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Schänzer A, Rupp S, Gräf S, Zengeler D, Jux C, Akintürk H, Gulatz L, Mazhari N, Acker T, Van Coster R, Garvalov BK, Hahn A. Dysregulated autophagy in restrictive cardiomyopathy due to Pro209Leu mutation in BAG3. Mol Genet Metab 2018; 123:388-399. [PMID: 29338979 DOI: 10.1016/j.ymgme.2018.01.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 01/02/2018] [Accepted: 01/02/2018] [Indexed: 12/13/2022]
Abstract
Myofibrillary myopathies (MFM) are hereditary myopathies histologically characterized by degeneration of myofibrils and aggregation of proteins in striated muscle. Cardiomyopathy is common in MFM but the pathophysiological mechanisms are not well understood. The BAG3-Pro209Leu mutation is associated with early onset MFM and severe restrictive cardiomyopathy (RCM), often necessitating heart transplantation during childhood. We report on a young male patient with a BAG3-Pro209Leu mutation who underwent heart transplantation at eight years of age. Detailed morphological analyses of the explanted heart tissue showed intracytoplasmic inclusions, aggregation of BAG3 and desmin, disintegration of myofibers and Z-disk alterations. The presence of undegraded autophagosomes, seen by electron microscopy, as well as increased levels of p62, LC3-I and WIPI1, detected by immunohistochemistry and western blot analyses, indicated a dysregulation of autophagy. Parkin and PINK1, proteins involved in mitophagy, were slightly increased whereas mitochondrial OXPHOS activities were not altered. These findings indicate that altered autophagy plays a role in the pathogenesis and rapid progression of RCM in MFM caused by the BAG3-Pro209Leu mutation, which could have implications for future therapeutic strategies.
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Affiliation(s)
- A Schänzer
- Institute of Neuropathology, Justus Liebig University Giessen, 35392 Giessen, Germany.
| | - S Rupp
- Pediatric Heart Center, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - S Gräf
- Institute of Neuropathology, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - D Zengeler
- Center for Genomics and Transcriptomics (CeGat) GmbH, 72076 Tübingen, Germany
| | - C Jux
- Pediatric Heart Center, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - H Akintürk
- Pediatric Heart Center, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - L Gulatz
- Institute of Neuropathology, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - N Mazhari
- Pediatric Heart Center, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - T Acker
- Institute of Neuropathology, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - R Van Coster
- Division of Child Neurology, Department of Pediatrics, University Hospital Gent, 9000 Gent, Belgium
| | - B K Garvalov
- Institute of Neuropathology, Justus Liebig University Giessen, 35392 Giessen, Germany; Department of Microvascular Biology and Pathobiology, Centre for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, University of Heidelberg, 68167 Mannheim, Germany
| | - A Hahn
- Department of Child Neurology, Justus Liebig University Giessen, 35392 Giessen, Germany
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2
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MYH7 mutation associated with two phenotypes of myopathy. Neurol Sci 2017; 39:333-339. [PMID: 29170849 DOI: 10.1007/s10072-017-3192-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 11/07/2017] [Indexed: 10/18/2022]
Abstract
The mutations of MYH7 (slow skeletal/β-cardiac myosin heavy chain) are commonly found in familial hypertrophic/dilated cardiomyopathy, and also can cause Laing early-onset distal myopathy (LDM), myosin storage myopathy (MSM), and congenital myopathy with fiber-type disproportion (CFTD). Here we report two cases whose diagnosis was hereditary myopathy according to clinical feature and muscle pathology analysis. High-throughput genomic sequencing (next generation sequencing) was performed to validate the diagnosis. Two MYH7 mutations, p.R1845W and p.E1687del, were identified. p.R1845W was found in a male patient showing weakness of both terminal lower legs without foot drop. Muscle pathology stainings characteristically showed the hyaline body in the intracytoplasmic location. The novel mutation p.E1687del was found in a family with seven patients. The proband showed foot drop, scoliosis, and winged scapula, while his mother only showed mild foot drop and winged scapula. Muscle pathology analysis showed congenital centronucleus myopathy. Both cases only showed muscular disorder and had no cardiomyopathy. This study, for the first time, reports the MYH7 mutations associated with centronucleus myopathy.
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3
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New insights into the protein aggregation pathology in myotilinopathy by combined proteomic and immunolocalization analyses. Acta Neuropathol Commun 2016; 4:8. [PMID: 26842778 PMCID: PMC4739336 DOI: 10.1186/s40478-016-0280-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Accepted: 01/23/2016] [Indexed: 01/09/2023] Open
Abstract
Introduction Myofibrillar myopathies are characterized by progressive muscle weakness and impressive abnormal protein aggregation in muscle fibers. In about 10 % of patients, the disease is caused by mutations in the MYOT gene encoding myotilin. The aim of our study was to decipher the composition of protein deposits in myotilinopathy to get new information about aggregate pathology. Results Skeletal muscle samples from 15 myotilinopathy patients were included in the study. Aggregate and control samples were collected from muscle sections by laser microdissection and subsequently analyzed by a highly sensitive proteomic approach that enables a relative protein quantification. In total 1002 different proteins were detected. Seventy-six proteins showed a significant over-representation in aggregate samples including 66 newly identified aggregate proteins. Z-disc-associated proteins were the most abundant aggregate components, followed by sarcolemmal and extracellular matrix proteins, proteins involved in protein quality control and degradation, and proteins with a function in actin dynamics or cytoskeletal transport. Forty over-represented proteins were evaluated by immunolocalization studies. These analyses validated our mass spectrometric data and revealed different regions of protein accumulation in abnormal muscle fibers. Comparison of data from our proteomic analysis in myotilinopathy with findings in other myofibrillar myopathy subtypes indicates a characteristic basic pattern of aggregate composition and resulted in identification of a highly sensitive and specific diagnostic marker for myotilinopathy. Conclusions Our findings i) indicate that main protein components of aggregates belong to a network of interacting proteins, ii) provide new insights into the complex regulation of protein degradation in myotilinopathy that may be relevant for new treatment strategies, iii) imply a combination of a toxic gain-of-function leading to myotilin-positive protein aggregates and a loss-of-function caused by a shift in subcellular distribution with a deficiency of myotilin at Z-discs that impairs the integrity of myofibrils, and iv) demonstrate that proteomic analysis can be helpful in differential diagnosis of protein aggregate myopathies. Electronic supplementary material The online version of this article (doi:10.1186/s40478-016-0280-0) contains supplementary material, which is available to authorized users.
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4
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Guglielmi V, Marini M, Masson ÉF, Malatesta M, Forget D, Tomelleri G, Coulombe B, Vattemi G. Abnormal expression of RNA polymerase II-associated proteins in muscle of patients with myofibrillar myopathies. Histopathology 2015; 67:859-65. [PMID: 25891782 DOI: 10.1111/his.12715] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 04/14/2015] [Indexed: 01/13/2023]
Abstract
AIMS Myofibrillar myopathies (MFMs) are a group of inherited or sporadic neuromuscular disorders characterized morphologically by foci of myofibril dissolution, disintegration of the Z-disk and insoluble protein aggregates within the muscle fibres. The sequential events leading to muscle fibre damage remains largely unknown. METHODS AND RESULTS We investigated the expression and the cellular localization of RNA polymerase II (RNAPII)-associated proteins (RPAPs) in muscle biopsies from patients with genetically proven and sporadic MFMs. Our data demonstrated that RPAP2, and to a lesser extent GPN1/RPAP4, are accumulated focally in the cytoplasm of MFM muscle fibres in which they co-localize with POLR2A/RPB1, the largest subunit of RNAPII, and correspond to αB-cystallin deposits in distribution and staining intensity. No abnormal staining for RPAP2 has been observed in muscle of patients with central cores, minicores and neurogenic target fibres. CONCLUSIONS Together, these findings could provide new insights into the molecular pathogenesis of MFMs and suggest that RPAP2 immunostaining can be a useful diagnostic tool to depict protein aggregates in MFMs.
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Affiliation(s)
- Valeria Guglielmi
- Department of Neurological and Movement Sciences, Section of Clinical Neurology, University of Verona, Verona, Italy
| | - Matteo Marini
- Department of Neurological and Movement Sciences, Section of Clinical Neurology, University of Verona, Verona, Italy
| | | | - Manuela Malatesta
- Department of Neurological and Movement Sciences, Section of Anatomy and Histology, University of Verona, Verona, Italy
| | - Diane Forget
- Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC, Canada
| | - Giuliano Tomelleri
- Department of Neurological and Movement Sciences, Section of Clinical Neurology, University of Verona, Verona, Italy
| | - Benoit Coulombe
- Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC, Canada
| | - Gaetano Vattemi
- Department of Neurological and Movement Sciences, Section of Clinical Neurology, University of Verona, Verona, Italy
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5
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Winter L, Staszewska I, Mihailovska E, Fischer I, Goldmann WH, Schröder R, Wiche G. Chemical chaperone ameliorates pathological protein aggregation in plectin-deficient muscle. J Clin Invest 2014; 124:1144-57. [PMID: 24487589 DOI: 10.1172/jci71919] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 11/21/2013] [Indexed: 11/17/2022] Open
Abstract
The ubiquitously expressed multifunctional cytolinker protein plectin is essential for muscle fiber integrity and myofiber cytoarchitecture. Patients suffering from plectinopathy-associated epidermolysis bullosa simplex with muscular dystrophy (EBS-MD) and mice lacking plectin in skeletal muscle display pathological desmin-positive protein aggregation and misalignment of Z-disks, which are hallmarks of myofibrillar myopathies (MFMs). Here, we developed immortalized murine myoblast cell lines to examine the pathogenesis of plectinopathies at the molecular and single cell level. Plectin-deficient myotubes, derived from myoblasts, were fully functional and mirrored the pathological features of EBS-MD myofibers, including the presence of desmin-positive protein aggregates and a concurrent disarrangement of the myofibrillar apparatus. Using this cell model, we demonstrated that plectin deficiency leads to increased intermediate filament network and sarcomere dynamics, marked upregulation of HSPs, and reduced myotube resilience following mechanical stretch. Currently, no specific therapy or treatment is available to improve plectin-related or other forms of MFMs; therefore, we assessed the therapeutic potential of chemical chaperones to relieve plectinopathies. Treatment with 4-phenylbutyrate resulted in remarkable amelioration of the pathological phenotypes in plectin-deficient myotubes as well as in plectin-deficient mice. Together, these data demonstrate the biological relevance of the MFM cell model and suggest that this model has potential use for the development of therapeutic approaches for EBS-MD.
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MESH Headings
- Animals
- Cell Differentiation
- Cells, Cultured
- Desmin/metabolism
- Drug Evaluation, Preclinical
- Heat-Shock Proteins/genetics
- Heat-Shock Proteins/metabolism
- Intermediate Filaments/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/metabolism
- Muscle Strength/drug effects
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Myoblasts/physiology
- Myopathies, Structural, Congenital/drug therapy
- Myopathies, Structural, Congenital/metabolism
- Myopathies, Structural, Congenital/pathology
- Phenylbutyrates/pharmacology
- Phenylbutyrates/therapeutic use
- Plectin/deficiency
- Plectin/genetics
- Protein Stability
- Sarcomeres/metabolism
- Sarcomeres/pathology
- Up-Regulation
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6
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Maerkens A, Kley RA, Olivé M, Theis V, van der Ven PFM, Reimann J, Milting H, Schreiner A, Uszkoreit J, Eisenacher M, Barkovits K, Güttsches AK, Tonillo J, Kuhlmann K, Meyer HE, Schröder R, Tegenthoff M, Fürst DO, Müller T, Goldfarb LG, Vorgerd M, Marcus K. Differential proteomic analysis of abnormal intramyoplasmic aggregates in desminopathy. J Proteomics 2013; 90:14-27. [PMID: 23639843 DOI: 10.1016/j.jprot.2013.04.026] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 04/03/2013] [Accepted: 04/18/2013] [Indexed: 11/27/2022]
Abstract
UNLABELLED Desminopathy is a subtype of myofibrillar myopathy caused by desmin mutations and characterized by protein aggregates accumulating in muscle fibers. The aim of this study was to assess the protein composition of these aggregates. Aggregates and intact myofiber sections were obtained from skeletal muscle biopsies of five desminopathy patients by laser microdissection and analyzed by a label-free spectral count-based proteomic approach. We identified 397 proteins with 22 showing significantly higher spectral indices in aggregates (ratio >1.8, p<0.05). Fifteen of these proteins not previously reported as specific aggregate components provide new insights regarding pathomechanisms of desminopathy. Results of proteomic analysis were supported by immunolocalization studies and parallel reaction monitoring. Three mutant desmin variants were detected directly on the protein level as components of the aggregates, suggesting their direct involvement in aggregate-formation and demonstrating for the first time that proteomic analysis can be used for direct identification of a disease-causing mutation in myofibrillar myopathy. Comparison of the proteomic results in desminopathy with our previous analysis of aggregate composition in filaminopathy, another myofibrillar myopathy subtype, allows to determine subtype-specific proteomic profile that facilitates identification of the specific disorder. BIOLOGICAL SIGNIFICANCE Our proteomic analysis provides essential new insights in the composition of pathological protein aggregates in skeletal muscle fibers of desminopathy patients. The results contribute to a better understanding of pathomechanisms in myofibrillar myopathies and provide the basis for hypothesis-driven studies. The detection of specific proteomic profiles in different myofibrillar myopathy subtypes indicates that proteomic analysis may become a useful tool in differential diagnosis of protein aggregate myopathies.
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Affiliation(s)
- A Maerkens
- Department of Neurology, Neuromuscular Centre Ruhrgebiet, University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany
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7
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Kley RA, Maerkens A, Leber Y, Theis V, Schreiner A, van der Ven PFM, Uszkoreit J, Stephan C, Eulitz S, Euler N, Kirschner J, Müller K, Meyer HE, Tegenthoff M, Fürst DO, Vorgerd M, Müller T, Marcus K. A combined laser microdissection and mass spectrometry approach reveals new disease relevant proteins accumulating in aggregates of filaminopathy patients. Mol Cell Proteomics 2012; 12:215-27. [PMID: 23115302 DOI: 10.1074/mcp.m112.023176] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Filaminopathy is a subtype of myofibrillar myopathy caused by mutations in FLNC, the gene encoding filamin C, and histologically characterized by pathologic accumulation of several proteins within skeletal muscle fibers. With the aim to get new insights in aggregate composition, we collected aggregates and control tissue from skeletal muscle biopsies of six myofibrillar myopathy patients harboring three different FLNC mutations by laser microdissection and analyzed the samples by a label-free mass spectrometry approach. A total of 390 proteins were identified, and 31 of those showed significantly higher spectral indices in aggregates compared with patient controls with a ratio >1.8. These proteins included filamin C, other known myofibrillar myopathy associated proteins, and a striking number of filamin C binding partners. Across the patients the patterns were extremely homogeneous. Xin actin-binding repeat containing protein 2, heat shock protein 27, nebulin-related-anchoring protein, and Rab35 could be verified as new filaminopathy biomarker candidates. In addition, further experiments identified heat shock protein 27 and Xin actin-binding repeat containing protein 2 as novel filamin C interaction partners and we could show that Xin actin-binding repeat containing protein 2 and the known interaction partner Xin actin-binding repeat containing protein 1 simultaneously associate with filamin C. Ten proteins showed significant lower spectral indices in aggregate samples compared with patient controls (ratio <0.56) including M-band proteins myomesin-1 and myomesin-2. Proteomic findings were consistent with previous and novel immunolocalization data. Our findings suggest that aggregates in filaminopathy have a largely organized structure of proteins also interacting under physiological conditions. Different filamin C mutations seem to lead to almost identical aggregate compositions. The finding that filamin C was detected as highly abundant protein in aggregates in filaminopathy indicates that our proteomic approach may be suitable to identify new candidate genes among the many MFM patients with so far unknown mutation.
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Affiliation(s)
- Rudolf A Kley
- Department of Neurology, Neuromuscular Center Ruhrgebiet, University Hospital Bergmannsheil, Ruhr-University Bochum, Germany
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8
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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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9
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Keduka E, Hayashi YK, Shalaby S, Mitsuhashi H, Noguchi S, Nonaka I, Nishino I. In vivo characterization of mutant myotilins. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 180:1570-80. [PMID: 22349301 DOI: 10.1016/j.ajpath.2011.12.040] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 12/27/2011] [Accepted: 12/29/2011] [Indexed: 10/28/2022]
Abstract
Myofibrillar myopathy (MFM) is a group of disorders that are pathologically defined by the disorganization of the myofibrillar alignment associated with the intracellular accumulation of Z-disk-associated proteins. MFM is caused by mutations in genes encoding Z-disk-associated proteins, including myotilin. Although a number of MFM mutations have been identified, it has been difficult to elucidate the precise roles of the mutant proteins. Here, we present a useful method for the characterization of mutant proteins associated with MFM. Expression of mutant myotilins in mouse tibialis anterior muscle by in vivo electroporation recapitulated both the pathological changes and the biochemical characteristics observed in patients with myotilinopathy. In mutant myotilin-expressing muscle fibers, myotilin aggregates and is costained with polyubiquitin, and Z-disk-associated proteins and myofibrillar disorganization were commonly seen. In addition, the expressed S60C mutant myotilin protein displayed marked detergent insolubility in electroporated mouse muscle, similar to that observed in human MFM muscle with the same mutation. Thus, in vivo electroporation can be a useful method for evaluating the pathogenicity of mutations identified in MFM.
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Affiliation(s)
- Etsuko Keduka
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
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10
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Kurapati R, McKenna C, Lindqvist J, Williams D, Simon M, LeProust E, Baker J, Cheeseman M, Carroll N, Denny P, Laval S, Lochmüller H, Ochala J, Blanco G. Myofibrillar myopathy caused by a mutation in the motor domain of mouse MyHC IIb. Hum Mol Genet 2011; 21:1706-24. [PMID: 22199023 DOI: 10.1093/hmg/ddr605] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Ariel is a mouse mutant that suffers from skeletal muscle myofibrillar degeneration due to the rapid accumulation of large intracellular protein aggregates. This fulminant disease is caused by an ENU-induced recessive mutation resulting in an L342Q change within the motor domain of the skeletal muscle myosin protein MYH4 (MyHC IIb). Although normal at birth, homozygous mice develop hindlimb paralysis from Day 13, consistent with the timing of the switch from developmental to adult myosin isoforms in mice. The mutated myosin (MYH4(L342Q)) is an aggregate-prone protein. Notwithstanding the speed of the process, biochemical analysis of purified aggregates showed the presence of proteins typically found in human myofibrillar myopathies, suggesting that the genesis of ariel aggregates follows a pathogenic pathway shared with other conformational protein diseases of skeletal muscle. In contrast, heterozygous mice are overtly and histologically indistinguishable from control mice. MYH4(L342Q) is present in muscles from heterozygous mice at only 7% of the levels of the wild-type protein, resulting in a small but significant increase in force production in isolated single fibres and indicating that elimination of the mutant protein in heterozygotes prevents the pathological changes observed in homozygotes. Recapitulation of the L342Q change in the functional equivalent of mouse MYH4 in human muscles, MYH1, results in a more aggregate-prone protein.
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11
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Vattemi G, Neri M, Piffer S, Vicart P, Gualandi F, Marini M, Guglielmi V, Filosto M, Tonin P, Ferlini A, Tomelleri G. Clinical, morphological and genetic studies in a cohort of 21 patients with myofibrillar myopathy. ACTA MYOLOGICA : MYOPATHIES AND CARDIOMYOPATHIES : OFFICIAL JOURNAL OF THE MEDITERRANEAN SOCIETY OF MYOLOGY 2011; 30:121-6. [PMID: 22106715 PMCID: PMC3235861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The term myofibrillar myopathies (MFM) refers to uncommon neuromuscular disorders that pathologically are characterized by myofibrillar degeneration and ectopic expression of several proteins. MFM are partly caused by mutations in genes that encode mainly Z-disk-related proteins (desmin, alphaB-crystallin, myotilin, ZASP, filamin C and BAG3). We reviewed clinical, light and electron microscopy, immunohistochemistry, immunoblotting and genetic findings of 21 patients with MFM (15 unrelated patients and three pairs of brothers) investigated at our neuromuscular center. MFM patients begin to show symptoms at any age, from juvenile to late adult life and present a different distribution of muscle weakness. Cardiac involvement and peripheral neuropathy are common. Typical histological features include focal areas with reduction/loss of ATPase and oxidative enzyme activity, and amorphous material (eosinophilic on hematoxylin and eosin and dark blue on Engel-Gomori trichrome) in these abnormal fiber areas. Electron microscopy shows disintegration of myofibrils starting from the Z-disk and accumulation of granular and filamentous material among the myofilaments. Immunohistochemical studies demonstrate focal accumulation of desmin, alphaB-crystallin and myotilin in abnormal muscle fibers while immunoblot analysis does not highlight differences in the expression of these proteins also including ZASP protein. Therefore, unlike immunoblot, immunohistochemistry together with light and electron microscopy is a useful diagnostic tool in MFM. Finally three of our 21 patients have missense mutations in the desmin gene, two brothers carry missense mutations in the gene encoding myotilin, one has a missense mutation in alphaB-crystallin, and none harbour pathogenic variations in the genes encoding ZASP and BAG3.
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Affiliation(s)
- G. Vattemi
- Address for correspondence: Gaetano Vattemi, Department of Neurological, Neuropsychological, Morphological and Movement Sciences, Section of Clinical Neurology, University of Verona, p.le L.A. Scuro 10, 37134 Verona, Italy. Tel. +39 045 8074285. Fax +39 045 8027492. E-mail:
| | - M. Neri
- Address for correspondence: Gaetano Vattemi, Department of Neurological, Neuropsychological, Morphological and Movement Sciences, Section of Clinical Neurology, University of Verona, p.le L.A. Scuro 10, 37134 Verona, Italy. Tel. +39 045 8074285. Fax +39 045 8027492. E-mail:
| | - S. Piffer
- Address for correspondence: Gaetano Vattemi, Department of Neurological, Neuropsychological, Morphological and Movement Sciences, Section of Clinical Neurology, University of Verona, p.le L.A. Scuro 10, 37134 Verona, Italy. Tel. +39 045 8074285. Fax +39 045 8027492. E-mail:
| | - P. Vicart
- Address for correspondence: Gaetano Vattemi, Department of Neurological, Neuropsychological, Morphological and Movement Sciences, Section of Clinical Neurology, University of Verona, p.le L.A. Scuro 10, 37134 Verona, Italy. Tel. +39 045 8074285. Fax +39 045 8027492. E-mail:
| | - F. Gualandi
- Address for correspondence: Gaetano Vattemi, Department of Neurological, Neuropsychological, Morphological and Movement Sciences, Section of Clinical Neurology, University of Verona, p.le L.A. Scuro 10, 37134 Verona, Italy. Tel. +39 045 8074285. Fax +39 045 8027492. E-mail:
| | - M. Marini
- Address for correspondence: Gaetano Vattemi, Department of Neurological, Neuropsychological, Morphological and Movement Sciences, Section of Clinical Neurology, University of Verona, p.le L.A. Scuro 10, 37134 Verona, Italy. Tel. +39 045 8074285. Fax +39 045 8027492. E-mail:
| | - V. Guglielmi
- Address for correspondence: Gaetano Vattemi, Department of Neurological, Neuropsychological, Morphological and Movement Sciences, Section of Clinical Neurology, University of Verona, p.le L.A. Scuro 10, 37134 Verona, Italy. Tel. +39 045 8074285. Fax +39 045 8027492. E-mail:
| | - M. Filosto
- Address for correspondence: Gaetano Vattemi, Department of Neurological, Neuropsychological, Morphological and Movement Sciences, Section of Clinical Neurology, University of Verona, p.le L.A. Scuro 10, 37134 Verona, Italy. Tel. +39 045 8074285. Fax +39 045 8027492. E-mail:
| | - P. Tonin
- Address for correspondence: Gaetano Vattemi, Department of Neurological, Neuropsychological, Morphological and Movement Sciences, Section of Clinical Neurology, University of Verona, p.le L.A. Scuro 10, 37134 Verona, Italy. Tel. +39 045 8074285. Fax +39 045 8027492. E-mail:
| | - A. Ferlini
- Address for correspondence: Gaetano Vattemi, Department of Neurological, Neuropsychological, Morphological and Movement Sciences, Section of Clinical Neurology, University of Verona, p.le L.A. Scuro 10, 37134 Verona, Italy. Tel. +39 045 8074285. Fax +39 045 8027492. E-mail:
| | - G. Tomelleri
- Address for correspondence: Gaetano Vattemi, Department of Neurological, Neuropsychological, Morphological and Movement Sciences, Section of Clinical Neurology, University of Verona, p.le L.A. Scuro 10, 37134 Verona, Italy. Tel. +39 045 8074285. Fax +39 045 8027492. E-mail:
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Finsterer J, Stöllberger C, Höftberger R. Restrictive cardiomyopathy as a cardiac manifestation of myofibrillar myopathy. Heart Lung 2011; 40:e123-7. [DOI: 10.1016/j.hrtlng.2010.07.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2010] [Revised: 07/24/2010] [Accepted: 07/27/2010] [Indexed: 12/27/2022]
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