1
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Novel compound heterozygous mutations in the TTN gene: elongation and truncation variants causing limb-girdle muscular dystrophy type 2J in a Han Chinese family. Neurol Sci 2022; 43:3427-3433. [DOI: 10.1007/s10072-022-05979-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 02/18/2022] [Indexed: 10/18/2022]
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2
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Panwar D, Singh KG, Mathur S, Prasad B, Joshi A, Lal V, Thatai A. Heterozygous missense variant in the TTN gene causing Tibial muscular dystrophy. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2022. [DOI: 10.1186/s43042-022-00284-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Tibial muscular dystrophy (TMD), tardive, is a dominantly inherited mild degenerative disorder of anterior tibial muscles. Mutations of Titin (TTN) have been reported in patients with different phenotypes such as skeletal muscular abnormalities or complex overlapping disorders of muscles. Titin (TTN) is a large 363 exon gene that encodes an abundant protein (the longest polypeptide known in nature) expressed in the heart and skeletal muscles.
Methods
DNA from peripheral blood sample was extracted, whole exome sequencing (WES) was performed, and a neuromuscular disorders related gene-filtering strategy was used to analyse the disease-causing mutations. Further, sanger sequencing was applied to confirm the variant.
Results
A novel missense variant (c.41529G > C;p.Arg13843Ser) of TTN gene was identified in a patient with lower limb weakness, occasional tongue fasciculation and mild scoliosis. This variant leads to a substitution of arginine with serine, causing structural changes in titin protein that is responsible for the TMD disease.
Conclusion
The novel variant detected has widened the genetic spectrum of TTN-associated diseases, further functional studies will aid in establishing the clinical diagnosis.
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3
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El Kadiri Y, Ratbi I, Sefiani A, Lyahyai J. Clinical and molecular genetic analysis of early-onset myopathy with fatal cardiomyopathy: Novel biallelic M-line TTN mutation and review of the literature. GENE REPORTS 2022. [DOI: 10.1016/j.genrep.2022.101587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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4
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In Vitro Fertilization Using Preimplantation Genetic Testing in a Romanian Couple Carrier of Mutations in the TTN Gene: A Case Report and Literature Review. Diagnostics (Basel) 2021; 11:diagnostics11122328. [PMID: 34943567 PMCID: PMC8699826 DOI: 10.3390/diagnostics11122328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 12/07/2021] [Accepted: 12/08/2021] [Indexed: 12/04/2022] Open
Abstract
Severe congenital myopathy with fatal cardiomyopathy (EOMFC) is a rare genetic neuromuscular disorder inherited in an autosomal recessive manner. Here we presented a successful pregnancy obtained by in vitro fertilization (IVF) using preimplantation genetic testing (PGT) in one young Romanian carrier couple that already lost mutation(s) within the TNN gene and whose first baby passed away due to multiple complications. It was delivered via emergency C-section at 36 weeks and fully dependent on artificial ventilation for a couple of months, weighing 2200 g and an APGAR score of 3. The aCGH + SNP analysis revealed an abnormal profile of the first newborn; three areas associated with loss of heterozygosity on chromosome 1 (q25.1–q25.3) of 6115 kb, 5 (p15.2–p15.1) of 2589 kb and 8 (q11.21–q11.23) of 4830 kb, a duplication of 1104 kb on chromosome 10 in the position q11.22, and duplication of 1193 kb on chromosome 16 in the position p11.2p11.1. Subsequently, we proceeded to test the parents and showed that both parents are carriers; confirmed by Sanger and NGS sequencing—father—on Chr2(GRCh37):g.179396832_179396833del—TTN variant c.104509_104510del p.(Leu34837Glufs*12)—exon 358 and mother—on Chr2(GRCh37):g.179479653G>C—TTN variant c.48681C>G p.(Tyr16227*)—exon 260. Their first child died shortly after birth due to multiple organ failures, possessing both parent’s mutations; weighing 2200 g at birth and received an APGAR score of 3 following premature delivery via emergency C-section at 36 weeks. Two embryos were obtained following the IVF protocol; one possessed the mother’s mutation, and the other had no mutations and was normal (WT). In contrast with the first birth, the second one was uneventful. A healthy female baby weighing 2990 g was delivered by C-section at 38 weeks, receiving an APGAR score of 9.
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5
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Salih MA, Hamad MH, Savarese M, Alorainy IA, Al-Jarallah AS, Alkhalidi H, AlQudairy H, Albader A, Alotaibi AJ, Alsagob M, Al-Bakheet A, Colak D, Udd B, Kaya N. Exome Sequencing Reveals Novel TTN Variants in Saudi Patients with Congenital Titinopathies. Genet Test Mol Biomarkers 2021; 25:757-764. [DOI: 10.1089/gtmb.2021.0085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Affiliation(s)
- Mustafa A. Salih
- Division of Pediatric Neurology, Department of Pediatrics, King Saud University, Riyadh, Saudi Arabia
| | - Muddathir H. Hamad
- Division of Pediatric Neurology, Department of Pediatrics, King Saud University, Riyadh, Saudi Arabia
| | - Marco Savarese
- The Folkhälsan Institute of Genetics and the Department of Medical Genetics, Haartman Institute, University of Helsinki, Helsinki, Finland
| | - Ibrahim A. Alorainy
- Department of Radiology and Diagnostic Imaging, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Abdullah S. Al-Jarallah
- Pediatric Cardiology Division, Cardiac Science Department, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Hisham Alkhalidi
- Department of Pathology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Hanan AlQudairy
- Translational Genomics Department, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, MBC: 03, Riyadh, Saudi Arabia
| | - Anoud Albader
- Translational Genomics Department, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, MBC: 03, Riyadh, Saudi Arabia
| | - Amal Jahz Alotaibi
- Translational Genomics Department, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, MBC: 03, Riyadh, Saudi Arabia
| | - Maysoon Alsagob
- Translational Genomics Department, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, MBC: 03, Riyadh, Saudi Arabia
| | - Albandary Al-Bakheet
- Translational Genomics Department, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, MBC: 03, Riyadh, Saudi Arabia
| | - Dilek Colak
- Biostatistics, Epidemiology, and Scientific Computing Department, MBC: 03, Riyadh, Saudi Arabia
| | - Bjarne Udd
- Tampere Neuromuscular Research Unit, The Folkhälsan Institute of Genetics and the Department of Medical Genetics, Haartman Institute, University of Helsinki, Helsinki, Finland
| | - Namik Kaya
- Translational Genomics Department, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, MBC: 03, Riyadh, Saudi Arabia
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6
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Diagnostic muscle biopsies in the era of genetics: the added value of myopathology in a selection of limb-girdle muscular dystrophy patients. Acta Neurol Belg 2021; 121:1019-1033. [PMID: 33400223 DOI: 10.1007/s13760-020-01559-0] [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: 08/10/2020] [Accepted: 11/19/2020] [Indexed: 10/22/2022]
Abstract
In the second most common dystrophy associated with predominant pelvic and shoulder girdle muscle weakness termed Limb-Girdle Muscular Dystrophy (LGMD), genetic complexity, large phenotypic variability, and clinical overlap can result in extensive diagnostic delays in certain individuals. In view of the large strides genetics has taken in this day and age, we address the question if muscle biopsies can still provide diagnostic evidence of substance for these patients. We reviewed and reanalyzed muscle biopsy characteristics in a cohort of LGMD patient pairs in which gene variants were picked up in CAPN3, FKRP, TTN, and ANO5, using histochemical-immunohistochemical-and immunofluorescent staining, and western blotting. We found that not the nature and severity of inflammatory changes, but the changed properties of the dystrophin complex were the most valuable assets to differentiate LGMD from myositis. Proteomic evaluation brought both primary and secondary deficiencies to light, which could be equally revealing for diagnosis. Though a muscle biopsy might, at present, not always be strictly necessary anymore, it still represents an irrefutable asset when the genetic diagnosis is complicated.
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Abstract
PURPOSE OF REVIEW The last few years have confirmed previous assumptions of an enormous impact of the titin gene (TTN) on the occurrence of muscle disease, cardiomyopathy, or both together. The reason for this rather late understanding of its importance is because of the huge size which prevented sequencing of the whole gene by the previous Sanger technique in the individual cases. An update of the advances in diagnosing titinopathies is the main focus of this review. RECENT FINDINGS High throughput methods are now widely available for TTN sequencing and a corresponding explosion of different types of identified titinopathies is observed and published in the literature, although final confirmation is lacking in many cases with recessive missense variants. SUMMARY The implications of these findings for clinical practice are easy to understand: patients with previously undiagnosed muscle disease can now have a correct diagnosis and subsequently receive a likely prognosis, can have accurate genetic counseling for the whole family and early treatment for predictable complications from the heart and respiratory muscles. In addition not to forget, they can avoid wrong diagnoses leading to wrong treatments.
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Savarese M, Välipakka S, Johari M, Hackman P, Udd B. Is Gene-Size an Issue for the Diagnosis of Skeletal Muscle Disorders? J Neuromuscul Dis 2021; 7:203-216. [PMID: 32176652 PMCID: PMC7369045 DOI: 10.3233/jnd-190459] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Human genes have a variable length. Those having a coding sequence of extraordinary length and a high number of exons were almost impossible to sequence using the traditional Sanger-based gene-by-gene approach. High-throughput sequencing has partly overcome the size-related technical issues, enabling a straightforward, rapid and relatively inexpensive analysis of large genes. Several large genes (e.g. TTN, NEB, RYR1, DMD) are recognized as disease-causing in patients with skeletal muscle diseases. However, because of their sheer size, the clinical interpretation of variants in these genes is probably the most challenging aspect of the high-throughput genetic investigation in the field of skeletal muscle diseases. The main aim of this review is to discuss the technical and interpretative issues related to the diagnostic investigation of large genes and to reflect upon the current state of the art and the future advancements in the field.
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Affiliation(s)
- Marco Savarese
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Salla Välipakka
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Mridul Johari
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Peter Hackman
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Bjarne Udd
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland.,Neuromuscular Research Center, Tampere University and University Hospital, Tampere, Finland.,Department of Neurology, Vaasa Central Hospital, Vaasa, Finland
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9
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Savarese M, Sarparanta J, Vihola A, Jonson PH, Johari M, Rusanen S, Hackman P, Udd B. Panorama of the distal myopathies. ACTA MYOLOGICA : MYOPATHIES AND CARDIOMYOPATHIES : OFFICIAL JOURNAL OF THE MEDITERRANEAN SOCIETY OF MYOLOGY 2020; 39:245-265. [PMID: 33458580 PMCID: PMC7783427 DOI: 10.36185/2532-1900-028] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 11/11/2020] [Indexed: 12/15/2022]
Abstract
Distal myopathies are genetic primary muscle disorders with a prominent weakness at onset in hands and/or feet. The age of onset (from early childhood to adulthood), the distribution of muscle weakness (upper versus lower limbs) and the histological findings (ranging from nonspecific myopathic changes to myofibrillar disarrays and rimmed vacuoles) are extremely variable. However, despite being characterized by a wide clinical and genetic heterogeneity, the distal myopathies are a category of muscular dystrophies: genetic diseases with progressive loss of muscle fibers. Myopathic congenital arthrogryposis is also a form of distal myopathy usually caused by focal amyoplasia. Massive parallel sequencing has further expanded the long list of genes associated with a distal myopathy, and contributed identifying as distal myopathy-causative rare variants in genes more often related with other skeletal or cardiac muscle diseases. Currently, almost 20 genes (ACTN2, CAV3, CRYAB, DNAJB6, DNM2, FLNC, HNRNPA1, HSPB8, KHLH9, LDB3, MATR3, MB, MYOT, PLIN4, TIA1, VCP, NOTCH2NLC, LRP12, GIPS1) have been associated with an autosomal dominant form of distal myopathy. Pathogenic changes in four genes (ADSSL, ANO5, DYSF, GNE) cause an autosomal recessive form; and disease-causing variants in five genes (DES, MYH7, NEB, RYR1 and TTN) result either in a dominant or in a recessive distal myopathy. Finally, a digenic mechanism, underlying a Welander-like form of distal myopathy, has been recently elucidated. Rare pathogenic mutations in SQSTM1, previously identified with a bone disease (Paget disease), unexpectedly cause a distal myopathy when combined with a common polymorphism in TIA1. The present review aims at describing the genetic basis of distal myopathy and at summarizing the clinical features of the different forms described so far.
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Affiliation(s)
- Marco Savarese
- Folkhälsan Research Center, Helsinki, Finland
- Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Jaakko Sarparanta
- Folkhälsan Research Center, Helsinki, Finland
- Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Anna Vihola
- Folkhälsan Research Center, Helsinki, Finland
- Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
- Neuromuscular Research Center, Department of Genetics, Fimlab Laboratories, Tampere, Finland
| | - Per Harald Jonson
- Folkhälsan Research Center, Helsinki, Finland
- Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Mridul Johari
- Folkhälsan Research Center, Helsinki, Finland
- Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Salla Rusanen
- Folkhälsan Research Center, Helsinki, Finland
- Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Peter Hackman
- Folkhälsan Research Center, Helsinki, Finland
- Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Bjarne Udd
- Folkhälsan Research Center, Helsinki, Finland
- Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
- Department of Neurology, Vaasa Central Hospital, Vaasa, Finland
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10
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Savarese M, Johari M, Johnson K, Arumilli M, Torella A, Töpf A, Rubegni A, Kuhn M, Giugliano T, Gläser D, Fattori F, Thompson R, Penttilä S, Lehtinen S, Gibertini S, Ruggieri A, Mora M, Maver A, Peterlin B, Mankodi A, Lochmüller H, Santorelli FM, Schoser B, Fajkusová L, Straub V, Nigro V, Hackman P, Udd B. Improved Criteria for the Classification of Titin Variants in Inherited Skeletal Myopathies. J Neuromuscul Dis 2020; 7:153-166. [PMID: 32039858 DOI: 10.3233/jnd-190423] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Extensive genetic screening results in the identification of thousands of rare variants that are difficult to interpret. Because of its sheer size, rare variants in the titin gene (TTN) are detected frequently in any individual. Unambiguous interpretation of molecular findings is almost impossible in many patients with myopathies or cardiomyopathies. OBJECTIVE To refine the current classification framework for TTN-associated skeletal muscle disorders and standardize the interpretation of TTN variants. METHODS We used the guidelines issued by the American College of Medical Genetics and Genomics (ACMG) and the Association for Molecular Pathology (AMP) to re-analyze TTN genetic findings from our patient cohort. RESULTS We identified in the classification guidelines three rules that are not applicable to titin-related skeletal muscle disorders; six rules that require disease-/gene-specific adjustments and four rules requiring quantitative thresholds for a proper use. In three cases, the rule strength need to be modified. CONCLUSIONS We suggest adjustments are made to the guidelines. We provide frequency thresholds to facilitate filtering of candidate causative variants and guidance for the use and interpretation of functional data and co-segregation evidence. We expect that the variant classification framework for TTN-related skeletal muscle disorders will be further improved along with a better understanding of these diseases.
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Affiliation(s)
- Marco Savarese
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Mridul Johari
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Katherine Johnson
- The John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Meharji Arumilli
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Annalaura Torella
- Dipartimento di Medicina di Precisione, Universitá degli Studi della Campania "Luigi Vanvitelli", Naples, Italy.,Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Ana Töpf
- The John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | | | | | - Teresa Giugliano
- Dipartimento di Medicina di Precisione, Universitá degli Studi della Campania "Luigi Vanvitelli", Naples, Italy.,Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | | | - Fabiana Fattori
- Unit for Neuromuscular and Neurodegenerative Disorders, Bambino Gesù Children's Hospital, Rome, Italy
| | - Rachel Thompson
- The John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Sini Penttilä
- Neuromuscular Research Center, Department of Genetics, Fimlab Laboratories, Tampere, Finland
| | - Sara Lehtinen
- Neuromuscular Research Center, Department of Genetics, Fimlab Laboratories, Tampere, Finland
| | - Sara Gibertini
- Neuromuscular Diseases and Neuroimmunology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Alessandra Ruggieri
- Neuromuscular Diseases and Neuroimmunology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy.,Department of Molecular and Translation Medicine, Unit of Biology and Genetics, University of Brescia, Brescia, Italy
| | - Marina Mora
- Neuromuscular Diseases and Neuroimmunology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Ales Maver
- Clinical Institute of Medical Genetics, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Borut Peterlin
- Clinical Institute of Medical Genetics, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Ami Mankodi
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, Unites States
| | - 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, Spain.,Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada.,Division of Neurology, Department of Medicine, The Ottawa Hospital, Ottawa, Canada
| | | | - Benedikt Schoser
- Friedrich-Baur-Institut, Neurologische Klinik Ludwig-Maximilians-Universität München, Munich, Germany
| | - Lenka Fajkusová
- Centre of Molecular Biology and Gene Therapy, University Hospital Brno and Masaryk University Brno, Brno, Czech Republic
| | - Volker Straub
- The John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Vincenzo Nigro
- Dipartimento di Medicina di Precisione, Universitá degli Studi della Campania "Luigi Vanvitelli", Naples, Italy.,Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Peter Hackman
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Bjarne Udd
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland.,Department of Neurology, Vaasa Central Hospital, Vaasa, Finland.,Neuromuscular Research Center, Tampere University and University Hospital, Tampere, Finland
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11
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Beecroft SJ, Lamont PJ, Edwards S, Goullée H, Davis MR, Laing NG, Ravenscroft G. The Impact of Next-Generation Sequencing on the Diagnosis, Treatment, and Prevention of Hereditary Neuromuscular Disorders. Mol Diagn Ther 2020; 24:641-652. [PMID: 32997275 DOI: 10.1007/s40291-020-00495-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/05/2020] [Indexed: 12/13/2022]
Abstract
The impact of high-throughput sequencing in genetic neuromuscular disorders cannot be overstated. The ability to rapidly and affordably sequence multiple genes simultaneously has enabled a second golden age of Mendelian disease gene discovery, with flow-on impacts for rapid genetic diagnosis, evidence-based treatment, tailored therapy development, carrier-screening, and prevention of disease recurrence in families. However, there are likely many more neuromuscular disease genes and mechanisms to be discovered. Many patients and families remain without a molecular diagnosis following targeted panel sequencing, clinical exome sequencing, or even genome sequencing. Here we review how massively parallel, or next-generation, sequencing has changed the field of genetic neuromuscular disorders, and anticipate future benefits of recent technological innovations such as RNA-seq implementation and detection of tandem repeat expansions from short-read sequencing.
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Affiliation(s)
- Sarah J Beecroft
- Neurogenetic Diseases Group, Centre for Medical Research, QEII Medical Centre, University of Western Australia, 6 Verdun St, Nedlands, WA, 6009, Australia.,Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA, 6009, Australia
| | | | - Samantha Edwards
- Neurogenetic Diseases Group, Centre for Medical Research, QEII Medical Centre, University of Western Australia, 6 Verdun St, Nedlands, WA, 6009, Australia.,Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA, 6009, Australia
| | - Hayley Goullée
- Neurogenetic Diseases Group, Centre for Medical Research, QEII Medical Centre, University of Western Australia, 6 Verdun St, Nedlands, WA, 6009, Australia.,Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA, 6009, Australia
| | - Mark R Davis
- Neurogenetic Unit, Department of Diagnostic Genomics, PP Block, QEII Medical Centre, Nedlands, WA, Australia
| | - Nigel G Laing
- Neurogenetic Diseases Group, Centre for Medical Research, QEII Medical Centre, University of Western Australia, 6 Verdun St, Nedlands, WA, 6009, Australia.,Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA, 6009, Australia.,Neurogenetic Clinic, Royal Perth Hospital, Perth, Australia
| | - Gianina Ravenscroft
- Neurogenetic Diseases Group, Centre for Medical Research, QEII Medical Centre, University of Western Australia, 6 Verdun St, Nedlands, WA, 6009, Australia. .,Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA, 6009, Australia.
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12
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The importance of an integrated genotype-phenotype strategy to unravel the molecular bases of titinopathies. Neuromuscul Disord 2020; 30:877-887. [PMID: 33127292 DOI: 10.1016/j.nmd.2020.09.032] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 08/26/2020] [Accepted: 09/23/2020] [Indexed: 02/06/2023]
Abstract
Next generation sequencing (NGS) has allowed the titin gene (TTN) to be identified as a major contributor to neuromuscular disorders, with high clinical heterogeneity. The mechanisms underlying the phenotypic variability and the dominant or recessive pattern of inheritance are unclear. Titin is involved in the formation and stability of the sarcomeres. The effects of the different TTN variants can be harmless or pathogenic (recessive or dominant) but the interpretation is tricky because the current bioinformatics tools can not predict their functional impact effectively. Moreover, TTN variants are very frequent in the general population. The combination of deep phenotyping associated with RNA molecular analyses, western blot (WB) and functional studies is often essential for the interpretation of genetic variants in patients suspected of titinopathy. In line with the current guidelines and suggestions, we implemented for patients with skeletal myopathy and with potentially disease causing TTN variant(s) an integrated genotype-transcripts-protein-phenotype approach, associated with phenotype and variants segregation studies in relatives and confrontation with published data on titinopathies to evaluate pathogenic effects of TTN variants (even truncating ones) on titin transcripts, amount, size and functionality. We illustrate this integrated approach in four patients with recessive congenital myopathy.
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13
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Genotype-phenotype correlations in recessive titinopathies. Genet Med 2020; 22:2029-2040. [PMID: 32778822 DOI: 10.1038/s41436-020-0914-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 07/15/2020] [Accepted: 07/16/2020] [Indexed: 12/20/2022] Open
Abstract
PURPOSE High throughput sequencing analysis has facilitated the rapid analysis of the entire titin (TTN) coding sequence. This has resulted in the identification of a growing number of recessive titinopathy patients. The aim of this study was to (1) characterize the causative genetic variants and clinical features of the largest cohort of recessive titinopathy patients reported to date and (2) to evaluate genotype-phenotype correlations in this cohort. METHODS We analyzed clinical and genetic data in a cohort of patients with biallelic pathogenic or likely pathogenic TTN variants. The cohort included both previously reported cases (100 patients from 81 unrelated families) and unreported cases (23 patients from 20 unrelated families). RESULTS Overall, 132 causative variants were identified in cohort members. More than half of the cases had hypotonia at birth or muscle weakness and a delayed motor development within the first 12 months of life (congenital myopathy) with causative variants located along the entire gene. The remaining patients had a distal or proximal phenotype and a childhood or later (noncongenital) onset. All noncongenital cases had at least one pathogenic variant in one of the final three TTN exons (362-364). CONCLUSION Our findings suggest a novel association between the location of nonsense variants and the clinical severity of the disease.
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14
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Papadimas GK, Xirou S, Kararizou E, Papadopoulos C. Update on Congenital Myopathies in Adulthood. Int J Mol Sci 2020; 21:ijms21103694. [PMID: 32456280 PMCID: PMC7279481 DOI: 10.3390/ijms21103694] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/17/2020] [Accepted: 05/19/2020] [Indexed: 12/11/2022] Open
Abstract
Congenital myopathies (CMs) constitute a group of heterogenous rare inherited muscle diseases with different incidences. They are traditionally grouped based on characteristic histopathological findings revealed on muscle biopsy. In recent decades, the ever-increasing application of modern genetic technologies has not just improved our understanding of their pathophysiology, but also expanded their phenotypic spectrum and contributed to a more genetically based approach for their classification. Later onset forms of CMs are increasingly recognised. They are often considered milder with slower progression, variable clinical presentations and different modes of inheritance. We reviewed the key features and genetic basis of late onset CMs with a special emphasis on those forms that may first manifest in adulthood.
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15
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Savarese M, Maggi L, Vihola A, Jonson PH, Tasca G, Ruggiero L, Bello L, Magri F, Giugliano T, Torella A, Evilä A, Di Fruscio G, Vanakker O, Gibertini S, Vercelli L, Ruggieri A, Antozzi C, Luque H, Janssens S, Pasanisi MB, Fiorillo C, Raimondi M, Ergoli M, Politano L, Bruno C, Rubegni A, Pane M, Santorelli FM, Minetti C, Angelini C, De Bleecker J, Moggio M, Mongini T, Comi GP, Santoro L, Mercuri E, Pegoraro E, Mora M, Hackman P, Udd B, Nigro V. Interpreting Genetic Variants in Titin in Patients With Muscle Disorders. JAMA Neurol 2019; 75:557-565. [PMID: 29435569 DOI: 10.1001/jamaneurol.2017.4899] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Importance Mutations in the titin gene (TTN) cause a wide spectrum of genetic diseases. The interpretation of the numerous rare variants identified in TTN is a difficult challenge given its large size. Objective To identify genetic variants in titin in a cohort of patients with muscle disorders. Design, Setting, and Participants In this case series, 9 patients with titinopathy and 4 other patients with possibly disease-causing variants in TTN were identified. Titin mutations were detected through targeted resequencing performed on DNA from 504 patients with muscular dystrophy, congenital myopathy, or other skeletal muscle disorders. Patients were enrolled from 10 clinical centers in April 2012 to December 2013. All of them had not received a diagnosis after undergoing an extensive investigation, including Sanger sequencing of candidate genes. The data analysis was performed between September 2013 and January 2017. Sequencing data were analyzed using an internal custom bioinformatics pipeline. Main Outcomes and Measures The identification of novel mutations in the TTN gene and novel patients with titinopathy. We performed an evaluation of putative causative variants in the TTN gene, combining genetic, clinical, and imaging data with messenger RNA and/or protein studies. Results Of the 9 novel patients with titinopathy, 5 (55.5%) were men and the mean (SD) age at onset was 25 (15.8) years (range, 0-46 years). Of the 4 other patients (3 men and 1 woman) with possibly disease-causing TTN variants, 2 (50%) had a congenital myopathy and 2 (50%) had a slowly progressive distal myopathy with onset in the second decade. Most of the identified mutations were previously unreported. However, all the variants, even the already described mutations, require careful clinical and molecular evaluation of probands and relatives. Heterozygous truncating variants or unique missense changes are not sufficient to make a diagnosis of titinopathy. Conclusions and Relevance The interpretation of TTN variants often requires further analyses, including a comprehensive evaluation of the clinical phenotype (deep phenotyping) as well as messenger RNA and protein studies. We propose a specific workflow for the clinical interpretation of genetic findings in titin.
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Affiliation(s)
- Marco Savarese
- Folkhälsan Research Center, Medicum, University of Helsinki, Helsinki, Finland.,Dipartimento di Biochimica, Biofisica e Patologia Generale, Università degli Studi della Campania "Luigi Vanvitelli," Napoli, Italy.,Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Lorenzo Maggi
- Neuromuscular Diseases and Neuroimmunology Unit, Institute for Research and Health Care Foundation Neurological Institute C. Besta, Milan, Italy
| | - Anna Vihola
- Folkhälsan Research Center, Medicum, University of Helsinki, Helsinki, Finland
| | - Per Harald Jonson
- Folkhälsan Research Center, Medicum, University of Helsinki, Helsinki, Finland
| | - Giorgio Tasca
- Istituto di Neurologia, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario "A. Gemelli," Rome, Italy
| | - Lucia Ruggiero
- Dipartimento di Neuroscienze e Scienze Riproduttive ed Odontostomatologiche, Università degli Studi di Napoli "Federico II," Napoli, Italy
| | - Luca Bello
- Neuromuscular Center, Dipartimento di Neuroscienze, Università di Padova, Padova, Italy
| | - Francesca Magri
- Centro Dino Ferrari, Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Fondazione Institute for Research and Health Care Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Teresa Giugliano
- Dipartimento di Biochimica, Biofisica e Patologia Generale, Università degli Studi della Campania "Luigi Vanvitelli," Napoli, Italy.,Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Annalaura Torella
- Dipartimento di Biochimica, Biofisica e Patologia Generale, Università degli Studi della Campania "Luigi Vanvitelli," Napoli, Italy.,Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Anni Evilä
- Folkhälsan Research Center, Medicum, University of Helsinki, Helsinki, Finland
| | - Giuseppina Di Fruscio
- Dipartimento di Biochimica, Biofisica e Patologia Generale, Università degli Studi della Campania "Luigi Vanvitelli," Napoli, Italy.,Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Olivier Vanakker
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Sara Gibertini
- Neuromuscular Diseases and Neuroimmunology Unit, Institute for Research and Health Care Foundation Neurological Institute C. Besta, Milan, Italy
| | - Liliana Vercelli
- Neuromuscular Unit, Department of Neurosciences, Rita Levi Montalcini, University of Torino, Torino, Italy
| | - Alessandra Ruggieri
- Neuromuscular Diseases and Neuroimmunology Unit, Institute for Research and Health Care Foundation Neurological Institute C. Besta, Milan, Italy
| | - Carlo Antozzi
- Neuromuscular Diseases and Neuroimmunology Unit, Institute for Research and Health Care Foundation Neurological Institute C. Besta, Milan, Italy
| | - Helena Luque
- Folkhälsan Research Center, Medicum, University of Helsinki, Helsinki, Finland
| | - Sandra Janssens
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Maria Barbara Pasanisi
- Neuromuscular Diseases and Neuroimmunology Unit, Institute for Research and Health Care Foundation Neurological Institute C. Besta, Milan, Italy
| | - Chiara Fiorillo
- Pediatric Neurology and Neuromuscular Disorders Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal, and Child Health; University of Genoa, Istituto G. Gaslini, Genova, Italy
| | | | - Manuela Ergoli
- Dipartimento di Medicina Sperimentale, Cardiomiologia e Genetica Medica, Università degli Studi della Campania "Luigi Vanvitelli," Napoli, Italy
| | - Luisa Politano
- Dipartimento di Medicina Sperimentale, Cardiomiologia e Genetica Medica, Università degli Studi della Campania "Luigi Vanvitelli," Napoli, Italy
| | - Claudio Bruno
- Center of Myology and Neurodegenerative Disease, Istituto Giannina Gaslini, Genova, Italy
| | - Anna Rubegni
- Medicina Molecolare, Institute for Research and Health Care Fondazione Stella Maris, Pisa, Italy
| | - Marika Pane
- Department of Pediatric Neurology, Catholic University and Nemo Roma Center for Neuromuscular Disorders, Rome, Italy
| | - Filippo M Santorelli
- Medicina Molecolare, Institute for Research and Health Care Fondazione Stella Maris, Pisa, Italy
| | - Carlo Minetti
- Pediatric Neurology and Neuromuscular Disorders Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal, and Child Health; University of Genoa, Istituto G. Gaslini, Genova, Italy
| | - Corrado Angelini
- Fondazione Hospital S.Camillo Institute for Research and Health Care, Venezia, Italy
| | - Jan De Bleecker
- Department of Neurology, Ghent University Hospital, Ghent, Belgium
| | - Maurizio Moggio
- Neuromuscular and Rare Disease Unit, Dipartimento di Neuroscienze, Università degli Studi di Milano, Fondazione Institute for Research and Health Care Ca' Granda, Ospedale Maggiore Policlinico, Milano, Italy
| | - Tiziana Mongini
- Neuromuscular Unit, Department of Neurosciences, Rita Levi Montalcini, University of Torino, Torino, Italy
| | - Giacomo Pietro Comi
- Centro Dino Ferrari, Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Fondazione Institute for Research and Health Care Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Lucio Santoro
- Dipartimento di Neuroscienze e Scienze Riproduttive ed Odontostomatologiche, Università degli Studi di Napoli "Federico II," Napoli, Italy
| | - Eugenio Mercuri
- Department of Pediatric Neurology, Catholic University and Nemo Roma Center for Neuromuscular Disorders, Rome, Italy
| | - Elena Pegoraro
- Neuromuscular Center, Dipartimento di Neuroscienze, Università di Padova, Padova, Italy
| | - Marina Mora
- Neuromuscular Diseases and Neuroimmunology Unit, Institute for Research and Health Care Foundation Neurological Institute C. Besta, Milan, Italy
| | - Peter Hackman
- Folkhälsan Research Center, Medicum, University of Helsinki, Helsinki, Finland
| | - Bjarne Udd
- Folkhälsan Research Center, Medicum, University of Helsinki, Helsinki, Finland.,Neuromuscular Research Center, University of Tampere and Tampere University Hospital, Tampere, Finland
| | - Vincenzo Nigro
- Dipartimento di Biochimica, Biofisica e Patologia Generale, Università degli Studi della Campania "Luigi Vanvitelli," Napoli, Italy.,Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
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16
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Oates EC, Jones KJ, Donkervoort S, Charlton A, Brammah S, Smith JE, Ware JS, Yau KS, Swanson LC, Whiffin N, Peduto AJ, Bournazos A, Waddell LB, Farrar MA, Sampaio HA, Teoh HL, Lamont PJ, Mowat D, Fitzsimons RB, Corbett AJ, Ryan MM, O'Grady GL, Sandaradura SA, Ghaoui R, Joshi H, Marshall JL, Nolan MA, Kaur S, Punetha J, Töpf A, Harris E, Bakshi M, Genetti CA, Marttila M, Werlauff U, Streichenberger N, Pestronk A, Mazanti I, Pinner JR, Vuillerot C, Grosmann C, Camacho A, Mohassel P, Leach ME, Foley AR, Bharucha-Goebel D, Collins J, Connolly AM, Gilbreath HR, Iannaccone ST, Castro D, Cummings BB, Webster RI, Lazaro L, Vissing J, Coppens S, Deconinck N, Luk HM, Thomas NH, Foulds NC, Illingworth MA, Ellard S, McLean CA, Phadke R, Ravenscroft G, Witting N, Hackman P, Richard I, Cooper ST, Kamsteeg EJ, Hoffman EP, Bushby K, Straub V, Udd B, Ferreiro A, North KN, Clarke NF, Lek M, Beggs AH, Bönnemann CG, MacArthur DG, Granzier H, Davis MR, Laing NG. Congenital Titinopathy: Comprehensive characterization and pathogenic insights. Ann Neurol 2019; 83:1105-1124. [PMID: 29691892 PMCID: PMC6105519 DOI: 10.1002/ana.25241] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 04/17/2018] [Accepted: 04/18/2018] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Comprehensive clinical characterization of congenital titinopathy to facilitate diagnosis and management of this important emerging disorder. METHODS Using massively parallel sequencing we identified 30 patients from 27 families with 2 pathogenic nonsense, frameshift and/or splice site TTN mutations in trans. We then undertook a detailed analysis of the clinical, histopathological and imaging features of these patients. RESULTS All patients had prenatal or early onset hypotonia and/or congenital contractures. None had ophthalmoplegia. Scoliosis and respiratory insufficiency typically developed early and progressed rapidly, whereas limb weakness was often slowly progressive, and usually did not prevent independent walking. Cardiac involvement was present in 46% of patients. Relatives of 2 patients had dilated cardiomyopathy. Creatine kinase levels were normal to moderately elevated. Increased fiber size variation, internalized nuclei and cores were common histopathological abnormalities. Cap-like regions, whorled or ring fibers, and mitochondrial accumulations were also observed. Muscle magnetic resonance imaging showed gluteal, hamstring and calf muscle involvement. Western blot analysis showed a near-normal sized titin protein in all samples. The presence of 2 mutations predicted to impact both N2BA and N2B cardiac isoforms appeared to be associated with greatest risk of cardiac involvement. One-third of patients had 1 mutation predicted to impact exons present in fetal skeletal muscle, but not included within the mature skeletal muscle isoform transcript. This strongly suggests developmental isoforms are involved in the pathogenesis of this congenital/early onset disorder. INTERPRETATION This detailed clinical reference dataset will greatly facilitate diagnostic confirmation and management of patients, and has provided important insights into disease pathogenesis. Ann Neurol 2018;83:1105-1124.
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Affiliation(s)
- Emily C Oates
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health, London, United Kingdom.,Institute for Neuroscience and Muscle Research, Kid's Research Institute, Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia.,School of Biotechnology and Biomolecular Sciences, Faculty of Science, The University of New South Wales, Sydney, New South Wales, Australia
| | - Kristi J Jones
- Institute for Neuroscience and Muscle Research, Kid's Research Institute, Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Sandra Donkervoort
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - Amanda Charlton
- Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia.,Department of Histopathology, Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Susan Brammah
- Electron Microscope Unit, Department of Anatomical Pathology, Concord Repatriation General Hospital, Concord, Sydney, New South Wales, Australia
| | - John E Smith
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ
| | - James S Ware
- National Heart and Lung Institute and MRC London Institute of Medical Science, Imperial College London, London, United Kingdom.,Royal Brompton and Harefield Hospitals NHS Trust, London, United Kingdom
| | - Kyle S Yau
- Institute for Medical Research and Centre for Medical Research, University of Western Australia, Nedlands, Western Australia, Australia
| | - Lindsay C Swanson
- Manton Center for Orphan Disease Research, Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Nicola Whiffin
- National Heart and Lung Institute and MRC London Institute of Medical Science, Imperial College London, London, United Kingdom.,Royal Brompton and Harefield Hospitals NHS Trust, London, United Kingdom
| | - Anthony J Peduto
- Department of Radiology, Westmead Hospital, Sydney, New South Wales, Australia.,University of Sydney Western Clinical School, Sydney, New South Wales, Australia
| | - Adam Bournazos
- Institute for Neuroscience and Muscle Research, Kid's Research Institute, Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Leigh B Waddell
- Institute for Neuroscience and Muscle Research, Kid's Research Institute, Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Michelle A Farrar
- Department of Neurology, Sydney Children's Hospital, Sydney, New South Wales, Australia.,School of Women's and Children's Health, University of New South Wales Sydney, Sydney, New South Wales, Australia
| | - Hugo A Sampaio
- Department of Neurology, Sydney Children's Hospital, Sydney, New South Wales, Australia.,School of Women's and Children's Health, University of New South Wales Sydney, Sydney, New South Wales, Australia
| | - Hooi Ling Teoh
- Department of Neurology, Sydney Children's Hospital, Sydney, New South Wales, Australia.,School of Women's and Children's Health, University of New South Wales Sydney, Sydney, New South Wales, Australia
| | - Phillipa J Lamont
- Neurogenetic Unit, Department of Neurology, Royal Perth Hospital, Perth, Western Australia, Australia
| | - David Mowat
- School of Women's and Children's Health, University of New South Wales Sydney, Sydney, New South Wales, Australia.,Department of Medical Genetics, Sydney Children's Hospital, Sydney, New South Wales, Australia
| | - Robin B Fitzsimons
- Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
| | - Alastair J Corbett
- Department of Neurology, Concord Repatriation General Hospital, Sydney, New South Wales, Australia
| | - Monique M Ryan
- Department of Neurology, Royal Children's Hospital, Parkville, Victoria, Australia.,Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia.,University of Melbourne, Parkville, Victoria, Australia
| | - Gina L O'Grady
- Institute for Neuroscience and Muscle Research, Kid's Research Institute, Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia.,Paediatric Neuroservices, Starship Child Health, Auckland, New Zealand
| | - Sarah A Sandaradura
- Institute for Neuroscience and Muscle Research, Kid's Research Institute, Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Roula Ghaoui
- Institute for Neuroscience and Muscle Research, Kid's Research Institute, Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Himanshu Joshi
- Institute for Neuroscience and Muscle Research, Kid's Research Institute, Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Jamie L Marshall
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA.,Medical and Population Genetics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA
| | - Melinda A Nolan
- Paediatric Neuroservices, Starship Child Health, Auckland, New Zealand
| | - Simranpreet Kaur
- Institute for Neuroscience and Muscle Research, Kid's Research Institute, Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Jaya Punetha
- Research Center for Genetic Medicine, Children's National Medical Center, Washington, DC.,Department of Integrative Systems Biology, George Washington University School of Medicine and Health Sciences, Washington, DC
| | - Ana Töpf
- John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Elizabeth Harris
- John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Madhura Bakshi
- Department of Clinical Genetics, Liverpool Hospital, Sydney, New South Wales, Australia
| | - Casie A Genetti
- Manton Center for Orphan Disease Research, Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Minttu Marttila
- Manton Center for Orphan Disease Research, Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Ulla Werlauff
- Danish National Rehabilitation Center for Neuromuscular Diseases, Aarhus, Denmark
| | - Nathalie Streichenberger
- Neuropathology Department, Hospices Civils Lyon, Claude Bernard University, Lyon1, France.,NeuroMyogene Institute, CNRS UMR 5310, INSERM U1217, Lyon, France
| | - Alan Pestronk
- Department of Neurology, Washington University School of Medicine, Saint Louis, MO.,Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO
| | - Ingrid Mazanti
- Cellular Pathology, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom
| | - Jason R Pinner
- Department of Medical Genomics, Royal Prince Alfred Hospital, Camperdown, Sydney, New South Wales, Australia
| | - Carole Vuillerot
- Woman-Mother-Child Hospital, Hospices Civils Lyon, Bron, France.,Claude Bernard University Lyon1, France
| | - Carla Grosmann
- University of California, San Diego/Rady Children's Hospital, San Diego, CA
| | - Ana Camacho
- Child Neurology Unit, Department of Neurology, October 12 University Hospital, Faculty of Medicine, Complutense University, Madrid, Spain
| | - Payam Mohassel
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - Meganne E Leach
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - A Reghan Foley
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - Diana Bharucha-Goebel
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD.,Division of Neurology, Children's National Health System, Washington, DC
| | | | - Anne M Connolly
- Neuromuscular Division, Departments of Neurology and Pediatrics, Washington University School of Medicine, Saint Louis, MO
| | - Heather R Gilbreath
- Department of Advanced Practice, Children's Medical Center of Dallas, Dallas, TX
| | - Susan T Iannaccone
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX.,Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX
| | - Diana Castro
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX.,Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX
| | - Beryl B Cummings
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA.,Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA.,Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, MA
| | - Richard I Webster
- T. Y. Nelson Department of Neurology and Neurosurgery, Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Leïla Lazaro
- Pediatric Service, Basque Coast Hospital Center, Bayonne, France
| | - John Vissing
- Neuromuscular Clinic and Research Unit, Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Sandra Coppens
- Department of Pediatric Neurology, Neuromuscular Reference Center, Erasmus Hospital, Free University of Brussels, Brussels, Belgium.,Department of Pediatric Neurology, Neuromuscular Reference Center, Queen Fabiola Children's University Hospital, Free University of Brussels, Brussels, Belgium
| | - Nicolas Deconinck
- Department of Pediatric Neurology, Neuromuscular Reference Center, Queen Fabiola Children's University Hospital, Free University of Brussels, Brussels, Belgium
| | - Ho-Ming Luk
- Clinical Genetic Service, Department of Health, Hong Kong, China
| | - Neil H Thomas
- Department of Paediatric Neurology, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom
| | - Nicola C Foulds
- Wessex Clinical Genetics Service, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom
| | - Marjorie A Illingworth
- Department of Paediatric Neurology, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom
| | - Sian Ellard
- University of Exeter Medical School, Exeter, United Kingdom.,Department of Molecular Genetics, Royal Devon and Exeter NHS Foundation Trust, Exeter, United Kingdom
| | - Catriona A McLean
- Department of Anatomical Pathology, Alfred Hospital, Melbourne, Victoria, Australia.,Faculty of Medicine, Nursing, and Health Sciences, Monash University, Melbourne, Victoria, Australia
| | - Rahul Phadke
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health, London, United Kingdom.,National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, London, United Kingdom
| | - Gianina Ravenscroft
- Harry Perkins Institute, University of Western Australia, Nedlands, Western Australia, Australia
| | - Nanna Witting
- Copenhagen Neuromuscular Unit and Department of Neurology, Rigshospitalet, Copenhagen University, Copenhagen, Denmark
| | - Peter Hackman
- Folkhälsan Institute of Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | | | - Sandra T Cooper
- Institute for Neuroscience and Muscle Research, Kid's Research Institute, Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Erik-Jan Kamsteeg
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Eric P Hoffman
- Research Center for Genetic Medicine, Children's National Medical Center, Washington, DC.,Department of Integrative Systems Biology, George Washington University School of Medicine and Health Sciences, Washington, DC
| | - Kate Bushby
- John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Volker Straub
- John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Bjarne Udd
- Folkhälsan Institute of Genetics, Medicum, University of Helsinki, Helsinki, Finland.,Neuromuscular Research Center, Tampere University and University Hospital, Neurology, Tampere, Finland.,Department of Medical Genetics, University of Helsinki, Helsinki, Finland.,Vaasa Central Hospital, Department of Neurology, Vaasa, Finland
| | - Ana Ferreiro
- Pathophysiology of Striated Muscles Laboratory, Unit of Functional and Adaptative Biology, BFA, Paris Diderot University/CNRS, Sorbonne Paris Cité, Paris, France.,Public Hospital Network of Paris, Paris-East Reference Center Neuromuscular Diseases, Pitié-Salpêtrière Hospital Group, Paris, France
| | - Kathryn N North
- Institute for Neuroscience and Muscle Research, Kid's Research Institute, Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Nigel F Clarke
- Institute for Neuroscience and Muscle Research, Kid's Research Institute, Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Monkol Lek
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA.,Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA
| | - Alan H Beggs
- Manton Center for Orphan Disease Research, Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Carsten G Bönnemann
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - Daniel G MacArthur
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA.,Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA
| | - Henk Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ
| | - Mark R Davis
- Department of Diagnostic Genomics, PathWest Laboratory Medicine WA, Nedlands, Western Australia, Australia
| | - Nigel G Laing
- Harry Perkins Institute, University of Western Australia, Nedlands, Western Australia, Australia
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17
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Abstract
There is a great clinical and genetic heterogeneity in congenital myopathies. Myo-MRI with pattern recognition has become a first-line complementary tool in clinical practice for this group of diseases. For diagnostic purposes, whole-body imaging techniques are preferred when involvement is axial or diffuse, as in most congenital myopathies, because of involvement of the tongue, masticator, neck or trunk muscles. Myo-MRI is widely used to identify abnormalities in muscle signal, volume or texture. Recognizable profiles or patterns have been identified in many of these genetic myopathies. The role of the radiologist is crucial in order to adapt the Myo-MRI protocols to the age of the patient and several clinical situations. Myo-MRI in children with congenital myopathies is a very demanding technique with a balance between acceptable time of examination and sufficient spatial resolution in order to detect subtle changes. Technical evolutions combining qualitative and quantitative analysis are useful to follow disease progression overtime. Outcome measures are expected to play a role in natural history description as well as in future therapeutic trials. Genetic diagnosis and interpretation of next generation sequencing results could be greatly influenced by statistical analysis with tools such as algorithms as well as graphical representations using heatmaps.
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18
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Ávila-Polo R, Malfatti E, Lornage X, Cheraud C, Nelson I, Nectoux J, Böhm J, Schneider R, Hedberg-Oldfors C, Eymard B, Monges S, Lubieniecki F, Brochier G, Thao Bui M, Madelaine A, Labasse C, Beuvin M, Lacène E, Boland A, Deleuze JF, Thompson J, Richard I, Taratuto AL, Udd B, Leturcq F, Bonne G, Oldfors A, Laporte J, Romero NB. Loss of Sarcomeric Scaffolding as a Common Baseline Histopathologic Lesion in Titin-Related Myopathies. J Neuropathol Exp Neurol 2018; 77:1101-1114. [DOI: 10.1093/jnen/nly095] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Indexed: 01/22/2023] Open
Affiliation(s)
- Rainiero Ávila-Polo
- Neuromuscular Morphology Unit, Myology Institute, GHU Pitié-Salpêtrière, Paris, France
- FISEVI-UGC Anatomía Patológica-HU Virgen del Rocío, Sevilla, Spain
- University of Granada, Granada, Spain
| | - Edoardo Malfatti
- Neuromuscular Morphology Unit, Myology Institute, GHU Pitié-Salpêtrière, Paris, France
- AP-HP, GHU Pitié-Salpêtrière, Centre de Référence des Maladies Neuromusculaires Nord/Est/Ile de France, Paris, France
| | - Xavière Lornage
- Department of Translational Medicine, IGBMC, INSERM U1258, UMR7104, Strasbourg University, Illkirch, France
| | - Chrystel Cheraud
- Department of Translational Medicine, IGBMC, INSERM U1258, UMR7104, Strasbourg University, Illkirch, France
| | - Isabelle Nelson
- Sorbonne University, INSERM UMRS974, GHU Pitié-Salpêtrière, Paris, France
| | - Juliette Nectoux
- Assistance Publique-Hôpitaux de Paris (AP-HP), GH Cochin-Broca-Hôtel Dieu, Laboratoire de Biochimie et Génétique Moléculaire, Paris, France
| | - Johann Böhm
- Department of Translational Medicine, IGBMC, INSERM U1258, UMR7104, Strasbourg University, Illkirch, France
| | - Raphaël Schneider
- Department of Translational Medicine, IGBMC, INSERM U1258, UMR7104, Strasbourg University, Illkirch, France
- Complex Systems and Translational Bioinformatics, ICube, Strasbourg University, CNRS UMR7357, Illkirch, France
| | - Carola Hedberg-Oldfors
- Department of Pathology and Genetics, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Bruno Eymard
- AP-HP, GHU Pitié-Salpêtrière, Centre de Référence des Maladies Neuromusculaires Nord/Est/Ile de France, Paris, France
| | - Soledad Monges
- Hospital Nacional de Pediatría J.P. Garrahan and Instituto de Investigaciones Neurológicas FLENI, Buenos Aires, Argentina
| | - Fabiana Lubieniecki
- Assistance Publique-Hôpitaux de Paris (AP-HP), GH Cochin-Broca-Hôtel Dieu, Laboratoire de Biochimie et Génétique Moléculaire, Paris, France
- Hospital Nacional de Pediatría J.P. Garrahan and Instituto de Investigaciones Neurológicas FLENI, Buenos Aires, Argentina
| | - Guy Brochier
- Neuromuscular Morphology Unit, Myology Institute, GHU Pitié-Salpêtrière, Paris, France
- Sorbonne University, INSERM UMRS974, GHU Pitié-Salpêtrière, Paris, France
| | - Mai Thao Bui
- Neuromuscular Morphology Unit, Myology Institute, GHU Pitié-Salpêtrière, Paris, France
| | - Angeline Madelaine
- Neuromuscular Morphology Unit, Myology Institute, GHU Pitié-Salpêtrière, Paris, France
| | | | - Maud Beuvin
- Neuromuscular Morphology Unit, Myology Institute, GHU Pitié-Salpêtrière, Paris, France
- Sorbonne University, INSERM UMRS974, GHU Pitié-Salpêtrière, Paris, France
| | - Emmanuelle Lacène
- Neuromuscular Morphology Unit, Myology Institute, GHU Pitié-Salpêtrière, Paris, France
- AP-HP, GHU Pitié-Salpêtrière, Centre de Référence des Maladies Neuromusculaires Nord/Est/Ile de France, Paris, France
| | - Anne Boland
- Centre National de Recherche en Génomique Humaine (CNRGH), Institut de Biologie François Jacob, CEA, Evry, France
| | - Jean-François Deleuze
- Centre National de Recherche en Génomique Humaine (CNRGH), Institut de Biologie François Jacob, CEA, Evry, France
| | - Julie Thompson
- Complex Systems and Translational Bioinformatics, ICube, Strasbourg University, CNRS UMR7357, Illkirch, France
| | | | - Ana Lía Taratuto
- Hospital Nacional de Pediatría J.P. Garrahan and Instituto de Investigaciones Neurológicas FLENI, Buenos Aires, Argentina
| | - Bjarne Udd
- Neuromuscular Research Center, Tampere University and University Hospital, Tampere, Finland
- Folkhalsan Institute of Genetics, Helsinki University, Helsinki, Finland
| | | | | | - Anders Oldfors
- Department of Pathology and Genetics, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Jocelyn Laporte
- Department of Translational Medicine, IGBMC, INSERM U1258, UMR7104, Strasbourg University, Illkirch, France
| | - Norma Beatriz Romero
- Neuromuscular Morphology Unit, Myology Institute, GHU Pitié-Salpêtrière, Paris, France
- Sorbonne University, INSERM UMRS974, GHU Pitié-Salpêtrière, Paris, France
- AP-HP, GHU Pitié-Salpêtrière, Centre de Référence des Maladies Neuromusculaires Nord/Est/Ile de France, Paris, France
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19
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Wang L, Zhang VW, Li S, Li H, Sun Y, Li J, Zhu Y, He R, Lin J, Zhang C. The clinical spectrum and genetic variability of limb-girdle muscular dystrophy in a cohort of Chinese patients. Orphanet J Rare Dis 2018; 13:133. [PMID: 30107846 PMCID: PMC6092860 DOI: 10.1186/s13023-018-0859-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 06/27/2018] [Indexed: 12/19/2022] Open
Abstract
Background Limb-girdle muscular dystrophy (LGMD) is a commonly diagnosed hereditary muscular disorder, characterized by the progressive weakness of the limb-girdle muscles. Although the condition has been well-characterized, clinical and genetic heterogeneity can be observed in patients with LGMD. Here, we aimed to describe the clinical manifestations and genetic variability among a cohort of patients with LGMD in South China. Results We analyzed the clinical information, muscle magnetic resonance imaging (MRI) findings, and genetic results obtained from 30 patients (24 families) with clinically suspected LGMD. In 24 probands, 38 variants were found in total, of which 18 were shown to be novel. Among the 30 patients, the most common subtypes were dysferlinopathy in eight (26.67%), sarcoglycanopathies in eight [26.67%; LGMD 2C in three (10.00%), LGMD 2D in three (10.00%), and LGMD 2F in two (6.67%)], LGMD 2A in seven (23.33%), followed by LGMD 1B in three (10.00%), LGMD 2I in three (10.00%), and early onset recessive Emery-Dreifuss-like phenotype without cardiomyopathy in one (3.33%). Furthermore, we also observed novel clinical presentations for LGMD 1B, 2F, and 2I patients with hypermobility of the joints in the upper limbs, a LGMD 2F patient with delayed language development, and other manifestations. Moreover, distinct distributions of fatty infiltration in patients with LGMD 2A, dysferlinopathy, and the early onset recessive Emery-Dreifuss-like phenotype without cardiomyopathy were also observed based on muscle MRI results. Conclusions In this study, we expanded the clinical spectrum and genetic variability found in patients with LGMD, which provided additional insights into genotype and phenotype correlations in this disease. Electronic supplementary material The online version of this article (10.1186/s13023-018-0859-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Liang Wang
- Department of Neurology, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-sen University, 58 Zhongshan 2 Road, Guangzhou, 510080, GD, China
| | - Victor Wei Zhang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.,AmCare Genomics Lab, Guangzhou, 510300, GD, China
| | - Shaoyuan Li
- AmCare Genomics Lab, Guangzhou, 510300, GD, China
| | - Huan Li
- Department of Neurology, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-sen University, 58 Zhongshan 2 Road, Guangzhou, 510080, GD, China
| | - Yiming Sun
- Department of Health Care, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510080, GD, China
| | - Jing Li
- Department of Neurology, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-sen University, 58 Zhongshan 2 Road, Guangzhou, 510080, GD, China
| | - Yuling Zhu
- Department of Neurology, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-sen University, 58 Zhongshan 2 Road, Guangzhou, 510080, GD, China
| | - Ruojie He
- Department of Neurology, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-sen University, 58 Zhongshan 2 Road, Guangzhou, 510080, GD, China
| | - Jinfu Lin
- Department of Neurology, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-sen University, 58 Zhongshan 2 Road, Guangzhou, 510080, GD, China
| | - Cheng Zhang
- Department of Neurology, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-sen University, 58 Zhongshan 2 Road, Guangzhou, 510080, GD, China.
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20
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Schiaffino S. Knockout of human muscle genes revealed by large scale whole-exome studies. Mol Genet Metab 2018; 123:411-415. [PMID: 29452748 DOI: 10.1016/j.ymgme.2018.02.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Revised: 02/06/2018] [Accepted: 02/06/2018] [Indexed: 12/22/2022]
Abstract
Large scale whole-exome sequence studies have revealed that a number of individuals from different populations have predicted loss-of-function of different genes due to nonsense, frameshift, or canonical splice-site mutations. Surprisingly, many of these mutations do not apparently show the deleterious phenotypic consequences expected from gene knockout. These homozygous null mutations, when confirmed, can provide insight into human gene function and suggest novel approaches to correct gene dysfunction, as the lack of the expected disease phenotype may reflect the existence of modifier genes that reveal potential therapeutic targets. Human knockouts complement the information derived from mouse knockouts, which are not always good models of human disease. We have examined human knockout datasets searching for genes expressed exclusively or predominantly in striated muscle. A number of well-known muscle genes was found in one or more datasets, including genes coding for sarcomeric myosins, components of the sarcomeric cytoskeleton, sarcoplasmic reticulum and plasma membrane, and enzymes involved in muscle metabolism. The surprising absence of phenotype in some of these human knockouts is critically discussed, focusing on the comparison with the corresponding mouse knockouts.
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21
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Savarese M, Jonson PH, Huovinen S, Paulin L, Auvinen P, Udd B, Hackman P. The complexity of titin splicing pattern in human adult skeletal muscles. Skelet Muscle 2018; 8:11. [PMID: 29598826 PMCID: PMC5874998 DOI: 10.1186/s13395-018-0156-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 03/05/2018] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Mutations in the titin gene (TTN) cause a large spectrum of diseases affecting skeletal and/or cardiac muscle. TTN includes 363 coding exons, a repeated region with a high degree of complexity, isoform-specific elements, and metatranscript-only exons thought to be expressed only during fetal development. Although three main classes of isoforms have been described so far, alternative splicing events (ASEs) in different tissues or in different developmental and physiological states have been reported. METHODS To achieve a comprehensive view of titin ASEs in adult human skeletal muscles, we performed a RNA-Sequencing experiment on 42 human biopsies collected from 12 anatomically different skeletal muscles of 11 individuals without any skeletal-muscle disorders. RESULTS We confirmed that the skeletal muscle N2A isoforms are highly prevalent, but we found an elevated number of alternative splicing events, some at a very high level. These include previously unknown exon skipping events and alternative 5' and 3' splice sites. Our data suggests the partial inclusion in the TTN transcript of some metatranscript-only exons and the partial exclusion of canonical N2A exons. CONCLUSIONS This study provides an extensive picture of the complex TTN splicing pattern in human adult skeletal muscle, which is crucial for a proper clinical interpretation of TTN variants.
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Affiliation(s)
- Marco Savarese
- Folkhälsan Research Center, University of Helsinki, Helsinki, Finland. .,Folkhälsan Institute of Genetics, Department of Medical Genetics, University of Helsinki, Biomedicum, Haartmaninkatu 8, Pb 63, 00014, Helsinki, Finland.
| | - Per Harald Jonson
- Folkhälsan Research Center, University of Helsinki, Helsinki, Finland
| | - Sanna Huovinen
- Department of Pathology, Fimlab Laboratories, Tampere University Hospital, Tampere, Finland
| | - Lars Paulin
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Petri Auvinen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Bjarne Udd
- Folkhälsan Research Center, University of Helsinki, Helsinki, Finland.,Department of Pathology, Fimlab Laboratories, Tampere University Hospital, Tampere, Finland.,Vaasa Central Hospital, Vaasa, Finland
| | - Peter Hackman
- Folkhälsan Research Center, University of Helsinki, Helsinki, Finland
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22
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Tasca G, Udd B. Hereditary myopathy with early respiratory failure (HMERF): Still rare, but common enough. Neuromuscul Disord 2018; 28:268-276. [DOI: 10.1016/j.nmd.2017.12.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 11/04/2017] [Accepted: 12/03/2017] [Indexed: 01/04/2023]
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23
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Congenital myopathies: disorders of excitation-contraction coupling and muscle contraction. Nat Rev Neurol 2018; 14:151-167. [PMID: 29391587 DOI: 10.1038/nrneurol.2017.191] [Citation(s) in RCA: 178] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The congenital myopathies are a group of early-onset, non-dystrophic neuromuscular conditions with characteristic muscle biopsy findings, variable severity and a stable or slowly progressive course. Pronounced weakness in axial and proximal muscle groups is a common feature, and involvement of extraocular, cardiorespiratory and/or distal muscles can implicate specific genetic defects. Central core disease (CCD), multi-minicore disease (MmD), centronuclear myopathy (CNM) and nemaline myopathy were among the first congenital myopathies to be reported, and they still represent the main diagnostic categories. However, these entities seem to belong to a much wider phenotypic spectrum. To date, congenital myopathies have been attributed to mutations in over 20 genes, which encode proteins implicated in skeletal muscle Ca2+ homeostasis, excitation-contraction coupling, thin-thick filament assembly and interactions, and other mechanisms. RYR1 mutations are the most frequent genetic cause, and CCD and MmD are the most common subgroups. Next-generation sequencing has vastly improved mutation detection and has enabled the identification of novel genetic backgrounds. At present, management of congenital myopathies is largely supportive, although new therapeutic approaches are reaching the clinical trial stage.
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Ferreiro A, Andoni Urtizberea J. [Titin-related muscle disorders: an expanding spectrum]. Med Sci (Paris) 2017; 33 Hors série n°1:16-26. [PMID: 29139381 DOI: 10.1051/medsci/201733s104] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Titin-related diseases of the skeletal and cardiac muscles open a new, fruitful chapter of myology. Confined for a long time to a limited number of clinical entities, the phenotypic spectrum of titinopthies is nowadays expanding rapidly together with the discovery of many pathogenic mutations of the TTN gene. Like for many genes of large size, the fine tuning and use of high-throughput sequencing (NGS) constitutes a little revolution in the field. This powerful tool allows, although with real technical hurdles, the establishment of the definite diagnosis of titinopathy. A better knowledge of the natural history of each subtype of titinopathy enables as of now an optimized management of patients, notably when a cardiac or respiratory risk factor is identified. Research efforts in the titin-related conditions are gradually getting organized. Interactions between clinicians and geneticists are an absolute necessity. The still fragmentary knowledge of the pathogenesis of each titinopathy prevents to date to figure out any curative therapy in the very near future.
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Affiliation(s)
- Ana Ferreiro
- Pathophysiology of Striated Muscles laboratory, Unit of Functional and Adaptive Biology, BFA, University Paris Diderot/CNRS, Sorbonne Paris Cité, Paris, France - AP-HP, Centre de Référence Maladies Neuromusculaires Paris-Est, Groupe Hospitalier Pitié-Salpêtrière, 75013, Paris, France
| | - J Andoni Urtizberea
- Centre de compétence neuromusculaire Filnemus/Hôpital Marin, Hendaye, France
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25
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Harris E, Topf A, Barresi R, Hudson J, Powell H, Tellez J, Hicks D, Porter A, Bertoli M, Evangelista T, Marini-Betollo C, Magnússon Ó, Lek M, MacArthur D, Bushby K, Lochmüller H, Straub V. Exome sequences versus sequential gene testing in the UK highly specialised Service for Limb Girdle Muscular Dystrophy. Orphanet J Rare Dis 2017; 12:151. [PMID: 28877744 PMCID: PMC5588739 DOI: 10.1186/s13023-017-0699-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 08/22/2017] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Limb girdle muscular dystrophies are a group of rare and genetically heterogeneous diseases that share proximal weakness as a common feature; however they are often lacking very specific phenotypic features to allow an accurate differential diagnosis based on the clinical signs only, limiting the diagnostic rate using phenotype driven genetic testing. Next generation sequencing provides an opportunity to obtain molecular diagnoses for undiagnosed patients, as well as identifying novel genetic causes of muscle diseases. We performed whole exome sequencing (WES) on 104 affected individuals from 75 families in who standard gene by gene testing had not yielded a diagnosis. For comparison we also evaluated the diagnostic rate using sequential gene by gene testing for 91 affected individuals from 84 families over a 2 year period. RESULTS Patients selected for WES had undergone more extensive prior testing than those undergoing standard genetic testing and on average had had 8 genes screened already. In this extensively investigated cohort WES identified the genetic diagnosis in 28 families (28/75, 37%), including the identification of the novel gene ZAK and two unpublished genes. WES of a single affected individual with sporadic disease yielded a diagnosis in 13/38 (34%) of cases. In comparison, conventional gene by gene testing provided a genetic diagnosis in 28/84 (33%) families. Titinopathies and collagen VI related dystrophy were the most frequent diagnoses made by WES. Reasons why mutations in known genes were not identified previously included atypical phenotypes, reassignment of pathogenicity of variants, and in one individual mosaicism for a COL6A1 mutation which was undetected by prior direct sequencing. CONCLUSION WES was able to overcome many limitations of standard testing and achieved a higher rate of diagnosis than standard testing even in this cohort of extensively investigated patients. Earlier application of WES is therefore likely to yield an even higher diagnostic rate. We obtained a high diagnosis rate in simplex cases and therefore such individuals should be included in exome or genome sequencing projects. Disease due to somatic mosaicism may be increasingly recognised due to the increased sensitivity of next generation sequencing techniques to detect low level mosaicism.
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Affiliation(s)
- Elizabeth Harris
- The John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Ana Topf
- The John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Rita Barresi
- Muscle Immunoanalysis Unit, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, NE2 4AZ, UK
| | - Judith Hudson
- Northern Genetics Service, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Helen Powell
- Northern Genetics Service, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - James Tellez
- Northern Genetics Service, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Debbie Hicks
- Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, UK
| | - Anna Porter
- The John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Marta Bertoli
- The John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Teresinha Evangelista
- The John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Chiara Marini-Betollo
- The John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | | | - Monkol Lek
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, USA
| | - Daniel MacArthur
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, USA
| | - Kate Bushby
- The John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Hanns Lochmüller
- The John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Volker Straub
- The John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK. .,Newcastle University John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle upon Tyne, UK.
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