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Buvoli M, Wilson GC, Buvoli A, Gugel JF, Hau A, Bönnemann CG, Paradas C, Ryba DM, Woulfe KC, Walker LA, Buvoli T, Ochala J, Leinwand LA. A Laing distal myopathy-associated proline substitution in the β-myosin rod perturbs myosin cross-bridging activity. J Clin Invest 2024; 134:e172599. [PMID: 38690726 PMCID: PMC11060730 DOI: 10.1172/jci172599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 03/11/2024] [Indexed: 05/03/2024] Open
Abstract
Proline substitutions within the coiled-coil rod region of the β-myosin gene (MYH7) are the predominant mutations causing Laing distal myopathy (MPD1), an autosomal dominant disorder characterized by progressive weakness of distal/proximal muscles. We report that the MDP1 mutation R1500P, studied in what we believe to be the first mouse model for the disease, adversely affected myosin motor activity despite being in the structural rod domain that directs thick filament assembly. Contractility experiments carried out on isolated mutant muscles, myofibrils, and myofibers identified muscle fatigue and weakness phenotypes, an increased rate of actin-myosin detachment, and a conformational shift of the myosin heads toward the more reactive disordered relaxed (DRX) state, causing hypercontractility and greater ATP consumption. Similarly, molecular analysis of muscle biopsies from patients with MPD1 revealed a significant increase in sarcomeric DRX content, as observed in a subset of myosin motor domain mutations causing hypertrophic cardiomyopathy. Finally, oral administration of MYK-581, a small molecule that decreases the population of heads in the DRX configuration, significantly improved the limited running capacity of the R1500P-transgenic mice and corrected the increased DRX state of the myofibrils from patients. These studies provide evidence of the molecular pathogenesis of proline rod mutations and lay the groundwork for the therapeutic advancement of myosin modulators.
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Affiliation(s)
- Massimo Buvoli
- Department of Molecular, Cellular and Developmental Biology, and
- BioFrontiers Institute, Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA
| | - Genevieve C.K. Wilson
- Department of Molecular, Cellular and Developmental Biology, and
- BioFrontiers Institute, Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA
| | - Ada Buvoli
- Department of Molecular, Cellular and Developmental Biology, and
- BioFrontiers Institute, Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA
| | - Jack F. Gugel
- Department of Molecular, Cellular and Developmental Biology, and
- BioFrontiers Institute, Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA
| | - Abbi Hau
- Centre of Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, Faculty of Life Sciences and Medicine, and
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, Faculty of Life Sciences and Medicine, Guy’s Campus, King’s College London, London, United Kingdom
| | - Carsten G. Bönnemann
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke (NINDS), NIH, Bethesda, Maryland, USA
| | - Carmen Paradas
- Neuromuscular Unit, Department of Neurology, Instituto de Biomedicina de Sevilla (IBIS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain
| | | | - Kathleen C. Woulfe
- Division of Cardiology, Department of Medicine, University of Colorado, Denver, Colorado, USA
| | - Lori A. Walker
- Division of Cardiology, Department of Medicine, University of Colorado, Denver, Colorado, USA
| | - Tommaso Buvoli
- Department of Mathematics, Tulane University, New Orleans, Louisiana, USA
| | - Julien Ochala
- Centre of Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, Faculty of Life Sciences and Medicine, and
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, Faculty of Life Sciences and Medicine, Guy’s Campus, King’s College London, London, United Kingdom
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Leslie A. Leinwand
- Department of Molecular, Cellular and Developmental Biology, and
- BioFrontiers Institute, Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA
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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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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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Alessi CE, Wu Q, Whitaker CH, Felice KJ. Laing Myopathy: Report of 4 New Families With Novel MYH7 Mutations, Double Mutations, and Severe Phenotype. J Clin Neuromuscul Dis 2020; 22:22-34. [PMID: 32833721 DOI: 10.1097/cnd.0000000000000297] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Laing distal myopathy (LDM) is an autosomal dominant disorder caused by mutations in the slow skeletal muscle fiber myosin heavy chain (MYH7) gene on chromosome 14q11.2. The classic LDM phenotype-including early-onset, initial involvement of foot dorsiflexors and great toe extensors, followed by weakness of neck flexors and finger extensors-is well documented. Since the original report by Laing et al in 1995, the spectrum of MYH7-related myopathies has expanded to include congenital myopathies, late-onset myopathies, myosin storage myopathy, and scapuloperoneal myopathies. Most patients with LDM harbor mutations in the midrod domain of the MYH7 gene, but rare cases document disease-associated mutations in the globular head region. In this report, we add to the medical literature by describing the clinicopathological findings in 8 affected family members from 4 new LDM families-including 2 with novel MYH7 mutations (Y162D and A1438P), one with dual mutations (V39M and K1617del), and one family (E1508del) with severe early-onset weakness associated with contractures, respiratory insufficiency, and dilated cardiomyopathy. Our families highlight the ever-expanding clinical spectrum and genetic variation of the skeletal myopathies related to MYH7 gene mutations.
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Affiliation(s)
| | - Qian Wu
- Pathology and Laboratory Medicine, University of Connecticut School of Medicine, Farmington, CT; and
| | - Charles H Whitaker
- Department of Neuromuscular Medicine, Muscular Dystrophy Association Care Center, Hospital for Special Care, New Britain, CT
| | - Kevin J Felice
- Department of Neuromuscular Medicine, Muscular Dystrophy Association Care Center, Hospital for Special Care, New Britain, CT
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Papadimas GK, Xirou S, Kararizou E, Papadopoulos C. Update on Congenital Myopathies in Adulthood. Int J Mol Sci 2020; 21:ijms21103694. [PMID: 32456280 PMCID: PMC7279481 DOI: 10.3390/ijms21103694] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/17/2020] [Accepted: 05/19/2020] [Indexed: 12/11/2022] Open
Abstract
Congenital myopathies (CMs) constitute a group of heterogenous rare inherited muscle diseases with different incidences. They are traditionally grouped based on characteristic histopathological findings revealed on muscle biopsy. In recent decades, the ever-increasing application of modern genetic technologies has not just improved our understanding of their pathophysiology, but also expanded their phenotypic spectrum and contributed to a more genetically based approach for their classification. Later onset forms of CMs are increasingly recognised. They are often considered milder with slower progression, variable clinical presentations and different modes of inheritance. We reviewed the key features and genetic basis of late onset CMs with a special emphasis on those forms that may first manifest in adulthood.
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Sarcomeric Gene Variants and Their Role with Left Ventricular Dysfunction in Background of Coronary Artery Disease. Biomolecules 2020; 10:biom10030442. [PMID: 32178433 PMCID: PMC7175236 DOI: 10.3390/biom10030442] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 03/11/2020] [Indexed: 12/18/2022] Open
Abstract
: Cardiovascular diseases are one of the leading causes of death in developing countries, generally originating as coronary artery disease (CAD) or hypertension. In later stages, many CAD patients develop left ventricle dysfunction (LVD). Left ventricular ejection fraction (LVEF) is the most prevalent prognostic factor in CAD patients. LVD is a complex multifactorial condition in which the left ventricle of the heart becomes functionally impaired. Various genetic studies have correlated LVD with dilated cardiomyopathy (DCM). In recent years, enormous progress has been made in identifying the genetic causes of cardiac diseases, which has further led to a greater understanding of molecular mechanisms underlying each disease. This progress has increased the probability of establishing a specific genetic diagnosis, and thus providing new opportunities for practitioners, patients, and families to utilize this genetic information. A large number of mutations in sarcomeric genes have been discovered in cardiomyopathies. In this review, we will explore the role of the sarcomeric genes in LVD in CAD patients, which is a major cause of cardiac failure and results in heart failure.
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Distal myopathy induced arrhythmogenic right ventricular cardiomyopathy in a pedigree carrying novel DSG2 null variant. Int J Cardiol 2020; 298:25-31. [DOI: 10.1016/j.ijcard.2019.10.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 06/14/2019] [Accepted: 10/02/2019] [Indexed: 01/15/2023]
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Ko JY, Lee M, Jang JH, Jang DH, Ryu JS. A novel de novo mutation in MYH7 gene in a patient with early onset muscular weakness and severe kyphoscoliosis: A case report. Medicine (Baltimore) 2019; 98:e16389. [PMID: 31305444 PMCID: PMC6641756 DOI: 10.1097/md.0000000000016389] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
INTRODUCTION Various phenotypes have been identified for MYH7 gene mutation-related myopathy. Here, we describe a patient with severe muscular weakness and skeletal deformity with de novo heterozygous MYH7 gene mutation. PATIENT CONCERNS A 33-year-old woman presented with early onset of muscular weakness, with delayed motor development during infancy. At age 8 years, she was unable to walk, with signs of skeletal deformity, including the progression of kyphoscoliosis. At age 31 years, she developed dyspnea. DIAGNOSIS She diagnosed with esophageal hiatal hernia with abdominal CT. In electromyography, short duration, small amplitude motor unit action potential (MUAP), and early recruitment patterns were observed in the involved proximal muscles, suggesting myopathy. Muscle histopathology showed fiber-type disproportion. INTERVENTIONS Next-generation sequencing study revealed a heterozygous in-frame deletion variation in the exon 14 of the MYH7 gene (c.1498_1500del/p.Glu500del), which is a novel variation confirmed by conventional Sanger sequencing. Compared with the parental test, this variant was concluded as de novo. OUTCOMES She received laparoscopic hiatal hernia repair and Nissen fundoplication for esophageal hiatal hernia. After surgery, her postural dyspnea improved. As there is no fundamental treatment for MYH7-related myopathies, she continued conservative treatment for her symptoms. CONCLUSION Here, we presented a rare case of de novo mutation of the myosin head domain in the MYH7 gene. This report broadens both the phenotypic and genotypic spectra of MYH7-related myopathies.
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Affiliation(s)
- Jin Young Ko
- Department of Rehabilitation Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam
| | - Minyong Lee
- Department of Rehabilitation Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul
| | | | - Dae-Hyun Jang
- Department of Rehabilitation Medicine, Incheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea
| | - Ju Seok Ryu
- Department of Rehabilitation Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam
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Mamelona J, Filice L, Oussedik Y, Crapoulet N, Ouellette RJ, Marrero A. A novel missense mutation in the MYH7 gene causes an uncharacteristic phenotype of myosin storage myopathy: a case report. BMC MEDICAL GENETICS 2019; 20:78. [PMID: 31068177 PMCID: PMC6507130 DOI: 10.1186/s12881-019-0804-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 04/09/2019] [Indexed: 11/10/2022]
Abstract
BACKGROUND Few manuscripts have reported phenotypes of skeletal muscle myopathies caused by mutations in the head region of slow/cardiac beta-myosin heavy chain (MyHCI). Among the patients, some of them showed the phenotype of skeletal muscle weakness with the obvious clinical features of cardiomyopathy while others showed pure skeletal muscle weakness with no symptoms of cardiac involvement. Genotype-phenotype relationship regarding the effect of a mutation on MyHCI is complex. Questions regarding why some mutations cause cardiomyopathy or skeletal muscle disorders alone or a combination of both still need to be answered. More findings in genetic variation are needed to extend knowledge of mutations in the MYH7 gene linked to skeletal muscle disorders. CASE PRESENTATION Here we present a female adult patient with a phenotype of childhood onset of muscular disorders and predominant involvement of thigh muscles with biopsy showing intrasarcoplasmic inclusion bodies. Whole exome sequencing showed that variant c.1370 T > G (p.Ile457Arg) in the MYH7 gene is a missense mutation possibly linked to the clinical findings. Our patient likely shows an uncharacteristic myosin storage myopathy associated with respiratory and cardiac involvement linked to a missense mutation in the head of MyHCI. CONCLUSIONS Given this mutation is located within the motor domain of MyHCI, this might affect the regulation of myosin mechano-chemical activity during the contractile cycle. Consequently, this potentially damaging effect can be easily amplified within the network of ~ 300-myosin molecules forming the thick filament and therefore become cumulatively deleterious, affecting, in turn, the overall organization and performance of sarcomere.
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Affiliation(s)
- Jean Mamelona
- Department of Neurology, Dr.-Georges-L.-Dumont University Hospital Center, 330 University Avenue, Moncton, NB, E1C 2Z3, Canada
| | - Louisa Filice
- Centre de Formation Médicale du Nouveau-Brunswick, 100 Des Aboiteaux Street, Moncton, NB, E1A 7R1, Canada
| | - Youcef Oussedik
- Department of Pathology, Dr.-Georges-L.-Dumont University Hospital Center, 330 University Avenue, Moncton, NB, E1C 2Z3, Canada
| | - Nicolas Crapoulet
- Molecular Genetics, Dr.-Alfred-Bastarche Laboratory, 37 Providence Street, Moncton, NB, E1C 8X3, Canada
| | - Rodney J Ouellette
- Molecular Genetics, Dr.-Alfred-Bastarche Laboratory, 37 Providence Street, Moncton, NB, E1C 8X3, Canada
| | - Alier Marrero
- Department of Neurology, Dr.-Georges-L.-Dumont University Hospital Center, 330 University Avenue, Moncton, NB, E1C 2Z3, Canada. .,Centre de Formation Médicale du Nouveau-Brunswick, 100 Des Aboiteaux Street, Moncton, NB, E1A 7R1, Canada.
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Drosophila model of myosin myopathy rescued by overexpression of a TRIM-protein family member. Proc Natl Acad Sci U S A 2018; 115:E6566-E6575. [PMID: 29946036 DOI: 10.1073/pnas.1800727115] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Myosin is a molecular motor indispensable for body movement and heart contractility. Apart from pure cardiomyopathy, mutations in MYH7 encoding slow/β-cardiac myosin heavy chain also cause skeletal muscle disease with or without cardiac involvement. Mutations within the α-helical rod domain of MYH7 are mainly associated with Laing distal myopathy. To investigate the mechanisms underlying the pathology of the recurrent causative MYH7 mutation (K1729del), we have developed a Drosophila melanogaster model of Laing distal myopathy by genomic engineering of the Drosophila Mhc locus. Homozygous MhcK1728del animals die during larval/pupal stages, and both homozygous and heterozygous larvae display reduced muscle function. Flies expressing only MhcK1728del in indirect flight and jump muscles, and heterozygous MhcK1728del animals, were flightless, with reduced movement and decreased lifespan. Sarcomeres of MhcK1728del mutant indirect flight muscles and larval body wall muscles were disrupted with clearly disorganized muscle filaments. Homozygous MhcK1728del larvae also demonstrated structural and functional impairments in heart muscle, which were not observed in heterozygous animals, indicating a dose-dependent effect of the mutated allele. The impaired jump and flight ability and the myopathy of indirect flight and leg muscles associated with MhcK1728del were fully suppressed by expression of Abba/Thin, an E3-ligase that is essential for maintaining sarcomere integrity. This model of Laing distal myopathy in Drosophila recapitulates certain morphological phenotypic features seen in Laing distal myopathy patients with the recurrent K1729del mutation. Our observations that Abba/Thin modulates these phenotypes suggest that manipulation of Abba/Thin activity levels may be beneficial in Laing distal myopathy.
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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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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] [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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13
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Laing distal myopathy with a novel mutation in exon 34 of the MYH7 gene. Neuromuscul Disord 2016; 26:598-603. [DOI: 10.1016/j.nmd.2016.06.458] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Revised: 06/19/2016] [Accepted: 06/20/2016] [Indexed: 12/12/2022]
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14
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Hedberg-Oldfors C, Darin N, Olsson Engman M, Orfanos Z, Thomsen C, van der Ven PFM, Oldfors A. A new early-onset neuromuscular disorder associated with kyphoscoliosis peptidase (KY) deficiency. Eur J Hum Genet 2016; 24:1771-1777. [PMID: 27485408 DOI: 10.1038/ejhg.2016.98] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 05/17/2016] [Accepted: 06/28/2016] [Indexed: 11/09/2022] Open
Abstract
We describe a new early-onset neuromuscular disorder due to a homozygous loss-of-function variant in the kyphoscoliosis peptidase gene (KY). A 7.5-year-old girl with walking difficulties from 2 years of age presented with generalized muscle weakness; mild contractures in the shoulders, hips and feet; cavus feet; and lordosis but no scoliosis. She had previously been operated with Achilles tendon elongation. Whole-body MRI showed atrophy and fatty infiltration in the calf muscles. Biopsy of the vastus lateralis muscle showed variability in fiber size, with some internalized nuclei and numerous very small fibers with variable expression of developmental myosin heavy chain isoforms. Some small fibers showed abnormal sarcomeres with thickened Z-discs and small nemaline rods. Whole-exome sequencing revealed a homozygous one-base deletion (c.1071delG, p.(Thr358Leufs*3)) in KY, predicted to result in a truncated protein. Analysis of an RNA panel showed that KY is predominantly expressed in skeletal muscle in humans. A recessive variant in the murine ortholog Ky was previously described in a spontaneously generated mouse mutant with kyphoscoliosis, which developed postnatally and was caused by dystrophy of postural muscles. The abnormal distribution of Xin and Ky-binding partner filamin C in the muscle fibers of our patient was highly similar to their altered localization in ky/ky mouse muscle fibers. We describe the first human case of disease associated with KY inactivation. As in the mouse model, the affected child showed a neuromuscular disorder - but in contrast, no kyphoscoliosis.
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Affiliation(s)
- Carola Hedberg-Oldfors
- Department of Pathology and Genetics, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Niklas Darin
- Department of Pediatrics, University of Gothenburg, The Queen Silvia Children's Hospital, Gothenburg, Sweden
| | | | - Zacharias Orfanos
- Department of Molecular Cell Biology, Institute for Cell Biology, University of Bonn, Bonn, Germany
| | - Christer Thomsen
- Department of Pathology and Genetics, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Peter F M van der Ven
- Department of Molecular Cell Biology, Institute for Cell Biology, University of Bonn, Bonn, Germany
| | - Anders Oldfors
- Department of Pathology and Genetics, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
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15
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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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16
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Brand P, Dyck PJB, Liu J, Berini S, Selcen D, Milone M. Distal myopathy with coexisting heterozygous TIA1 and MYH7 Variants. Neuromuscul Disord 2016; 26:511-5. [PMID: 27282841 DOI: 10.1016/j.nmd.2016.05.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 04/28/2016] [Accepted: 05/19/2016] [Indexed: 01/20/2023]
Abstract
TIA1 mutations cause Welander distal myopathy. MYH7 mutations result in various clinical phenotypes, including Laing distal myopathy and cardiomyopathy. We describe a family with coexisting TIA1 and MYH7 variants. The proband is a 67-year-old woman with easy tripping since childhood and progressive asymmetric distal limb weakness, but no cardiac involvement. Muscle biopsy showed rare rimmed vacuoles, minicore-like structures and congophilic inclusions. Her 66-year-old sister has a mild distal myopathy, supraventricular tachycardia and hypertrophic cardiomyopathy. Both sisters carry the only known pathogenic TIA1 mutation and a heterozygous MYH7 variant (c.5459G > A; p.Arg1820Gln). Another sibling with isolated distal myopathy carries only the TIA1 mutation. MYH7 p.Arg1820Gln involves a highly conserved residue and is predicted to be deleterious. Furthermore, the proband's childhood-onset distal leg weakness and sister's cardiomyopathy suggest that MYH7 p.Arg1820Gln likely affects function, favoring a digenic etiology of the myopathy.
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Affiliation(s)
- Patricio Brand
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905, USA
| | - P James B Dyck
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905, USA
| | - Jie Liu
- PreventionGenetics, 3800 S. Business Park Ave, Marshfield, Wisconsin 54449, USA; Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Sarah Berini
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905, USA
| | - Duygu Selcen
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905, USA
| | - Margherita Milone
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905, USA.
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17
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Astrea G, Petrucci A, Cassandrini D, Savarese M, Trovato R, Lispi L, Rubegni A, Giacanelli M, Massa R, Nigro V, Santorelli FM. Myoimaging in the NGS era: the discovery of a novel mutation in MYH7 in a family with distal myopathy and core-like features--a case report. BMC MEDICAL GENETICS 2016; 17:25. [PMID: 27005958 PMCID: PMC4804697 DOI: 10.1186/s12881-016-0288-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 03/11/2016] [Indexed: 11/22/2022]
Abstract
Background Myosin heavy chain 7 related myopathies are rare disorders characterized by a wide phenotypic spectrum and heterogeneous pathological features. In the present study, we performed clinical, morphological, genetic and imaging investigations in three relatives affected by autosomal dominant distal myopathy. Whilst earlier traditional Sanger investigations had pointed to the wrong gene as disease causative, next-generation sequencing allowed us to obtain the definitive molecular genetic diagnosis in the family. Case presentation The proposita, being found to harbor a novel heterozygous mutation in the RYR1 gene (p.Glu294Lys), was initially diagnosed with core myopathy. Subsequently, consideration of muscle magnetic resonance imaging (MRI) features and extension of family study led this diagnosis to be questioned. Use of next-generation sequencing analysis identified a novel mutation in the MYH7gene (p.Ser1435Pro) that segregated in the affected family members. Conclusions This study identified a novel mutation in MYH7 in a family where the conclusive molecular diagnosis was reached through a complicated path. This case report might raise awareness, among clinicians, of the need to interpret NGS data in combination with muscle MRI patterns so as to facilitate the pinpointing of the main molecular etiology in inherited muscle disorders. Electronic supplementary material The online version of this article (doi:10.1186/s12881-016-0288-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Guja Astrea
- Molecular Medicine, IRCCS Stella Maris, via dei Giacinti 2, 56128, Calambrone, Pisa, Italy
| | - Antonio Petrucci
- Center for Neuromuscular and Neurological Rare Diseases, S. Camillo-Forlanini Hospital, Rome, Italy
| | - Denise Cassandrini
- Molecular Medicine, IRCCS Stella Maris, via dei Giacinti 2, 56128, Calambrone, Pisa, Italy
| | - Marco Savarese
- Department of Biochemistry, Biophysics and General Pathology (Medical Genetics), Second University of Naples, Naples, Italy
| | - Rosanna Trovato
- Molecular Medicine, IRCCS Stella Maris, via dei Giacinti 2, 56128, Calambrone, Pisa, Italy
| | - Ludovico Lispi
- Center for Neuromuscular and Neurological Rare Diseases, S. Camillo-Forlanini Hospital, Rome, Italy
| | - Anna Rubegni
- Molecular Medicine, IRCCS Stella Maris, via dei Giacinti 2, 56128, Calambrone, Pisa, Italy
| | - Manlio Giacanelli
- Center for Neuromuscular and Neurological Rare Diseases, S. Camillo-Forlanini Hospital, Rome, Italy
| | - Roberto Massa
- Department of Systems Medicine (Neurology), University of Tor Vergata, Rome, Italy
| | - Vincenzo Nigro
- Department of Biochemistry, Biophysics and General Pathology (Medical Genetics), Second University of Naples, Naples, Italy.,Telethon Institute of Genetics and Medicine, Naples, Italy
| | - Filippo M Santorelli
- Molecular Medicine, IRCCS Stella Maris, via dei Giacinti 2, 56128, Calambrone, Pisa, Italy.
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18
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Two families with MYH7 distal myopathy associated with cardiomyopathy and core formations. J Clin Neuromuscul Dis 2015; 16:164-9. [PMID: 25695922 DOI: 10.1097/cnd.0000000000000069] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
INTRODUCTION Laing distal myopathy is caused by MYH7 gene mutations. Multiple families have been reported with varying patterns of skeletal and cardiac involvement as well as histopathological findings. CASE SERIES We report 2 families with p.Glu1508del mutation with detailed electrophysiological and muscle pathology findings. RESULTS All patients displayed the classic phenotype with weakness starting in the anterior compartment of the legs with a "hanging great toe." It was followed by finger extensors involvement, relatively sparing the extensor indicis proprius, giving the appearance of a "pointing index" finger. All the affected individuals had a dilated cardiomyopathy and core formations on muscle biopsy. Unexpectedly, neurogenic changes were also observed in some individuals. Both families were initially misdiagnosed with either central core disease or hereditary neuropathy. CONCLUSIONS Recognizing the classic phenotype, screening for cardiac involvement that may be clinically silent, and determining the mode of inheritance help with selecting the appropriate genetic test.
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19
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Lefter S, Hardiman O, McLaughlin RL, Murphy SM, Farrell M, Ryan AM. A novel MYH7 Leu1453pro mutation resulting in Laing distal myopathy in an Irish family. Neuromuscul Disord 2015; 25:155-60. [DOI: 10.1016/j.nmd.2014.09.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 08/24/2014] [Accepted: 09/17/2014] [Indexed: 12/12/2022]
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20
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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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21
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Laing early-onset distal myopathy in a Belgian family. Acta Neurol Belg 2014; 114:253-6. [PMID: 24710723 DOI: 10.1007/s13760-014-0298-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Accepted: 03/24/2014] [Indexed: 10/25/2022]
Abstract
We report the first Belgian family with Laing early-onset distal myopathy (MPD1). The proposita started limping at age 7. Later, there was severe weakness of proximal and distal muscles, including neck flexors. Her daughter developed foot drop at age 4. Progressive weakness of distal limb extensor muscles and mild weakness of the neck flexor and proximal muscles were noted. In both patients, CK and nerve conductions were normal, but EMG showed a brief, small amplitude, abundant, polyphasic potential pattern. Heart and respiration were normal. Several muscle biopsies have been performed in each with various diagnoses, including aspecific myopathic changes, congenital fibre type disproportion, and denervation-reinnervation. Analysis of MYH7 revealed a c.4522_4524del mutation (p.Glu1508del). This appears to be a de novo mutation, which has been reported in French, Norwegian, and Finnish patients.
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22
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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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23
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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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24
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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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25
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Park JM, Kim YJ, Yoo JH, Hong YB, Park JH, Koo H, Chung KW, Choi BO. A novel MYH7 mutation with prominent paraspinal and proximal muscle involvement. Neuromuscul Disord 2013; 23:580-6. [PMID: 23707328 DOI: 10.1016/j.nmd.2013.04.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 03/20/2013] [Accepted: 04/22/2013] [Indexed: 12/12/2022]
Abstract
Laing distal myopathy (LDM) is caused by mutations in the MYH7 gene, and known to have muscle weakness of distal limbs and neck flexors. Through whole exome sequencing, we identified a novel p.Ala1439Pro MYH7 mutation in a Korean LDM family. This missense mutation is located in more N-terminal than any reported rod domain LDM mutations. In the early stage of disease, the present patients showed similar clinical patterns to the previously described patients of LDM. However, in the later stage, fatty replacement and atrophy of paraspinal or proximal leg muscles was more severely marked than lower leg muscles, and asymmetric atrophies were observed in trapezius, subscapularis and adductor magnus muscles. Distal myopathy like LDM showed marked and predominant fatty infiltrations in paraspinal or proximal leg muscles with marked asymmetry. These observations expand the clinical spectrum of LDM with the MYH7 mutation.
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Affiliation(s)
- Jin-Mo Park
- Department of Neurology, Ewha Womans University School of Medicine, Seoul, Republic of Korea
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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: 38] [Impact Index Per Article: 3.5] [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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Roadmap to determine the point mutations involved in cardiomyopathy disorder: A Bayesian approach. Gene 2013; 519:34-40. [DOI: 10.1016/j.gene.2013.01.056] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 12/31/2012] [Accepted: 01/27/2013] [Indexed: 11/18/2022]
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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: 127] [Impact Index Per Article: 11.5] [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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Murgiano L, Tammen I, Harlizius B, Drögemüller C. A de novo germline mutation in MYH7 causes a progressive dominant myopathy in pigs. BMC Genet 2012; 13:99. [PMID: 23153285 PMCID: PMC3542579 DOI: 10.1186/1471-2156-13-99] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 10/25/2012] [Indexed: 11/20/2022] Open
Abstract
Background About 9% of the offspring of a clinically healthy Piétrain boar named ‘Campus’ showed a progressive postural tremor called Campus syndrome (CPS). Extensive backcross experiments suggested a dominant mode of inheritance, and the founder boar was believed to be a gonadal mosaic. A genome-scan mapped the disease-causing mutation to an 8 cM region of porcine chromosome 7 containing the MHY7 gene. Human distal myopathy type 1 (MPD1), a disease partially resembling CPS in pigs, has been associated with mutations in the MYH7 gene. Results The porcine MYH7 gene structure was predicted based on porcine reference genome sequence, porcine mRNA, and in comparison to the human ortholog. The gene structure was highly conserved with the exception of the first exon. Mutation analysis of a contiguous genomic interval of more than 22 kb spanning the complete MYH7 gene revealed an in-frame insertion within exon 30 of MYH7 (c.4320_4321insCCCGCC) which was perfectly associated with the disease phenotype and confirmed the dominant inheritance. The mutation is predicted to insert two amino acids (p.Ala1440_Ala1441insProAla) in a very highly conserved region of the myosin tail. The boar ‘Campus’ was shown to be a germline and somatic mosaic as assessed by the presence of the mutant allele in seven different organs. Conclusion This study illustrates the usefulness of recently established genomic resources in pigs. We have identified a spontaneous mutation in MYH7 as the causative mutation for CPS. This paper describes the first case of a disorder caused by a naturally occurring mutation in the MYH7 gene of a non-human mammalian species. Our study confirms the previous classification as a primary myopathy and provides a defined large animal model for human MPD1. We provide evidence that the CPS mutation occurred during the early development of the boar ‘Campus’. Therefore, this study provides an example of germline mosaicism with an asymptomatic founder.
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Affiliation(s)
- Leonardo Murgiano
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bremgartenstrasse 109a, Bern, 3001, Switzerland
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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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31
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New phenotype and pathology features in MYH7-related distal myopathy. Neuromuscul Disord 2012; 22:640-7. [PMID: 22521714 DOI: 10.1016/j.nmd.2012.03.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 02/06/2012] [Accepted: 03/02/2012] [Indexed: 11/22/2022]
Abstract
Laing distal myopathy is an autosomal dominant disease due to mutations in the gene encoding for the human slow-β myosin heavy chain, MYH7. Most reports describe it as a mild, early onset myopathy with involvement usually restricted to foot extensors, hand finger extensors and neck flexors, and unspecific findings on muscle biopsy. We identified the first two Italian families with Laing distal myopathy, harboring two novel mutations in the MYH7 gene and performed clinical, neurophysiological, pathological, muscle MRI and cardiological investigations on affected members from the two families. Subjects from one family presented a moderate-severe phenotype, with proximal together with distal involvement and even loss of ambulation at advanced age. One patient displayed atypical muscle biopsy findings including cytoplasmic bodies and myofibrillar myopathy-like features. Affected members from the second family shared a very mild phenotype, with weakness largely limited to long toe and foot extensors and/or late onset. No patient showed any sign of heart involvement. Our study significantly broadens the clinical and pathological spectrum of Laing distal myopathy. We suggest that MYH7 screening should be considered in undiagnosed late-onset distal myopathy or cytoplasmic body myopathy patients.
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Buvoli M, Buvoli A, Leinwand LA. Effects of pathogenic proline mutations on myosin assembly. J Mol Biol 2011; 415:807-18. [PMID: 22155079 DOI: 10.1016/j.jmb.2011.11.042] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 11/04/2011] [Accepted: 11/23/2011] [Indexed: 12/27/2022]
Abstract
Laing distal myopathy (MPD1) is a genetically dominant myopathy characterized by early and selective weakness of the distal muscles. Mutations in the MYH7 gene encoding for the β-myosin heavy chain are the underlying genetic cause of MPD1. However, their pathogenic mechanisms are currently unknown. Here, we measure the biological effects of the R1500P and L1706P MPD1 mutations in different cellular systems. We show that, while the two mutations inhibit myosin self-assembly in non-muscle cells, they do not prevent incorporation of the mutant myosin into sarcomeres. Nevertheless, we find that the L1706P mutation affects proper antiparallel myosin association by accumulating in the bare zone of the sarcomere. Furthermore, bimolecular fluorescence complementation assay shows that the α-helix containing the R1500P mutation folds into homodimeric (mutant/mutant) and heterodimeric [mutant/wild type (WT)] myosin molecules that are competent for sarcomere incorporation. Both mutations also form aggregates consisting of cytoplasmic vacuoles surrounding paracrystalline arrays and amorphous rod-like inclusions that sequester WT myosin. Myosin aggregates were also detected in transgenic nematodes expressing the R1500P mutation. By showing that the two MPD1 mutations can have dominant effects on distinct components of the contractile apparatus, our data provide the first insights into the pathogenesis of the disease.
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Affiliation(s)
- Massimo Buvoli
- Department of Molecular, Cellular, and Developmental Biology and Biofrontiers Institute, University of Colorado, Boulder, CO 80309, USA
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33
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Muelas N, Hackman P, Luque H, Suominen T, Espinós C, Garcés-Sánchez M, Sevilla T, Azorín I, Millán JM, Udd B, Vílchez JJ. Spanish MYH7 founder mutation of Italian ancestry causing a large cluster of Laing myopathy patients. Clin Genet 2011; 81:491-4. [DOI: 10.1111/j.1399-0004.2011.01667.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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34
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A novel MYH7 mutation links congenital fiber type disproportion and myosin storage myopathy. Neuromuscul Disord 2011; 21:254-62. [DOI: 10.1016/j.nmd.2010.12.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 12/01/2010] [Accepted: 12/20/2010] [Indexed: 02/07/2023]
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35
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Homayoun H, Khavandgar S, Hoover JM, Mohsen AW, Vockley J, Lacomis D, Clemens PR. Novel mutation in MYH7 gene associated with distal myopathy and cardiomyopathy. Neuromuscul Disord 2011; 21:219-22. [PMID: 21211974 DOI: 10.1016/j.nmd.2010.12.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 11/28/2010] [Accepted: 12/07/2010] [Indexed: 01/17/2023]
Abstract
A 25-year-old woman had childhood-onset muscle weakness and dilated cardiomyopathy. She exhibited predominantly distal weakness with early toe walking. Dilated cardiomyopathy required cardiac transplantation at age 15 years. We identified a de-novo, heterozygous, missense mutation, c.2348G>C (p. Arg783Pro), in exon 21 of the MYH7 gene, which encodes slow skeletal muscle fiber/β-cardiac myosin heavy chain protein, that replaces a highly conserved arginine with a proline. This novel mutation that results in the unusual combined cardiac and skeletal muscle phenotype localizes to the essential light chain binding area, a region only previously shown to be mutated in hypertrophic cardiomyopathy.
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Affiliation(s)
- Houman Homayoun
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA
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36
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37
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Uro-Coste E, Arné-Bes MC, Pellissier JF, Richard P, Levade T, Heitz F, Figarella-Branger D, Delisle MB. Striking phenotypic variability in two familial cases of myosin storage myopathy with a MYH7 Leu1793pro mutation. Neuromuscul Disord 2009; 19:163-6. [PMID: 19138847 DOI: 10.1016/j.nmd.2008.11.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Revised: 11/14/2008] [Accepted: 11/17/2008] [Indexed: 12/11/2022]
Abstract
Myosin Storage Myopathies (MSM) have emerged as a new group of inherited myopathies with heterogenous clinical severity and age of onset. We have identified in a woman and her daughter, a pLeu1793Pro mutation in MYH7. This mutation has already been reported to be associated with MSM presenting as neonatal hypotony. Our index case complained of proximal muscle weakness at age 30. Her daughter presented at birth with a cardiomyopathy without any skeletal muscle involvement. This report underlines the clinical variability of MSM even with a given mutation or in a same family.
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Affiliation(s)
- Emmanuelle Uro-Coste
- Department of Pathology, Rangueil University Hospital, TSA 50032, 31059 Toulouse Cedex 9, France.
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Kachur TM, Pilgrim DB. Myosin assembly, maintenance and degradation in muscle: Role of the chaperone UNC-45 in myosin thick filament dynamics. Int J Mol Sci 2008; 9:1863-1875. [PMID: 19325835 PMCID: PMC2635755 DOI: 10.3390/ijms9091863] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Revised: 09/08/2008] [Accepted: 09/13/2008] [Indexed: 12/27/2022] Open
Abstract
Myofibrillogenesis in striated muscle cells requires a precise ordered pathway to assemble different proteins into a linear array of sarcomeres. The sarcomere relies on interdigitated thick and thin filaments to ensure muscle contraction, as well as properly folded and catalytically active myosin head. Achieving this organization requires a series of protein folding and assembly steps. The folding of the myosin head domain requires chaperone activity to attain its functional conformation. Folded or unfolded myosin can spontaneously assemble into short myosin filaments, but further assembly requires the short and incomplete myosin filaments to assemble into the developing thick filament. These longer filaments are then incorporated into the developing sarcomere of the muscle. Both myosin folding and assembly require factors to coordinate the formation of the thick filament in the sarcomere and these factors include chaperone molecules. Myosin folding and sarcomeric assembly requires association of classical chaperones as well as folding cofactors such as UNC-45. Recent research has suggested that UNC-45 is required beyond initial myosin head folding and may be directly or indirectly involved in different stages of myosin thick filament assembly, maintenance and degradation.
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Affiliation(s)
| | - David B. Pilgrim
- Author to whom correspondence should be addressed; E-Mail:
; Tel. +1-780-492-2792
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39
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Thick and thin filament gene mutations in striated muscle diseases. Int J Mol Sci 2008; 9:1259-1275. [PMID: 19325803 PMCID: PMC2635722 DOI: 10.3390/ijms9071259] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Revised: 05/23/2008] [Accepted: 06/12/2008] [Indexed: 01/05/2023] Open
Abstract
The sarcomere is the fundamental unit of cardiac and skeletal muscle contraction. During the last ten years, there has been growing awareness of the etiology of skeletal and cardiac muscle diseases originating in the sarcomere, an important evolving field. Many sarcomeric diseases affect newborn children, i. e. are congenital myopathies. The discovery and characterization of several myopathies caused by mutations in myosin heavy chain genes, coding for the major component of skeletal muscle thick filaments, has led to the introduction of a new entity in the field of neuromuscular disorders: myosin myopathies. Recently, mutations in genes coding for skeletal muscle thin filaments, associated with various clinical features, have been identified. These mutations evoke distinct structural changes within the sarcomeric thin filament. Current knowledge regarding contractile protein dysfunction as it relates to disease pathogenesis has failed to decipher the mechanistic links between mutations identified in sarcomeric proteins and skeletal myopathies, which will no doubt require an integrated physiological approach. The discovery of additional genes associated with myopathies and the elucidation of the molecular mechanisms of pathogenesis will lead to improved and more accurate diagnosis, including prenatally, and to enhanced potential for prognosis, genetic counseling and developing possible treatments for these diseases. The goal of this review is to present recent progress in the identification of gene mutations from each of the major structural components of the sarcomere, the thick and thin filaments, related to skeletal muscle disease. The genetics and clinical manifestations of these disorders will be discussed.
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40
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41
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Oldfors A. Hereditary myosin myopathies. Neuromuscul Disord 2007; 17:355-67. [PMID: 17434305 DOI: 10.1016/j.nmd.2007.02.008] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Revised: 02/03/2007] [Accepted: 02/03/2007] [Indexed: 12/11/2022]
Abstract
Hereditary myosin myopathies have emerged as a new group of muscle diseases with highly variable clinical features and onset during fetal development, childhood or adulthood. They are caused by mutations in skeletal muscle myosin heavy chain (MyHC) genes. Mutations have been reported in two of the three MyHC isoforms expressed in adult limb skeletal muscle: type I (slow/beta-cardiac MyHC; MYH7) and type IIa (MYH2). The majority of more than 200 dominant missense mutations in MYH7 are associated with hypertrophic/dilated cardiomyopathy without signs or symptoms of skeletal myopathy. Several mutations in two different parts of the slow/beta-cardiac MyHC rod region are associated with two distinct skeletal myopathies without cardiomyopathy: Laing early onset distal myopathy and myosin storage myopathy (MSM). However, early onset distal myopathy and MSM caused by MYH7 mutations may also occur together with cardiomyopathy. MSM affects proximal or scapuloperoneal muscles whereas Laing distal myopathy primarily affects the dorsiflexor muscles of the toes and ankles. MSM is morphologically characterized by subsarcolemmal accumulation of myosin in type 1 fibers, whereas Laing distal myopathy is associated with variable and unspecific muscle pathology, frequently with hypotrophic type 1 muscle fibers. A myopathy associated with a specific mutation in MYH2 is associated with congenital joint contractures and external ophthalmoplegia. The disease is mild in childhood but may be progressive in adulthood, with proximal muscle weakness affecting ambulation. Mutations in embryonic MyHC (MYH3) and perinatal MyHC (MYH8), which are myosin isoforms expressed during muscle development, are associated with distal arthrogryposis syndromes with no or minor muscle weakness. Clinical findings, muscle morphology and molecular genetics in hereditary myosin myopathies are summarized in this review.
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Affiliation(s)
- Anders Oldfors
- Department of Pathology, Sahlgrenska University Hospital, S-413 45 Göteborg, Sweden.
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