and its association with late-onset LAMA2-MD. Finally, we report diagnostically challenging cases, highlighting the relevance of modern genetic analysis in the characterization of clinically heterogeneous muscle diseases.
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Affiliation(s)
- Jorge Oliveira
- Unidade de Genética Molecular, Centro de Genética Médica Dr. Jacinto Magalhães, Centro Hospitalar do Porto, Porto, Portugal.,Unidade Multidisciplinar de Investigação Biomédica (UMIB), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | | | - Márcio Cardoso
- Consulta de Doenças Neuromusculares e Serviço de Neurofisiologia, Departamento de Neurociências, Centro Hospitalar do Porto, Porto, Portugal
| | - Ricardo Taipa
- Unidade de Neuropatologia, Centro Hospitalar do Porto, Porto, Portugal
| | - Isabel Fineza
- Unidade de Neuropediatria, Centro de Desenvolvimento da Criança Luís Borges, Hospital Pediátrico de Coimbra, Centro Hospitalar Universitário de Coimbra, Coimbra, Portugal
| | - Ana Gonçalves
- Unidade de Genética Molecular, Centro de Genética Médica Dr. Jacinto Magalhães, Centro Hospitalar do Porto, Porto, Portugal.,Unidade Multidisciplinar de Investigação Biomédica (UMIB), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | | | | | | | - Julie Rath
- PreventionGenetics, Marshfield, Wisconsin
| | - Márcia E Oliveira
- Unidade de Genética Molecular, Centro de Genética Médica Dr. Jacinto Magalhães, Centro Hospitalar do Porto, Porto, Portugal.,Unidade Multidisciplinar de Investigação Biomédica (UMIB), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Emília Vieira
- Unidade de Genética Molecular, Centro de Genética Médica Dr. Jacinto Magalhães, Centro Hospitalar do Porto, Porto, Portugal.,Unidade Multidisciplinar de Investigação Biomédica (UMIB), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Ana Paula Sousa
- Consulta de Doenças Neuromusculares e Serviço de Neurofisiologia, Departamento de Neurociências, Centro Hospitalar do Porto, Porto, Portugal
| | - José Pedro Vieira
- Serviço de Neurologia, Hospital de Dona Estefânia, Centro Hospitalar de Lisboa Central, Lisboa, Portugal
| | - Teresa Lourenço
- Serviço de Genética Médica, Hospital de Dona Estefânia, Centro Hospitalar de Lisboa Central, Lisboa, Portugal
| | - Luciano Almendra
- Consulta de Doenças Neuromusculares, Hospitais da Universidade de Coimbra, Centro Hospitalar Universitário de Coimbra, Coimbra, Portugal
| | - Luís Negrão
- Consulta de Doenças Neuromusculares, Hospitais da Universidade de Coimbra, Centro Hospitalar Universitário de Coimbra, Coimbra, Portugal
| | - Manuela Santos
- Consulta de Doenças Neuromusculares e Serviço de Neuropediatria, Centro Hospitalar do Porto, Porto, Portugal
| | - Manuel Melo-Pires
- Unidade de Neuropatologia, Centro Hospitalar do Porto, Porto, Portugal
| | - Teresa Coelho
- Consulta de Doenças Neuromusculares e Serviço de Neurofisiologia, Departamento de Neurociências, Centro Hospitalar do Porto, Porto, Portugal
| | - Johan T den Dunnen
- Departments of Human Genetics and Clinical Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Rosário Santos
- Unidade de Genética Molecular, Centro de Genética Médica Dr. Jacinto Magalhães, Centro Hospitalar do Porto, Porto, Portugal.,Unidade Multidisciplinar de Investigação Biomédica (UMIB), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.,UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Bioquímica, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Mário Sousa
- Unidade Multidisciplinar de Investigação Biomédica (UMIB), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.,Departamento de Microscopia, Laboratório de Biologia Celular, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.,Centro de Genética da Reprodução Prof. Alberto Barros, Porto, Portugal
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