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Chen Z, Saini M, Koh JS, Prasad K, Koh SH, Tay KSS, Lee M, Tan YJ, Ng ASL, Tay SKH, Tan KB, Tandon A, Tan JMM, Chai JYH. Unique Clinical, Radiological and Histopathological Characteristics of a Southeast Asian Cohort of Patients with Limb-Girdle Muscular Dystrophy 2G/LGMD-R7-Telethonin-Related. J Neuromuscul Dis 2023; 10:91-106. [PMID: 36463458 DOI: 10.3233/jnd-221517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIM We describe a cohort of five patients with limb-girdle muscular dystrophy (LGMD) 2G/LGMD-R7 in a South-east Asian cohort. BACKGROUND LGMD2G/LGMD-R7-telethonin-related is caused by mutations in the TCAP gene that encodes for telethonin. METHODS We identified consecutive patients with LGMD2G/LGMD-R7-telethonin-related, diagnosed at the National Neuroscience Institute (NNI) and National University Hospital (NUH) between January 2000 and June 2021. RESULTS At onset, three patients presented with proximal lower limb weakness, one patient presented with Achilles tendon contractures, and one patient presented with delayed gross motor milestones. At last follow up, three patients had a limb girdle pattern of muscle weakness and two had a facioscapular humeral pattern of weakness. Whole body muscle MRI performed for one patient with a facioscapular-humeral pattern of weakness showed a pattern of muscle atrophy similar to facioscapular-humeral dystrophy. One patient had histological features consistent with myofibrillar myopathy; electron microscopy confirmed the disruption of myofibrillar architecture. One patients also had reduced staining to telethonin antibody on immunohistochemistry. CONCLUSION We report the unique clinical and histological features of a Southeast Asian cohort of five patients with LGMD2G/LGMD-R7-telethonin-related muscular dystrophy and further expand its clinical and histopathological spectrum.
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Affiliation(s)
- Zhiyong Chen
- Department of Neurology, National Neuroscience Institute, Singapore
| | - Monica Saini
- Department of Neurology, National Neuroscience Institute, Singapore
| | - Jasmine S Koh
- Department of Neurology, National Neuroscience Institute, Singapore
| | - Kalpana Prasad
- Department of Neurology, National Neuroscience Institute, Singapore
| | - Swee Hoon Koh
- Neuromuscular Laboratory, National Neuroscience Institute, Singapore
| | - Karine S S Tay
- Neuromuscular Laboratory, National Neuroscience Institute, Singapore
| | - Ming Lee
- Department of Pathology, Singapore General Hospital, Singapore
| | - Yi Jayne Tan
- Department of Neurology, National Neuroscience Institute, Singapore
| | - Adeline S L Ng
- Department of Neurology, National Neuroscience Institute, Singapore.,Duke NUS Graduate Medical School, Singapore
| | - Stacey Kiat Hong Tay
- Department of Paediatrics, Khoo Teck Puat-National University Children's Medical Institute, National University Health System, Singapore.,Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Kong Bing Tan
- Department of Pathology, National University Hospital, Singapore
| | - Ankit Tandon
- Department of Diagnostic Radiology, Tan Tock Seng Hospital, Singapore
| | - Jeane M M Tan
- Department of Neurology, National Neuroscience Institute, Singapore
| | - Josiah Y H Chai
- Department of Neurology, National Neuroscience Institute, Singapore.,Neuromuscular Laboratory, National Neuroscience Institute, Singapore
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2
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Findings of limb-girdle muscular dystrophy R7 telethonin-related patients from a Chinese neuromuscular center. Neurogenetics 2022; 23:37-44. [PMID: 34982307 DOI: 10.1007/s10048-021-00681-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 12/23/2021] [Indexed: 12/29/2022]
Abstract
Limb-girdle muscular dystrophy (LGMD) is a group of clinically and genetically heterogeneous neuromuscular disorders. LGMD-R7, which is caused by telethonin gene (TCAP) mutations, is one of the rarest forms of LGMD, and only a small number of LGMD-R7 cases have been described and mostly include patients from Brazil. A total of two LGMD-R7 patients were enrolled at a Chinese neuromuscular center. Demographic and clinical data were collected. Laboratory investigations and electromyography were performed. Routine and immunohistochemistry staining of muscle specimens was performed, and a next-generation sequencing panel array for genes associated with hereditary neuromuscular disorders was used for analysis. The patients exhibited predominant muscle weakness. Electromyography revealed myopathic changes. The muscle biopsy showed myopathic features, such as increased fiber size variation, muscle fiber atrophy and regeneration, slight hyperplasia of the connective tissue, and disarray of the myofibrillar network. Two patients were confirmed to have mutations in the open reading frame of TCAP by next-generation sequencing. One patient had compound heterozygous mutations, and the other patient harbored a novel homozygous mutation. Western blotting analysis of the skeletal muscle lysate confirmed the absence of telethonin in the patients. We described two LGMD-R7 patients presenting a classical LGMD phenotype and a novel homozygous TCAP mutation. Our research expands the spectrum of LGMD-R7 due to TCAP mutations based on patients from a Chinese neuromuscular center.
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3
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Singh S, Singh T, Kunja C, Dhoat NS, Dhania NK. Gene-editing, immunological and iPSCs based therapeutics for muscular dystrophy. Eur J Pharmacol 2021; 912:174568. [PMID: 34656607 DOI: 10.1016/j.ejphar.2021.174568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 09/25/2021] [Accepted: 10/11/2021] [Indexed: 10/20/2022]
Abstract
Muscular dystrophy is a well-known genetically heterogeneous group of rare muscle disorders. This progressive disease causes the breakdown of skeletal muscles over time and leads to grave weakness. This breakdown is caused by a diverse pattern of mutations in dystrophin and dystrophin associated protein complex. These mutations lead to the production of altered proteins in response to which, the body stimulates production of various cytokines and immune cells, particularly reactive oxygen species and NFκB. Immune cells display/exhibit a dual role by inducing muscle damage and muscle repair. Various anti-oxidants, anti-inflammatory and glucocorticoid drugs serve as potent therapeutics for muscular dystrophy. Along with the above mentioned therapeutics, induced pluripotent stem cells also serve as a novel approach paving a way for personalized treatment. These pluripotent stem cells allow regeneration of large numbers of regenerative myogenic progenitors that can be administered in muscular dystrophy patients which assist in the recovery of lost muscle fibers. In this review, we have summarized gene-editing, immunological and induced pluripotent stem cell based therapeutics for muscular dystrophy treatment.
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Affiliation(s)
- Shagun Singh
- Department of Human Genetics and Molecular Medicine, School of Health Sciences, Central University of Punjab, Bathinda-151001, Punjab, India
| | - Tejpal Singh
- Department of Human Genetics and Molecular Medicine, School of Health Sciences, Central University of Punjab, Bathinda-151001, Punjab, India
| | - Chaitanya Kunja
- Department of Human Genetics and Molecular Medicine, School of Health Sciences, Central University of Punjab, Bathinda-151001, Punjab, India
| | - Navdeep S Dhoat
- Department of Pediatrics Surgery, All India Institute of Medical Sciences, Bathinda, 151001, Punjab, India
| | - Narender K Dhania
- Department of Human Genetics and Molecular Medicine, School of Health Sciences, Central University of Punjab, Bathinda-151001, Punjab, India.
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4
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Xing K, Liu H, Zhang F, Liu Y, Shi Y, Ding X, Wang C. Identification of key genes affecting porcine fat deposition based on co-expression network analysis of weighted genes. J Anim Sci Biotechnol 2021; 12:100. [PMID: 34419151 PMCID: PMC8379819 DOI: 10.1186/s40104-021-00616-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 07/01/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Fat deposition is an important economic consideration in pig production. The amount of fat deposition in pigs seriously affects production efficiency, quality, and reproductive performance, while also affecting consumers' choice of pork. Weighted gene co-expression network analysis (WGCNA) is effective in pig genetic studies. Therefore, this study aimed to identify modules that co-express genes associated with fat deposition in pigs (Songliao black and Landrace breeds) with extreme levels of backfat (high and low) and to identify the core genes in each of these modules. RESULTS We used RNA sequences generated in different pig tissues to construct a gene expression matrix consisting of 12,862 genes from 36 samples. Eleven co-expression modules were identified using WGCNA and the number of genes in these modules ranged from 39 to 3,363. Four co-expression modules were significantly correlated with backfat thickness. A total of 16 genes (RAD9A, IGF2R, SCAP, TCAP, SMYD1, PFKM, DGAT1, GPS2, IGF1, MAPK8, FABP, FABP5, LEPR, UCP3, APOF, and FASN) were associated with fat deposition. CONCLUSIONS RAD9A, TCAP, SMYD1, PFKM, GPS2, and APOF were the key genes in the four modules based on the degree of gene connectivity. Combining these results with those from differential gene analysis, SMYD1 and PFKM were proposed as strong candidate genes for body size traits. This study explored the key genes that regulate porcine fat deposition and lays the foundation for further research into the molecular regulatory mechanisms underlying porcine fat deposition.
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Affiliation(s)
- Kai Xing
- Animal Science and Technology College, Beijing University of Agriculture, Beijing, China
| | - Huatao Liu
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Fengxia Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Yibing Liu
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Yong Shi
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Xiangdong Ding
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China.
| | - Chuduan Wang
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China.
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5
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The Role of Z-disc Proteins in Myopathy and Cardiomyopathy. Int J Mol Sci 2021; 22:ijms22063058. [PMID: 33802723 PMCID: PMC8002584 DOI: 10.3390/ijms22063058] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/07/2021] [Accepted: 03/11/2021] [Indexed: 12/11/2022] Open
Abstract
The Z-disc acts as a protein-rich structure to tether thin filament in the contractile units, the sarcomeres, of striated muscle cells. Proteins found in the Z-disc are integral for maintaining the architecture of the sarcomere. They also enable it to function as a (bio-mechanical) signalling hub. Numerous proteins interact in the Z-disc to facilitate force transduction and intracellular signalling in both cardiac and skeletal muscle. This review will focus on six key Z-disc proteins: α-actinin 2, filamin C, myopalladin, myotilin, telethonin and Z-disc alternatively spliced PDZ-motif (ZASP), which have all been linked to myopathies and cardiomyopathies. We will summarise pathogenic variants identified in the six genes coding for these proteins and look at their involvement in myopathy and cardiomyopathy. Listing the Minor Allele Frequency (MAF) of these variants in the Genome Aggregation Database (GnomAD) version 3.1 will help to critically re-evaluate pathogenicity based on variant frequency in normal population cohorts.
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6
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Distal myopathy due to TCAP variants in four unrelated Chinese patients. Neurogenetics 2020; 22:1-10. [PMID: 32761539 DOI: 10.1007/s10048-020-00623-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 08/01/2020] [Indexed: 10/23/2022]
Abstract
Distal myopathies are a group of clinically and genetically heterogeneous hereditary muscle disorders characterized by progressive muscular weakness starting in the distal parts of the limbs. The most common subtype of distal myopathy is GNE myopathy, a rare muscle disease with autosomal recessive inheritance. Limb-girdle muscular dystrophy 2G (LGMD2G) is a rare autosomal recessive subtype of LGMDs caused by TCAP variant. Patients with LGMD2G can present with distal myopathy and rimmed vacuoles on muscle pathology. Thus far, the most reported TCAP mutations related to LGMD2G were recessive frameshift or nonsense variants. Here, we described four Chinese patients from unrelated families with LGMD2G due to TCAP mutations. The clinical symptoms of our patients were similar to those previously reported in LGMD2G patients. Three different pathogenic TCAP variants were identified in these patients, including two frameshift variants and one intronic variant. Autophagolysosomes have been observed in one patient by electron microscopy. Our research expands the genetic spectrum of TCAP mutations in China, indicating c.165-166insG is likely the common pathogenic variant. We also provide evidences that autophagy may be involved in the pathophysiology of LGMD2G.
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7
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Chen H, Xu G, Lin F, Jin M, Cai N, Qiu L, Ye Z, Wang L, Lin M, Wang N. Clinical and genetic characterization of limb girdle muscular dystrophy R7 telethonin-related patients from three unrelated Chinese families. Neuromuscul Disord 2019; 30:137-143. [PMID: 32005491 DOI: 10.1016/j.nmd.2019.12.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 11/30/2019] [Accepted: 12/13/2019] [Indexed: 02/02/2023]
Abstract
Limb girdle muscular dystrophy LGMD R7 telethonin-related is a rare autosomal recessive muscle disorder characterized by proximal muscle weakness of pelvic and shoulder girdles. Mutation in TCAP is responsible for LGMD R7, and the disease has a wide geographic distribution in diverse populations, but genotype-phenotype relationships remain unclear. We collected 5 LGMD R7 patients from three unrelated Chinese families. The average onset age was 16 ± 1.41; the initial symptoms included progressive proximal muscle weakness in limbs, difficulty in fast running, and asymmetric muscle atrophy in calves. Muscle MR imaging showed varying severity of fatty infiltration in the pelvic girdle, thigh, and calf muscles, and the severity of muscle infiltration was related to the length of the disease course. Muscle histopathology revealed aberrantly sized muscle fibers, internal nuclei, split fibers, rimmed vacuoles, monocyte invasion, and necrotic fibers. Sequencing identified one novel and one previously reported TCAP mutation. Our study extends the known distribution of this rare muscular dystrophy and presents the first detailed clinical and genetic characterizations of LGMD R7 cases from the Chinese population. Our work expands the mutation spectrum known for LGMD R7 and emphasizes the need for clinicians to consider TCAP mutations when evaluating patients with symptoms of limb girdle muscular dystrophy.
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Affiliation(s)
- Haizhu Chen
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, 20 Chazhong Road, Fuzhou, Fujian 350005, China
| | - Guorong Xu
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, 20 Chazhong Road, Fuzhou, Fujian 350005, China
| | - Feng Lin
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, 20 Chazhong Road, Fuzhou, Fujian 350005, China
| | - Ming Jin
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, 20 Chazhong Road, Fuzhou, Fujian 350005, China
| | - Naiqing Cai
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, 20 Chazhong Road, Fuzhou, Fujian 350005, China
| | - Liangliang Qiu
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, 20 Chazhong Road, Fuzhou, Fujian 350005, China
| | - Zhixian Ye
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, 20 Chazhong Road, Fuzhou, Fujian 350005, China
| | - Lili Wang
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, 20 Chazhong Road, Fuzhou, Fujian 350005, China
| | - Minting Lin
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, 20 Chazhong Road, Fuzhou, Fujian 350005, China; Fujian Key Laboratory of Molecular Neurology, Fuzhou, Fujian 350005, China
| | - Ning Wang
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, 20 Chazhong Road, Fuzhou, Fujian 350005, China; Fujian Key Laboratory of Molecular Neurology, Fuzhou, Fujian 350005, China.
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8
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Blanco-Palmero VA, Hernández-Laín A, Uriarte-Pérez de Urabayen D, Cantero-Montenegro D, Olivé M, Domínguez-González C. Late onset distal myopathy: A new telethoninopathy. Neuromuscul Disord 2018; 29:80-83. [PMID: 30553702 DOI: 10.1016/j.nmd.2018.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 08/09/2018] [Accepted: 11/05/2018] [Indexed: 10/27/2022]
Affiliation(s)
| | | | | | - Diana Cantero-Montenegro
- Servicio de Neuropatología, Instituto de Investigación, Hospital Universitario 12 de Octubre, Spain
| | - Montse Olivé
- Servicio de Anatomía Patológica, Hospital Universitario de Bellvitge, Spain
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9
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Chamova T, Bichev S, Todorov T, Gospodinova M, Taneva A, Kastreva K, Zlatareva D, Krupev M, Hadjiivanov R, Guergueltcheva V, Grozdanova L, Tzoneva D, Huebner A, V der Hagen M, Schoser B, Lochmüller H, Todorova A, Tournev I. Limb girdle muscular dystrophy 2G in a religious minority of Bulgarian Muslims homozygous for the c.75G>A, p.Trp25X mutation. Neuromuscul Disord 2018; 28:625-632. [PMID: 29935994 DOI: 10.1016/j.nmd.2018.05.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Revised: 05/10/2018] [Accepted: 05/10/2018] [Indexed: 10/16/2022]
Abstract
Mutations in TCAP gene cause autosomal recessive limb-girdle muscular dystrophy type 2G (LGMD2G), congenital muscular dystrophy and autosomal dominant dilated and hypertrophic cardiomyopathy. We studied 18 affected individuals from 12 pedigrees, belonging to a Bulgarian Muslim minority from the South-West of Bulgaria, homozygous for the c.75G>A, p.Trp25X mutation in TCAP gene. The heterozygous carrier rate of p.Trp25X among 100 newborns in this region was found to be 2%. The clinical features in the Bulgarian TCAP group include disease onset in the first to the third decade of life, proximal muscle weakness in the lower limbs, followed or accompanied by difficulties in ankle dorsiflexion and involvement of the proximal muscles of the upper limbs 5-9 years after the disease onset. Asymmetry between left and right was present in more than 20% of the affected. Respiratory and cardiac functions were not affected. On the MRI the muscles of the posterior pelvic area, thigh and anterior leg were predominantly affected, while sartorius, gracilis and biceps femoris muscles remained relatively spared. In conclusion, LGMD2G appears to be a common form among Bulgarian Muslims. Homozygosity for c.75G>A, p.Trp25X is associated with a homogeneous clinical presentation, but the clinical course and severity of the disease show inter- and intra-familial variation.
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Affiliation(s)
- Teodora Chamova
- Department of Neurology, University Hospital "Alexandrovska", Medical University, Sofia, Bulgaria.
| | - Stoyan Bichev
- National Genetics Laboratory, Medical University, Sofia, Bulgaria
| | - Tihomir Todorov
- Genetic Medico-Diagnostic Laboratory 'Genica", Sofia, Bulgaria
| | - Mariana Gospodinova
- Department of Cardiology, Medical Institute of Ministry of Interior Affairs, Sofia, Bulgaria
| | - Ani Taneva
- Department of Neurology, University Hospital "Alexandrovska", Medical University, Sofia, Bulgaria
| | - Kristina Kastreva
- Department of Neurology, University Hospital "Alexandrovska", Medical University, Sofia, Bulgaria
| | - Dora Zlatareva
- Department of Diagnostic Imaging, University Hospital "Alexandrovska", Medical University, Sofia, Bulgaria
| | - Martin Krupev
- Department of Diagnostic Imaging, University Hospital "Alexandrovska", Medical University, Sofia, Bulgaria
| | | | | | - Liliana Grozdanova
- Department of Medical genetic, University Hospital "St. George", Plovdiv, Bulgaria
| | - Dochka Tzoneva
- Department of Anesthesiology and Intensive Care, University Hospital "Alexandrovska", Sofia, Bulgaria
| | - Angela Huebner
- Children's Hospital Technical University Dresden, Germany
| | | | - Benedikt Schoser
- Friedrich-Baur-Institut, Neurologische Klinik, Klinikum der Universität München, München, Germany
| | - Hanns Lochmüller
- Department of Neuropediatrics and Muscle Disorders, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany; Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Catalonia, Spain
| | - Albena Todorova
- Genetic Medico-Diagnostic Laboratory 'Genica", Sofia, Bulgaria; Department of Medical Chemistry and Biochemistry, Sofia, Bulgaria
| | - Ivailo Tournev
- Department of Neurology, University Hospital "Alexandrovska", Medical University, Sofia, Bulgaria; Department of Cognitive Science and Psychology, New Bulgarian University, Sofia, Bulgaria
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10
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Brusa R, Magri F, Papadimitriou D, Govoni A, Del Bo R, Ciscato P, Savarese M, Cinnante C, Walter MC, Abicht A, Bulst S, Corti S, Moggio M, Bresolin N, Nigro V, Comi GP. A new case of limb girdle muscular dystrophy 2G in a Greek patient, founder effect and review of the literature. Neuromuscul Disord 2018; 28:532-537. [PMID: 29759638 DOI: 10.1016/j.nmd.2018.04.006] [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] [Received: 10/20/2017] [Revised: 01/16/2018] [Accepted: 04/10/2018] [Indexed: 12/01/2022]
Abstract
Limb girdle muscular dystrophy (LGMD) type 2G is a rare form of muscle disease, described only in a few patients worldwide, caused by mutations in TCAP gene, encoding the protein telethonin. It is characterised by proximal limb muscle weakness associated with distal involvement of lower limbs, starting in the first or second decade of life. We describe the case of a 37-year-old woman of Greek origin, affected by disto-proximal lower limb weakness. No cardiac or respiratory involvement was detected. Muscle biopsy showed myopathic changes with type I fibre hypotrophy, cytoplasmic vacuoles, lipid overload, multiple central nuclei and fibre splittings; ultrastructural examination showed metabolic abnormalities. Next generation sequencing analysis detected a homozygous frameshift mutation in the TCAP gene (c.90_91del), previously described in one Turkish family. Immunostaining and Western blot analysis showed complete absence of telethonin. Interestingly, Single Nucleotide Polymorphism analysis of the 10 Mb genomic region containing the TCAP gene showed a shared homozygous haplotype of both the Greek and the Turkish patients, thus suggesting a possible founder effect of TCAP gene c.90_91del mutation in this part of the Mediterranean area.
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Affiliation(s)
- Roberta Brusa
- Dino Ferrari Centre, Department of Neurological Sciences, University of Milan, I.R.C.C.S. Foundation Cà Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Francesca Magri
- Dino Ferrari Centre, Department of Neurological Sciences, University of Milan, I.R.C.C.S. Foundation Cà Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Dimitra Papadimitriou
- Division of Basic Neurosciences, Biomedical Research Foundation of the Academy of Athens (BRFAA), Soranou Efesiou 4, Athens, 115 27, Greece
| | - Alessandra Govoni
- Dino Ferrari Centre, Department of Neurological Sciences, University of Milan, I.R.C.C.S. Foundation Cà Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Roberto Del Bo
- Dino Ferrari Centre, Department of Neurological Sciences, University of Milan, I.R.C.C.S. Foundation Cà Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Patrizia Ciscato
- Neuromuscular Unit, Department of Neurological Sciences, I.R.C.C.S. Foundation Cà Granda, Ospedale Maggiore Policlinico, Dino Ferrari Centre, Milan, Italy
| | - Marco Savarese
- "Luigi Vanvitelli" University and Telethon Institute of Genetics and Medicine (TIGEM), Italy; Folkhälsan Research Center, Medicum, University of Helsinki, Helsinki, Finland
| | - Claudia Cinnante
- U.O. Neuroradiologia, I.R.C.C.S. Foundation Cà Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Maggie C Walter
- Friedrich-Baur-Institute, Department of Neurology, Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Angela Abicht
- Friedrich-Baur-Institute, Department of Neurology, Ludwig-Maximilians-University of Munich, Munich, Germany; Medical Genetic Centre, Munich, Germany
| | | | - Stefania Corti
- Dino Ferrari Centre, Department of Neurological Sciences, University of Milan, I.R.C.C.S. Foundation Cà Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Maurizio Moggio
- Neuromuscular Unit, Department of Neurological Sciences, I.R.C.C.S. Foundation Cà Granda, Ospedale Maggiore Policlinico, Dino Ferrari Centre, Milan, Italy
| | - Nereo Bresolin
- Dino Ferrari Centre, Department of Neurological Sciences, University of Milan, I.R.C.C.S. Foundation Cà Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Vincenzo Nigro
- "Luigi Vanvitelli" University and Telethon Institute of Genetics and Medicine (TIGEM), Italy
| | - Giacomo Pietro Comi
- Dino Ferrari Centre, Department of Neurological Sciences, University of Milan, I.R.C.C.S. Foundation Cà Granda, Ospedale Maggiore Policlinico, Milan, Italy.
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11
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Ikenberg E, Karin I, Ertl-Wagner B, Abicht A, Bulst S, Krause S, Schoser B, Reilich P, Walter MC. Rare diagnosis of telethoninopathy (LGMD2G) in a Turkish patient. Neuromuscul Disord 2017; 27:856-860. [PMID: 28666572 DOI: 10.1016/j.nmd.2017.05.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 05/01/2017] [Accepted: 05/30/2017] [Indexed: 10/19/2022]
Abstract
Telethoninopathy is one of the rarest forms of Limb-girdle muscular dystrophy (LGMD). So far, only a small number of LGMD type 2 G (LGMD2G) patients have been described, mostly patients from Brazil. Here we present a 35-year-old female patient of Turkish ethnicity with LGMD2G due to a novel homozygous frame-shift mutation c.90_91del (p.Ser31Hisfs*11) in the telethonin gene, probably leading to truncated protein or nonsense mediated decay. Myalgia and walking on tiptoes were the first symptoms starting in early childhood, around age 22 proximal, later distal leg muscles became affected. Muscle biopsy showed a degenerative myopathy with lobulated fibers, creatine kinase levels were elevated to 1200 U/l. No cardiomyopathy has been detected but ventricular extrasystoles were treated with verapamil. Even though telethoninopathy represents a rare condition, testing for LGMD2G should be included into the diagnostic work-up of mild myopathies with early toe walking and distal and proximal involvement.
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Affiliation(s)
- Elena Ikenberg
- Friedrich-Baur-Institute, Dept. of Neurology, Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Ivan Karin
- Friedrich-Baur-Institute, Dept. of Neurology, Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Birgit Ertl-Wagner
- Dept. of Radiology, Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Angela Abicht
- Friedrich-Baur-Institute, Dept. of Neurology, Ludwig-Maximilians-University of Munich, Munich, Germany; Medical Genetics Center - MGZ, Munich, Germany
| | | | - Sabine Krause
- Friedrich-Baur-Institute, Dept. of Neurology, Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Benedikt Schoser
- Friedrich-Baur-Institute, Dept. of Neurology, Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Peter Reilich
- Friedrich-Baur-Institute, Dept. of Neurology, Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Maggie C Walter
- Friedrich-Baur-Institute, Dept. of Neurology, Ludwig-Maximilians-University of Munich, Munich, Germany.
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12
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de Fuenmayor-Fernández de la Hoz CP, Hernández-Laín A, Olivé M, Fernández-Marmiesse A, Domínguez-González C. Novel mutation in TCAP manifesting with asymmetric calves and early-onset joint retractions. Neuromuscul Disord 2016; 26:749-753. [PMID: 27618135 DOI: 10.1016/j.nmd.2016.07.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 06/18/2016] [Accepted: 07/11/2016] [Indexed: 11/28/2022]
Abstract
A 29-year-old man, born from consanguineous parents, started with toe walking and frequent falls during his second year of life. He developed weakness in lower limbs during the first decade that subsequently extended to upper limbs. On examination, the patient had weakness in proximal muscles of all four limbs and in the tibialis anterior muscle. In addition, he had bilateral Achilles and patellar contractures, bilateral scapular winging, asymmetric calves and a positive Beevor sign, an upward movement of the umbilicus on contraction of rectus femoris due to weakness in the lower part. The muscle biopsy showed dystrophic changes and lobulated fibers. Genetic analysis through a next-generation sequencing panel of genes related to neuromuscular disorders revealed a novel homozygous nonsense mutation (p.Tyr85*) in the TCAP gene. Subsequent western blot assay showed a complete telethonin deficiency. Our observation expands the phenotypic spectrum of TCAP mutations and indicates that telethonin deficiency should be considered in the differential diagnosis of patients presenting with asymmetric calves and early joint retractions.
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Affiliation(s)
| | - Aurelio Hernández-Laín
- Unidad de Neuromuscular, Hospital Universitario 12 de Octubre, Madrid, Spain; Instituto de Investigación I+12, Madrid, Spain; Servicio de Neuropatología, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Montse Olivé
- Hospitalet de Llobregat, Spain; Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Spain
| | - Ana Fernández-Marmiesse
- Unidad de Diagnóstico y Tratamiento de Enfermedades Metabólicas Congénitas (UDyTEMC), Hospital Clínico Universitario de Santiago de Compostela, Santiago de Compostela, Spain
| | - Cristina Domínguez-González
- Servicio de Neurología, Hospital Universitario 12 de Octubre, Madrid, Spain; Unidad de Neuromuscular, Hospital Universitario 12 de Octubre, Madrid, Spain; Instituto de Investigación I+12, Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), grupo U-723, Spain
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13
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Murphy AP, Straub V. The Classification, Natural History and Treatment of the Limb Girdle Muscular Dystrophies. J Neuromuscul Dis 2015; 2:S7-S19. [PMID: 27858764 PMCID: PMC5271430 DOI: 10.3233/jnd-150105] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Over sixty years ago John Walton and Frederick Nattrass defined limb girdle muscular dystrophy (LGMD) as a separate entity from the X-linked dystrophinopathies such as Duchenne and Becker muscular dystrophies. LGMD is a highly heterogeneous group of very rare neuromuscular disorders whose common factor is their autosomal inheritance. Sixty years later, with the development of increasingly advanced molecular genetic investigations, a more precise classification and understanding of the pathogenesis is possible.To date, over 30 distinct subtypes of LGMD have been identified, most of them inherited in an autosomal recessive fashion. There are significant differences in the frequency of subtypes of LGMD between different ethnic populations, providing evidence of founder mutations. Clinically there is phenotypic heterogeneity between subtypes of LGMD with varying severity and age of onset of symptoms. The first natural history studies into subtypes of LGMD are in process, but large scale longitudinal data have been lacking due to the rare nature of these diseases. Following natural history data collection, the next challenge is to develop more effective, disease specific treatments. Current management is focussed on symptomatic and supportive treatments. Advances in the application of new omics technologies and the generation of large-scale biomedical data will help to better understand disease mechanisms in LGMD and should ultimately help to accelerate the development of novel and more effective therapeutic approaches.
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Affiliation(s)
| | - Volker Straub
- Correspondence to: Volker Straub, The John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, The International Centre for Life, Newcastle University, Central Parkway, Newcastle Upon Tyne, United Kingdom. NE1 3BZ. Tel.: +44 1912 418652; Fax: +44 1912 418770;
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14
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Cotta A, Carvalho E, da-Cunha-Júnior AL, Paim JF, Navarro MM, Valicek J, Menezes MM, Nunes SV, Xavier Neto R, Takata RI, Vargas AP. Common recessive limb girdle muscular dystrophies differential diagnosis: why and how? ARQUIVOS DE NEURO-PSIQUIATRIA 2015; 72:721-34. [PMID: 25252238 DOI: 10.1590/0004-282x20140110] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 06/26/2014] [Indexed: 01/27/2023]
Abstract
Limb girdle muscular dystrophies are heterogeneous autosomal hereditary neuromuscular disorders. They produce dystrophic changes on muscle biopsy and they are associated with mutations in several genes involved in muscular structure and function. Detailed clinical, laboratorial, imaging, diagnostic flowchart, photographs, tables, and illustrated diagrams are presented for the differential diagnosis of common autosomal recessive limb girdle muscular dystrophy subtypes diagnosed nowadays at one reference center in Brazil. Preoperative image studies guide muscle biopsy site selection. Muscle involvement image pattern differs depending on the limb girdle muscular dystrophy subtype. Muscle involvement is conspicuous at the posterior thigh in calpainopathy and fukutin-related proteinopathy; anterior thigh in sarcoglycanopathy; whole thigh in dysferlinopathy, and telethoninopathy. The precise differential diagnosis of limb girdle muscular dystrophies is important for genetic counseling, prognostic orientation, cardiac and respiratory management. Besides that, it may probably, in the future, provide specific genetic therapies for each subtype.
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Affiliation(s)
- Ana Cotta
- Departamento de Patologia, Rede SARAH de Hospitais de Reabilitação, Brazil
| | - Elmano Carvalho
- Departamento de Neurofisiologia, Rede SARAH de Hospitais de Reabilitação, Brazil
| | | | - Júlia Filardi Paim
- Departamento de Patologia, Rede SARAH de Hospitais de Reabilitação, Brazil
| | - Monica M Navarro
- Departamento de Pediatria, Rede SARAH de Hospitais de Reabilitação, Brazil
| | - Jaquelin Valicek
- Departamento de Neurofisiologia, Rede SARAH de Hospitais de Reabilitação, Brazil
| | | | | | - Rafael Xavier Neto
- Departamento de Neurologia, Rede SARAH de Hospitais de Reabilitação, Brazil
| | - Reinaldo Issao Takata
- Departamento de Biologia Molecular, Rede SARAH de Hospitais de Reabilitação, Brasília DF, Brazil
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15
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Barresi R, Morris C, Hudson J, Curtis E, Pickthall C, Bushby K, Davies NP, Straub V. Conserved expression of truncated telethonin in a patient with limb-girdle muscular dystrophy 2G. Neuromuscul Disord 2014; 25:349-52. [PMID: 25724973 DOI: 10.1016/j.nmd.2014.12.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 12/04/2014] [Accepted: 12/11/2014] [Indexed: 11/19/2022]
Abstract
Limb-girdle muscular dystrophy 2G is caused by mutations in the TCAP gene that encodes for telethonin. Here we describe a 49 year-old male patient of Indian descent presenting a classical LGMD phenotype. He had normal motor milestones but became noticeably slower in his early teens and was wheelchair bound by age 44. The muscle biopsy showed myopathic features and absence of labeling with an antibody to the C-terminal portion of telethonin. Sequence analysis of the TCAP gene revealed a novel homozygous mutation in exon 2, predicted to generate a truncated protein of 81 amino acids. Interestingly, an antibody for the full-length protein showed labeling on sections and a single band of ~10 kDa on Western blot. The truncated protein co-localized with filamin C at the Z-line. Our findings indicate that mutant telethonin can be incorporated into the sarcomere and that other LGMD2G patients with retention of telethonin expression may exist.
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Affiliation(s)
- Rita Barresi
- Rare Diseases Advisory Group Service for Neuromuscular Diseases, Muscle Immunoanalysis Unit, Dental Hospital, Richardson Road, Newcastle upon Tyne, UK; The JW Muscular Dystrophy Research Centre and MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.
| | - Charlotte Morris
- Rare Diseases Advisory Group Service for Neuromuscular Diseases, Muscle Immunoanalysis Unit, Dental Hospital, Richardson Road, Newcastle upon Tyne, UK
| | - Judith Hudson
- The JW Muscular Dystrophy Research Centre and MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Elizabeth Curtis
- Department of Cellular Pathology, University Hospital of Birmingham NHS Foundation Trust, Birmingham, UK
| | - Clare Pickthall
- The JW Muscular Dystrophy Research Centre and MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Kate Bushby
- The JW Muscular Dystrophy Research Centre and MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Nicholas P Davies
- Department of Neurology, University Hospital of Birmingham NHS Foundation Trust, Birmingham, UK
| | - Volker Straub
- The JW Muscular Dystrophy Research Centre and MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
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16
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Cotta A, Paim JF, da-Cunha-Junior AL, Neto RX, Nunes SV, Navarro MM, Valicek J, Carvalho E, Yamamoto LU, Almeida CF, Braz SV, Takata RI, Vainzof M. Limb girdle muscular dystrophy type 2G with myopathic-neurogenic motor unit potentials and a novel muscle image pattern. BMC Clin Pathol 2014; 14:41. [PMID: 25298746 PMCID: PMC4188961 DOI: 10.1186/1472-6890-14-41] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 09/24/2014] [Indexed: 11/18/2022] Open
Abstract
Background Limb girdle muscular dystrophy type 2G (LGMD2G) is a subtype of autosomal recessive muscular dystrophy caused by mutations in the telethonin gene. There are few LGMD2G patients worldwide reported, and this is the first description associated with early tibialis anterior sparing on muscle image and myopathic-neurogenic motor unit potentials. Case presentation Here we report a 31 years old caucasian male patient with progressive gait disturbance, and severe lower limb proximal weakness since the age of 20 years, associated with subtle facial muscle weakness. Computed tomography demonstrated soleus, medial gastrocnemius, and diffuse thigh muscles involvement with tibialis anterior sparing. Electromyography disclosed both neurogenic and myopathic motor unit potentials. Muscle biopsy demonstrated large groups of atrophic and hypertrophic fibers, frequent fibers with intracytoplasmic rimmed vacuoles full of autophagic membrane and sarcoplasmic debris, and a total deficiency of telethonin. Molecular investigation identified the common homozygous c.157C > T in the TCAP gene. Conclusion This report expands the phenotypic variability of telethoninopathy/ LGMD2G, including: 1) mixed neurogenic and myopathic motor unit potentials, 2) facial weakness, and 3) tibialis anterior sparing. Appropriate diagnosis in these cases is important for genetic counseling and prognosis.
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Affiliation(s)
- Ana Cotta
- Department of Pathology, SARAH Network of Rehabilitation Hospitals, Belo Horizonte, Brazil
| | - Julia Filardi Paim
- Department of Pathology, SARAH Network of Rehabilitation Hospitals, Belo Horizonte, Brazil
| | | | - Rafael Xavier Neto
- Department of Neurology, SARAH Network of Rehabilitation Hospitals, Belo Horizonte, Brazil
| | - Simone Vilela Nunes
- Department of Neurology, SARAH Network of Rehabilitation Hospitals, Belo Horizonte, Brazil
| | - Monica Magalhaes Navarro
- Departments of Pediatrics and Genetics, SARAH Network of Rehabilitation Hospitals, Belo Horizonte, Brazil
| | - Jaquelin Valicek
- Department of Neurophysiology, SARAH Network of Rehabilitation Hospitals, Belo Horizonte, Brazil
| | - Elmano Carvalho
- Department of Neurophysiology, SARAH Network of Rehabilitation Hospitals, Belo Horizonte, Brazil
| | - Lydia U Yamamoto
- Human Genome Research Center, University of São Paulo, São Paulo, Brazil
| | - Camila F Almeida
- Human Genome Research Center, University of São Paulo, São Paulo, Brazil
| | | | - Reinaldo Issao Takata
- Department of Molecular Biology, SARAH Network of Rehabilitation Hospitals, Brasília, Brazil
| | - Mariz Vainzof
- Human Genome Research Center, University of São Paulo, São Paulo, Brazil
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17
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Francis A, Sunitha B, Vinodh K, Polavarapu K, Katkam SK, Modi S, Bharath MMS, Gayathri N, Nalini A, Thangaraj K. Novel TCAP mutation c.32C>A causing limb girdle muscular dystrophy 2G. PLoS One 2014; 9:e102763. [PMID: 25055047 PMCID: PMC4108395 DOI: 10.1371/journal.pone.0102763] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Accepted: 06/23/2014] [Indexed: 11/19/2022] Open
Abstract
TCAP encoded telethonin is a 19 kDa protein, which plays an important role in anchoring titin in Z disc of the sarcomere, and is known to cause LGMD2G, a rare muscle disorder characterised by proximal and distal lower limb weakness, calf hypertrophy and loss of ambulation. A total of 300 individuals with ARLGMD were recruited for this study. Among these we identified 8 clinically well characterised LGMD2G cases from 7 unrelated Dravidian families. Clinical examination revealed predominantly proximo-distal form of weakness, scapular winging, muscle atrophy, calf hypertrophy and foot drop, immunoblot showed either complete absence or severe reduction of telethonin. Genetic analysis revealed a novel nonsense homozygous mutation c.32C>A, p.(Ser11*) in three patients of a consanguineous family and an 8 bp homozygous duplication c.26_33dupAGGTGTCG, p.(Arg12fs31*) in another patient. Both mutations possibly lead to truncated protein or nonsense mediated decay. We could not find any functionally significant TCAP mutation in the remaining 6 samples, except for two other polymorphisms, c.453A>C, p.( = ) and c.-178G>T, which were found in cases and controls. This is the first report from India to demonstrate TCAP association with LGMD2G.
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Affiliation(s)
| | - Balaraju Sunitha
- Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | | | - Kiran Polavarapu
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | | | - Sailesh Modi
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - M. M. Srinivas Bharath
- Department of Neurochemistry, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Narayanappa Gayathri
- Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Atchayaram Nalini
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
- * E-mail: (KT); (AN)
| | - Kumarasamy Thangaraj
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
- * E-mail: (KT); (AN)
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18
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Buyandelger B, Mansfield C, Knöll R. Mechano-signaling in heart failure. Pflugers Arch 2014; 466:1093-9. [PMID: 24531746 PMCID: PMC4033803 DOI: 10.1007/s00424-014-1468-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 01/29/2014] [Accepted: 01/30/2014] [Indexed: 02/07/2023]
Abstract
Mechanosensation and mechanotransduction are fundamental aspects of biology, but the link between physical stimuli and biological responses remains not well understood. The perception of mechanical stimuli, their conversion into biochemical signals, and the transmission of these signals are particularly important for dynamic organs such as the heart. Various concepts have been introduced to explain mechanosensation at the molecular level, including effects on signalosomes, tensegrity, or direct activation (or inactivation) of enzymes. Striated muscles, including cardiac myocytes, differ from other cells in that they contain sarcomeres which are essential for the generation of forces and which play additional roles in mechanosensation. The majority of cardiomyopathy causing candidate genes encode structural proteins among which titin probably is the most important one. Due to its elastic elements, titin is a length sensor and also plays a role as a tension sensor (i.e., stress sensation). The recent discovery of titin mutations being a major cause of dilated cardiomyopathy (DCM) also underpins the importance of mechanosensation and mechanotransduction in the pathogenesis of heart failure. Here, we focus on sarcomere-related mechanisms, discuss recent findings, and provide a link to cardiomyopathy and associated heart failure.
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Affiliation(s)
- Byambajav Buyandelger
- Imperial College, British Heart Foundation-Centre for Research Excellence, National Heart and Lung Institute, Imperial Centre for Translational and Experimental Medicine, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK
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19
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Abstract
Cardiovascular diseases are the leading cause of morbidity and mortality worldwide. Heart failure, which contributes significantly to the incidence and prevalence of cardiovascular-related diseases, can be the result of a myriad of diverse aetiologies including viral infections, coronary heart disease and genetic abnormalities—just to name a few. Interestingly, almost every type of heart failure is characterized by the loss of cardiac myocytes, either via necrosis, apoptosis or autophagy. While the former for a long time mainly has been characterized by passive loss of cells and only the latter two have been regarded as active processes, a new view is now emerging, whereby all three forms of cell death are regarded as different types of programmed cell death which can be induced via different stimuli and pathways, most of which are probably not well understood (Kung et al., Circulation Research 108(8):1017–1036, 2011). Here, we focus on the sarcomeric Z-disc, Z-disc transcriptional coupling and its role in pro-survival pathways as well as in striated muscle specific forms of cell death (sarcomeroptosis) and mechanically induced apoptosis or mechanoptosis.
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Affiliation(s)
- Ralph Knöll
- Myocardial Genetics, British Heart Foundation-Centre of Research Excellence, National Heart & Lung Institute, Imperial College, Hammersmith Campus, London, UK.
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20
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Abstract
BACKGROUND AND PURPOSE At present, more than 20 different forms of limb-girdle muscular dystrophies (LGMDs) are known (at least 7 autosomal dominant and 14 autosomal recessive). Although these different forms show some typical phenotypic characteristics, the existing clinical overlap makes their differential diagnosis difficult. Limb-girdle muscular dystrophy type 2 (LGMD2A) is the most prevalent LGMD in many European as well as Brazilian communities and is caused by mutations in the gene CAPN3. Laboratory testing, such as calpain immunohistochemistry and Western-blot analysis, is not totally reliable, since up to 20% of molecularly confirmed LGMD2A show normal content of calpain 3 and a third of LGMD2A biopsies have normal calpain 3 proteo-lytic activity in the muscle. Thus, genetic testing is considered as the only reliable diagnostic criterion in LGMD2A. MATERIAL AND METHODS In an attempt to find a correlation between genotype and muscle pathology in limb-girdle muscular dystrophy 2A we performed histopathological investigation of a group of 31 patients subdivided according to the type of pathologic CAPN3 gene mutation. RESULTS In all biopsies typical features of muscular dystrophy such as fiber necrosis and regeneration, variation in fiber size and fibrosis were noted. Lobulated fibers were often encountered in the muscle biopsies of LGMD2A patients. Such fibers were more frequent in patients with 550delA mutation. CONCLUSIONS These findings may be helpful in establishing diagnostic strategies in LGMD.
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21
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Paim JF, Cotta A, Vargas AP, Navarro MM, Valicek J, Carvalho E, da-Cunha AL, Plentz E, Braz SV, Takata RI, Almeida CF, Vainzof M. Muscle phenotypic variability in limb girdle muscular dystrophy 2 G. J Mol Neurosci 2013; 50:339-44. [PMID: 23479141 DOI: 10.1007/s12031-013-9987-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 02/22/2013] [Indexed: 11/26/2022]
Abstract
Limb girdle muscular dystrophy type 2 G (LGMD2G) is caused by mutations in the telethonin gene. Only few families were described presenting this disease, and they are mainly Brazilians. Here, we identified one additional case carrying the same common c.157C > T mutation in the telethonin gene but with an atypical histopathological muscle pattern. In a female patient with a long duration of symptoms (46 years), muscle biopsy showed, in addition to telethonin deficiency, the presence of nemaline rods, type 1 fiber predominance, nuclear internalization, lobulated fibers, and mitochondrial paracrystalline inclusions. Her first clinical signs were identified at 8 years old, which include tiptoe walking, left lower limb deformity, and frequent falls. Ambulation loss occurred at 41 years old, and now, at 54 years old, she presented pelvic girdle atrophy, winging scapula, foot deformity with incapacity to perform ankle dorsiflexion, and absent tendon reflexes. The presence of nemaline bodies could be a secondary phenomenon, possibly associated with focal Z-line abnormalities of a long-standing disease. However, these new histopathological findings, characteristic of congenital myopathies, expand muscle phenotypic variability of telethoninopathy.
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Affiliation(s)
- Julia F Paim
- Surgical Pathology Department, SARAH Network of Rehabilitation Hospitals, Belo Horizonte, Brazil
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22
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Smith LR, Chambers HG, Subramaniam S, Lieber RL. Transcriptional abnormalities of hamstring muscle contractures in children with cerebral palsy. PLoS One 2012; 7:e40686. [PMID: 22956992 PMCID: PMC3431909 DOI: 10.1371/journal.pone.0040686] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 06/13/2012] [Indexed: 12/26/2022] Open
Abstract
Cerebral palsy (CP) is an upper motor neuron disease that results in a spectrum of movement disorders. Secondary to the neurological lesion, muscles from patients with CP are often spastic and form debilitating contractures that limit range of motion and joint function. With no genetic component, the pathology of skeletal muscle in CP is a response to aberrant complex neurological input in ways that are not fully understood. This study was designed to gain further understanding of the skeletal muscle response in CP using transcriptional profiling correlated with functional measures to broadly investigate muscle adaptations leading to mechanical deficits.Biopsies were obtained from both the gracilis and semitendinosus muscles from a cohort of patients with CP (n = 10) and typically developing patients (n = 10) undergoing surgery. Biopsies were obtained to define the unique expression profile of the contractures and passive mechanical testing was conducted to determine stiffness values in previously published work. Affymetrix HG-U133A 2.0 chips (n = 40) generated expression data, which was validated for selected transcripts using quantitative real-time PCR. Chips were clustered based on their expression and those from patients with CP clustered separately. Significant genes were determined conservatively based on the overlap of three summarization algorithms (n = 1,398). Significantly altered genes were analyzed for over-representation among gene ontologies and muscle specific networks.The majority of altered transcripts were related to increased extracellular matrix expression in CP and a decrease in metabolism and ubiquitin ligase activity. The increase in extracellular matrix products was correlated with mechanical measures demonstrating the importance in disability. These data lay a framework for further studies and development of novel therapies.
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Affiliation(s)
- Lucas R. Smith
- Department of Bioengineering, University of
California San Diego, La Jolla, California, United States of
America
| | - Henry G. Chambers
- Department of Orthopedic Surgery, Rady
Children's Hospital, San Diego, California, United States of
America
- Department of Orthopedic Surgery, University
of California San Diego, La Jolla, California, United States of
America
| | - Shankar Subramaniam
- Department of Bioengineering, University of
California San Diego, La Jolla, California, United States of
America
| | - Richard L. Lieber
- Department of Bioengineering, University of
California San Diego, La Jolla, California, United States of
America
- Department of Orthopedic Surgery, University
of California San Diego, La Jolla, California, United States of
America
- Department of Veterans Affairs, Medical
Center, San Diego, California, United States of America
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23
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Abstract
Current concepts of mechanosensation are general and applicable to almost every cell type. However, striated muscle cells are distinguished by their ability to generate strong forces via actin/myosin interaction, and this process is fine-tuned for optimum contractility. This aspect, unique for actively contracting cells, may be defined as "sensing of the magnitude and dynamics of contractility," as opposed to the well-known concepts of the "perception of extracellular mechanical stimuli." The acto/myosin interaction, by producing changes in ATP, ADP, Pi, and force on a millisecond timescale, may be regarded as a novel and previously unappreciated mechanosensory mechanism. In addition, sarcomeric mechanosensory structures, such as the Z-disc, are directly linked to autophagy, survival, and cell death-related pathways. One emerging example is telethonin and its ability to interfere with p53 metabolism and hence apoptosis (mechanoptosis). In this article, we introduce contractility per se as an important mechanosensory mechanism, and we differentiate extracellular from intracellular mechanosensory effects.
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Affiliation(s)
- Ralph Knöll
- Heart Science Section, National Heart & Lung Institute, Imperial College, London W12 0NN, UK.
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24
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Kojic S, Radojkovic D, Faulkner G. Muscle ankyrin repeat proteins: their role in striated muscle function in health and disease. Crit Rev Clin Lab Sci 2011; 48:269-94. [DOI: 10.3109/10408363.2011.643857] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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25
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The sarcomeric Z-disc and Z-discopathies. J Biomed Biotechnol 2011; 2011:569628. [PMID: 22028589 PMCID: PMC3199094 DOI: 10.1155/2011/569628] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 08/12/2011] [Indexed: 02/06/2023] Open
Abstract
The sarcomeric Z-disc defines the lateral borders of the sarcomere and has primarily been seen as a structure important for mechanical stability. This view has changed dramatically within the last one or two decades. A multitude of novel Z-disc proteins and their interacting partners have been identified, which has led to the identification of additional functions and which have now been assigned to this structure. This includes its importance for intracellular signalling, for mechanosensation and mechanotransduction in particular, an emerging importance for protein turnover and autophagy, as well as its molecular links to the t-tubular system and the sarcoplasmic reticulum. Moreover, the discovery of mutations in a wide variety of Z-disc proteins, which lead to perturbations of several of the above-mentioned systems, gives rise to a diverse group of diseases which can be termed Z-discopathies. This paper provides a brief overview of these novel aspects as well as points to future research directions.
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26
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Knöll R, Linke WA, Zou P, Miocic S, Kostin S, Buyandelger B, Ku CH, Neef S, Bug M, Schäfer K, Knöll G, Felkin LE, Wessels J, Toischer K, Hagn F, Kessler H, Didié M, Quentin T, Maier LS, Teucher N, Unsöld B, Schmidt A, Birks EJ, Gunkel S, Lang P, Granzier H, Zimmermann WH, Field LJ, Faulkner G, Dobbelstein M, Barton PJR, Sattler M, Wilmanns M, Chien KR. Telethonin deficiency is associated with maladaptation to biomechanical stress in the mammalian heart. Circ Res 2011; 109:758-69. [PMID: 21799151 DOI: 10.1161/circresaha.111.245787] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Telethonin (also known as titin-cap or t-cap) is a 19-kDa Z-disk protein with a unique β-sheet structure, hypothesized to assemble in a palindromic way with the N-terminal portion of titin and to constitute a signalosome participating in the process of cardiomechanosensing. In addition, a variety of telethonin mutations are associated with the development of several different diseases; however, little is known about the underlying molecular mechanisms and telethonin's in vivo function. OBJECTIVE Here we aim to investigate the role of telethonin in vivo and to identify molecular mechanisms underlying disease as a result of its mutation. METHODS AND RESULTS By using a variety of different genetically altered animal models and biophysical experiments we show that contrary to previous views, telethonin is not an indispensable component of the titin-anchoring system, nor is deletion of the gene or cardiac specific overexpression associated with a spontaneous cardiac phenotype. Rather, additional titin-anchorage sites, such as actin-titin cross-links via α-actinin, are sufficient to maintain Z-disk stability despite the loss of telethonin. We demonstrate that a main novel function of telethonin is to modulate the turnover of the proapoptotic tumor suppressor p53 after biomechanical stress in the nuclear compartment, thus linking telethonin, a protein well known to be present at the Z-disk, directly to apoptosis ("mechanoptosis"). In addition, loss of telethonin mRNA and nuclear accumulation of this protein is associated with human heart failure, an effect that may contribute to enhanced rates of apoptosis found in these hearts. CONCLUSIONS Telethonin knockout mice do not reveal defective heart development or heart function under basal conditions, but develop heart failure following biomechanical stress, owing at least in part to apoptosis of cardiomyocytes, an effect that may also play a role in human heart failure.
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Affiliation(s)
- Ralph Knöll
- Imperial College, National Heart & Lung Institute, British Heart Foundation, Centre for Research Excellence, Myocardial Genetics, London, UK.
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Abstract
The secondary α-dystroglycanopathies usually present in infancy as congenital muscular dystrophies but may manifest later in childhood or adult life (limb-girdle muscular dystrophy (LGMD) 2I, LGMD2K, LGMD2M, LGMD2N, and LGMD2O). Patients with telethoninopathy (LGMD2B) may present with mainly proximal or distal lower extremity weakness, and notably the muscle biopsies may demonstrate rimmed vacuoles. LGMD2L is caused by newly described mutations in ANO5 and can sometimes present with distal weakness resembling Miyoshi myopathy.
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28
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Barresi R. From proteins to genes: immunoanalysis in the diagnosis of muscular dystrophies. Skelet Muscle 2011; 1:24. [PMID: 21798100 PMCID: PMC3156647 DOI: 10.1186/2044-5040-1-24] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Accepted: 06/24/2011] [Indexed: 12/23/2022] Open
Abstract
Muscular dystrophies are a large heterogeneous group of inherited diseases that cause progressive muscle weakness and permanent muscle damage. Very few muscular dystrophies show sufficient specific clinical features to allow a definite diagnosis. Because of the currently limited capacity to screen for numerous genes simultaneously, muscle biopsy is a time and cost-effective test for many of these disorders. Protein analysis interpreted in correlation with the clinical phenotype is a useful way of directing genetic testing in many types of muscular dystrophies. Immunohistochemistry and western blot are complementary techniques used to gather quantitative and qualitative information on the expression of proteins involved in this group of diseases. Immunoanalysis has a major diagnostic application mostly in recessive conditions where the absence of labelling for a particular protein is likely to indicate a defect in that gene. However, abnormalities in protein expression can vary from absence to very subtle reduction. It is good practice to test muscle biopsies with antibodies for several proteins simultaneously and to interpret the results in context. Indeed, there is a degree of direct or functional association between many of these proteins that is reflected by the presence of specific secondary abnormalities that are of value, especially when the diagnosis is not straightforward.
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Affiliation(s)
- Rita Barresi
- NCG Diagnostic & Advisory Service for Rare Neuromuscular Diseases, Muscle Immunoanalysis Unit, Dental Hospital, Richardson Road, Newcastle upon Tyne, UK.
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29
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A study of FHL1, BAG3, MATR3, PTRF and TCAP in Australian muscular dystrophy patients. Neuromuscul Disord 2011; 21:776-81. [PMID: 21683594 DOI: 10.1016/j.nmd.2011.05.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 05/17/2011] [Accepted: 05/18/2011] [Indexed: 01/26/2023]
Abstract
FHL1, BAG3, MATR3 and PTRF are recently identified myopathy genes associated with phenotypes that overlap muscular dystrophy. TCAP is a rare reported cause of muscular dystrophy not routinely screened in most centres. We hypothesised that these genes may account for patients with undiagnosed forms of muscular dystrophy in Australia. We screened a large cohort of muscular dystrophy patients for abnormalities in FHL1 (n=102) and TCAP (n=100) and selected patients whose clinical features overlapped the phenotypes previously described for BAG3 (n=9), MATR3 (n=15) and PTRF (n=7). We found one FHL1 mutation (c.311G>A, p.C104Y) in a boy with rapidly progressive muscle weakness and reducing body myopathy who was initially diagnosed with muscular dystrophy. We identified no pathogenic mutations in BAG3, MATR3, PTRF or TCAP. In conclusion, we have excluded these five genes as common causes of muscular dystrophy in Australia. Patients with reducing body myopathy may be initially diagnosed as muscular dystrophy.
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30
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Telethonin-deficiency initially presenting as a congenital muscular dystrophy. Neuromuscul Disord 2011; 21:433-8. [DOI: 10.1016/j.nmd.2011.03.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 02/18/2011] [Accepted: 03/21/2011] [Indexed: 02/02/2023]
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31
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Muscular dystrophies: an update on pathology and diagnosis. Acta Neuropathol 2010; 120:343-58. [PMID: 20652576 DOI: 10.1007/s00401-010-0727-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 07/09/2010] [Accepted: 07/12/2010] [Indexed: 12/31/2022]
Abstract
Muscular dystrophies are clinically, genetically, and molecularly a heterogeneous group of neuromuscular disorders. Considerable advances have been made in recent years in the identification of causative genes, the differentiation of the different forms and in broadening the understanding of pathogenesis. Muscle pathology has an important role in these aspects, but correlation of the pathology with clinical phenotype is essential. Immunohistochemistry has a major role in differential diagnosis, particularly in recessive forms where an absence or reduction in protein expression can be detected. Several muscular dystrophies are caused by defects in genes encoding sarcolemmal proteins, several of which are known to interact. Others are caused by defects in nuclear membrane proteins or enzymes. Assessment of both primary and secondary abnormalities in protein expression is useful, in particular the hypoglycosylation of alpha-dystroglycan. In dominantly inherited muscular dystrophies it is rarely possible to detect a change in the expression of the primary defective protein; an exception to this is caveolin-3.
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32
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Sadikot T, Hammond CR, Ferrari MB. Distinct roles for telethonin N-versus C-terminus in sarcomere assembly and maintenance. Dev Dyn 2010; 239:1124-35. [PMID: 20235223 DOI: 10.1002/dvdy.22263] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The N-terminus of telethonin forms a unique structure linking two titin N-termini at the Z-disc. While a specific role for the C-terminus has not been established, several studies indicate it may have a regulatory function. Using a morpholino approach in Xenopus, we show that telethonin knockdown leads to embryonic paralysis, myocyte defects, and sarcomeric disruption. These myopathic defects can be rescued by expressing full-length telethonin mRNA in morpholino background, indicating that telethonin is required for myofibrillogenesis. However, a construct missing C-terminal residues is incapable of rescuing motility or sarcomere assembly in cultured myocytes. We, therefore, tested two additional constructs: one where four C-terminal phosphorylatable residues were mutated to alanines and another where terminal residues were randomly replaced. Data from these experiments support that the telethonin C-terminus is required for assembly, but in a context-dependent manner, indicating that factors and forces present in vivo can compensate for C-terminal truncation or mutation.
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Affiliation(s)
- Takrima Sadikot
- Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri, Kansas City, Missouri 64110, USA
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33
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Negrão L, Matos A, Geraldo A, Rebelo O. Limb-girdle muscular dystrophy in a Portuguese patient caused by a mutation in the telethonin gene. ACTA MYOLOGICA : MYOPATHIES AND CARDIOMYOPATHIES : OFFICIAL JOURNAL OF THE MEDITERRANEAN SOCIETY OF MYOLOGY 2010; 29:21-24. [PMID: 22029105 PMCID: PMC2954583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Limb-girdle muscular dystrophy 2G is caused by mutations in the telethonin (TCAP) gene in chromosome 17q11-12. This rare form of hereditary muscle disease was originally described in Brazilian patients and was recently identified in Chinese and Moldavian patients. We present the first Portuguese patient with a limb-girdle muscular dystrophy caused by a mutation in the TCAP gene. A Caucasian male, 50 years old, presented in his early twenties, slowly progressive weakness in upper and lower limbs. Neurologic examination revealed severe atrophy and weakness in the muscles of the arms, thighs and legs' anterior compartment. Muscle MRI of the thighs and legs revealed severe atrophy of all the muscles of the thighs and legs' anterolateral compartment, in a symmetrical way. Molecular studies identified the homozygous c.157C > T (p.Gln53X) mutation in exon 2 of the TCAP gene, already described in Brazilian patients.
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Affiliation(s)
- L Negrão
- Neuromuscular Outpatient Clinic, Neurology Department, Coimbra's University Hospital, Coimbra, Portugal
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34
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Markert CD, Meaney MP, Voelker KA, Grange RW, Dalley HW, Cann JK, Ahmed M, Bishwokarma B, Walker SJ, Yu SX, Brown M, Lawlor MW, Beggs AH, Childers MK. Functional muscle analysis of the Tcap knockout mouse. Hum Mol Genet 2010; 19:2268-83. [PMID: 20233748 DOI: 10.1093/hmg/ddq105] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Autosomal recessive limb-girdle muscular dystrophy type 2G (LGMD2G) is an adult-onset myopathy characterized by distal lower limb weakness, calf hypertrophy and progressive decline in ambulation. The disease is caused by mutations in Tcap, a z-disc protein of skeletal muscle, although the precise mechanisms resulting in clinical symptoms are unknown. To provide a model for preclinical trials and for mechanistic studies, we generated knockout (KO) mice carrying a null mutation in the Tcap gene. Here we present the first report of a Tcap KO mouse model for LGMD2G and the results of an investigation into the effects of Tcap deficiency on skeletal muscle function in 4- and 12-month-old mice. Muscle histology of Tcap-null mice revealed abnormal myofiber size variation with central nucleation, similar to findings in the muscles of LGMD2G patients. An analysis of a Tcap binding protein, myostatin, showed that deletion of Tcap was accompanied by increased protein levels of myostatin. Our Tcap-null mice exhibited a decline in the ability to maintain balance on a rotating rod, relative to wild-type controls. No differences were detected in force or fatigue assays of isolated extensor digitorum longus (EDL) and soleus (SOL) muscles. Finally, a mechanical investigation of EDL and SOL indicated an increase in muscle stiffness in KO animals. We are the first to establish a viable KO mouse model of Tcap deficiency and our model mice demonstrate a dystrophic phenotype comparable to humans with LGMD2G.
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Affiliation(s)
- C D Markert
- Department of Neurology, Wake Forest University, Winston-Salem, NC 27101, USA
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35
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Otey CA, Dixon R, Stack C, Goicoechea SM. Cytoplasmic Ig-domain proteins: cytoskeletal regulators with a role in human disease. ACTA ACUST UNITED AC 2009; 66:618-34. [PMID: 19466753 DOI: 10.1002/cm.20385] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Immunoglobulin domains are found in a wide variety of functionally diverse transmembrane proteins, and also in a smaller number of cytoplasmic proteins. Members of this latter group are usually associated with the actin cytoskeleton, and most of them bind directly to either actin or myosin, or both. Recently, studies of inherited human disorders have identified disease-causing mutations in five cytoplasmic Ig-domain proteins: myosin-binding protein C, titin, myotilin, palladin, and myopalladin. Together with results obtained from cultured cells and mouse models, these clinical studies have yielded novel insights into the unexpected roles of Ig domain proteins in mechanotransduction and signaling to the nucleus. An emerging theme in this field is that cytoskeleton-associated Ig domain proteins are more than structural elements of the cell, and may have evolved to fill different needs in different cellular compartments. Cell Motil. Cytoskeleton 2009. (c) 2009 Wiley-Liss, Inc.
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Affiliation(s)
- Carol A Otey
- Department of Cell and Molecular Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
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36
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Zhang R, Yang J, Zhu J, Xu X. Depletion of zebrafish Tcap leads to muscular dystrophy via disrupting sarcomere-membrane interaction, not sarcomere assembly. Hum Mol Genet 2009; 18:4130-40. [PMID: 19679566 DOI: 10.1093/hmg/ddp362] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Tcap/telethonin encodes a Z-disc protein that plays important roles in sarcomere assembly, sarcomere-membrane interaction and stretch sensing. It remains unclear why mutations in Tcap lead to limb-girdle muscular dystrophy 2G (LGMD2G) in human patients. Here, we cloned tcap in zebrafish and conducted genetic studies. We show that tcap is functionally conserved, as the Tcap protein appears in the sarcomeric Z-disc and reduction of Tcap resulted in muscular dystrophy-like phenotypes including deformed muscle structure and impaired swimming ability. However, the observations that Tcap integrates into the sarcomere at a stage after the Z-disc becomes periodic, and that the sarcomere remains intact in tcap morphants, suggest that defective sarcomere assembly does not contribute to this particular type of muscular dystrophy. Instead, a defective interaction between the sarcomere and plasma membrane was detected, which was further underscored by the disrupted development of the T-tubule system. Pertinent to a potential function in stretch sensor signaling, zebrafish tcap exhibits a variable expression pattern during somitogenesis. The variable expression is inducible by stretch force, and the expression level of Tcap is negatively regulated by integrin-link kinase (ILK), a protein kinase that is involved in stretch sensing signaling. Together, our genetic studies of tcap in zebrafish suggested that pathogenesis in LGMD2G is due to a disruption of sarcomere-T-tubular interaction, but not of sarcomere assembly per se. In addition, our data prompted a novel hypothesis that predicts that the transcription level of Tcap can be regulated by the stretch force to ensure proper sarcomere-membrane interaction in striated muscles.
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Affiliation(s)
- Ruilin Zhang
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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