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Lambert MR, Gussoni E. Tropomyosin 3 (TPM3) function in skeletal muscle and in myopathy. Skelet Muscle 2023; 13:18. [PMID: 37936227 PMCID: PMC10629095 DOI: 10.1186/s13395-023-00327-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 10/10/2023] [Indexed: 11/09/2023] Open
Abstract
The tropomyosin genes (TPM1-4) contribute to the functional diversity of skeletal muscle fibers. Since its discovery in 1988, the TPM3 gene has been recognized as an indispensable regulator of muscle contraction in slow muscle fibers. Recent advances suggest that TPM3 isoforms hold more extensive functions during skeletal muscle development and in postnatal muscle. Additionally, mutations in the TPM3 gene have been associated with the features of congenital myopathies. The use of different in vitro and in vivo model systems has leveraged the discovery of several disease mechanisms associated with TPM3-related myopathy. Yet, the precise mechanisms by which TPM3 mutations lead to muscle dysfunction remain unclear. This review consolidates over three decades of research about the role of TPM3 in skeletal muscle. Overall, the progress made has led to a better understanding of the phenotypic spectrum in patients affected by mutations in this gene. The comprehensive body of work generated over these decades has also laid robust groundwork for capturing the multiple functions this protein plays in muscle fibers.
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Affiliation(s)
- Matthias R Lambert
- Division of Genetics and Genomics, Boston Children's Hospital, 300 Longwood Ave., Boston, MA, 02115, USA.
- Department of Pediatrics, Harvard Medical School, Boston, MA, 02115, USA.
| | - Emanuela Gussoni
- Division of Genetics and Genomics, Boston Children's Hospital, 300 Longwood Ave., Boston, MA, 02115, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, 02115, USA
- The Stem Cell Program, Boston Children's Hospital, Boston, MA, 02115, USA
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Bevilacqua JA, Contreras JP, Trangulao A, Hernández Ú, Brochier G, Díaz J, Hughes R, Campero M, Romero NB. Novel autosomal dominant TPM3 mutation causes a combined congenital fibre type disproportion-cap disease histological pattern. Neuromuscul Disord 2022; 32:687-691. [PMID: 35688744 DOI: 10.1016/j.nmd.2022.05.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 04/16/2022] [Accepted: 05/26/2022] [Indexed: 11/17/2022]
Abstract
Tropomyosin 3 (TPM3) gene mutations associate with autosomal dominant and recessive nemaline myopathy 1 (NEM1), congenital fiber type disproportion myopathy (CFTD) and cap myopathy (CAPM1), and a combination of caps and nemaline bodies. We report on a 47-year-old man with polyglobulia, restricted vital capacity and mild apnea hypopnea syndrome, requiring noninvasive ventilation. Physical assessment revealed bilateral ptosis and facial paresis, with high arched palate and retrognathia; global hypotonia and diffuse axial weakness, including neck and upper and lower limb girdle and foot dorsiflexion weakness. Whole body MRI showed a diffuse fatty replacement with an unspecific pattern. A 122 gene NGS neuromuscular disorders panel revealed the heterozygous VUS c.709G>A (p.Glu237Lys) on exon 8 of TMP3. A deltoid muscle biopsy showed a novel histological pattern combining fiber type disproportion and caps. Our findings support the pathogenicity of the novel TPM3 variant and widen the phenotypic gamut of TMP3-related congenital myopathy.
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Affiliation(s)
- Jorge A Bevilacqua
- Unidad Neuromuscular, Departamento Neurología y Neurocirugía, Hospital Clínico Universidad de Chile, Santiago, Chile; Departamento de Anatomía y Medicina Legal, Facultad de Medicina, Universidad de Chile. Santiago, Chile; Unidad de Patología Neuromuscular, Departamento de Neurología y Neurocirugía, Clínica Dávila, Santiago, Chile.
| | - Juan Pablo Contreras
- Unidad Neuromuscular, Departamento Neurología y Neurocirugía, Hospital Clínico Universidad de Chile, Santiago, Chile; Departamento de Especialidades, Facultad de Medicina, Universidad de Concepción, Concepción, Chile; Servicio Neurología, Hospital Clínico Regional de Concepción: "Dr. Guillermo Grant Benavente", Concepción, Chile
| | - Alejandra Trangulao
- Departamento de Anatomía y Medicina Legal, Facultad de Medicina, Universidad de Chile. Santiago, Chile; Unidad de Patología Neuromuscular, Departamento de Neurología y Neurocirugía, Clínica Dávila, Santiago, Chile
| | - Úrsula Hernández
- Unidad Neuromuscular, Departamento Neurología y Neurocirugía, Hospital Clínico Universidad de Chile, Santiago, Chile; Equipo de Neurología, Servicio de Medicina. Hospital San Juan de Dios La Serena, La Serena, Chile
| | - Guy Brochier
- Unité Morphologie Neuromusculaire, Institut de Myologie, GHU Pitié-Salpêtrière, Paris, France
| | - Jorge Díaz
- Centro de Imagenología, Hospital Clínico Universidad de Chile, Santiago, Chile
| | - Ricardo Hughes
- Unidad Neuromuscular, Departamento Neurología y Neurocirugía, Hospital Clínico Universidad de Chile, Santiago, Chile
| | - Mario Campero
- Unidad Neuromuscular, Departamento Neurología y Neurocirugía, Hospital Clínico Universidad de Chile, Santiago, Chile
| | - Norma B Romero
- Unité Morphologie Neuromusculaire, Institut de Myologie, GHU Pitié-Salpêtrière, Paris, France
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3
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Borovikov YS, Rysev NA, Avrova SV, Karpicheva OE, Borys D, Moraczewska J. Molecular mechanisms of deregulation of the thin filament associated with the R167H and K168E substitutions in tropomyosin Tpm1.1. Arch Biochem Biophys 2016; 614:28-40. [PMID: 27956029 DOI: 10.1016/j.abb.2016.12.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 12/06/2016] [Accepted: 12/08/2016] [Indexed: 12/01/2022]
Abstract
Point mutations R167H and K168E in tropomyosin Tpm1.1 (TM) disturb Ca2+-dependent regulation of the actomyosin ATPase. To understand mechanisms of this defect we studied multistep changes in mobility and spatial arrangement of tropomyosin, actin and myosin heads during the ATPase cycle in reconstituted ghost fibres using the polarized fluorescence microscopy. It was found that both mutations disturbed the mode of troponin operation in the fibres. At high Ca2+, troponin increased the fraction of actin monomers that were in the "switched on" state, but both mutant tropomyosins were shifted toward the outer actin domains, which decreased the fraction of strongly bound myosin heads throughout the ATPase cycle. At low Ca2+, the R167H-TM was located close to the outer actin domains, which reduced the number of strongly-bound myosin heads. However, under these conditions troponin increased the number of actin monomers that were switched on. The K168E-TM was displaced far to the outer actin domains and troponin binding decreased the fraction of switched on actin monomers, but the proportion of the strongly bound myosin heads was abnormally high. Thus, the mutations differently disturbed transmission of conformational changes between troponin, tropomyosin and actin, which is essential for the Са2+-dependent regulation of the thin filament.
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Affiliation(s)
- Yurii S Borovikov
- Institute of Cytology, Tikhoretsky Pr., 4, Saint Petersburg, 194064, Russia.
| | - Nikita A Rysev
- Institute of Cytology, Tikhoretsky Pr., 4, Saint Petersburg, 194064, Russia
| | | | - Olga E Karpicheva
- Institute of Cytology, Tikhoretsky Pr., 4, Saint Petersburg, 194064, Russia
| | - Danuta Borys
- Kazimierz Wielki University in Bydgoszcz, Ks. J. Poniatowski 12, Str., 85-671 Bydgoszcz, Poland
| | - Joanna Moraczewska
- Kazimierz Wielki University in Bydgoszcz, Ks. J. Poniatowski 12, Str., 85-671 Bydgoszcz, Poland
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4
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Marttila M, Lehtokari VL, Marston S, Nyman TA, Barnerias C, Beggs AH, Bertini E, Ceyhan-Birsoy O, Cintas P, Gerard M, Gilbert-Dussardier B, Hogue JS, Longman C, Eymard B, Frydman M, Kang PB, Klinge L, Kolski H, Lochmüller H, Magy L, Manel V, Mayer M, Mercuri E, North KN, Peudenier-Robert S, Pihko H, Probst FJ, Reisin R, Stewart W, Taratuto AL, de Visser M, Wilichowski E, Winer J, Nowak K, Laing NG, Winder TL, Monnier N, Clarke NF, Pelin K, Grönholm M, Wallgren-Pettersson C. Mutation update and genotype-phenotype correlations of novel and previously described mutations in TPM2 and TPM3 causing congenital myopathies. Hum Mutat 2014; 35:779-90. [PMID: 24692096 DOI: 10.1002/humu.22554] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 03/17/2014] [Indexed: 01/14/2023]
Abstract
Mutations affecting skeletal muscle isoforms of the tropomyosin genes may cause nemaline myopathy, cap myopathy, core-rod myopathy, congenital fiber-type disproportion, distal arthrogryposes, and Escobar syndrome. We correlate the clinical picture of these diseases with novel (19) and previously reported (31) mutations of the TPM2 and TPM3 genes. Included are altogether 93 families: 53 with TPM2 mutations and 40 with TPM3 mutations. Thirty distinct pathogenic variants of TPM2 and 20 of TPM3 have been published or listed in the Leiden Open Variant Database (http://www.dmd.nl/). Most are heterozygous changes associated with autosomal-dominant disease. Patients with TPM2 mutations tended to present with milder symptoms than those with TPM3 mutations, DA being present only in the TPM2 group. Previous studies have shown that five of the mutations in TPM2 and one in TPM3 cause increased Ca(2+) sensitivity resulting in a hypercontractile molecular phenotype. Patients with hypercontractile phenotype more often had contractures of the limb joints (18/19) and jaw (6/19) than those with nonhypercontractile ones (2/22 and 1/22), whereas patients with the non-hypercontractile molecular phenotype more often (19/22) had axial contractures than the hypercontractile group (7/19). Our in silico predictions show that most mutations affect tropomyosin-actin association or tropomyosin head-to-tail binding.
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Affiliation(s)
- Minttu Marttila
- The Folkhälsan Institute of Genetics and the Department of Medical Genetics, University of Helsinki, Haartman Institute, Biomedicum Helsinki, Finland
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5
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Citirak G, Witting N, Duno M, Werlauff U, Petri H, Vissing J. Frequency and phenotype of patients carrying TPM2 and TPM3 gene mutations in a cohort of 94 patients with congenital myopathy. Neuromuscul Disord 2014; 24:325-30. [PMID: 24507666 DOI: 10.1016/j.nmd.2013.12.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Revised: 12/08/2013] [Accepted: 12/23/2013] [Indexed: 01/08/2023]
Abstract
Congenital myopathies are difficult to classify correctly through molecular testing due to the size and heterogeneity of the genes involved. Therefore, the prevalence of the various genetic causes of congenital myopathies is largely unknown. In our cohort of 94 patients with congenital myopathy, two related female patients and two sporadic, male patients were found to carry mutations in the tropomyosin 2 (TPM2) and tropomyosin 3 (TPM3) genes, respectively. This indicates a low (4.3%) frequency of TPM2 and TPM3 mutations as a cause of congenital myopathy. Compared to previously described patients carrying the same mutations as found in our study (c.503G>A, and c.502C>T in TPM3, and c.415_417delGAG in TPM2), clinical presentation and muscle morphological findings differed in our patients. Differences included variation in distribution of muscle weakness, presence of scoliosis and ptosis, physical performance and joint contractures. The variation in clinical profiles emphasizes the phenotypic heterogeneity. However, common features were also present, such as onset of symptoms in infancy or childhood, musculoskeletal deformities and normal or low plasma levels of creatine kinase. One patient had nemaline myopathy and fiber size disproportion, while three patients had congenital fiber type disproportion (CFTD) on muscle biopsies. TPM2-related CFTD has only been described in two cases, indicating that mutations in TPM2 are rare causes of CFTD.
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Affiliation(s)
- Gülsenay Citirak
- Neuromuscular Research Unit, Department of Neurology, University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Nanna Witting
- Neuromuscular Research Unit, Department of Neurology, University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Morten Duno
- Department of Clinical Genetics, University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Ulla Werlauff
- The Danish National Rehabilitation Center for Neuromuscular Diseases, Aarhus, Denmark
| | - Helle Petri
- Department of Cardiology, University Hospital Rigshospitalet, Copenhagen, Denmark
| | - John Vissing
- Neuromuscular Research Unit, Department of Neurology, University Hospital Rigshospitalet, Copenhagen, Denmark.
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Schreckenbach T, Schröder JM, Voit T, Abicht A, Neuen-Jacob E, Roos A, Bulst S, Kuhl C, Schulz JB, Weis J, Claeys KG. Novel TPM3 mutation in a family with cap myopathy and review of the literature. Neuromuscul Disord 2013; 24:117-24. [PMID: 24239060 DOI: 10.1016/j.nmd.2013.10.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 10/08/2013] [Accepted: 10/16/2013] [Indexed: 10/26/2022]
Abstract
Cap myopathy is a rare congenital myopathy characterized by the presence of caps within muscle fibres and caused by mutations in ACTA1, TPM2 or TPM3. Thus far, only three cases with TPM3-related cap myopathy have been described. Here, we report on the first autosomal dominant family with cap myopathy in three-generations, caused by a novel heterozygous mutation in the alpha-tropomyosin-slow-encoding gene (TPM3; exon 4; c.445C>A; p.Leu149Ile). The three patients experienced first symptoms of muscle weakness in childhood and followed a slowly progressive course. They presented generalized hypotrophy and mild muscle weakness, elongated face, high arched palate, micrognathia, scoliosis and respiratory involvement. Intrafamilial variability of skeletal deformities, respiratory involvement and mild cardiac abnormalities was noted. Muscle MRI revealed a recognizable pattern of fatty muscle infiltration and masseter muscle hypertrophy. Subsarcolemmal caps were present in 6-10% of the fibres and immunoreactive with anti-tropomyosin antibodies. We conclude that the MRI-pattern of muscle involvement and the presence of masseter muscle hypertrophy in cap myopathy may guide molecular genetic diagnosis towards a mutation in TPM3. Regular respiratory examinations are important, even if patients have no anamnestic clues. We compare our findings to all cases of cap myopathy with identified mutations (n=11), thus far reported in the literature.
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Affiliation(s)
- T Schreckenbach
- Department of Neurology, University Hospital RWTH Aachen, Aachen, Germany; Institute of Neuropathology, University Hospital RWTH Aachen, Aachen, Germany
| | - J M Schröder
- Institute of Neuropathology, University Hospital RWTH Aachen, Aachen, Germany
| | - T Voit
- Institut de Myologie, Université Pierre et Marie Curie Paris, UM76, INSERM U 974, CNRS UMR 7215, Paris, France
| | - A Abicht
- Medizinisch Genetisches Zentrum München, München, Germany
| | - E Neuen-Jacob
- Institute of Neuropathology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - A Roos
- Institute of Neuropathology, University Hospital RWTH Aachen, Aachen, Germany; JARA Translational Brain Medicine, Germany
| | - S Bulst
- Medizinisch Genetisches Zentrum München, München, Germany
| | - C Kuhl
- Department of Radiology, University Hospital RWTH Aachen, Aachen, Germany
| | - J B Schulz
- Department of Neurology, University Hospital RWTH Aachen, Aachen, Germany; JARA Translational Brain Medicine, Germany
| | - J Weis
- Institute of Neuropathology, University Hospital RWTH Aachen, Aachen, Germany; JARA Translational Brain Medicine, Germany
| | - K G Claeys
- Department of Neurology, University Hospital RWTH Aachen, Aachen, Germany; Institute of Neuropathology, University Hospital RWTH Aachen, Aachen, Germany; JARA Translational Brain Medicine, Germany.
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7
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Malfatti E, Schaeffer U, Chapon F, Yang Y, Eymard B, Xu R, Laporte J, Romero NB. Combined cap disease and nemaline myopathy in the same patient caused by an autosomal dominant mutation in the TPM3 gene. Neuromuscul Disord 2013; 23:992-7. [PMID: 24095155 DOI: 10.1016/j.nmd.2013.07.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 07/02/2013] [Accepted: 07/09/2013] [Indexed: 11/23/2022]
Abstract
The slow α-tropomyosin gene (TPM3) has been associated with three distinct histological entities: nemaline myopathy (NM, NEM1), congenital fibre-type disproportion (CFTD), and cap disease (CD). Here we describe a patient presenting an early-onset congenital myopathy associated with a combination of well separated cap structures and nemaline bodies in his muscle biopsy. Exome sequencing analysis allowed us to identify a de novo missense mutation in the TPM3 gene. Our study confirms the extreme variability of morphological findings in TPM3-related myopathies, and proves that cap and nemaline bodies are two sides of the same 'coin'.
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Robaszkiewicz K, Dudek E, Kasprzak AA, Moraczewska J. Functional effects of congenital myopathy-related mutations in gamma-tropomyosin gene. Biochim Biophys Acta Mol Basis Dis 2012; 1822:1562-9. [PMID: 22749829 DOI: 10.1016/j.bbadis.2012.06.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 06/15/2012] [Accepted: 06/18/2012] [Indexed: 12/25/2022]
Abstract
Missense mutations in human TPM3 gene encoding γ-tropomyosin expressed in slow muscle type 1 fibers, were associated with three types of congenital myopathies-nemaline myopathy, cap disease and congenital fiber type disproportion. Functional effects of the following substitutions: Leu100Met, Ala156Thr, Arg168His, Arg168Cys, Arg168Gly, Lys169Glu, and Arg245Gly, were examined in biochemical assays using recombinant tropomyosin mutants and native proteins isolated from skeletal muscle. Most, but not all, mutations decreased the affinity of tropomyosin for actin alone and in complex with troponin (±Ca(2+)). All studied tropomyosin mutants reduced Ca-induced activation but had no effect on the inhibition of actomyosin cross-bridges. Ca(2+)-sensitivity of the actomyosin interactions, as well as cooperativity of myosin-induced activation of the thin filament was affected by individual tropomyosin mutants with various degrees. Decreased motility of the reconstructed thin filaments was a result of combined functional defects caused by myopathy-related tropomyosin mutants. We conclude that muscle weakness and structural abnormalities observed in TPM3-related congenital myopathies result from reduced capability of the thin filament to fully activate actin-myosin cross-bridges.
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Affiliation(s)
- Katarzyna Robaszkiewicz
- Kazimierz Wielki University in Bydgoszcz, Department of Biochemistry and Cell Biology, Chodkiewicza , Bydgoszcz, Poland
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Lawlor MW, Dechene ET, Roumm E, Geggel AS, Moghadaszadeh B, Beggs AH. Mutations of tropomyosin 3 (TPM3) are common and associated with type 1 myofiber hypotrophy in congenital fiber type disproportion. Hum Mutat 2010; 31:176-83. [PMID: 19953533 DOI: 10.1002/humu.21157] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Congenital fiber type disproportion (CFTD) is a rare congenital myopathy characterized by hypotonia and generalized muscle weakness. Pathologic diagnosis of CFTD is based on the presence of type 1 fiber hypotrophy of at least 12% in the absence of other notable pathological findings. Mutations of the ACTA1 and SEPN1 genes have been identified in a small percentage of CFTD cases. The muscle tropomyosin 3 gene, TPM3, is mutated in rare cases of nemaline myopathy that typically exhibit type 1 fiber hypotrophy with nemaline rods, and recently mutations in the TPM3 gene were also found to cause CFTD. We screened the TPM3 gene in patients with a clinical diagnosis of CFTD, nemaline myopathy, and with undefined congenital myopathies. Mutations in TPM3 were identified in 6 out of 13 patients with CFTD, as well as in one case of nemaline myopathy. Review of muscle biopsies from patients with diagnoses of CFTD revealed that patients with a TPM3 mutation all displayed marked disproportion of fiber size, without type 1 fiber predominance. Several mutation-negative cases exhibited other abnormalities, such as central nuclei and central cores. These results support the utility of the CFTD diagnosis in directing the course of genetic testing.
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Affiliation(s)
- Michael W Lawlor
- Division of Genetics and Program in Genomics, The Manton Center for Orphan Disease Research, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts, USA
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De Paula AM, Franques J, Fernandez C, Monnier N, Lunardi J, Pellissier JF, Figarella-Branger D, Pouget J. A TPM3 mutation causing cap myopathy. Neuromuscul Disord 2009; 19:685-8. [PMID: 19553118 DOI: 10.1016/j.nmd.2009.06.365] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 05/28/2009] [Accepted: 06/03/2009] [Indexed: 11/17/2022]
Abstract
Cap disease is a rare congenital myopathy associated with skeletal malformations and respiratory involvement. Abnormally arranged myofibrils taking the appearance of a "cap" are the morphological hallmark of this entity. We report a case of cap disease concerning a 42-year-old man, without any family history and presenting a p.Arg168His mutation on the TPM3 gene. His first biopsy at 7years had only shown selective type I hypotrophy. Mutations of TPM3 gene have been found in nemaline myopathy, congenital fiber type disproportion, but never before in cap disease.
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Affiliation(s)
- Andre Maues De Paula
- Department of Anatomic Pathology and Neuropathology, C.H.U. Timone, Marseille, France.
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11
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Ilkovski B, Mokbel N, Lewis RA, Walker K, Nowak KJ, Domazetovska A, Laing NG, Fowler VM, North KN, Cooper ST. Disease severity and thin filament regulation in M9R TPM3 nemaline myopathy. J Neuropathol Exp Neurol 2008; 67:867-77. [PMID: 18716557 DOI: 10.1097/NEN.0b013e318183a44f] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The mechanism of muscle weakness was investigated in an Australian family with an M9R mutation in TPM3 (alpha-tropomyosin(slow)). Detailed protein analyses of 5 muscle samples from 2 patients showed that nemaline bodies are restricted to atrophied Type 1 (slow) fibers in which the TPM3 gene is expressed. Developmental expression studies showed that alpha-tropomyosin(slow) is not expressed at significant levels until after birth, thereby likely explaining the childhood (rather than congenital) disease onset in TPM3 nemaline myopathy. Isoelectric focusing demonstrated that alpha-tropomyosin(slow) dimers, composed of equal ratios of wild-type and M9R-alpha-tropomyosin(slow), are the dominant tropomyosin species in 3 separate muscle groups from an affected patient. These findings suggest that myopathy-related slow fiber predominance likely contributes to the severity of weakness in TPM3 nemaline myopathy because of increased proportions of fibers that express the mutant protein. Using recombinant proteins and far Western blot, we demonstrated a higher affinity of tropomodulin for alpha-tropomyosin(slow) compared with beta-tropomyosin; the M9R substitution within alpha-tropomyosin(slow) greatly reduced this interaction. Finally, transfection of the M9R mutated and wild-type alpha-tropomyosin(slow) into myoblasts revealed reduced incorporation into stress fibers and disruption of the filamentous actin network by the mutant protein. Collectively, these results provide insights into the clinical features and pathogenesis of M9R-TPM3 nemaline myopathy.
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12
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Tajsharghi H. Thick and thin filament gene mutations in striated muscle diseases. Int J Mol Sci 2008; 9:1259-75. [PMID: 19325803 DOI: 10.3390/ijms9071259] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [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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Abstract
This review focuses on congenital myopathies, a distinct but markedly heterogeneous group of muscle disorders that present with muscle weakness and typically appear at birth or in infancy. These myopathies have characteristic histopathologic abnormalities on muscle biopsy, allowing a preliminary morphologic classification. Advances in molecular genetics have allowed a more rational classification of these disorders and have reshuffled taxonomy for some of these conditions. Here, we focus on recent research advances in specific congenital myopathies, including nemaline myopathy, myotubular myopathy, centronuclear myopathy, central core myopathy, multi-minicore myopathy, congenital fiber-type disproportion myopathy, and hyaline body myopathy. Scientific progress has not only elucidated the pathologic mechanisms of these disorders, but it has also provided the basis for therapeutic strategies.
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Affiliation(s)
- Adele D'Amico
- Ospedale Bambino Gesù Research Chidren's Hospital, P.za S. Onofrio, 4, 00165 Rome, Italy
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Clarke NF, Kolski H, Dye DE, Lim E, Smith RLL, Patel R, Fahey MC, Bellance R, Romero NB, Johnson ES, Labarre-Vila A, Monnier N, Laing NG, North KN. Mutations in TPM3 are a common cause of congenital fiber type disproportion. Ann Neurol 2008; 63:329-37. [PMID: 18300303 DOI: 10.1002/ana.21308] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Congenital fiber type disproportion (CFTD) is a rare form of congenital myopathy in which the principal histological abnormality is hypotrophy of type 1 (slow-twitch) fibers compared with type 2 (fast-twitch) fibers. To date, mutation of ACTA1 and SEPN1 has been associated with CFTD, but the genetic basis in most patients is unclear. The gene encoding alpha-tropomyosin(slow) (TPM3) is a rare cause of nemaline myopathy, previously reported in only five families. We investigated whether mutation of TPM3 is a cause of CFTD. METHODS AND RESULTS We sequenced TPM3 in 23 unrelated probands with CFTD or CFTD-like presentations of unknown cause and identified novel heterozygous missense mutations in five CFTD families (p. Leu100Met, p.Arg168Cys, p.Arg168Gly, p.Lys169Glu, p.Arg245Gly). All affected family members that underwent biopsy had typical histological features of CFTD, with type 1 fibers, on average, at least 50% smaller than type 2 fibers. We also report a sixth family in which a recurrent TPM3 mutation (p.Arg168His) was associated with histological features of CFTD and nemaline myopathy in different family members. We describe the clinical features of 11 affected patients. Typically, there was proximal limb girdle weakness, prominent weakness of neck flexion and ankle dorsiflexion, mild facial weakness, and mild ptosis. The age of onset and severity varied, even within the same family. Many patients required nocturnal noninvasive ventilation despite remaining ambulant. INTERPRETATION Mutation of TPM3 is the most common cause of CFTD reported to date.
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Affiliation(s)
- Nigel F Clarke
- Institute for Neuromuscular Research, Children's Hospital at Westmead, Discipline of Paediatrics and Child Health, University of Sydney, Sydney, Australia
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Lehtokari VL, Pelin K, Donner K, Voit T, Rudnik-Schöneborn S, Stoetter M, Talim B, Topaloglu H, Laing NG, Wallgren-Pettersson C. Identification of a founder mutation in TPM3 in nemaline myopathy patients of Turkish origin. Eur J Hum Genet 2008; 16:1055-61. [PMID: 18382475 DOI: 10.1038/ejhg.2008.60] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
To date, six genes are known to cause nemaline (rod) myopathy (NM), a rare congenital neuromuscular disorder. In an attempt to find a seventh gene, we performed linkage and subsequent sequence analyses in 12 Turkish families with recessive NM. We found homozygosity in two of the families at 1q12-21.2, a region encompassing the gamma-tropomyosin gene (TPM3) encoding slow skeletal muscle alpha-tropomyosin, a known NM gene. Sequencing revealed homozygous deletion of the first nucleotide of the last exon, c.913delA of TPM3 in both families. The mutation removes the last nucleotide before the stop codon, causing a frameshift and readthrough across the termination signal. The encoded alphaTm(slow) protein is predicted to be 73 amino acids longer than normal, and the extension to the protein is hypothesised to be unable to form a coiled coil. The resulting tropomyosin protein may therefore be non-functional. The affected children in both families were homozygous for the mutation, while the healthy parents were mutation carriers. Both of the patients in Family 1 had the severe form of NM, and also an unusual chest deformity. The affected children in Family 2 had the intermediate form of NM. Muscle biopsies showed type 1 (slow) fibres to be markedly smaller than type 2 (fast) fibres. Previously, there had been five reports, only, of NM caused by mutations in TPM3. The mutation reported here is the first deletion to be identified in TPM3, and it is likely to be a founder mutation in the Turkish population.
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Abstract
Tropomyosins are rodlike coiled coil dimers that form continuous polymers along the major groove of most actin filaments. In striated muscle, tropomyosin regulates the actin-myosin interaction and, hence, contraction of muscle. Tropomyosin also contributes to most, if not all, functions of the actin cytoskeleton, and its role is essential for the viability of a wide range of organisms. The ability of tropomyosin to contribute to the many functions of the actin cytoskeleton is related to the temporal and spatial regulation of expression of tropomyosin isoforms. Qualitative and quantitative changes in tropomyosin isoform expression accompany morphogenesis in a range of cell types. The isoforms are segregated to different intracellular pools of actin filaments and confer different properties to these filaments. Mutations in tropomyosins are directly involved in cardiac and skeletal muscle diseases. Alterations in tropomyosin expression directly contribute to the growth and spread of cancer. The functional specificity of tropomyosins is related to the collaborative interactions of the isoforms with different actin binding proteins such as cofilin, gelsolin, Arp 2/3, myosin, caldesmon, and tropomodulin. It is proposed that local changes in signaling activity may be sufficient to drive the assembly of isoform-specific complexes at different intracellular sites.
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Affiliation(s)
- Peter Gunning
- Oncology Research Unit, The Children's Hospital at Westmead, and Muscle Development Unit, Children's Medical Research Institute, Westmead; New South Wales, Australia.
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Clarke NF. Skeletal Muscle Disease Due to Mutations in Tropomyosin, Troponin and Cofilin. Advances in Experimental Medicine and Biology 2008. [DOI: 10.1007/978-0-387-84847-1_4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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Abstract
A number of congenital muscle diseases and disorders are caused by mutations in genes that encode the proteins present in or associated with the thin filaments of the muscle sarcomere. These genes include alpha-skeletal actin (ACTA1), beta-tropomyosin (TPM2), alpha-tropomyosin slow (TPM3), nebulin (NEB), troponin I fast (TNNI2), troponin T slow (TNNT1), troponin T fast (TNNT3) and cofilin (CFL2). Mutations in two of the four tropomyosin (Tm) genes, TPM2 and TPM3, result in at least three different skeletal muscle diseases and one disorder as distinguished by the presence of specific clinical features and/or structural abnormalities--nemaline myopathy (TPM2 and TPM3), distal arthrogryposis (TPM2), cap disease (TPM2) and congenital fiber type disproportion (TPM3). These diseases have overlapping clinical features and pathologies and there are cases of family members who have the same mutation, but different diseases (Table 1). The relatively recent discovery of nonmuscle or cytoskeletal Tms in skeletal muscle adds to this complexity since it is now possible that a disease-causing mutation could be in a striated isoform and a cytoskeletal isoform both present in muscle.
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Pénisson-Besnier I, Monnier N, Toutain A, Dubas F, Laing N. A second pedigree with autosomal dominant nemaline myopathy caused by TPM3 mutation: A clinical and pathological study. Neuromuscul Disord 2007; 17:330-7. [PMID: 17376686 DOI: 10.1016/j.nmd.2007.01.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2006] [Revised: 01/05/2007] [Accepted: 01/22/2007] [Indexed: 10/23/2022]
Abstract
The slow alpha-tropomyosin (TPM3) gene has to date been associated with few cases of both dominant and recessive nemaline myopathies. We report the identification of a p.Arg167His mutation in a four-generation family presenting with a mild classical form of the disease. Clinically, there was no correlation between the age at presentation and the severity of the disease. The dominant-negative p.Arg167His mutation is a recurrent mutation, previously reported in one sporadic case. Histological studies showed discrepancy between the two reports. While a type II fibre predominance was described in the sporadic case, we observed an almost complete type I fibre predominance. This study emphasizes the variability in histopathological phenotypes seen with TPM3 mutations.
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Affiliation(s)
- Nigel G Laing
- Centre for Medical Research, University of Western Australia, West Australian Institute for Medical Research, Nedlands, Western Australia, Australia
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Sanoudou D, Corbett MA, Han M, Ghoddusi M, Nguyen MAT, Vlahovich N, Hardeman EC, Beggs AH. Skeletal muscle repair in a mouse model of nemaline myopathy. Hum Mol Genet 2006; 15:2603-12. [PMID: 16877500 PMCID: PMC3372923 DOI: 10.1093/hmg/ddl186] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Nemaline myopathy (NM), the most common non-dystrophic congenital myopathy, is a variably severe neuromuscular disorder for which no effective treatment is available. Although a number of genes have been identified in which mutations can cause NM, the pathogenetic mechanisms leading to the phenotypes are poorly understood. To address this question, we examined gene expression patterns in an NM mouse model carrying the human Met9Arg mutation of alpha-tropomyosin slow (Tpm3). We assessed five different skeletal muscles from affected mice, which are representative of muscles with differing fiber-type compositions, different physiological specializations and variable degrees of pathology. Although these same muscles in non-affected mice showed marked variation in patterns of gene expression, with diaphragm being the most dissimilar, the presence of the mutant protein in nemaline muscles resulted in a more similar pattern of gene expression among the muscles. This result suggests a common process or mechanism operating in nemaline muscles independent of the variable degrees of pathology. Transcriptional and protein expression data indicate the presence of a repair process and possibly delayed maturation in nemaline muscles. Markers indicative of satellite cell number, activated satellite cells and immature fibers including M-Cadherin, MyoD, desmin, Pax7 and Myf6 were elevated by western-blot analysis or immunohistochemistry. Evidence suggesting elevated focal repair was observed in nemaline muscle in electron micrographs. This analysis reveals that NM is characterized by a novel repair feature operating in multiple different muscles.
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Affiliation(s)
- Despina Sanoudou
- Program in Genomics and Genetics Division, Children’s Hospital Boston, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA
- Molecular Biology Division, Foundation for Biomedical Research, Academy of Athens, Soranou Efesiou 4, Athens 115-27, Greece
| | - Mark A. Corbett
- Muscle Development Unit, Children’s Medical Research Institute, Locked Bag 23, Westmead, NSW 2145, Australia
| | - Mei Han
- Program in Genomics and Genetics Division, Children’s Hospital Boston, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA
| | - Majid Ghoddusi
- Muscle Development Unit, Children’s Medical Research Institute, Locked Bag 23, Westmead, NSW 2145, Australia
| | - Mai-Anh T. Nguyen
- Muscle Development Unit, Children’s Medical Research Institute, Locked Bag 23, Westmead, NSW 2145, Australia
| | - Nicole Vlahovich
- Muscle Development Unit, Children’s Medical Research Institute, Locked Bag 23, Westmead, NSW 2145, Australia
| | - Edna C. Hardeman
- Muscle Development Unit, Children’s Medical Research Institute, Locked Bag 23, Westmead, NSW 2145, Australia
| | - Alan H. Beggs
- Program in Genomics and Genetics Division, Children’s Hospital Boston, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA
- To whom correspondence should be addressed. Tel: +1 6179192170; Fax: +1 6177300253;
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Cuisset JM, Maurage CA, Pellissier JF, Barois A, Urtizberea JA, Laing N, Tajsharghi H, Vallée L. 'Cap myopathy': case report of a family. Neuromuscul Disord 2006; 16:277-81. [PMID: 16531045 DOI: 10.1016/j.nmd.2006.01.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2005] [Revised: 01/17/2006] [Accepted: 01/31/2006] [Indexed: 11/21/2022]
Abstract
We report the observation of an 18-year-old girl, whose clinical presentation was very suggestive of a congenital myopathy with neonatal onset. A congenital myopathy had been already diagnosed in her brother and in addition her half-cousin died diagnosed with a severe nemaline myopathy at age 4 years. A muscle biopsy performed on both siblings revealed histological and ultrastructural features of 'cap myopathy'. This case report suggests that 'cap myopathy' and some cases of nemaline myopathy with neonatal onset might be two phenotypic expressions of the same genetic disorder. These two entities could therefore, perhaps, be regarded as 'Z-line disorders' possibly caused by defective myofibrillogenesis.
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Affiliation(s)
- J M Cuisset
- Service de Neuropédiatrie, Centre hospitalier régional universitaire et faculté de médecine, 59037 Lille, France.
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Abstract
Most neuromuscular disorders display only non-specific myopathological features in routine histological preparations. However, a number of proteins, including sarcolemmal, sarcomeric, and nuclear proteins as well as enzymes with defects responsible for neuromuscular disorders, have been identified during the past two decades, allowing a more specific and firm diagnosis of muscle diseases. Identification of protein defects relies predominantly on immunohistochemical preparations and on Western blot analysis. While immunohistochemistry is very useful in identifying abnormal expression of primary protein abnormalities in recessive conditions, it is less helpful in detecting primary defects in dominantly inherited disorders. Abnormal immunohistochemical expression patterns can be confirmed by Western blot analysis which may also be informative in dominant disorders, although its role has yet to be established. Besides identification of specific protein defects, immunohistochemistry is also helpful in the differentiation of inflammatory myopathies by subtyping cellular infiltrates and demonstrating up-regulation of subtle immunological parameters such as cell adhesion molecules. The role of immunohistochemistry in denervating disorders, however, remains controversial in the absence of a reliable marker of muscle fibre denervation. Nevertheless, as well as the diagnostic value of immunocytochemical analysis it may also widen understanding of muscle fibre pathology as well as help in the development of therapeutic strategies.
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Affiliation(s)
- D S Tews
- Edinger-Institute of the Johann-Wolfgang Goethe-University, Frankfurt, Germany.
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