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Gao Y, Peng L, Zhao C. MYH7 in cardiomyopathy and skeletal muscle myopathy. Mol Cell Biochem 2024; 479:393-417. [PMID: 37079208 DOI: 10.1007/s11010-023-04735-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 04/07/2023] [Indexed: 04/21/2023]
Abstract
Myosin heavy chain gene 7 (MYH7), a sarcomeric gene encoding the myosin heavy chain (myosin-7), has attracted considerable interest as a result of its fundamental functions in cardiac and skeletal muscle contraction and numerous nucleotide variations of MYH7 are closely related to cardiomyopathy and skeletal muscle myopathy. These disorders display significantly inter- and intra-familial variability, sometimes developing complex phenotypes, including both cardiomyopathy and skeletal myopathy. Here, we review the current understanding on MYH7 with the aim to better clarify how mutations in MYH7 affect the structure and physiologic function of sarcomere, thus resulting in cardiomyopathy and skeletal muscle myopathy. Importantly, the latest advances on diagnosis, research models in vivo and in vitro and therapy for precise clinical application have made great progress and have epoch-making significance. All the great advance is discussed here.
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Affiliation(s)
- Yuan Gao
- Department of Pediatrics, Qilu Hospital of Shandong University, Jinan, 250012, China
| | - Lu Peng
- Department of Pediatrics, Qilu Hospital of Shandong University, Jinan, 250012, China
| | - Cuifen Zhao
- Department of Pediatrics, Qilu Hospital of Shandong University, Jinan, 250012, China.
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2
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Naderi N, Mohsen-Pour N, Nilipour Y, Pourirahim M, Maleki M, Kalayinia S. A novel heterozygous missense MYH7 mutation potentially causes an autosomal dominant form of myosin storage myopathy with dilated cardiomyopathy. BMC Cardiovasc Disord 2023; 23:487. [PMID: 37794383 PMCID: PMC10552240 DOI: 10.1186/s12872-023-03538-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Accepted: 09/27/2023] [Indexed: 10/06/2023] Open
Abstract
BACKGROUND The MYH7 gene, which encodes the slow/ß-cardiac myosin heavy chain, is mutated in myosin storage myopathy (MSM). The clinical spectrum of MSM is quite heterogeneous in that it ranges from cardiomyopathies to skeletal myopathies or a combination of both, depending on the affected region. In this study, we performed clinical and molecular examinations of the proband of an Iranian family with MSM in an autosomal dominant condition exhibiting proximal muscle weakness and dilated cardiomyopathy. METHODS Following thorough clinical and paraclinical examinations, whole-exome sequencing `was performed on the proband (II-5). Pathogenicity prediction of the candidate variant was performed through in-silico analysis. Co-segregation analysis of the WES data among the family members was carried out by PCR-based Sanger sequencing. RESULTS A novel heterozygous missense variant, MYH7 (NM_000257): c.C1888A: p.Pro630Thr, was found in the DNA of the proband and his children and confirmed by Sanger sequencing. The in-silico analysis revealed that p.Pro630Thr substitution was deleterious. The novel sequence variant fell within a highly conserved region of the head domain. Our findings expand the spectrum of MYH7 mutations. CONCLUSIONS This finding could improve genetic counseling and prenatal diagnosis in families with clinical manifestations associated with MYH7-related myopathy.
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Affiliation(s)
- Niloofar Naderi
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, University of Medical Sciences, Tehran, Iran
| | - Neda Mohsen-Pour
- Zanjan Pharmaceutical Biotechnology Research Center, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Yalda Nilipour
- Pediatric pathology research center, Research institute for children's health, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Maryam Pourirahim
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, University of Medical Sciences, Tehran, Iran
| | - Majid Maleki
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, University of Medical Sciences, Tehran, Iran
| | - Samira Kalayinia
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, University of Medical Sciences, Tehran, Iran.
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3
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Rossi D, Catallo MR, Pierantozzi E, Sorrentino V. Mutations in proteins involved in E-C coupling and SOCE and congenital myopathies. J Gen Physiol 2022; 154:e202213115. [PMID: 35980353 PMCID: PMC9391951 DOI: 10.1085/jgp.202213115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 07/15/2022] [Accepted: 07/21/2022] [Indexed: 11/24/2022] Open
Abstract
In skeletal muscle, Ca2+ necessary for muscle contraction is stored and released from the sarcoplasmic reticulum (SR), a specialized form of endoplasmic reticulum through the mechanism known as excitation-contraction (E-C) coupling. Following activation of skeletal muscle contraction by the E-C coupling mechanism, replenishment of intracellular stores requires reuptake of cytosolic Ca2+ into the SR by the activity of SR Ca2+-ATPases, but also Ca2+ entry from the extracellular space, through a mechanism called store-operated calcium entry (SOCE). The fine orchestration of these processes requires several proteins, including Ca2+ channels, Ca2+ sensors, and Ca2+ buffers, as well as the active involvement of mitochondria. Mutations in genes coding for proteins participating in E-C coupling and SOCE are causative of several myopathies characterized by a wide spectrum of clinical phenotypes, a variety of histological features, and alterations in intracellular Ca2+ balance. This review summarizes current knowledge on these myopathies and discusses available knowledge on the pathogenic mechanisms of disease.
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Affiliation(s)
- Daniela Rossi
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
- Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliero Universitaria Senese, Siena, Italy
| | - Maria Rosaria Catallo
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Enrico Pierantozzi
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Vincenzo Sorrentino
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
- Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliero Universitaria Senese, Siena, Italy
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4
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Garg B, Tomar N, Biswas A, Mehta N, Malhotra R. Understanding Musculoskeletal Disorders Through Next-Generation Sequencing. JBJS Rev 2022; 10:01874474-202204000-00001. [PMID: 35383688 DOI: 10.2106/jbjs.rvw.21.00165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
» An insight into musculoskeletal disorders through advancements in next-generation sequencing (NGS) promises to maximize benefits and improve outcomes through improved genetic diagnosis. » The primary use of whole exome sequencing (WES) for musculoskeletal disorders is to identify functionally relevant variants. » The current evidence has shown the superiority of NGS over conventional genotyping for identifying novel and rare genetic variants in patients with musculoskeletal disorders, due to its high throughput and low cost. » Genes identified in patients with scoliosis, osteoporosis, osteoarthritis, and osteogenesis imperfecta using NGS technologies are listed for further reference.
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Affiliation(s)
- Bhavuk Garg
- Department of Orthopaedics, All India Institute of Medical Sciences, New Delhi, India
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5
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Molecular and cellular basis of genetically inherited skeletal muscle disorders. Nat Rev Mol Cell Biol 2021; 22:713-732. [PMID: 34257452 PMCID: PMC9686310 DOI: 10.1038/s41580-021-00389-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2021] [Indexed: 02/06/2023]
Abstract
Neuromuscular disorders comprise a diverse group of human inborn diseases that arise from defects in the structure and/or function of the muscle tissue - encompassing the muscle cells (myofibres) themselves and their extracellular matrix - or muscle fibre innervation. Since the identification in 1987 of the first genetic lesion associated with a neuromuscular disorder - mutations in dystrophin as an underlying cause of Duchenne muscular dystrophy - the field has made tremendous progress in understanding the genetic basis of these diseases, with pathogenic variants in more than 500 genes now identified as underlying causes of neuromuscular disorders. The subset of neuromuscular disorders that affect skeletal muscle are referred to as myopathies or muscular dystrophies, and are due to variants in genes encoding muscle proteins. Many of these proteins provide structural stability to the myofibres or function in regulating sarcolemmal integrity, whereas others are involved in protein turnover, intracellular trafficking, calcium handling and electrical excitability - processes that ensure myofibre resistance to stress and their primary activity in muscle contraction. In this Review, we discuss how defects in muscle proteins give rise to muscle dysfunction, and ultimately to disease, with a focus on pathologies that are most common, best understood and that provide the most insight into muscle biology.
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6
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Jirka C, Pak JH, Grosgogeat CA, Marchetii MM, Gupta VA. Dysregulation of NRAP degradation by KLHL41 contributes to pathophysiology in nemaline myopathy. Hum Mol Genet 2021; 28:2549-2560. [PMID: 30986853 DOI: 10.1093/hmg/ddz078] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 03/29/2019] [Accepted: 04/08/2019] [Indexed: 12/13/2022] Open
Abstract
Nemaline myopathy (NM) is the most common form of congenital myopathy that results in hypotonia and muscle weakness. This disease is clinically and genetically heterogeneous, but three recently discovered genes in NM encode for members of the Kelch family of proteins. Kelch proteins act as substrate-specific adaptors for Cullin 3 (CUL3) E3 ubiquitin ligase to regulate protein turnover through the ubiquitin-proteasome machinery. Defects in thin filament formation and/or stability are key molecular processes that underlie the disease pathology in NM; however, the role of Kelch proteins in these processes in normal and diseases conditions remains elusive. Here, we describe a role of NM causing Kelch protein, KLHL41, in premyofibil-myofibil transition during skeletal muscle development through a regulation of the thin filament chaperone, nebulin-related anchoring protein (NRAP). KLHL41 binds to the thin filament chaperone NRAP and promotes ubiquitination and subsequent degradation of NRAP, a process that is critical for the formation of mature myofibrils. KLHL41 deficiency results in abnormal accumulation of NRAP in muscle cells. NRAP overexpression in transgenic zebrafish resulted in a severe myopathic phenotype and absence of mature myofibrils demonstrating a role in disease pathology. Reducing Nrap levels in KLHL41 deficient zebrafish rescues the structural and function defects associated with disease pathology. We conclude that defects in KLHL41-mediated ubiquitination of sarcomeric proteins contribute to structural and functional deficits in skeletal muscle. These findings further our understanding of how the sarcomere assembly is regulated by disease-causing factors in vivo, which will be imperative for developing mechanism-based specific therapeutic interventions.
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Affiliation(s)
- Caroline Jirka
- Division of Genetics, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jasmine H Pak
- Division of Genetics, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Claire A Grosgogeat
- Division of Genetics, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | | | - Vandana A Gupta
- Division of Genetics, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
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7
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Sadeh M, Rahat D, Meiner V, Fellig Y, Arad M, Schueler-Furman O, Hu Y, Li Y, Bönnemann CG, Lossos A. Multi-system neurological disorder associated with a CRYAB variant. Neurogenetics 2021; 22:117-125. [PMID: 33811585 DOI: 10.1007/s10048-021-00640-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 03/18/2021] [Indexed: 10/21/2022]
Abstract
We report a multiplex family with extended multisystem neurological phenotype associated with a CRYAB variant. Two affected siblings were evaluated with whole exome sequencing, muscle biopsy, laser microdissection, and mass spectrometry-based proteomic analysis. Both patients and their mother manifested a combination of early-onset cataracts, cardiomyopathy, cerebellar ataxia, optic atrophy, cognitive impairment, and myopathy. Whole exome sequencing identified a heterozygous c.458C>T variant mapped to the C-terminal extension domain of the Alpha-crystallin B chain, disrupting its function as a molecular chaperone and its ability to suppress protein aggregation. In accordance with the molecular findings, muscle biopsies revealed subsarcolemmal deposits that appeared dark with H&E and trichrome staining were negative for the other routine histochemical staining and for amyloid with the Congo-red stain. Electron microscopy demonstrated that the deposits were composed of numerous parallel fibrils. Laser microdissection and mass spectrometry-based proteomic analysis revealed that the inclusions are almost exclusively composed of crystallized chaperones/heat shock proteins. Moreover, a structural model suggests that Ser153 could be involved in monomer stabilization, dimer association, and possible binding of partner proteins. We propose that our report potentially expands the complex phenotypic spectrum of alpha B-crystallinopathies with possible effect of a CRYAB variant on the central nervous system.
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Affiliation(s)
- Menachem Sadeh
- Department of Neurology, Wolfson Medical Center and Tel Aviv University, Holon, Israel.
| | - Dolev Rahat
- Department of Microbiology and Molecular Genetics, Faculty of Medicine, Institute for Biomedical Research Israel-Canada, Hebrew University, Jerusalem, Israel
| | - Vardiella Meiner
- Department of Genetics, Hadassah Medical Organization and Faculty of Medicine, Hebrew University, Jerusalem, Israel
| | - Yakov Fellig
- Department of Pathology, Genetics, Hadassah Medical Organization and Faculty of Medicine, Hebrew University, Jerusalem, Israel
| | - Michael Arad
- Leviev Heart Center, Sheba Medical Center, Tel Hashomer and Tel Aviv University, Tel Aviv, Israel
| | - Ora Schueler-Furman
- Department of Microbiology and Molecular Genetics, Faculty of Medicine, Institute for Biomedical Research Israel-Canada, Hebrew University, Jerusalem, Israel
| | - Ying Hu
- National Institute of Neurological Disorders and Stroke, Neurogenetics Branch, Bethesda, MD, USA
| | - Yan Li
- National Institute of Neurological Disorders and Stroke, Proteomics Core Facility, Bethesda, MD, USA
| | - Carsten G Bönnemann
- National Institute of Neurological Disorders and Stroke, Neurogenetics Branch, Bethesda, MD, USA
| | - Alexander Lossos
- Department of Neurology, Genetics, Hadassah Medical Organization and Faculty of Medicine, Hebrew University, Jerusalem, Israel
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8
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Dahl-Halvarsson M, Olive M, Pokrzywa M, Norum M, Ejeskär K, Tajsharghi H. Impaired muscle morphology in a Drosophila model of myosin storage myopathy was supressed by overexpression of an E3 ubiquitin ligase. Dis Model Mech 2020; 13:dmm047886. [PMID: 33234710 PMCID: PMC7790189 DOI: 10.1242/dmm.047886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 11/02/2020] [Indexed: 11/29/2022] Open
Abstract
Myosin is vital for body movement and heart contractility. Mutations in MYH7, encoding slow/β-cardiac myosin heavy chain, are an important cause of hypertrophic and dilated cardiomyopathy, as well as skeletal muscle disease. A dominant missense mutation (R1845W) in MYH7 has been reported in several unrelated cases of myosin storage myopathy. We have developed a Drosophila model for a myosin storage myopathy in order to investigate the dose-dependent mechanisms underlying the pathological roles of the R1845W mutation. This study shows that a higher expression level of the mutated allele is concomitant with severe impairment of muscle function and progressively disrupted muscle morphology. The impaired muscle morphology associated with the mutant allele was suppressed by expression of Thin (herein referred to as Abba), an E3 ubiquitin ligase. This Drosophila model recapitulates pathological features seen in myopathy patients with the R1845W mutation and severe ultrastructural abnormalities, including extensive loss of thick filaments with selective A-band loss, and preservation of I-band and Z-disks were observed in indirect flight muscles of flies with exclusive expression of mutant myosin. Furthermore, the impaired muscle morphology associated with the mutant allele was suppressed by expression of Abba. These findings suggest that modification of the ubiquitin proteasome system may be beneficial in myosin storage myopathy by reducing the impact of MYH7 mutation in patients.
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Affiliation(s)
- Martin Dahl-Halvarsson
- Department of Pathology, Institute of Biomedicine, University of Gothenburg, 41345 Gothenburg, Sweden
| | - Montse Olive
- Institute of Neuropathology, Department of Pathology and Neuromuscular Unit, Department of Neurology, IDIBELL-Hospital de Bellvitge, 08907 Hospitalet de Llobregat, Barcelona, Spain
| | - Malgorzata Pokrzywa
- Department of Pathology, Institute of Biomedicine, University of Gothenburg, 41345 Gothenburg, Sweden
| | - Michaela Norum
- Department of Pathology, Institute of Biomedicine, University of Gothenburg, 41345 Gothenburg, Sweden
| | - Katarina Ejeskär
- Translational Medicine, School of Health Sciences, University of Skövde, SE-541 28, Skövde, Sweden
| | - Homa Tajsharghi
- Translational Medicine, School of Health Sciences, University of Skövde, SE-541 28, Skövde, Sweden
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9
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Abstract
Myosins constitute a superfamily of actin-based molecular motor proteins that mediates a variety of cellular activities including muscle contraction, cell migration, intracellular transport, the formation of membrane projections, cell adhesion, and cell signaling. The 12 myosin classes that are expressed in humans share sequence similarities especially in the N-terminal motor domain; however, their enzymatic activities, regulation, ability to dimerize, binding partners, and cellular functions differ. It is becoming increasingly apparent that defects in myosins are associated with diseases including cardiomyopathies, colitis, glomerulosclerosis, neurological defects, cancer, blindness, and deafness. Here, we review the current state of knowledge regarding myosins and disease.
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10
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Arbab M, Shen MW, Mok B, Wilson C, Matuszek Ż, Cassa CA, Liu DR. Determinants of Base Editing Outcomes from Target Library Analysis and Machine Learning. Cell 2020; 182:463-480.e30. [PMID: 32533916 PMCID: PMC7384975 DOI: 10.1016/j.cell.2020.05.037] [Citation(s) in RCA: 148] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 04/09/2020] [Accepted: 05/19/2020] [Indexed: 12/26/2022]
Abstract
Although base editors are widely used to install targeted point mutations, the factors that determine base editing outcomes are not well understood. We characterized sequence-activity relationships of 11 cytosine and adenine base editors (CBEs and ABEs) on 38,538 genomically integrated targets in mammalian cells and used the resulting outcomes to train BE-Hive, a machine learning model that accurately predicts base editing genotypic outcomes (R ≈ 0.9) and efficiency (R ≈ 0.7). We corrected 3,388 disease-associated SNVs with ≥90% precision, including 675 alleles with bystander nucleotides that BE-Hive correctly predicted would not be edited. We discovered determinants of previously unpredictable C-to-G, or C-to-A editing and used these discoveries to correct coding sequences of 174 pathogenic transversion SNVs with ≥90% precision. Finally, we used insights from BE-Hive to engineer novel CBE variants that modulate editing outcomes. These discoveries illuminate base editing, enable editing at previously intractable targets, and provide new base editors with improved editing capabilities.
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Affiliation(s)
- Mandana Arbab
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA; Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA
| | - Max W Shen
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA; Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA; Computational and Systems Biology Program, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Beverly Mok
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA; Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA
| | - Christopher Wilson
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA; Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA
| | - Żaneta Matuszek
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA; Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Christopher A Cassa
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - David R Liu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA; Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA.
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11
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Mair D, Biskup S, Kress W, Abicht A, Brück W, Zechel S, Knop KC, Koenig FB, Tey S, Nikolin S, Eggermann K, Kurth I, Ferbert A, Weis J. Differential diagnosis of vacuolar myopathies in the NGS era. Brain Pathol 2020; 30:877-896. [PMID: 32419263 PMCID: PMC8017999 DOI: 10.1111/bpa.12864] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 04/10/2020] [Accepted: 05/07/2020] [Indexed: 12/12/2022] Open
Abstract
Altered autophagy accompanied by abnormal autophagic (rimmed) vacuoles detectable by light and electron microscopy is a common denominator of many familial and sporadic non-inflammatory muscle diseases. Even in the era of next generation sequencing (NGS), late-onset vacuolar myopathies remain a diagnostic challenge. We identified 32 adult vacuolar myopathy patients from 30 unrelated families, studied their clinical, histopathological and ultrastructural characteristics and performed genetic testing in index patients and relatives using Sanger sequencing and NGS including whole exome sequencing (WES). We established a molecular genetic diagnosis in 17 patients. Pathogenic mutations were found in genes typically linked to vacuolar myopathy (GNE, LDB3/ZASP, MYOT, DES and GAA), but also in genes not regularly associated with severely altered autophagy (FKRP, DYSF, CAV3, COL6A2, GYG1 and TRIM32) and in the digenic facioscapulohumeral muscular dystrophy 2. Characteristic histopathological features including distinct patterns of myofibrillar disarray and evidence of exocytosis proved to be helpful to distinguish causes of vacuolar myopathies. Biopsy validated the pathogenicity of the novel mutations p.(Phe55*) and p.(Arg216*) in GYG1 and of the p.(Leu156Pro) TRIM32 mutation combined with compound heterozygous deletion of exon 2 of TRIM32 and expanded the phenotype of Ala93Thr-caveolinopathy and of limb-girdle muscular dystrophy 2i caused by FKRP mutation. In 15 patients no causal variants were detected by Sanger sequencing and NGS panel analysis. In 12 of these cases, WES was performed, but did not yield any definite mutation or likely candidate gene. In one of these patients with a family history of muscle weakness, the vacuolar myopathy was eventually linked to chloroquine therapy. Our study illustrates the wide phenotypic and genotypic heterogeneity of vacuolar myopathies and validates the role of histopathology in assessing the pathogenicity of novel mutations detected by NGS. In a sizable portion of vacuolar myopathy cases, it remains to be shown whether the cause is hereditary or degenerative.
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Affiliation(s)
- Dorothea Mair
- Institute of Neuropathology, RWTH Aachen University, Aachen, Germany.,Department of Neurology, Kassel School of Medicine, Klinikum Kassel, Kassel, Germany.,University of Southampton, Southampton, UK
| | - Saskia Biskup
- Centre for Genomics and Transcriptomics CeGaT, Tübingen, Germany
| | - Wolfram Kress
- Institute of Human Genetics, University Würzburg, Würzburg, Germany
| | | | - Wolfgang Brück
- Institute of Neuropathology, Göttingen University, Göttingen, Germany
| | - Sabrina Zechel
- Institute of Neuropathology, Göttingen University, Göttingen, Germany
| | | | | | - Shelisa Tey
- Institute of Neuropathology, RWTH Aachen University, Aachen, Germany
| | - Stefan Nikolin
- Institute of Neuropathology, RWTH Aachen University, Aachen, Germany
| | - Katja Eggermann
- Institute of Human Genetics, RWTH Aachen University, Aachen, Germany
| | - Ingo Kurth
- Institute of Human Genetics, RWTH Aachen University, Aachen, Germany
| | - Andreas Ferbert
- Department of Neurology, Kassel School of Medicine, Klinikum Kassel, Kassel, Germany
| | - Joachim Weis
- Institute of Neuropathology, RWTH Aachen University, Aachen, Germany
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12
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Maran S, Ee R, Faten SA, Sy Bing C, Khaw KY, Erin Lim SH, Lai KS, Wan Ibrahim WP, Mohd Zain MR, Chan KG, Gan SH, Tan HL. Mutations in the tail domain of MYH3 contributes to atrial septal defect. PLoS One 2020; 15:e0230982. [PMID: 32315303 PMCID: PMC7173802 DOI: 10.1371/journal.pone.0230982] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 03/12/2020] [Indexed: 11/18/2022] Open
Abstract
Atrial septal defect (ASD) is one of the most common congenital heart defects diagnosed in children. Sarcomeric genes has been attributed to ASD and knockdown of MYH3 functionally homologues gene in chick models indicated abnormal atrial septal development. Here, we report for the first time, a case-control study investigating the role of MYH3 among non-syndromic ASD patients in contributing to septal development. Four amplicons which will amplifies the 40 kb MYH3 were designed and amplified using long range-PCR. The amplicons were then sequenced using indexed paired-end libraries on the MiSeq platform. The STREGA guidelines were applied for planning and reporting. The non-synonymous c. 3574G>A (p.Ala1192Thr) [p = 0.001, OR = 2.30 (1.36-3.87)] located within the tail domain indicated a highly conserved protein region. The mutant model of c. 3574G>A (p.Ala1192Thr) showed high root mean square deviation (RMSD) values compared to the wild model. To our knowledge, this is the first study to provide compelling evidence on the pathogenesis of MYH3 variants towards ASD hence, suggesting the crucial role of non-synonymous variants in the tail domain of MYH3 towards atrial septal development. It is hoped that this gene can be used as panel for diagnosis of ASD in future.
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Affiliation(s)
- Sathiya Maran
- School of Pharmacy, Monash University, Sunway, Selangor, Malaysia
- Human Genome Centre, Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia
- * E-mail:
| | - Robson Ee
- Division of Genetics and Molecular Biology, Faculty of Science, Institute of Biological Sciences, University of Malaya, Kuala Lumpur, Malaysia
| | - Siti Aisyah Faten
- Human Genome Centre, Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia
| | - Choi Sy Bing
- School of Data Sciences, Perdana University, Selangor, Malaysia
| | - Kooi Yeong Khaw
- School of Pharmacy, Monash University, Sunway, Selangor, Malaysia
| | - Swee-Hua Erin Lim
- Health Sciences Division, Abu Dhabi Women's College, Higher Colleges of Technology, Abu Dhabi, United Arab Emirates
| | - Kok-Song Lai
- Health Sciences Division, Abu Dhabi Women's College, Higher Colleges of Technology, Abu Dhabi, United Arab Emirates
| | - Wan Pauzi Wan Ibrahim
- Faculty of Medicine and Health Sciences, Universiti Sultan Zainal Abidin, Kuala Terengganu, Terengganu, Malaysia
| | - Mohd Rizal Mohd Zain
- Department of Paediatrics, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia
| | - Kok Gan Chan
- Division of Genetics and Molecular Biology, Faculty of Science, Institute of Biological Sciences, University of Malaya, Kuala Lumpur, Malaysia
- International Genome Centre, Jiangsu University, Zhenjiang, China
| | - Siew Hua Gan
- School of Pharmacy, Monash University, Sunway, Selangor, Malaysia
| | - Huay Lin Tan
- Human Genome Centre, Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia
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13
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Gil-Gálvez A, Carbonell-Corvillo P, Paradas C, Miranda-Vizuete A. Cautionary note on the use of Caenorhabditis elegans to study muscle phenotypes caused by mutations in the human MYH7 gene. Biotechniques 2020; 68:296-299. [PMID: 32301330 DOI: 10.2144/btn-2020-0012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Mutations in the human MYH7 gene, encoding a slow skeletal muscle/β-cardiac myosin heavy chain, cause different types of myopathies. The nematode model Caenorhabditis elegans has frequently been employed to study the molecular and physiological consequences of MYH7 mutations in muscle function by introducing mutations into the unc-54 gene, the worm MYH7 ortholog. We report here that the C. elegans model is not appropriate for such studies if they involve expression of the UNC-54 protein (wild-type or fused to green fluorescent protein) above endogenous levels.
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Affiliation(s)
- Alejandro Gil-Gálvez
- Redox Homeostasis Group, Instituto de Biomedicina de Sevilla (IBIS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013 Sevilla, Spain
| | - Pilar Carbonell-Corvillo
- Neuromuscular Unit, Department of Neurology, Instituto de Biomedicina de Sevilla (IBIS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013 Sevilla, Spain
| | - Carmen Paradas
- Neuromuscular Unit, Department of Neurology, Instituto de Biomedicina de Sevilla (IBIS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013 Sevilla, Spain
| | - Antonio Miranda-Vizuete
- Redox Homeostasis Group, Instituto de Biomedicina de Sevilla (IBIS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013 Sevilla, Spain
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14
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Pagola-Lorz I, Vicente E, Ibáñez B, Torné L, Elizalde-Beiras I, Garcia-Solaesa V, García F, Delfrade J, Jericó I. Epidemiological study and genetic characterization of inherited muscle diseases in a northern Spanish region. Orphanet J Rare Dis 2019; 14:276. [PMID: 31791368 PMCID: PMC6889463 DOI: 10.1186/s13023-019-1227-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 10/10/2019] [Indexed: 01/26/2023] Open
Abstract
Background Inherited muscle diseases are a group of rare heterogeneous muscle conditions with great impact on quality of life, for which variable prevalence has previously been reported, probably due to case selection bias. The aim of this study is to estimate the overall and selective prevalence rates of inherited muscle diseases in a northern Spanish region and to describe their demographic and genetic features. Retrospective identification of patients with inherited muscle diseases between 2000 and 2015 from multiple data sources. Demographic and molecular data were registered. Results On January 1, 2016, the overall prevalence of inherited muscle diseases was 59.00/ 100,000 inhabitants (CI 95%; 53.35–65.26). Prevalence was significantly greater in men (67.33/100,000) in comparison to women (50.80/100,000) (p = 0.006). The highest value was seen in the age range between 45 and 54 (91.32/100,000) years. Myotonic dystrophy type 1 was the most common condition (35.90/100,000), followed by facioscapulohumeral muscular dystrophy (5.15/100,000) and limb-girdle muscular dystrophy type 2A (2.5/100,000). Conclusions Prevalence of inherited muscle diseases in Navarre is high in comparison with the data reported for other geographical regions. Standard procedures and analyses of multiple data sources are needed for epidemiological studies of this heterogeneous group of diseases.
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Affiliation(s)
- Inmaculada Pagola-Lorz
- Department of Neurology, Complejo Hospitalario de Navarra, IdiSNA (Navarre Institute for Health Research), Pamplona, Spain
| | - Esther Vicente
- Community Health Observatory Section, Instituto de Salud Pública y Laboral de Navarra, IdiSNA, Pamplona, Spain.,Department of Health Sciences, Universidad Pública de Navarra (UPNA), IdiSNA, Pamplona, Spain
| | - Berta Ibáñez
- Methodology Unit. Navarrabiomed, Universidad Pública de Navarra (UPNA), IdiSNA, Pamplona, Spain
| | - Laura Torné
- Department of Neurology, Complejo Hospitalario de Navarra, IdiSNA (Navarre Institute for Health Research), Pamplona, Spain
| | - Itsaso Elizalde-Beiras
- Primary Care, Servicio Navarro de Salud - Osasunbidea, IdiSNA, Pamplona, Spain.,Miguel Servet Foundation, Navarrabiomed, Pamplona, Spain
| | - Virginia Garcia-Solaesa
- Department of Neurology, Complejo Hospitalario de Navarra, IdiSNA (Navarre Institute for Health Research), Pamplona, Spain.,Department of Genetics, Complejo Hospitalario de Navarra, IdiSNA, Pamplona, Spain
| | - Fermín García
- Department of Genetics, Complejo Hospitalario de Navarra, IdiSNA, Pamplona, Spain
| | - Josu Delfrade
- Community Health Observatory Section, Instituto de Salud Pública y Laboral de Navarra, IdiSNA, Pamplona, Spain.,CIBER Epidemiology and Public Health (CIBERESP), Madrid, Spain
| | - Ivonne Jericó
- Department of Neurology, Complejo Hospitalario de Navarra, IdiSNA (Navarre Institute for Health Research), Pamplona, Spain. .,Department of Neurology, Complejo Hospitalario de Navarra, 31008, Pamplona, C/ Irunlarrea, Spain.
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15
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Milone M, Liewluck T. The unfolding spectrum of inherited distal myopathies. Muscle Nerve 2018; 59:283-294. [PMID: 30171629 DOI: 10.1002/mus.26332] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 08/26/2018] [Accepted: 08/28/2018] [Indexed: 12/30/2022]
Abstract
Distal myopathies are a group of rare muscle diseases characterized by distal weakness at onset. Although acquired myopathies can occasionally present with distal weakness, the majority of distal myopathies have a genetic etiology. Their age of onset varies from early-childhood to late-adulthood while the predominant muscle weakness can affect calf, ankle dorsiflexor, or distal upper limb muscles. A spectrum of muscle pathological changes, varying from nonspecific myopathic changes to rimmed vacuoles to myofibrillar pathology to nuclei centralization, have been noted. Likewise, the underlying molecular defect is heterogeneous. In addition, there is emerging evidence that distal myopathies can result from defective proteins encoded by genes causative of neurogenic disorders, be manifestation of multisystem proteinopathies or the result of the altered interplay between different genes. In this review, we provide an overview on the clinical, electrophysiological, pathological, and molecular aspects of distal myopathies, focusing on the most recent developments in the field. Muscle Nerve 59:283-294, 2019.
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Affiliation(s)
| | - Teerin Liewluck
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
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16
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Carbonell-Corvillo P, Tristán-Clavijo E, Cabrera-Serrano M, Servián-Morilla E, García-Martín G, Villarreal-Pérez L, Rivas-Infante E, Area-Gómez E, Chamorro-Muñoz M, Gil-Gálvez A, Miranda-Vizuete A, Martinez-Mir A, Laing N, Paradas C. A novel MYH7 founder mutation causing Laing distal myopathy in Southern Spain. Neuromuscul Disord 2018; 28:828-836. [DOI: 10.1016/j.nmd.2018.07.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/12/2018] [Accepted: 07/19/2018] [Indexed: 01/11/2023]
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17
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Viswanathan MC, Tham RC, Kronert WA, Sarsoza F, Trujillo AS, Cammarato A, Bernstein SI. Myosin storage myopathy mutations yield defective myosin filament assembly in vitro and disrupted myofibrillar structure and function in vivo. Hum Mol Genet 2018; 26:4799-4813. [PMID: 28973424 DOI: 10.1093/hmg/ddx359] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 09/11/2017] [Indexed: 12/19/2022] Open
Abstract
Myosin storage myopathy (MSM) is a congenital skeletal muscle disorder caused by missense mutations in the β-cardiac/slow skeletal muscle myosin heavy chain rod. It is characterized by subsarcolemmal accumulations of myosin that have a hyaline appearance. MSM mutations map near or within the assembly competence domain known to be crucial for thick filament formation. Drosophila MSM models were generated for comprehensive physiological, structural, and biochemical assessment of the mutations' consequences on muscle and myosin structure and function. L1793P, R1845W, and E1883K MSM mutant myosins were expressed in an indirect flight (IFM) and jump muscle myosin null background to study the effects of these variants without confounding influences from wild-type myosin. Mutant animals displayed highly compromised jump and flight ability, disrupted muscle proteostasis, and severely perturbed IFM structure. Electron microscopy revealed myofibrillar disarray and degeneration with hyaline-like inclusions. In vitro assembly assays demonstrated a decreased ability of mutant myosin to polymerize, with L1793P filaments exhibiting shorter lengths. In addition, limited proteolysis experiments showed a reduced stability of L1793P and E1883K filaments. We conclude that the disrupted hydropathy or charge of residues in the heptad repeat of the mutant myosin rods likely alters interactions that stabilize coiled-coil dimers and thick filaments, causing disruption in ordered myofibrillogenesis and/or myofibrillar integrity, and the consequent myosin aggregation. Our Drosophila models are the first to recapitulate the human MSM phenotype with ultrastructural inclusions, suggesting that the diminished ability of the mutant myosin to form stable thick filaments contributes to the dystrophic phenotype observed in afflicted subjects.
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Affiliation(s)
- Meera C Viswanathan
- Department of Biology, Molecular Biology Institute and Heart Institute, San Diego State University, San Diego, CA 92182-4614, USA.,Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Rick C Tham
- Department of Biology, Molecular Biology Institute and Heart Institute, San Diego State University, San Diego, CA 92182-4614, USA
| | - William A Kronert
- Department of Biology, Molecular Biology Institute and Heart Institute, San Diego State University, San Diego, CA 92182-4614, USA
| | - Floyd Sarsoza
- Department of Biology, Molecular Biology Institute and Heart Institute, San Diego State University, San Diego, CA 92182-4614, USA
| | - Adriana S Trujillo
- Department of Biology, Molecular Biology Institute and Heart Institute, San Diego State University, San Diego, CA 92182-4614, USA
| | - Anthony Cammarato
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Sanford I Bernstein
- Department of Biology, Molecular Biology Institute and Heart Institute, San Diego State University, San Diego, CA 92182-4614, USA
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18
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Tordjman M, Dabaj I, Laforet P, Felter A, Ferreiro A, Biyoukar M, Law-Ye B, Zanoteli E, Castiglioni C, Rendu J, Beroud C, Chamouni A, Richard P, Mompoint D, Quijano-Roy S, Carlier RY. Muscular MRI-based algorithm to differentiate inherited myopathies presenting with spinal rigidity. Eur Radiol 2018; 28:5293-5303. [PMID: 29802573 DOI: 10.1007/s00330-018-5472-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 04/01/2018] [Accepted: 04/10/2018] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Inherited myopathies are major causes of muscle atrophy and are often characterized by rigid spine syndrome, a clinical feature designating patients with early spinal contractures. We aim to present a decision algorithm based on muscular whole body magnetic resonance imaging (mWB-MRI) as a unique tool to orientate the diagnosis of each inherited myopathy long before the genetically confirmed diagnosis. METHODS This multicentre retrospective study enrolled 79 patients from referral centres in France, Brazil and Chile. The patients underwent 1.5-T or 3-T mWB-MRI. The protocol comprised STIR and T1 sequences in axial and coronal planes, from head to toe. All images were analyzed manually by multiple raters. Fatty muscle replacement was evaluated on mWB-MRI using both the Mercuri scale and statistical comparison based on the percentage of affected muscle. RESULTS Between February 2005 and December 2015, 76 patients with genetically confirmed inherited myopathy were included. They were affected by Pompe disease or harbored mutations in RYR1, Collagen VI, LMNA, SEPN1, LAMA2 and MYH7 genes. Each myopathy had a specific pattern of affected muscles recognizable on mWB-MRI. This allowed us to create a novel decision algorithm for patients with rigid spine syndrome by segregating these signs. This algorithm was validated by five external evaluators on a cohort of seven patients with a diagnostic accuracy of 94.3% compared with the genetic diagnosis. CONCLUSION We provide a novel decision algorithm based on muscle fat replacement graded on mWB-MRI that allows diagnosis and differentiation of inherited myopathies presenting with spinal rigidity. KEY POINTS • Inherited myopathies are rare, diagnosis is challenging and genetic tests require specialized centres and often take years. • Inherited myopathies are often characterized by spinal rigidity. • Whole body magnetic resonance imaging is a unique tool to orientate the diagnosis of each inherited myopathy presenting with spinal rigidity. • Each inherited myopathy in this study has a specific pattern of affected muscles that orientate diagnosis. • A novel MRI-based algorithm, usable by every radiologist, can help the early diagnosis of these myopathies.
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Affiliation(s)
- Mickael Tordjman
- Assistance Publique des Hôpitaux de Paris (AP-HP), Service d'Imagerie Médicale, Pôle Neuro-locomoteur, Hôpital Raymond Poincaré, Garches, Hôpitaux Universitaires Paris-Ile-de-France Ouest, Garches, France.
| | - Ivana Dabaj
- Pôle Pédiatrie, Hôpital Raymond Poincaré, Garches, France - Centre de Référence Maladies Neuromusculaires GNMH, FILNEMUS, Garches, France
| | - Pascal Laforet
- Département de Neurologie, Unité Clinique de Pathologie Neuromusculaire, Institut de Myologie, CHU La Pitié Salpêtrière, APHP, Paris, France
| | - Adrien Felter
- Assistance Publique des Hôpitaux de Paris (AP-HP), Service d'Imagerie Médicale, Pôle Neuro-locomoteur, Hôpital Raymond Poincaré, Garches, Hôpitaux Universitaires Paris-Ile-de-France Ouest, Garches, France
| | - Ana Ferreiro
- Service de Génétique, Hôpital Raymond Poincaré, APHP, Garches, Hôpitaux Universitaires Paris-Ile-de-France Ouest, Garches, France
| | - Moustafa Biyoukar
- Unité de Recherche Clinique, Hôpital Saint-Antoine, APHP, Paris, Hôpitaux Universitaires Est Parisien, Garches, France
| | - Bruno Law-Ye
- Assistance Publique des Hôpitaux de Paris (AP-HP), Service d'Imagerie Médicale, Pôle Neuro-locomoteur, Hôpital Raymond Poincaré, Garches, Hôpitaux Universitaires Paris-Ile-de-France Ouest, Garches, France
| | - Edmar Zanoteli
- Department of Neurology, Medical School of the University of São Paulo, São Paulo, Brazil
| | - Claudia Castiglioni
- Neuromuscular and Motor Disorders Program Clinica Las Condes, Pediatric Neurology, Santiago, Chile
| | - John Rendu
- Département de Biochimie, Toxicologie, Pharmacologie et Génétique Moléculaire, CHU Grenoble Alpes, Grenoble, France
| | - Christophe Beroud
- Département de Génétique Médicale, AP-HM, Hôpital Timone Enfants, Marseille, France
| | | | - Pascale Richard
- UF de Cardiogénétique et Myogénétique Moléculaire et Cellulaire, Centre de Génétique Moléculaire et Chromosomique, CHU La Pitié Salpêtrière, APHP, Paris, France
| | - Dominique Mompoint
- Assistance Publique des Hôpitaux de Paris (AP-HP), Service d'Imagerie Médicale, Pôle Neuro-locomoteur, Hôpital Raymond Poincaré, Garches, Hôpitaux Universitaires Paris-Ile-de-France Ouest, Garches, France
| | - Susana Quijano-Roy
- Pôle Pédiatrie, Hôpital Raymond Poincaré, Garches, France - Centre de Référence Maladies Neuromusculaires GNMH, FILNEMUS, Garches, France
| | - Robert-Yves Carlier
- Assistance Publique des Hôpitaux de Paris (AP-HP), Service d'Imagerie Médicale, Pôle Neuro-locomoteur, Hôpital Raymond Poincaré, Garches, Hôpitaux Universitaires Paris-Ile-de-France Ouest, Garches, France
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19
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MYH7 mutation associated with two phenotypes of myopathy. Neurol Sci 2017; 39:333-339. [PMID: 29170849 DOI: 10.1007/s10072-017-3192-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 11/07/2017] [Indexed: 10/18/2022]
Abstract
The mutations of MYH7 (slow skeletal/β-cardiac myosin heavy chain) are commonly found in familial hypertrophic/dilated cardiomyopathy, and also can cause Laing early-onset distal myopathy (LDM), myosin storage myopathy (MSM), and congenital myopathy with fiber-type disproportion (CFTD). Here we report two cases whose diagnosis was hereditary myopathy according to clinical feature and muscle pathology analysis. High-throughput genomic sequencing (next generation sequencing) was performed to validate the diagnosis. Two MYH7 mutations, p.R1845W and p.E1687del, were identified. p.R1845W was found in a male patient showing weakness of both terminal lower legs without foot drop. Muscle pathology stainings characteristically showed the hyaline body in the intracytoplasmic location. The novel mutation p.E1687del was found in a family with seven patients. The proband showed foot drop, scoliosis, and winged scapula, while his mother only showed mild foot drop and winged scapula. Muscle pathology analysis showed congenital centronucleus myopathy. Both cases only showed muscular disorder and had no cardiomyopathy. This study, for the first time, reports the MYH7 mutations associated with centronucleus myopathy.
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20
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Cassandrini D, Trovato R, Rubegni A, Lenzi S, Fiorillo C, Baldacci J, Minetti C, Astrea G, Bruno C, Santorelli FM. Congenital myopathies: clinical phenotypes and new diagnostic tools. Ital J Pediatr 2017; 43:101. [PMID: 29141652 PMCID: PMC5688763 DOI: 10.1186/s13052-017-0419-z] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 11/02/2017] [Indexed: 12/26/2022] Open
Abstract
Congenital myopathies are a group of genetic muscle disorders characterized clinically by hypotonia and weakness, usually from birth, and a static or slowly progressive clinical course. Historically, congenital myopathies have been classified on the basis of major morphological features seen on muscle biopsy. However, different genes have now been identified as associated with the various phenotypic and histological expressions of these disorders, and in recent years, because of their unexpectedly wide genetic and clinical heterogeneity, next-generation sequencing has increasingly been used for their diagnosis. We reviewed clinical and genetic forms of congenital myopathy and defined possible strategies to improve cost-effectiveness in histological and imaging diagnosis.
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Affiliation(s)
| | - Rosanna Trovato
- Molecular Medicine, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Anna Rubegni
- Molecular Medicine, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Sara Lenzi
- Neurology, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Chiara Fiorillo
- Molecular Medicine, IRCCS Fondazione Stella Maris, Pisa, Italy.,Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Genoa, Italy
| | - Jacopo Baldacci
- Molecular Medicine, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Carlo Minetti
- Unit of Pediatric Neurology and Muscular Disorders, Istituto G. Gaslini, Genoa, Italy.,Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Genoa, Italy
| | - Guja Astrea
- Neurology, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Claudio Bruno
- Department of Neuroscience, Center of Myology and Neurodegenerative Disorders, Istituto G. Gaslini, Genoa, Italy
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21
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Bánfai Z, Hadzsiev K, Pál E, Komlósi K, Melegh M, Balikó L, Melegh B. Novel phenotypic variant in the MYH7 spectrum due to a stop-loss mutation in the C-terminal region: a case report. BMC MEDICAL GENETICS 2017; 18:105. [PMID: 28927399 PMCID: PMC5606036 DOI: 10.1186/s12881-017-0463-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 09/08/2017] [Indexed: 12/29/2022]
Abstract
Background Defects of the slow myosin heavy chain isoform coding MYH7 gene primarily cause skeletal myopathies including Laing Distal Myopathy, Myosin Storage Myopathy and are also responsible for cardiomyopathies. Scapuloperoneal and limb-girdle muscle weakness, congenital fiber type disproportion, multi-minicore disease were also reported in connection of MYH7. Pathogeneses of the defects in the head and proximal rod region of the protein are well described. However, the C-terminal mutations of the MYH7 gene are less known. Moreover, only two articles describe the phenotypic impact of the elongated mature protein product caused by termination signal loss. Case presentation Here we present a male patient with an unusual phenotypic variant of early-onset and predominant involvement of neck muscles with muscle biopsy indicating myopathy and sarcoplasmic storage material. Cardiomyopathic involvements could not be observed. Sequencing of MYH7 gene revealed a stop-loss mutation on the 3-prime end of the rod region, which causes the elongation of the mature protein. Conclusions The elongated protein likely disrupts the functions of the sarcomere by multiple functional abnormalities. This elongation could also affect the thick filament degradation leading to protein deposition and accumulation in the sarcomere, resulting in the severe myopathy of certain axial muscles. The phenotypic expression of the detected novel MYH7 genotype could strengthen and further expand our knowledge about mutations affecting the structure of MyHCI by termination signal loss in the MYH7 gene.
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Affiliation(s)
- Zsolt Bánfai
- Department of Medical Genetics, University of Pécs, Szigeti út 12, Pécs, H-7624, Hungary.,Szentágothai Research Centre, University of Pécs, Ifjúság út 20, Pécs, H-7624, Hungary
| | - Kinga Hadzsiev
- Department of Medical Genetics, University of Pécs, Szigeti út 12, Pécs, H-7624, Hungary.,Szentágothai Research Centre, University of Pécs, Ifjúság út 20, Pécs, H-7624, Hungary
| | - Endre Pál
- Neurology Clinic, University of Pécs, Rét u. 2, Pécs, H-7623, Hungary
| | - Katalin Komlósi
- Department of Medical Genetics, University of Pécs, Szigeti út 12, Pécs, H-7624, Hungary.,Szentágothai Research Centre, University of Pécs, Ifjúság út 20, Pécs, H-7624, Hungary
| | - Márton Melegh
- Department of Medical Genetics, University of Pécs, Szigeti út 12, Pécs, H-7624, Hungary.,Szentágothai Research Centre, University of Pécs, Ifjúság út 20, Pécs, H-7624, Hungary
| | - László Balikó
- Department of Neurology, Zala County Hospital, Zrínyi u. 1, Zalaegerszeg, H-8900, Hungary
| | - Béla Melegh
- Department of Medical Genetics, University of Pécs, Szigeti út 12, Pécs, H-7624, Hungary. .,Szentágothai Research Centre, University of Pécs, Ifjúság út 20, Pécs, H-7624, Hungary.
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22
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Abstract
Cardiac and skeletal striated muscles are intricately designed machines responsible for muscle contraction. Coordination of the basic contractile unit, the sarcomere, and the complex cytoskeletal networks are critical for contractile activity. The sarcomere is comprised of precisely organized individual filament systems that include thin (actin), thick (myosin), titin, and nebulin. Connecting the sarcomere to other organelles (e.g., mitochondria and nucleus) and serving as the scaffold to maintain cellular integrity are the intermediate filaments. The costamere, on the other hand, tethers the sarcomere to the cell membrane. Unique structures like the intercalated disc in cardiac muscle and the myotendinous junction in skeletal muscle help synchronize and transmit force. Intense investigation has been done on many of the proteins that make up these cytoskeletal assemblies. Yet the details of their function and how they interconnect have just started to be elucidated. A vast number of human myopathies are contributed to mutations in muscle proteins; thus understanding their basic function provides a mechanistic understanding of muscle disorders. In this review, we highlight the components of striated muscle with respect to their interactions, signaling pathways, functions, and connections to disease. © 2017 American Physiological Society. Compr Physiol 7:891-944, 2017.
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Affiliation(s)
- Christine A Henderson
- Department of Cellular and Molecular Medicine, The University of Arizona, Tucson, Arizona, USA.,Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, Arizona, USA
| | - Christopher G Gomez
- Department of Cellular and Molecular Medicine, The University of Arizona, Tucson, Arizona, USA.,Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, Arizona, USA
| | - Stefanie M Novak
- Department of Cellular and Molecular Medicine, The University of Arizona, Tucson, Arizona, USA.,Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, Arizona, USA
| | - Lei Mi-Mi
- Department of Cellular and Molecular Medicine, The University of Arizona, Tucson, Arizona, USA.,Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, Arizona, USA
| | - Carol C Gregorio
- Department of Cellular and Molecular Medicine, The University of Arizona, Tucson, Arizona, USA.,Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, Arizona, USA
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23
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Veltri T, Landim-Vieira M, Parvatiyar MS, Gonzalez-Martinez D, Dieseldorff Jones KM, Michell CA, Dweck D, Landstrom AP, Chase PB, Pinto JR. Hypertrophic Cardiomyopathy Cardiac Troponin C Mutations Differentially Affect Slow Skeletal and Cardiac Muscle Regulation. Front Physiol 2017; 8:221. [PMID: 28473771 PMCID: PMC5397416 DOI: 10.3389/fphys.2017.00221] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 03/27/2017] [Indexed: 12/22/2022] Open
Abstract
Mutations in TNNC1-the gene encoding cardiac troponin C (cTnC)-that have been associated with hypertrophic cardiomyopathy (HCM) and cardiac dysfunction may also affect Ca2+-regulation and function of slow skeletal muscle since the same gene is expressed in both cardiac and slow skeletal muscle. Therefore, we reconstituted rabbit soleus fibers and bovine masseter myofibrils with mutant cTnCs (A8V, C84Y, E134D, and D145E) associated with HCM to investigate their effects on contractile force and ATPase rates, respectively. Previously, we showed that these HCM cTnC mutants, except for E134D, increased the Ca2+ sensitivity of force development in cardiac preparations. In the current study, an increase in Ca2+ sensitivity of isometric force was only observed for the C84Y mutant when reconstituted in soleus fibers. Incorporation of cTnC C84Y in bovine masseter myofibrils reduced the ATPase activity at saturating [Ca2+], whereas, incorporation of cTnC D145E increased the ATPase activity at inhibiting and saturating [Ca2+]. We also tested whether reconstitution of cardiac fibers with troponin complexes containing the cTnC mutants and slow skeletal troponin I (ssTnI) could emulate the slow skeletal functional phenotype. Reconstitution of cardiac fibers with troponin complexes containing ssTnI attenuated the Ca2+ sensitization of isometric force when cTnC A8V and D145E were present; however, it was enhanced for C84Y. In summary, although the A8V and D145E mutants are present in both muscle types, their functional phenotype is more prominent in cardiac muscle than in slow skeletal muscle, which has implications for the protein-protein interactions within the troponin complex. The C84Y mutant warrants further investigation since it drastically alters the properties of both muscle types and may account for the earlier clinical onset in the proband.
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Affiliation(s)
- Tiago Veltri
- Department of Biomedical Sciences, Florida State University College of MedicineTallahassee, FL, USA
| | - Maicon Landim-Vieira
- Department of Biomedical Sciences, Florida State University College of MedicineTallahassee, FL, USA
| | - Michelle S. Parvatiyar
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of MedicineMiami, FL, USA
| | - David Gonzalez-Martinez
- Department of Biomedical Sciences, Florida State University College of MedicineTallahassee, FL, USA
| | | | - Clara A. Michell
- Department of Biomedical Sciences, Florida State University College of MedicineTallahassee, FL, USA
| | - David Dweck
- Department of Biomedical Sciences, Florida State University College of MedicineTallahassee, FL, USA
| | - Andrew P. Landstrom
- Section of Pediatric Cardiology, Department of Pediatrics, Baylor College of MedicineHouston, TX, USA
| | - P. Bryant Chase
- Department of Biological Science, Florida State UniversityTallahassee, FL, USA
| | - Jose R. Pinto
- Department of Biomedical Sciences, Florida State University College of MedicineTallahassee, FL, USA
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Myosin Storage Myopathy in C. elegans and Human Cultured Muscle Cells. PLoS One 2017; 12:e0170613. [PMID: 28125727 PMCID: PMC5268365 DOI: 10.1371/journal.pone.0170613] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 01/06/2017] [Indexed: 02/06/2023] Open
Abstract
Myosin storage myopathy is a protein aggregate myopathy associated with the characteristic subsarcolemmal accumulation of myosin heavy chain in muscle fibers. Despite similar histological findings, the clinical severity and age of onset are highly variable, ranging from no weakness to severe impairment of ambulation, and usually childhood-onset to onset later in life. Mutations located in the distal end of the tail of slow/ß-cardiac myosin heavy chain are associated with myosin storage myopathy. Four missense mutations (L1793P, R1845W, E1883K and H1901L), two of which have been reported in several unrelated families, are located within or closed to the assembly competence domain. This location is critical for the proper assembly of sarcomeric myosin rod filaments. To assess the mechanisms leading to protein aggregation in myosin storage myopathy and to evaluate the impact of these mutations on myosin assembly and muscle function, we expressed mutated myosin proteins in cultured human muscle cells and in the nematode Caenorhabditis elegans. While L1793P mutant myosin protein efficiently incorporated into the sarcomeric thick filaments, R1845W and H1901L mutants were prone to formation of myosin aggregates without assembly into striated sarcomeric thick filaments in cultured muscle cells. In C. elegans, mutant alleles of the myosin heavy chain gene unc-54 corresponding to R1845W, E1883K and H1901L, were as effective as the wild-type myosin gene in rescuing the null mutant worms, indicating that they retain functionality. Taken together, our results suggest that the basis for the pathogenic effect of the R1845W and H1901L mutations are primarily structural rather than functional. Further analyses are needed to identify the primary trigger for the histological changes seen in muscle biopsies of patients with L1793P and E1883K mutations.
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Detection of clinically relevant copy-number variants by exome sequencing in a large cohort of genetic disorders. Genet Med 2016; 19:667-675. [PMID: 28574513 PMCID: PMC5460076 DOI: 10.1038/gim.2016.163] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 08/31/2016] [Indexed: 01/08/2023] Open
Abstract
Purpose: Copy-number variation is a common source of genomic variation and an important genetic cause of disease. Microarray-based analysis of copy-number variants (CNVs) has become a first-tier diagnostic test for patients with neurodevelopmental disorders, with a diagnostic yield of 10–20%. However, for most other genetic disorders, the role of CNVs is less clear and most diagnostic genetic studies are generally limited to the study of single-nucleotide variants (SNVs) and other small variants. With the introduction of exome and genome sequencing, it is now possible to detect both SNVs and CNVs using an exome- or genome-wide approach with a single test. Methods: We performed exome-based read-depth CNV screening on data from 2,603 patients affected by a range of genetic disorders for which exome sequencing was performed in a diagnostic setting. Results: In total, 123 clinically relevant CNVs ranging in size from 727 bp to 15.3 Mb were detected, which resulted in 51 conclusive diagnoses and an overall increase in diagnostic yield of ~2% (ranging from 0 to –5.8% per disorder). Conclusions: This study shows that CNVs play an important role in a broad range of genetic disorders and that detection via exome-based CNV profiling results in an increase in the diagnostic yield without additional testing, bringing us closer to single-test genomics. Genet Med advance online publication 27 October 2016
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26
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Fiorillo C, Astrea G, Savarese M, Cassandrini D, Brisca G, Trucco F, Pedemonte M, Trovato R, Ruggiero L, Vercelli L, D'Amico A, Tasca G, Pane M, Fanin M, Bello L, Broda P, Musumeci O, Rodolico C, Messina S, Vita GL, Sframeli M, Gibertini S, Morandi L, Mora M, Maggi L, Petrucci A, Massa R, Grandis M, Toscano A, Pegoraro E, Mercuri E, Bertini E, Mongini T, Santoro L, Nigro V, Minetti C, Santorelli FM, Bruno C. MYH7-related myopathies: clinical, histopathological and imaging findings in a cohort of Italian patients. Orphanet J Rare Dis 2016; 11:91. [PMID: 27387980 PMCID: PMC4936326 DOI: 10.1186/s13023-016-0476-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 06/22/2016] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Myosin heavy chain 7 (MYH7)-related myopathies are emerging as an important group of muscle diseases of childhood and adulthood, with variable clinical and histopathological expression depending on the type and location of the mutation. Mutations in the head and neck domains are a well-established cause of hypertrophic cardiomyopathy whereas mutation in the distal regions have been associated with a range of skeletal myopathies with or without cardiac involvement, including Laing distal myopathy and Myosin storage myopathy. Recently the spectrum of clinical phenotypes associated with mutations in MYH7 has increased, blurring this scheme and adding further phenotypes to the list. A broader disease spectrum could lead to misdiagnosis of different congenital myopathies, neurogenic atrophy and other neuromuscular conditions. RESULTS As a result of a multicenter Italian study we collected clinical, histopathological and imaging data from a population of 21 cases from 15 families, carrying reported or novel mutations in MYH7. Patients displayed a variable phenotype including atypical pictures, as dropped head and bent spine, which cannot be classified in previously described groups. Half of the patients showed congenital or early infantile weakness with predominant distal weakness. Conversely, patients with later onset present prevalent proximal weakness. Seven patients were also affected by cardiomyopathy mostly in the form of non-compacted left ventricle. Muscle biopsy was consistent with minicores myopathy in numerous cases. Muscle MRI was meaningful in delineating a shared pattern of selective involvement of tibialis anterior muscles, with relative sparing of quadriceps. CONCLUSION This work adds to the genotype-phenotype correlation of MYH7-relatedmyopathies confirming the complexity of the disorder.
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Affiliation(s)
- C Fiorillo
- IRCCS Stella Maris, Molecular Medicine and Neuromuscular Disorders, Via dei Giacinti 2, 56128, Calambrone, Pisa, Italy. .,Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternad and Child Health, University of Genova, University of Genoa, Genoa, Italy.
| | - G Astrea
- IRCCS Stella Maris, Molecular Medicine and Neuromuscular Disorders, Via dei Giacinti 2, 56128, Calambrone, Pisa, Italy
| | - M Savarese
- Telethon Institute of Genetics and Medicine, Naples, Italy
| | - D Cassandrini
- IRCCS Stella Maris, Molecular Medicine and Neuromuscular Disorders, Via dei Giacinti 2, 56128, Calambrone, Pisa, Italy
| | - G Brisca
- Unit of Pediatric Neurology and Muscular Disorders, Istituto G.Gaslini, Genoa, Italy.,Department of Neuroscience, Center of Myology and Neurodegenerative Disorders, Istituto Giannina Gaslini, Genoa, Italy
| | - F Trucco
- Unit of Pediatric Neurology and Muscular Disorders, Istituto G.Gaslini, Genoa, Italy
| | - M Pedemonte
- Unit of Pediatric Neurology and Muscular Disorders, Istituto G.Gaslini, Genoa, Italy
| | - R Trovato
- IRCCS Stella Maris, Molecular Medicine and Neuromuscular Disorders, Via dei Giacinti 2, 56128, Calambrone, Pisa, Italy
| | - L Ruggiero
- Department of Neurosciences and Reproductive and Odontostomatologic Sciences, University Federico II, Naples, Italy
| | - L Vercelli
- Department of Neurosciences "Rita Levi Montalcini", University of Turin, Turin, Italy
| | - A D'Amico
- Unit of Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - G Tasca
- Don Carlo Gnocchi ONLUS Foundation, Rome, Italy
| | - M Pane
- Department of Paediatric Neurology, Catholic University, Rome, Italy
| | - M Fanin
- Department of Neurosciences, University of Padua, Padua, Italy
| | - L Bello
- Department of Neurosciences, University of Padua, Padua, Italy
| | - P Broda
- Unit of Pediatric Neurology and Muscular Disorders, Istituto G.Gaslini, Genoa, Italy
| | - O Musumeci
- Department of Clinical and Experimental Medicine and Nemo Sud Clinical Centre, University of Messina, Messina, Italy
| | - C Rodolico
- Department of Clinical and Experimental Medicine and Nemo Sud Clinical Centre, University of Messina, Messina, Italy
| | - S Messina
- Department of Clinical and Experimental Medicine and Nemo Sud Clinical Centre, University of Messina, Messina, Italy
| | - G L Vita
- Department of Clinical and Experimental Medicine and Nemo Sud Clinical Centre, University of Messina, Messina, Italy
| | - M Sframeli
- Department of Clinical and Experimental Medicine and Nemo Sud Clinical Centre, University of Messina, Messina, Italy
| | - S Gibertini
- Neuromuscular Diseases and Neuroimmunology Unit, IRCCS Foundation C Besta Neurological Institute, Milan, Italy
| | - L Morandi
- Neuromuscular Diseases and Neuroimmunology Unit, IRCCS Foundation C Besta Neurological Institute, Milan, Italy
| | - M Mora
- Neuromuscular Diseases and Neuroimmunology Unit, IRCCS Foundation C Besta Neurological Institute, Milan, Italy
| | - L Maggi
- Neuromuscular Diseases and Neuroimmunology Unit, IRCCS Foundation C Besta Neurological Institute, Milan, Italy
| | - A Petrucci
- Center for Neuromuscular and Neurological Rare Diseases, S. Camillo-Forlanini Hospital, Rome, Italy
| | - R Massa
- Department of Systems Medicine (Neurology), University of Tor Vergata, Rome, Italy
| | - M Grandis
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternad and Child Health, University of Genova, University of Genoa, Genoa, Italy
| | - A Toscano
- Department of Clinical and Experimental Medicine and Nemo Sud Clinical Centre, University of Messina, Messina, Italy
| | - E Pegoraro
- Department of Neurosciences, University of Padua, Padua, Italy
| | - E Mercuri
- Department of Paediatric Neurology, Catholic University, Rome, Italy
| | - E Bertini
- Unit of Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - T Mongini
- Department of Neurosciences "Rita Levi Montalcini", University of Turin, Turin, Italy
| | - L Santoro
- Department of Neurosciences and Reproductive and Odontostomatologic Sciences, University Federico II, Naples, Italy
| | - V Nigro
- Telethon Institute of Genetics and Medicine, Naples, Italy
| | - C Minetti
- Unit of Pediatric Neurology and Muscular Disorders, Istituto G.Gaslini, Genoa, Italy.,Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternad and Child Health, University of Genova, University of Genoa, Genoa, Italy
| | - F M Santorelli
- IRCCS Stella Maris, Molecular Medicine and Neuromuscular Disorders, Via dei Giacinti 2, 56128, Calambrone, Pisa, Italy
| | - C Bruno
- Department of Neuroscience, Center of Myology and Neurodegenerative Disorders, Istituto Giannina Gaslini, Genoa, Italy
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Massalska D, Zimowski JG, Bijok J, Kucińska-Chahwan A, Łusakowska A, Jakiel G, Roszkowski T. Prenatal diagnosis of congenital myopathies and muscular dystrophies. Clin Genet 2016; 90:199-210. [PMID: 27197572 DOI: 10.1111/cge.12801] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 05/05/2016] [Accepted: 05/08/2016] [Indexed: 12/14/2022]
Abstract
Congenital myopathies and muscular dystrophies constitute a genetically and phenotypically heterogeneous group of rare inherited diseases characterized by muscle weakness and atrophy, motor delay and respiratory insufficiency. To date, curative care is not available for these diseases, which may severely affect both life-span and quality of life. We discuss prenatal diagnosis and genetic counseling for families at risk, as well as diagnostic possibilities in sporadic cases.
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Affiliation(s)
- D Massalska
- Department of Obstetrics and Gynecology, Centre of Postgraduate Medical Education, Warsaw, Poland
| | - J G Zimowski
- Department of Genetics, Institute of Psychiatry and Neurology, Warsaw, Poland
| | - J Bijok
- Department of Obstetrics and Gynecology, Centre of Postgraduate Medical Education, Warsaw, Poland
| | - A Kucińska-Chahwan
- Department of Obstetrics and Gynecology, Centre of Postgraduate Medical Education, Warsaw, Poland
| | - A Łusakowska
- Department of Neurology, Medical University of Warsaw, Poland
| | - G Jakiel
- Department of Obstetrics and Gynecology, Centre of Postgraduate Medical Education, Warsaw, Poland
| | - T Roszkowski
- Department of Obstetrics and Gynecology, Centre of Postgraduate Medical Education, Warsaw, Poland
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Pajusalu S, Talvik I, Noormets K, Talvik T, Põder H, Joost K, Puusepp S, Piirsoo A, Stenzel W, Goebel HH, Nikopensius T, Annilo T, Nõukas M, Metspalu A, Õunap K, Reimand T. De novo exonic mutation in MYH7 gene leading to exon skipping in a patient with early onset muscular weakness and fiber-type disproportion. Neuromuscul Disord 2015; 26:236-9. [PMID: 26782017 DOI: 10.1016/j.nmd.2015.11.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Accepted: 11/23/2015] [Indexed: 02/05/2023]
Abstract
Here we report on a case of MYH7-related myopathy in a boy with early onset of muscular weakness and delayed motor development in infancy. His most affected muscles were neck extensors showing a dropped head sign, proximal muscles of lower limbs with positive Gower's sign, and trunk muscles. Brain and spinal cord MRI scans, echocardiography, and laboratory analyses including creatine kinase and lactate did not reveal any abnormalities. Muscle histopathology showed fiber-type disproportion. Whole exome sequencing of the parents-offspring trio revealed a novel de novo c.5655G>A p.(Ala1885=) synonymous substitution of the last nucleotide in exon 38 of the MYH7 gene. Further RNA investigations proved the skipping of exon 38 (p.1854_1885del). This is a first report of an exon-skipping mutation in the MYH7 gene causing myopathy. This report broadens both the phenotypic and genotypic spectra of MYH7-related myopathies.
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Affiliation(s)
- Sander Pajusalu
- Department of Genetics, United Laboratories, Tartu University Hospital, Tartu, Estonia; Institute of Biomedicine and Translational Medicine, Department of Biomedicine, University of Tartu, Tartu, Estonia.
| | - Inga Talvik
- Department of Pediatrics, University of Tartu, Tartu, Estonia; Children's Clinic, Tartu University Hospital, Tartu, Estonia
| | - Klari Noormets
- Children's Clinic, Tartu University Hospital, Tartu, Estonia
| | - Tiina Talvik
- Department of Pediatrics, University of Tartu, Tartu, Estonia; Children's Clinic, Tartu University Hospital, Tartu, Estonia
| | - Haide Põder
- Tallinn Children's Hospital, Tallinn, Estonia
| | - Kairit Joost
- Department of Genetics, United Laboratories, Tartu University Hospital, Tartu, Estonia
| | - Sanna Puusepp
- Department of Genetics, United Laboratories, Tartu University Hospital, Tartu, Estonia
| | - Andres Piirsoo
- Institute of Biomedicine and Translational Medicine, Department of Biomedicine, University of Tartu, Tartu, Estonia
| | - Werner Stenzel
- Department of Neuropathology, Charité - Universitätsmedizin, Berlin, Germany
| | - Hans H Goebel
- Department of Neuropathology, Charité - Universitätsmedizin, Berlin, Germany
| | | | - Tarmo Annilo
- Estonian Genome Center, University of Tartu, Tartu, Estonia
| | - Margit Nõukas
- Estonian Genome Center, University of Tartu, Tartu, Estonia; Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Andres Metspalu
- Estonian Genome Center, University of Tartu, Tartu, Estonia; Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Katrin Õunap
- Department of Genetics, United Laboratories, Tartu University Hospital, Tartu, Estonia; Department of Pediatrics, University of Tartu, Tartu, Estonia
| | - Tiia Reimand
- Department of Genetics, United Laboratories, Tartu University Hospital, Tartu, Estonia; Institute of Biomedicine and Translational Medicine, Department of Biomedicine, University of Tartu, Tartu, Estonia; Department of Pediatrics, University of Tartu, Tartu, Estonia
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29
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A de novo mutation of the MYH7 gene in a large Chinese family with autosomal dominant myopathy. Hum Genome Var 2015; 2:15022. [PMID: 27081534 PMCID: PMC4785580 DOI: 10.1038/hgv.2015.22] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 04/24/2015] [Accepted: 05/11/2015] [Indexed: 02/07/2023] Open
Abstract
Laing distal myopathy (LDM) is an autosomal dominant myopathy that is caused by mutations in the slow/beta cardiac myosin heavy-chain (MYH7) gene. It has been recently reported that LDM presents with a wide range of clinical manifestations. We herein report a large Chinese family with autosomal dominant myopathy. The affected individuals in the family presented with foot drop in early childhood, along with progressive distal and proximal limb weakness. Their characteristic symptoms include scapular winging and scoliosis in the early disease phase and impairment of ambulation in the advanced phase. Although limb-girdle muscle dystrophy (LGMD) was suspected initially, a definite diagnosis could not be reached. As such, we performed linkage analysis and detected four linkage regions, namely 1q23.2-24.1, 14q11.2-12, 15q26.2-26.3 and 17q24.3. Through subsequent whole exome sequencing, we found a de novo p.K1617del causative mutation in the MYH7 gene and diagnosed the disease as LDM. This is the first LDM case in China. Our patients have severe clinical manifestations that mimic LGMD in comparison with the patients with the same mutation reported elsewhere.
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30
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Reis GF, de la Motte G, Gooding R, Laing NG, Margeta M. Complex sarcolemmal invaginations mimicking myotendinous junctions in a case of Laing early-onset distal myopathy. Neuropathology 2015; 35:575-81. [DOI: 10.1111/neup.12220] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 04/20/2015] [Accepted: 04/21/2015] [Indexed: 02/01/2023]
Affiliation(s)
- Gerald F. Reis
- Department of Pathology; University of California; San Francisco CA USA
| | | | - Rebecca Gooding
- Neurogenetics Unit, PathWest Laboratory Medicine; QEII Medical Centre; Nedlands WA Australia
| | - Nigel G. Laing
- Centre for Medical Research, University of Western Australia and Harry Perkins Institute of Medical Research, QEII Medical Centre; Nedlands WA Australia
| | - Marta Margeta
- Department of Pathology; University of California; San Francisco CA USA
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The sarcomeric M-region: a molecular command center for diverse cellular processes. BIOMED RESEARCH INTERNATIONAL 2015; 2015:714197. [PMID: 25961035 PMCID: PMC4413555 DOI: 10.1155/2015/714197] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 02/08/2015] [Indexed: 02/07/2023]
Abstract
The sarcomeric M-region anchors thick filaments and withstands the mechanical stress of contractions by deformation, thus enabling distribution of physiological forces along the length of thick filaments. While the role of the M-region in supporting myofibrillar structure and contractility is well established, its role in mediating additional cellular processes has only recently started to emerge. As such, M-region is the hub of key protein players contributing to cytoskeletal remodeling, signal transduction, mechanosensing, metabolism, and proteasomal degradation. Mutations in genes encoding M-region related proteins lead to development of severe and lethal cardiac and skeletal myopathies affecting mankind. Herein, we describe the main cellular processes taking place at the M-region, other than thick filament assembly, and discuss human myopathies associated with mutant or truncated M-region proteins.
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32
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Olivé M, Abdul-Hussein S, Oldfors A, González-Costello J, van der Ven PFM, Fürst DO, González L, Moreno D, Torrejón-Escribano B, Alió J, Pou A, Ferrer I, Tajsharghi H. New cardiac and skeletal protein aggregate myopathy associated with combined MuRF1 and MuRF3 mutations. Hum Mol Genet 2015; 24:3638-50. [PMID: 25801283 DOI: 10.1093/hmg/ddv108] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 03/18/2015] [Indexed: 12/22/2022] Open
Abstract
Protein aggregate myopathies (PAMs) define muscle disorders characterized by protein accumulation in muscle fibres. We describe a new PAM in a patient with proximal muscle weakness and hypertrophic cardiomyopathy, whose muscle fibres contained inclusions containing myosin and myosin-associated proteins, and aberrant distribution of microtubules. These lesions appear as intact A- and M-bands lacking thin filaments and Z-discs. These features differ from inclusions in myosin storage myopathy (MSM), but are highly similar to those in mice deficient for the muscle-specific RING finger proteins MuRF1 and MuRF3. Sanger sequencing excluded mutations in the MSM-associated gene MYH7 but identified mutations in TRIM63 and TRIM54, encoding MuRF1 and MuRF3, respectively. No mutations in other potentially disease-causing genes were identified by Sanger and whole exome sequencing. Analysis of seven family members revealed that both mutations segregated in the family but only the homozygous TRIM63 null mutation in combination with the heterozygous TRIM54 mutation found in the proband caused the disease phenotype. Both MuRFs are microtubule-associated proteins localizing to sarcomeric M-bands and Z-discs. They are E3 ubiquitin ligases that play a role in degradation of sarcomeric proteins, stabilization of microtubules and myogenesis. Lack of ubiquitin and the 20S proteasome subunit in the inclusions found in the patient suggested impaired turnover of thick filament proteins. Disruption of microtubules in cultured myotubes was rescued by transient expression of wild-type MuRF1. The unique features of this novel myopathy point to defects in homeostasis of A-band proteins in combination with instability of microtubules as cause of the disease.
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Affiliation(s)
- Montse Olivé
- Institute of Neuropathology, Department of Pathology and Neuromuscular Unit, Department of Neurology, CIBERNED, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto Carlos III, Barcelona, Spain
| | - Saba Abdul-Hussein
- Department of Pathology, University of Gothenburg, Sahlgrenska University Hospital, Gothenburg SE-413 45, Sweden
| | - Anders Oldfors
- Department of Pathology, University of Gothenburg, Sahlgrenska University Hospital, Gothenburg SE-413 45, Sweden
| | | | - Peter F M van der Ven
- Department of Molecular Cell Biology, Institute for Cell Biology, University of Bonn, D-53121 Bonn, Germany
| | - Dieter O Fürst
- Department of Molecular Cell Biology, Institute for Cell Biology, University of Bonn, D-53121 Bonn, Germany
| | - Laura González
- Institute of Neuropathology, Department of Pathology and Neuromuscular Unit, Department of Neurology
| | - Dolores Moreno
- Institute of Neuropathology, Department of Pathology and
| | - Benjamín Torrejón-Escribano
- Scientific and Technical Services Facility, Biology Unit, CCiTUB, IDIBELL-University of Barcelona, Barcelona, Spain
| | | | - Adolf Pou
- Department of Neurology, Hospital del Mar, Barcelona, Spain
| | - Isidro Ferrer
- CIBERNED, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto Carlos III, Barcelona, Spain, Institute of Neuropathology, Department of Pathology and
| | - Homa Tajsharghi
- Department of Pathology, University of Gothenburg, Sahlgrenska University Hospital, Gothenburg SE-413 45, Sweden, Department of Clinical and Medical Genetics, University of Gothenburg, Gothenburg SE-405 30, Sweden and Systems Biology Research Centre, School of Biomedicine, University of Skövde, Skövde SE-541 28, Sweden
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Homozygous MYH7 R1820W mutation results in recessive myosin storage myopathy: scapuloperoneal and respiratory weakness with dilated cardiomyopathy. Neuromuscul Disord 2015; 25:340-4. [PMID: 25666907 DOI: 10.1016/j.nmd.2015.01.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 01/13/2015] [Accepted: 01/20/2015] [Indexed: 01/28/2023]
Abstract
Myosin storage myopathy (MSM) is a protein aggregate myopathy caused by the accumulation of myosin in muscle fibres and results from MYH7 mutation. Although MYH7 mutation is also an established cause of variable cardiomyopathy with or without skeletal myopathy, cardiomyopathy with MSM is a rare combination. Here, we update the clinical findings in the two brothers that we previously reported as having recessively inherited MSM characterized by scapuloperoneal distribution of weakness and typical hyaline-like bodies in type 1 muscle fibres. One of the patients, weak from childhood but not severely symptomatic until 28 years of age, had an unusual combination of MSM, severe dilated cardiomyopathy, and respiratory impairment at the age of 44 years. We identified homozygous missense mutation c.5458C>T (p.R1820W) in exon 37 in these patients as the second recessive MYH7 mutation reported to date.
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A rare mutation in MYH7 gene occurs with overlapping phenotype. Biochem Biophys Res Commun 2015; 457:262-6. [PMID: 25576864 DOI: 10.1016/j.bbrc.2014.12.098] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 12/22/2014] [Indexed: 01/22/2023]
Abstract
Mutations in the beta-myosin heavy chain gene (MYH7) cause different muscle disorders. The specific molecular pathobiological processes that cause these different phenotypes remains unexplained. We describe three members of a family with an autosomal dominant mutation in the distal rod of MYH7 [c.5401G> A (p.Glu1801Lys)] displaying a complex phenotype characterized by Laing Distal Myopathy like phenotype, left ventricular non compaction cardiomyopathy and Fiber Type Disproportion picture at muscle biopsy. We suggest that this overlapping presentation confirm the phenotypic variability of MYH7 myopathy and may be helpful to improve the genotype phenotype correlation.
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35
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Abstract
ABSTRACT:Background:Hyaline body myopathy (HBM) is a rare chronic nonprogressive congenital myopathy, with variable patterns of inheritance.Methods:We describe a patient with congenital HBM with progression of weakness and increasing muscle pain in adulthood. Three muscle biopsies, done at various times in her life, are reported.Results:Symptoms started during childhood; however, as an adult, following a period of stability with no progression of the disease, the patient became symptomatic with worsening proximal limb weakness, severe aching pain and hypertrophy of calves. Moderate elevations of serum creatine kinase and myopathic features were noted on electrophysiologic testing. Muscle pathology showed significant fatty infiltration of skeletal muscle and increased number of fibers with internal nuclei. Histology demonstrated the presence of subsarcolemmal, well-delineated hyaline areas, which on histochemical studies was shown to be limited to type1 fibers. The hyaline bodies were dark with pH 4.2 ATPase and with immunohistochemical studies reacted only with myosin heavy chain slow. Electron microscopy showed the hyaline bodies to be composed of nonmembrane bound, fairly even sized granular material, which merged with the adjacent myofibrils. Earlier muscle biopsies, done during childhood, also revealed presence of similar subsarcolemmal hyaline deposits.Conclusion:There appears to be a pattern of presentation with adulthood progression in HBM, which has not been described before. Further case studies are required to understand the clinical progression in HBM.
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Affiliation(s)
- Mubeen F Rafay
- Division of Neurology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada
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Roda RH, Schindler AB, Blackstone C, Mammen AL, Corse AM, Lloyd TE. Laing distal myopathy pathologically resembling inclusion body myositis. Ann Clin Transl Neurol 2014; 1:1053-8. [PMID: 25574480 PMCID: PMC4284131 DOI: 10.1002/acn3.140] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 10/13/2014] [Accepted: 10/14/2014] [Indexed: 11/18/2022] Open
Abstract
Mutations in MYH7 cause autosomal dominant Laing distal myopathy. We present a family with a previously reported deletion (c.5186_5188delAGA, p.K1729del). Muscle pathology in one family member was characterized by an inflammatory myopathy with rimmed vacuoles, increased MHC Class I expression, and perivascular and endomysial muscle inflammation comprising CD3+, CD4+, CD8+, and CD68+ inflammatory cells. Interestingly, this biopsy specimen contained TDP-43, p62, and SMI-31-positive protein aggregates typical of inclusion body myositis. These findings should alert physicians to the possibility that patients with MYH7 mutations may have muscle biopsies showing pathologic findings similar to inclusion body myositis.
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Affiliation(s)
- Ricardo H Roda
- Neuromuscular Disorders and Neurogenetics Divisions, Department of Neurology, New York University Langone Medical Center New York, New York ; Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health Bethesda, Maryland
| | - Alice B Schindler
- Hereditary Neurological Diseases Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health Bethesda, Maryland
| | - Craig Blackstone
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health Bethesda, Maryland
| | - Andrew L Mammen
- Department of Neurology, Johns Hopkins University School of Medicine Baltimore, Maryland ; Department of Medicine, Johns Hopkins University School of Medicine Baltimore, Maryland ; Muscle Disease Unit, Laboratory of Muscle Stem Cells and Gene Regulation, National Institutes of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health Bethesda, Maryland
| | - Andrea M Corse
- Department of Neurology, Johns Hopkins University School of Medicine Baltimore, Maryland
| | - Thomas E Lloyd
- Department of Neurology, Johns Hopkins University School of Medicine Baltimore, Maryland ; Department of Neuroscience, Johns Hopkins University School of Medicine Baltimore, Maryland
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Finsterer J, Brandau O, Stöllberger C, Wallefeld W, Laing NG, Laccone F. Distal myosin heavy chain-7 myopathy due to the novel transition c.5566G>A (p.E1856K) with high interfamilial cardiac variability and putative anticipation. Neuromuscul Disord 2014; 24:721-5. [PMID: 24953931 DOI: 10.1016/j.nmd.2014.05.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 05/17/2014] [Accepted: 05/21/2014] [Indexed: 11/25/2022]
Abstract
Myosin-heavy-chain 7 (MYH7)-myopathy manifests clinically with a distal, scapuloperoneal, limb-girdle (proximal), or axial distribution and may involve the respiratory muscles. Cardiac involvement is frequent, ranging from relaxation impairment to severe dilative cardiomyopathy. Progression and earlier onset of cardiac disease in successive generations with MYH7-myopathy is unreported. In a five-generation family MYH7-myopathy due to the novel c.5566G > A (p.E1856K) mutation manifested with late-onset, distal > proximal myopathy and variable degree of cardiac involvement. The index patient developed distal myopathy since age 49 y and anginal chest pain. Her mother had distal myopathy and impaired myocardial relaxation. The daughter of the index patient had discrete myopathy but left ventricular hypertrabeculation/noncompaction and ventricular arrhythmias requiring an implantable cardioverter defibrillator. The granddaughter of the index patient had infantile dilated cardiomyopathy without overt myopathy. Cardiac involvement may be present in MYH7-myopathy and may be progressive between the generations, ranging from relaxation abnormality to noncompaction, ventricular arrhythmias, and dilated cardiomyopathy.
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Affiliation(s)
| | - Oliver Brandau
- Institute of Medical Genetics, Medical University of Vienna, Währinger Strasse 10, 1090 Vienna, Austria
| | - Claudia Stöllberger
- 2nd Medical Department with Cardiology and Intensive Care Medicine Krankenanstalt Rudolfstiftung, Vienna, Austria
| | - William Wallefeld
- Centre for Medical Research, University of Western Australia and Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia 6009, Australia
| | - Nigel G Laing
- Centre for Medical Research, University of Western Australia and Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia 6009, Australia
| | - Franco Laccone
- Institute of Medical Genetics, Medical University of Vienna, Währinger Strasse 10, 1090 Vienna, Austria
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Lamont PJ, Wallefeld W, Hilton-Jones D, Udd B, Argov Z, Barboi AC, Bonneman C, Boycott KM, Bushby K, Connolly AM, Davies N, Beggs AH, Cox GF, Dastgir J, DeChene ET, Gooding R, Jungbluth H, Muelas N, Palmio J, Penttilä S, Schmedding E, Suominen T, Straub V, Staples C, Van den Bergh PYK, Vilchez JJ, Wagner KR, Wheeler PG, Wraige E, Laing NG. Novel mutations widen the phenotypic spectrum of slow skeletal/β-cardiac myosin (MYH7) distal myopathy. Hum Mutat 2014; 35:868-79. [PMID: 24664454 DOI: 10.1002/humu.22553] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 03/10/2014] [Indexed: 01/01/2023]
Abstract
Laing early onset distal myopathy and myosin storage myopathy are caused by mutations of slow skeletal/β-cardiac myosin heavy chain encoded by the gene MYH7, as is a common form of familial hypertrophic/dilated cardiomyopathy. The mechanisms by which different phenotypes are produced by mutations in MYH7, even in the same region of the gene, are not known. To explore the clinical spectrum and pathobiology, we screened the MYH7 gene in 88 patients from 21 previously unpublished families presenting with distal or generalized skeletal muscle weakness, with or without cardiac involvement. Twelve novel mutations have been identified in thirteen families. In one of these families, the father of the proband was found to be a mosaic for the MYH7 mutation. In eight cases, de novo mutation appeared to have occurred, which was proven in four. The presenting complaint was footdrop, sometimes leading to delayed walking or tripping, in members of 17 families (81%), with other presentations including cardiomyopathy in infancy, generalized floppiness, and scoliosis. Cardiac involvement as well as skeletal muscle weakness was identified in nine of 21 families. Spinal involvement such as scoliosis or rigidity was identified in 12 (57%). This report widens the clinical and pathological phenotypes, and the genetics of MYH7 mutations leading to skeletal muscle diseases.
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Affiliation(s)
- Phillipa J Lamont
- Neurogenetic Unit, Department of Neurology, Royal Perth Hospital, Western Australia, Australia; Diagnostic Genomics Laboratory, Pathwest, Queen Elizabeth II Medical Centre, Nedlands, Western Australia, Australia
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North KN, Wang CH, Clarke N, Jungbluth H, Vainzof M, Dowling JJ, Amburgey K, Quijano-Roy S, Beggs AH, Sewry C, Laing NG, Bönnemann CG. Approach to the diagnosis of congenital myopathies. Neuromuscul Disord 2014; 24:97-116. [PMID: 24456932 PMCID: PMC5257342 DOI: 10.1016/j.nmd.2013.11.003] [Citation(s) in RCA: 187] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 11/06/2013] [Accepted: 11/08/2013] [Indexed: 10/26/2022]
Abstract
Over the past decade there have been major advances in defining the genetic basis of the majority of congenital myopathy subtypes. However the relationship between each congenital myopathy, defined on histological grounds, and the genetic cause is complex. Many of the congenital myopathies are due to mutations in more than one gene, and mutations in the same gene can cause different muscle pathologies. The International Standard of Care Committee for Congenital Myopathies performed a literature review and consulted a group of experts in the field to develop a summary of (1) the key features common to all forms of congenital myopathy and (2) the specific features that help to discriminate between the different genetic subtypes. The consensus statement was refined by two rounds of on-line survey, and a three-day workshop. This consensus statement provides guidelines to the physician assessing the infant or child with hypotonia and weakness. We summarise the clinical features that are most suggestive of a congenital myopathy, the major differential diagnoses and the features on clinical examination, investigations, muscle pathology and muscle imaging that are suggestive of a specific genetic diagnosis to assist in prioritisation of genetic testing of known genes. As next generation sequencing becomes increasingly used as a diagnostic tool in clinical practise, these guidelines will assist in determining which sequence variations are likely to be pathogenic.
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Affiliation(s)
- Kathryn N North
- Murdoch Childrens Research Institute, Royal Children's Hospital, Flemington Road, Parkville, Melbourne, Victoria 3052, Australia; Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, University of Sydney, Sydney, Australia.
| | - Ching H Wang
- Driscoll Children's Hospital, Corpus Christi, TX, United States
| | - Nigel Clarke
- Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, University of Sydney, Sydney, Australia
| | - Heinz Jungbluth
- Evelina Children's Hospital, Department of Paediatric Neurology, London, United Kingdom; Randall Division for Cell and Molecular Biophysics, Muscle Signalling Section, King's College, London, United Kingdom; Clinical Neuroscience Division, IoP, London, United Kingdom
| | - Mariz Vainzof
- Human Genome Research Center, University of Sao Paulo, Sao Paulo, Brazil
| | - James J Dowling
- Division of Neurology, Department of Paediatrics, Hospital for Sick Children, Toronto, ON, Canada
| | - Kimberly Amburgey
- Division of Neurology, Department of Paediatrics, Hospital for Sick Children, Toronto, ON, Canada
| | - Susana Quijano-Roy
- Department of Pediatrics, Garches Neuromuscular Reference Center (GNMH), APHP Raymond Poincare University Hospital (UVSQ), Garches, France
| | - Alan H Beggs
- Children's Hospital Boston, Boston, MA, United States
| | - Caroline Sewry
- Dubowitz Neuromuscular Centre, London, United Kingdom; Wolfson Centre of Inherited Neuromuscular Diseases, RJAH Orthopaedic Hospital, Oswestry, United Kingdom
| | - Nigel G Laing
- Centre for Medical Research, University of Western Australia and Harry Perkins Institute of Medical Research, QQ Building, QEII Medical Centre, Nedlands, Western Australia 6009, Australia
| | - Carsten G Bönnemann
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, Bethesda, MD, United States
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40
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Exome sequencing identifies Laing distal myopathy MYH7 mutation in a Roma family previously diagnosed with distal neuronopathy. Neuromuscul Disord 2014; 24:156-61. [DOI: 10.1016/j.nmd.2013.10.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 10/08/2013] [Accepted: 10/31/2013] [Indexed: 11/22/2022]
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Recessive myosin myopathy with external ophthalmoplegia associated with MYH2 mutations. Eur J Hum Genet 2013; 22:801-8. [PMID: 24193343 DOI: 10.1038/ejhg.2013.250] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 08/28/2013] [Accepted: 10/01/2013] [Indexed: 11/08/2022] Open
Abstract
Myosin myopathies comprise a group of inherited diseases caused by mutations in myosin heavy chain (MyHC) genes. Homozygous or compound heterozygous truncating MYH2 mutations have been demonstrated to cause recessive myopathy with ophthalmoplegia, mild-to-moderate muscle weakness and complete lack of type 2A muscle fibers. In this study, we describe for the first time the clinical and morphological characteristics of recessive myosin IIa myopathy associated with MYH2 missense mutations. Seven patients of five different families with a myopathy characterized by ophthalmoplegia and mild-to-moderate muscle weakness were investigated. Muscle biopsy was performed to study morphological changes and MyHC isoform expression. Five of the patients were homozygous for MYH2 missense mutations, one patient was compound heterozygous for a missense and a nonsense mutation and one patient was homozygous for a frame-shift MYH2 mutation. Muscle biopsy demonstrated small or absent type 2A muscle fibers and reduced or absent expression of the corresponding MyHC IIa transcript and protein. We conclude that mild muscle weakness and ophthalmoplegia in combination with muscle biopsy demonstrating small or absent type 2A muscle fibers are the hallmark of recessive myopathy associated with MYH2 mutations.
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Al-Khayat HA. Three-dimensional structure of the human myosin thick filament: clinical implications. Glob Cardiol Sci Pract 2013; 2013:280-302. [PMID: 24689030 PMCID: PMC3963759 DOI: 10.5339/gcsp.2013.36] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 10/11/2013] [Indexed: 11/27/2022] Open
Abstract
High resolution information about the three-dimensional (3D) structure of myosin filaments has always been hard to obtain. Solving the 3D structure of myosin filaments is very important because mutations in human cardiac muscle myosin and its associated proteins (e.g. titin and myosin binding protein C) are known to be associated with a number of familial human cardiomyopathies (e.g. hypertrophic cardiomyopathy and dilated cardiomyopathy). In order to understand how normal heart muscle works and how it fails, as well as the effects of the known mutations on muscle contractility, it is essential to properly understand myosin filament 3D structure and properties in both healthy and diseased hearts. The aim of this review is firstly to provide a general overview of the 3D structure of myosin thick filaments, as studied so far in both vertebrates and invertebrate striated muscles. Knowledge of this 3D structure is the starting point from which myosin filaments isolated from human cardiomyopathic samples, with known mutations in either myosin or its associated proteins (titin or C-protein), can be studied in detail. This should, in turn, enable us to relate the structure of myosin thick filament to its function and to understanding the disease process. A long term objective of this research would be to assist the design of possible therapeutic solutions to genetic myosin-related human cardiomyopathies.
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Affiliation(s)
- Hind A Al-Khayat
- Qatar Cardiovascular Research Centre, Qatar Foundation, PO Box 5825, Doha, Qatar
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43
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Weterman MAJ, Barth PG, van Spaendonck-Zwarts KY, Aronica E, Poll-The BT, Brouwer OF, van Tintelen JP, Qahar Z, Bradley EJ, de Wissel M, Salviati L, Angelini C, van den Heuvel L, Thomasse YEM, Backx AP, Nürnberg G, Nürnberg P, Baas F. Recessive MYL2 mutations cause infantile type I muscle fibre disease and cardiomyopathy. ACTA ACUST UNITED AC 2013; 136:282-93. [PMID: 23365102 DOI: 10.1093/brain/aws293] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A cardioskeletal myopathy with onset and death in infancy, morphological features of muscle type I hypotrophy with myofibrillar disorganization and dilated cardiomyopathy was previously reported in three Dutch families. Here we report the genetic cause of this disorder. Multipoint parametric linkage analysis of six Dutch patients identified a homozygous region of 2.1 Mb on chromosome 12, which was shared between all Dutch patients, with a log of odds score of 10.82. Sequence analysis of the entire linkage region resulted in the identification of a homozygous mutation in the last acceptor splice site of the myosin regulatory light chain 2 gene (MYL2) as the genetic cause. MYL2 encodes a myosin regulatory light chain (MLC-2V). The myosin regulatory light chains bind, together with the essential light chains, to the flexible neck region of the myosin heavy chain in the hexameric myosin complex and have a structural and regulatory role in muscle contraction. The MYL2 mutation results in use of a cryptic splice site upstream of the last exon causing a frameshift and replacement of the last 32 codons by 20 different codons. Whole exome sequencing of an Italian patient with similar clinical features showed compound heterozygosity for two other mutations affecting the same exon of MYL2, also resulting in mutant proteins with altered C-terminal tails. As a consequence of these mutations, the second EF-hand domain is disrupted. EF-hands, assumed to function as calcium sensors, can undergo a conformational change upon binding of calcium that is critical for interactions with downstream targets. Immunohistochemical staining of skeletal muscle tissue of the Dutch patients showed a diffuse and weak expression of the mutant protein without clear fibre specificity, while normal protein was absent. Heterozygous missense mutations in MYL2 are known to cause dominant hypertrophic cardiomyopathy; however, none of the parents showed signs of cardiomyopathy. In conclusion, the mutations in the last exon of MYL2 are responsible for a novel autosomal recessive lethal myosinopathy due to defects changing the C-terminal tail of the ventricular form of the myosin regulatory light chain. We propose 'light chain myopathy' as a name for this MYL2-associated myopathy.
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Affiliation(s)
- Marian A J Weterman
- Department of Genome Analysis k2-213, Academic Medical Centre Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
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Clarke NF, Amburgey K, Teener J, Camelo-Piragua S, Kesari A, Punetha J, Waddell LB, Davis M, Laing NG, Monnier N, North KN, Hoffman EP, Dowling JJ. A novel mutation expands the genetic and clinical spectrum of MYH7-related myopathies. Neuromuscul Disord 2013; 23:432-6. [PMID: 23478172 DOI: 10.1016/j.nmd.2013.02.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 02/08/2013] [Accepted: 02/12/2013] [Indexed: 01/16/2023]
Abstract
MYH7 mutations are an established cause of Laing distal myopathy, myosin storage myopathy, and cardiomyopathy, as well as additional myopathy subtypes. We report a novel MYH7 mutation (p.Leu1597Arg) that arose de novo in two unrelated probands. Proband 1 has a myopathy characterized by distal weakness and prominent contractures and histopathology typical of multi-minicore disease. Proband 2 has an axial myopathy and histopathology consistent with congenital fiber type disproportion. These cases highlight the broad spectrum of clinical and histological patterns associated with MYH7 mutations, and provide further evidence that MYH7 is likely responsible for a greater proportion of congenital myopathies than currently appreciated.
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Affiliation(s)
- Nigel F Clarke
- INMR, The Children's Hospital at Westmead & Discipline of Paediatrics and Child Health, University of Sydney, Sydney, Australia
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Tajsharghi H, Oldfors A. Myosinopathies: pathology and mechanisms. Acta Neuropathol 2013; 125:3-18. [PMID: 22918376 PMCID: PMC3535372 DOI: 10.1007/s00401-012-1024-2] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 06/27/2012] [Accepted: 07/19/2012] [Indexed: 11/24/2022]
Abstract
The myosin heavy chain (MyHC) is the molecular motor of muscle and forms the backbone of the sarcomere thick filaments. Different MyHC isoforms are of importance for the physiological properties of different muscle fiber types. Hereditary myosin myopathies have emerged as an important group of diseases with variable clinical and morphological expression depending on the mutated isoform and type and location of the mutation. Dominant mutations in developmental MyHC isoform genes (MYH3 and MYH8) are associated with distal arthrogryposis syndromes. Dominant or recessive mutations affecting the type IIa MyHC (MYH2) are associated with early-onset myopathies with variable muscle weakness and ophthalmoplegia as a consistent finding. Myopathies with scapuloperoneal, distal or limb-girdle muscle weakness including entities, such as myosin storage myopathy and Laing distal myopathy are the result of usually dominant mutations in the gene for slow/β cardiac MyHC (MYH7). Protein aggregation is part of the features in some of these myopathies. In myosin storage myopathy protein aggregates are formed by accumulation of myosin beneath the sarcolemma and between myofibrils. In vitro studies on the effects of different mutations associated with myosin storage myopathy and Laing distal myopathy indicate altered biochemical and biophysical properties of the light meromyosin, which is essential for thick filament assembly. Protein aggregates in the form of tubulofilamentous inclusions in association with vacuolated muscle fibers are present at late stage of dominant myosin IIa myopathy and sometimes in Laing distal myopathy. These protein aggregates exhibit features indicating defective degradation of misfolded proteins. In addition to protein aggregation and muscle fiber degeneration some of the myosin mutations cause functional impairment of the molecular motor adding to the pathogenesis of myosinopathies.
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Affiliation(s)
- Homa Tajsharghi
- Department of Pathology, Institute of Biomedicine, University of Gothenburg, Sahlgrenska University Hospital, 413 45 Gothenburg, Sweden
| | - Anders Oldfors
- Department of Pathology, Institute of Biomedicine, University of Gothenburg, Sahlgrenska University Hospital, 413 45 Gothenburg, Sweden
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46
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Abstract
Congenital myopathies are a heterogeneous group of inherited muscle disorders, characterized by the predominance of particular histopathological features on muscle biopsy, such as cores (central core disease) or rods (nemaline myopathy). Clinically, early onset of the disease, stable or slowly progressive muscle weakness, hypotonia and delayed motor development are common in most forms. As a result, the diagnosis of a subtype of congenital myopathy is largely based on the presence of specific structural abnormalities in the skeletal muscle detected by enzyme-histochemistry and electron microscopy studies. During the last decades there have been significant advances in the identification of the genetic basis of most congenital myopathies. However, there is significant genetic heterogeneity within the main groups of congenital myopathies, and mutations in one particular gene may also cause diverse clinical and morphological phenotypes. Thus, the nosography and nosology in this field is still evolving.
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Affiliation(s)
- Norma Beatriz Romero
- Morphology Neuromuscular Unit of the Myology Institute, GHU Pitié-Salpêtrière, Paris, France.
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Tasca G, Odgerel Z, Monforte M, Aurino S, Clarke NF, Waddell LB, Udd B, Ricci E, Goldfarb LG. Novel FLNC mutation in a patient with myofibrillar myopathy in combination with late-onset cerebellar ataxia. Muscle Nerve 2012; 46:275-82. [PMID: 22806379 DOI: 10.1002/mus.23349] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
INTRODUCTION Mutations in the gene that encodes filamin C, FLNC, represent a rare cause of a distinctive type of myofibrillar myopathy (MFM). METHODS We investigated an Italian patient by means of muscle biopsy, muscle and brain imaging and molecular analysis of MFM genes. RESULTS The patient harbored a novel 7256C>T, p.Thr2419Met mutation in exon 44 of FLNC. Clinical, pathological and muscle MRI findings were similar to the previously described filaminopathy cases. This patient had, in addition, cerebellar ataxia with atrophy of cerebellum and vermis evident on brain MRI scan. Extensive screening failed to establish a cause of cerebellar atrophy. CONCLUSIONS We report an Italian filaminopathy patient, with a novel mutation in a highly conserved region. This case raises the possibility that the disease spectrum caused by FLNC may include cerebellar dysfunction.
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McMillan EM, Graham DA, Rush JWE, Quadrilatero J. Decreased DNA fragmentation and apoptotic signaling in soleus muscle of hypertensive rats following 6 weeks of treadmill training. J Appl Physiol (1985) 2012; 113:1048-57. [DOI: 10.1152/japplphysiol.00290.2012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cardiovascular diseases such as hypertension are associated with a generalized skeletal myopathy including a proapoptotic phenotype. Current evidence suggests that exercise may alter apoptosis-related signaling in skeletal muscle; however, the effect of exercise on skeletal muscle DNA fragmentation and apoptotic signaling is unclear in hypertensive animals. Male normotensive Wistar Kyoto (WKY; n = 24) and spontaneously hypertensive rats (SHR; n = 24) were assigned to a sedentary (SED) condition or exercise (EX) consisting of progressive treadmill running 5 days/wk for 6 wks. Consistent with our previous work we found that soleus muscle of hypertensive animals had significantly higher DNA fragmentation (a hallmark of apoptosis), elevated proapoptotic factors (Bax, caspase-3 activity), and lower antiapoptotic proteins (apoptosis repressor with caspase recruitment domain, Bcl-2, X-linked inhibitor of apoptosis protein) compared with normotensive rats. In addition, soleus muscle of hypertensive animals displayed myosin accumulation and fragmentation, had elevated cytosolic cytochrome c, second mitochondrial-derived activator of caspase (Smac), apoptosis inducing factor (AIF), and endonuclease G protein levels, higher nuclear AIF content, and greater muscle reactive oxygen species generation compared with normotensive animals. Interestingly, exercise training significantly lowered DNA fragmentation and myosin accumulation/fragmentation in soleus muscle of hypertensive rats. Furthermore, exercise training significantly reduced cytosolic levels of cytochrome c as well as cytosolic and nuclear AIF in soleus muscle of hypertensive animals. This beneficial response is likely due to exercise-mediated elevations in Bcl-2, heat shock protein 70, and manganese superoxide dismutase protein content, as well as reductions in Bax protein levels and the Bax-to-Bcl-2 ratio. These results suggest that regular exercise training provides protection against skeletal muscle apoptosis by altering a number of apoptosis regulatory proteins and by influencing mitochondrial-mediated apoptotic signaling mechanisms.
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Affiliation(s)
- Elliott M. McMillan
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Drew A. Graham
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - James W. E. Rush
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Joe Quadrilatero
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
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Abstract
Neuromuscular disorders affect the peripheral nervous system and muscle. The principle effect of neuromuscular disorders is therefore on the ability to perform voluntary movements. Neuromuscular disorders cause significant incapacity, including, at the most extreme, almost complete paralysis. Neuromuscular diseases include some of the most devastating disorders that afflict mankind, for example motor neuron disease. Neuromuscular diseases have onset any time from in utero until old age. They are most often genetic. The last 25 years has been the golden age of genetics, with the disease genes responsible for many genetic neuromuscular disorders now identified. Neuromuscular disorders may be inherited as autosomal dominant, autosomal recessive, or X-linked traits. They may also result from mutations in mitochondrial DNA or from de novo mutations not present in the peripheral blood DNA of either parent. The high incidence of de novo mutation has been one of the surprises of the recent increase in information about the genetics of neuromuscular disorders. The disease burden imposed on families is enormous including decision making in relation to presymptomatic diagnosis for late onset neurodegenerative disorders and reproductive choices. Diagnostic molecular neurogenetics laboratories have been faced with an ever-increasing range of disease genes that could be tested for and usually a finite budget with which to perform the possible testing. Neurogenetics has moved from one known disease gene, the Duchenne muscular dystrophy gene in July 1987, to hundreds of disease genes in 2011. It can be anticipated that with the advent of next generation sequencing (NGS), most, if not all, causative genes will be identified in the next few years. Any type of mutation possible in human DNA has been shown to cause genetic neuromuscular disorders, including point mutations, small insertions and deletions, large deletions and duplications, repeat expansions or contraction and somatic mosaicism. The diagnostic laboratory therefore has to be capable of a large number of techniques in order to identify the different mutation types and requires highly skilled staff. Mutations causing neuromuscular disorders affect the largest human proteins for example titin and nebulin. Successful molecular diagnosis can make invasive and expensive diagnostic procedures such as muscle biopsy unnecessary. Molecular diagnosis is currently largely based on Sanger sequencing, which at most can sequence a small number of exons in one gene at a time. NGS techniques will facilitate molecular diagnostics, but not for all types of mutations. For example, NGS is not good at identifying repeat expansions or copy number variations. Currently, diagnostic molecular neurogenetics is focused on identifying the causative mutation(s) in a patient. In the future, the focus might move to prevention, by identifying carriers of recessive diseases before they have affected children. The pathobiology of many of the diseases remains obscure, as do factors affecting disease severity. The aim of this review is to describe molecular diagnosis of genetic neuromuscular disorders in the past, the present and speculate on the future.
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Affiliation(s)
- Nigel G Laing
- Centre for Medical Research, University of Western Australia, Western Australian Institute for Medical Research, Nedlands, Western Australia, Australia.
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Cullup T, Lamont PJ, Cirak S, Damian MS, Wallefeld W, Gooding R, Tan SV, Sheehan J, Muntoni F, Abbs S, Sewry CA, Dubowitz V, Laing NG, Jungbluth H. Mutations in MYH7 cause Multi-minicore Disease (MmD) with variable cardiac involvement. Neuromuscul Disord 2012; 22:1096-104. [PMID: 22784669 DOI: 10.1016/j.nmd.2012.06.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Revised: 05/28/2012] [Accepted: 06/12/2012] [Indexed: 10/28/2022]
Abstract
Central Core Disease (CCD) and Multi-minicore Disease (MmD) (the "core myopathies") have been mainly associated with mutations in the skeletal muscle ryanodine receptor (RYR1) and the selenoprotein N (SEPN1) gene. A proportion of cases remain unresolved. Mutations in MYH7 encoding the beta myosin heavy chain protein have been implicated in cardiac and, less frequently, skeletal muscle disorders. Here we report four patients from two families with a histopathological diagnosis of MmD, presenting in childhood with slowly progressive muscle weakness, more proximal in Family 1 and more distal in Family 2, and variable degrees of cardiorespiratory impairment evolving later in life. There was also a strong family history of sudden death in the first family. Muscle biopsies obtained in early childhood showed multiple minicores as the most prominent feature. Sequencing of the MYH7 gene revealed heterozygous missense mutations, c.4399C>G; p.Leu1467Val (exon 32) in Family 1 and c.4763G>C; p.Arg1588Pro (exon 34) in Family 2. These findings suggest MYH7 mutations as another cause of a myopathy with multiple cores, in particular if associated with dominant inheritance and cardiac involvement. However, clinical features previously associated with this genetic background, namely a more distal distribution of weakness and an associated cardiomyopathy, may only evolve over time.
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Affiliation(s)
- T Cullup
- DNA Laboratory, GSTS Pathology, Guy's Hospital, London, UK
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