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Karimi E, Gohlke J, van der Borgh M, Lindqvist J, Hourani Z, Kolb J, Cossette S, Lawlor MW, Ottenheijm C, Granzier H. Characterization of NEB pathogenic variants in patients reveals novel nemaline myopathy disease mechanisms and omecamtiv mecarbil force effects. Acta Neuropathol 2024; 147:72. [PMID: 38634969 PMCID: PMC11026289 DOI: 10.1007/s00401-024-02726-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 03/19/2024] [Accepted: 03/26/2024] [Indexed: 04/19/2024]
Abstract
Nebulin, a critical protein of the skeletal muscle thin filament, plays important roles in physiological processes such as regulating thin filament length (TFL), cross-bridge cycling, and myofibril alignment. Pathogenic variants in the nebulin gene (NEB) cause NEB-based nemaline myopathy (NEM2), a genetically heterogeneous disorder characterized by hypotonia and muscle weakness, currently lacking curative therapies. In this study, we examined a cohort of ten NEM2 patients, each with unique pathogenic variants, aiming to understand their impact on mRNA, protein, and functional levels. Results show that pathogenic truncation variants affect NEB mRNA stability and lead to nonsense-mediated decay of the mutated transcript. Moreover, a high incidence of cryptic splice site activation was found in patients with pathogenic splicing variants that are expected to disrupt the actin-binding sites of nebulin. Determination of protein levels revealed patients with either relatively normal or markedly reduced nebulin. We observed a positive relation between the reduction in nebulin and a reduction in TFL, or reduction in tension (both maximal and submaximal tension). Interestingly, our study revealed a pathogenic duplication variant in nebulin that resulted in a four-copy gain in the triplicate region of NEB and a much larger nebulin protein and longer TFL. Additionally, we investigated the effect of Omecamtiv mecarbil (OM), a small-molecule activator of cardiac myosin, on force production of type 1 muscle fibers of NEM2 patients. OM treatment substantially increased submaximal tension across all NEM2 patients ranging from 87 to 318%, with the largest effects in patients with the lowest level of nebulin. In summary, this study indicates that post-transcriptional or post-translational mechanisms regulate nebulin expression. Moreover, we propose that the pathomechanism of NEM2 involves not only shortened but also elongated thin filaments, along with the disruption of actin-binding sites resulting from pathogenic splicing variants. Significantly, our findings highlight the potential of OM treatment to improve skeletal muscle function in NEM2 patients, especially those with large reductions in nebulin levels.
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Affiliation(s)
- Esmat Karimi
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, USA
| | - Jochen Gohlke
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, USA
| | - Mila van der Borgh
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, USA
| | - Johan Lindqvist
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, USA
| | - Zaynab Hourani
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, USA
| | - Justin Kolb
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, USA
| | - Stacy Cossette
- Department of Pathology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Michael W Lawlor
- Department of Pathology, Medical College of Wisconsin, Milwaukee, WI, USA
- Diverge Translational Science Laboratory, Milwaukee, WI, USA
| | - Coen Ottenheijm
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, USA
- Department of Physiology, Amsterdam UMC (Location VUMC), Amsterdam, Netherlands
| | - Henk Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, USA.
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2
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Perrin A, Métay C, Savarese M, Ben Yaou R, Demidov G, Nelson I, Solé G, Péréon Y, Bertini ES, Fattori F, D'Amico A, Ricci F, Ginsberg M, Seferian A, Boespflug-Tanguy O, Servais L, Chapon F, Lagrange E, Gaudon K, Bloch A, Ghanem R, Guyant-Maréchal L, Johari M, Van Goethem C, Fardeau M, Morales RJ, Genetti CA, Marttila M, Koenig M, Beggs AH, Udd B, Bonne G, Cossée M. Titin copy number variations associated with dominant inherited phenotypes. J Med Genet 2024; 61:369-377. [PMID: 37935568 PMCID: PMC10957311 DOI: 10.1136/jmg-2023-109473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 10/18/2023] [Indexed: 11/09/2023]
Abstract
BACKGROUND Titinopathies are caused by mutations in the titin gene (TTN). Titin is the largest known human protein; its gene has the longest coding phase with 364 exons. Titinopathies are very complex neuromuscular pathologies due to the variable age of onset of symptoms, the great diversity of pathological and muscular impairment patterns (cardiac, skeletal muscle or mixed) and both autosomal dominant and recessive modes of transmission. Until now, only few CNVs in TTN have been reported without clear genotype-phenotype associations. METHODS Our study includes eight families with dominant titinopathies. We performed next-generation sequencing or comparative genomic hybridisation array analyses and found CNVs in the TTN gene. We characterised these CNVs by RNA sequencing (RNAseq) analyses in six patients' muscles and performed genotype-phenotype inheritance association study by combining the clinical and biological data of these eight families. RESULTS Seven deletion-type CNVs in the TTN gene were identified among these families. Genotype and RNAseq results showed that five deletions do not alter the reading frame and one is out-of-reading frame. The main phenotype identified was distal myopathy associated with contractures. The analysis of morphological, clinical and genetic data and imaging let us draw new genotype-phenotype associations of titinopathies. CONCLUSION Identifying TTN CNVs will further increase diagnostic sensitivity in these complex neuromuscular pathologies. Our cohort of patients enabled us to identify new deletion-type CNVs in the TTN gene, with unexpected autosomal dominant transmission. This is valuable in establishing new genotype-phenotype associations of titinopathies, mainly distal myopathy in most of the patients.
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Affiliation(s)
- Aurélien Perrin
- Laboratoire de Génétique Moléculaire, Centre Hospitalier Universitaire de Montpellier, Montpellier, France
- PhyMedExp, Université de Montpellier, INSERM, CNRS, Montpellier, France
| | - Corinne Métay
- Unité Fonctionnelle de Cardiogénétique et Myogénétique moléculaire et cellulaire, Centre de Génétique Moléculaire et Chromosomique, Groupe Hospitalier La Pitié-Salpêtrière-Charles Foix, Paris, France
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, Paris, France
| | - Marco Savarese
- Tampere Neuromuscular Center, Folkhälsan Research Center, Helsinki, Finland
| | - Rabah Ben Yaou
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, Paris, France
| | - German Demidov
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tubingen, Germany
| | - Isabelle Nelson
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, Paris, France
| | - Guilhem Solé
- CHU de Bordeaux, AOC National Reference Center for Neuromuscular Disorders, Bordeaux, France
| | - Yann Péréon
- Department of Clinical Neurophysiology, Reference Centre for Neuromuscular Diseases AOC, Filnemus, Euro-NMD, CHU Nantes, Nantes Université, Place Alexis-Ricordeau, Nantes, France
| | - Enrico Silvio Bertini
- Unit of Muscular and Neurodegenerative Disorders, Bambino Gesù Children Research Hospital, IRCCS, Rome, Italy
| | - Fabiana Fattori
- Unit of Muscular and Neurodegenerative Disorders, Bambino Gesù Children Research Hospital, IRCCS, Rome, Italy
| | - Adele D'Amico
- Unit of Muscular and Neurodegenerative Disorders, Bambino Gesù Children Research Hospital, IRCCS, Rome, Italy
| | - Federica Ricci
- Division of Child and Adolescent Neuropsychiatry, University of Turin, Turin, Italy
| | - Mira Ginsberg
- Department of Pediatric Neurology, Wolfson Medical Center, Holon, Israel
| | | | - Odile Boespflug-Tanguy
- Institut I-MOTION, Hôpital Armand Trousseau, Paris, France
- UMR 1141, INSERM, NeuroDiderot Université Paris Cité and APHP, Neuropédiatrie, French Reference Center for Leukodystrophies, LEUKOFRANCE, Hôpital Robert Debré, Paris, France
| | - Laurent Servais
- Institut I-MOTION, Hôpital Armand Trousseau, Paris, France
- MDUK Oxford Neuromuscular Centre & NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, UK
- Neuromuscular Reference Center, Division of Paediatrics, University and Hospital University of Liège, Liège, Belgium
| | - Françoise Chapon
- Département de pathologie, Centre de Compétence des Maladies Neuromusculaires, Centre Hospitalier Universitaire de Caen, Caen, France
| | - Emmeline Lagrange
- Centre de Compétences des Maladies Neuro Musculaires, Centre Hospitalier Universitaire Grenoble Alpes, Grenoble, France
| | - Karen Gaudon
- Unité Fonctionnelle de Cardiogénétique et Myogénétique moléculaire et cellulaire, Centre de Génétique Moléculaire et Chromosomique, Groupe Hospitalier La Pitié-Salpêtrière-Charles Foix, Paris, France
| | - Adrien Bloch
- Unité Fonctionnelle de Cardiogénétique et Myogénétique moléculaire et cellulaire, Centre de Génétique Moléculaire et Chromosomique, Groupe Hospitalier La Pitié-Salpêtrière-Charles Foix, Paris, France
| | - Robin Ghanem
- Unité Fonctionnelle de Cardiogénétique et Myogénétique moléculaire et cellulaire, Centre de Génétique Moléculaire et Chromosomique, Groupe Hospitalier La Pitié-Salpêtrière-Charles Foix, Paris, France
| | | | - Mridul Johari
- Tampere Neuromuscular Center, Folkhälsan Research Center, Helsinki, Finland
- Harry Perkins Institute of Medical Research, Centre for Medical Research, University of Western Australia, Nedlands, Western Australia, Australia
| | - Charles Van Goethem
- Laboratoire de Génétique Moléculaire, Centre Hospitalier Universitaire de Montpellier, Montpellier, France
- Montpellier BioInformatique pour le Diagnostic Clinique (MOBIDIC), Plateau de Médecine Moléculaire et Génomique (PMMG), CHU Montpellier, Montpellier, France
| | - Michel Fardeau
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, Paris, France
| | - Raul Juntas Morales
- Department of Neurology, Hospital Universitario Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Casie A Genetti
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Minttu Marttila
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
- HiLIFE Helsinki Institute of Life Science, Tukholmankatu 8, FI-00014, University of Helsinki, Helsinki, Finland
| | - Michel Koenig
- Laboratoire de Génétique Moléculaire, Centre Hospitalier Universitaire de Montpellier, Montpellier, France
- PhyMedExp, Université de Montpellier, INSERM, CNRS, Montpellier, France
| | - Alan H Beggs
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Bjarne Udd
- Tampere Neuromuscular Center, Folkhälsan Research Center, Helsinki, Finland
| | - Gisèle Bonne
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, Paris, France
| | - Mireille Cossée
- Laboratoire de Génétique Moléculaire, Centre Hospitalier Universitaire de Montpellier, Montpellier, France
- PhyMedExp, Université de Montpellier, INSERM, CNRS, Montpellier, France
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Haidong L, Yin L, Ping C, Xianzhao Z, Qi Q, Xiaoli M, Zheng L, Wenhao C, Yaguang Z, Qianqian Q. Clinico-pathological and gene features of 15 nemaline myopathy patients from a single Chinese neuromuscular center. Acta Neurol Belg 2024; 124:91-99. [PMID: 37525074 PMCID: PMC10874337 DOI: 10.1007/s13760-023-02333-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 07/12/2023] [Indexed: 08/02/2023]
Abstract
BACKGROUND Nemaline myopathy, the most common of the congenital myopathies, is caused by various genetic mutations. In this study, we attempted to investigate the clinical features, muscle pathology and genetic features of 15 patients with nemaline myopathy. RESULTS Among the 15 patients, there were 9 (60.00%) males and 6 (40.00%) females, and 9 (60.00%) of them came from three families respectively. The age of seeing a doctor ranged from 9 to 52 years old, the age of onset was from 5 to 23 years old, and the duration of disease ranged from 3 to 35 years. Ten out of the 15 patients had high arched palate and elongated face. Only one patient had mild respiratory muscle involvement and none had dysphagia. Muscle biopsies were performed in 9 out of the 15 patients. Pathologically, muscle fibers of different sizes, atrophic muscle fibers and compensatory hypertrophic fibers could be found, and occasionally degenerated and necrotic muscle fibers were observed. Different degrees of nemaline bodies aggregation could be seen in all 9 patients. The distribution of type I and type II muscle fibers were significantly abnormal in patients with nemaline myopathy caused by NEB gene, however, it was basically normal in patients with nemaline myopathy caused by TPM3 gene and ACTA1 gene. Electron microscopic analysis of 6 patients showed that nemaline bodies aggregated between myofibrils were found in 5(83.33%) cases, and most of them were located near the Z band, but no intranuclear rods were found. The gene analysis of 15 NM patients showed that three NM-related genes were harbored, including 11 (73.33%) patients with NEB, 3 (20.00%) patients with TPM3, and 1 (6.67%) patient with ACTA1, respectively. A total of 12 mutation sites were identified and included 10 (83.33%) mutations in exon and 2(16.67%) mutations in intron. CONCLUSIONS The clinical phenotype of nemaline myopathy is highly heterogeneous. Muscle pathology shows that nemaline bodies aggregation is an important feature for the diagnosis of NM. NEB is the most frequent causative gene in this cohort. The splicing mutation, c.21522 + 3A > G may be the hotspot mutation of the NEB gene in Chinese NM patients.
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Affiliation(s)
- Lv Haidong
- Department of Neurology, Jiaozuo People's Hospital of Henan Province, Henan, 454002, Henan Province, People's Republic of China
| | - Liu Yin
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei Province, People's Republic of China
| | - Chen Ping
- Department of Neurology, Jiaozuo People's Hospital of Henan Province, Henan, 454002, Henan Province, People's Republic of China
| | - Zheng Xianzhao
- Department of Neurology, Jiaozuo People's Hospital of Henan Province, Henan, 454002, Henan Province, People's Republic of China
| | - Qian Qi
- Department of Neurology, Jiaozuo People's Hospital of Henan Province, Henan, 454002, Henan Province, People's Republic of China
| | - Ma Xiaoli
- Department of Neurology, Jiaozuo People's Hospital of Henan Province, Henan, 454002, Henan Province, People's Republic of China
| | - Lv Zheng
- Department of Neurology, Jiaozuo People's Hospital of Henan Province, Henan, 454002, Henan Province, People's Republic of China
| | - Cui Wenhao
- Department of Neurology, Jiaozuo People's Hospital of Henan Province, Henan, 454002, Henan Province, People's Republic of China
| | - Zhou Yaguang
- Department of Neurology, Jiaozuo People's Hospital of Henan Province, Henan, 454002, Henan Province, People's Republic of China
| | - Qu Qianqian
- Department of Neurology, Jiaozuo People's Hospital of Henan Province, Henan, 454002, Henan Province, People's Republic of China.
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4
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Karimi E, van der Borgh M, Lindqvist J, Gohlke J, Hourani Z, Kolb J, Cossette S, Lawlor MW, Ottenheijm C, Granzier H. Characterization of NEB mutations in patients reveals novel nemaline myopathy disease mechanisms and omecamtiv mecarbil force effects. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.20.572678. [PMID: 38187705 PMCID: PMC10769406 DOI: 10.1101/2023.12.20.572678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Nebulin, a critical protein of the skeletal muscle thin filament, plays important roles in physiological processes such as regulating thin filament length (TFL), cross-bridge cycling, and myofibril alignment. Mutations in the nebulin gene ( NEB ) cause NEB-based nemaline myopathy (NEM2), a genetically heterogeneous disorder characterized by hypotonia and muscle weakness, currently lacking therapies targeting the underlying pathological mechanisms. In this study, we examined a cohort of ten NEM2 patients, each with unique mutations, aiming to understand their impact on mRNA, protein, and functional levels. Results show that truncation mutations affect NEB mRNA stability and lead to nonsense-mediated decay of the mutated transcript. Moreover, a high incidence of cryptic splice site activation was found in patients with splicing mutations which is expected to disrupt the actin-binding sites of nebulin. Determination of protein levels revealed patients with relatively normal nebulin levels and others with markedly reduced nebulin. We observed a positive relation between the reduction in nebulin and a reduction in TFL, and a positive relation between the reduction in nebulin level and the reduction in tension (both maximal and submaximal tension). Interestingly, our study revealed a duplication mutation in nebulin that resulted in a larger nebulin protein and longer TFL. Additionally, we investigated the effect of Omecamtiv mecarbil (OM), a small-molecule activator of cardiac myosin, on force production of type I muscle fibers of NEM2 patients. OM treatment substantially increased submaximal tension across all NEM2 patients ranging from 87-318%, with the largest effects in patients with the lowest level of nebulin. In summary, this study indicates that post-transcriptional or post-translational mechanisms regulate nebulin expression. Moreover, we propose that the pathomechanism of NEM2 involves not only shortened but also elongated thin filaments, along with the disruption of actin-binding sites resulting from splicing mutations. Significantly, our findings highlight the potential of OM treatment to improve skeletal muscle function in NEM2 patients, especially those with large reductions in nebulin levels.
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5
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Lehtokari VL, Similä M, Tammepuu M, Wallgren-Pettersson C, Strang-Karlsson S, Hiekkala S. Self-reported functioning among patients with ultra-rare nemaline myopathy or a related disorder in Finland: a pilot study. Orphanet J Rare Dis 2023; 18:374. [PMID: 38037113 PMCID: PMC10691147 DOI: 10.1186/s13023-023-02973-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 11/18/2023] [Indexed: 12/02/2023] Open
Abstract
BACKGROUND Nemaline myopathy (NM) and related disorders (NMr) form a heterogenous group of ultra-rare (1:50,000 live births or less) congenital muscle disorders. To elucidate the self-reported physical, psychological, and social functioning in the daily lives of adult persons with congenital muscle disorders, we designed a survey using items primarily from the Patient Reported Outcomes Measurement Information System, PROMIS®, and conducted a pilot study in patients with NM and NMr in Finland. The items were linked to International Classification of Functioning, Disability and Health (ICF) categories. RESULTS In total, 20 (62.5%) out of 32 invited persons resident in Finland participated in the study; 12 had NM and 8 NMr, 15 were women and 5 men aged 19-75 years. Sixteen (80%) were ambulatory and 4 (20%) NM patients used wheelchairs. The results from the PROMIS measuring system and ICF categories both indicated that non-ambulatory patients of this study faced more challenges in all areas of functioning than ambulatory ones, but the differences were smaller in the domains measuring psychological and social functioning than in physical functioning. In addition, the COVID-19 pandemic adversely affected the functioning of non-ambulatory patients more than that of ambulatory patients. The interindividual differences were, however, noticeable. CONCLUSIONS To our knowledge, this pilot study is the first comprehensive survey-based study of the physical, psychological, and social functioning of adult persons with nemaline myopathy or related disorders. The results indicate vulnerability of non-ambulatory patients being at higher risk to a decrease in general functioning during global or national exceptional periods. The responses also gave directions for modifying and improving the survey for future studies.
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Affiliation(s)
- Vilma-Lotta Lehtokari
- Folkhälsan Research Center, Helsinki, Finland.
- Medicum, University of Helsinki, Helsinki, Finland.
| | - Minna Similä
- Clinical Nutrition Unit, Internal Medicine and Rehabilitation, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Marianne Tammepuu
- Department of Paediatric Neurology, New Children's Hospital, Helsinki University Hospital, Helsinki, Finland
| | | | - Sonja Strang-Karlsson
- Department of Clinical Genetics, HUS Diagnostic Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Sinikka Hiekkala
- The Finnish Association of People with Physical Disabilities, Helsinki, Finland
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6
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Haghighi A, Alvandi Z, Nilipour Y, Haghighi A, Kornreich R, Nafissi S, Desnick RJ. Nemaline myopathy: reclassification of previously reported variants according to ACMG guidelines, and report of novel genetic variants. Eur J Hum Genet 2023; 31:1237-1250. [PMID: 37460656 PMCID: PMC10620380 DOI: 10.1038/s41431-023-01378-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 12/11/2022] [Accepted: 04/26/2023] [Indexed: 11/03/2023] Open
Abstract
Nemaline myopathy (NM) is a heterogeneous genetic neuromuscular disorder characterized by rod bodies in muscle fibers resulting in multiple complications due to muscle weakness. NM patients and their families could benefit from genetic analysis for early diagnosis, carrier and prenatal testing; however, clinical classification of variants is subject to change as further information becomes available. Reclassification can significantly alter the clinical management of patients and their families. We used the newly published data and ACMG/AMP guidelines to reassess NM-associated variants previously reported by clinical laboratories (ClinVar). Our analyses on rare variants that were not canonical loss-of-function (LOF) resulted in the downgrading of ~29% (28/97) of variants from pathogenic or likely-pathogenic (P/LP) to variants of uncertain significance (VUS). In addition, we analyzed the splicing effect of variants identified in NM patients by clinical laboratories or research, using an accurate in silico prediction tool that applies a deep-learning network. We identified 55 rare variants that may impact splicing (cryptic splicing). We also analyzed six new NM families and identified eight variants in NEB and ACTA1, including three novel variants: homozygous pathogenic c.164A > G (p.Tyr55Cys), and homozygous likely pathogenic c.980T > C (p.Met327Thr) in ACTA1, and heterozygous VUS c.18694-3T > G in NEB. This study demonstrates the importance of reclassifying variants to facilitate more definitive "calls" on causality or no causality in clinical genetic testing of patients with NM. Reclassification of ~150 variants is now available for improved clinical management, risk counseling and screening of NM patients.
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Affiliation(s)
- Alireza Haghighi
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
- Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA.
- Howard Hughes Medical Institute, Brigham and Women's Hospital, Boston, MA, 02115, USA.
- The Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.
| | - Zahra Alvandi
- Department of Surgery, Harvard Medical School, Boston, MA, 02115, USA
- Vascular Biology Program, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Yalda Nilipour
- Pediatric Pathology Research Center, Research Institute for Children's Health, and Mofid Children Hospital, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Amirreza Haghighi
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Ruth Kornreich
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Shahriar Nafissi
- Department of Neurology, Neuromuscular Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Robert J Desnick
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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7
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Chen Q, Chen Y, Shi L, Tao Y, Li X, Zhu X, Yang Y, Xu W. Uniparental disomy: expanding the clinical and molecular phenotypes of whole chromosomes. Front Genet 2023; 14:1232059. [PMID: 37860673 PMCID: PMC10582337 DOI: 10.3389/fgene.2023.1232059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 09/22/2023] [Indexed: 10/21/2023] Open
Abstract
Uniparental disomy (UPD) refers to as both homologous chromosomes inherited from only one parent without identical copies from the other parent. Studies on clinical phenotypes in UPDs are usually focused on the documented UPD 6, 7, 11, 14, 15, and 20, which directly lead to imprinting disorders. This study describes clinical phenotypes and genetic findings of three patients with UPD 2, 9, and 14, respectively. Chromosomal microarray (CMA), UPDtool, methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) and whole-exome sequencing (WES) analysis were performed to characterize the genetic etiology. The CMA revealed a homozygous region involving the whole chromosome 2 and 9, a partial region of homozygosity in chromosome 14. UPD-tool revealed a paternal origin of the UPD2. MS-MLPA showed hypomethylation of imprinting gene MEG3 from maternal origin in the UPD14 case. In addition, UPD14 case displayed complex symptoms including growth failure, hypotonia and acute respiratory distress syndrome (ARDS), accompanied by several gene mutations with heterozygous genotype by WES analysis. Furthermore, we reviewed the documented UPDs and summarized the clinical characteristics and prognosis. This study highlighted the importance to confirm the diagnosis and origin of UPD using genetic testing. Therefore, it is suggested that expanding of the detailed phenotypes and genotypes provide effective guidance for molecule testing and genetic counseling, and promote further biological investigation to the underlying mechanisms of imprinted disorders and accompanied copy number variations.
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Affiliation(s)
- Qi Chen
- Genetic and Prenatal Diagnosis Center, Fourth Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Yunpeng Chen
- Genetic and Prenatal Diagnosis Center, Fourth Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Lin Shi
- Department of Ultrasound, Fourth Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Ying Tao
- Genetic and Prenatal Diagnosis Center, Fourth Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Xiaoguang Li
- Genetic and Prenatal Diagnosis Center, Fourth Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Xiaolan Zhu
- Reproductive Medicine Center, Fourth Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Yan Yang
- Genetic and Prenatal Diagnosis Center, Fourth Affiliated Hospital of Jiangsu University, Zhenjiang, China
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8
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A review of major causative genes in congenital myopathies. J Hum Genet 2023; 68:215-225. [PMID: 35668205 DOI: 10.1038/s10038-022-01045-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 04/25/2022] [Accepted: 05/11/2022] [Indexed: 02/07/2023]
Abstract
In this review, we focus on congenital myopathies, which are a genetically heterogeneous group of hereditary muscle diseases with slow or minimal progression. They are mainly defined and classified according to pathological features, with the major subtypes being core myopathy (central core disease), nemaline myopathy, myotubular/centronuclear myopathy, and congenital fiber-type disproportion myopathy. Recent advances in molecular genetics, especially next-generation sequencing technology, have rapidly increased the number of known causative genes for congenital myopathies; however, most of the diseases related to the novel causative genes are extremely rare. There remains no cure for congenital myopathies. However, there have been recent promising findings that could inform the development of therapy for several types of congenital myopathies, including myotubular myopathy, which indicates the importance of prompt and correct diagnosis. This review discusses the major causative genes (NEB, ACTA1, ADSSL1, RYR1, SELENON, MTM1, DNM2, and TPM3) for each subtype of congenital myopathies and the relevant latest findings.
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Moreno CAM, Artilheiro MC, Fonseca ATQSM, Camelo CG, de Medeiros GC, Sassi FC, de Andrade CRF, Donkervoort S, Silva AMS, Dalfior-Junior L, Abath-Neto OL, Reed UC, Bönnemann C, Zanoteli E. Clinical Manifestation of Nebulin-Associated Nemaline Myopathy. Neurol Genet 2023; 9:e200056. [PMID: 36714460 PMCID: PMC9879277 DOI: 10.1212/nxg.0000000000200056] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 11/28/2022] [Indexed: 01/26/2023]
Abstract
Background and Objectives Nemaline myopathy (NM) is a genetically heterogeneous inherited myopathy related with at least 12 genes, whereas pathogenic variants in NEB gene are the most common genetic cause. The clinical spectrum of NM caused by NEB pathogenic variants (NM-NEB) is very broad, ranging from mild to severe presentations manifesting with generalized weakness, as well as respiratory and bulbar involvement. There is currently not enough data regarding the progression of the disease. In this study, we present a genotypic and phenotypic spectrum of 33 patients with NM caused by NEB variants (NM-NEB) classified according to age groups and the use of ventilatory support. We focused on interventional support, genotype-phenotype correlation, and association between respiratory, bulbar, and motor systems in groups of patients stratified by age and by the use of ventilatory support (VS). Methods Clinical and genetic data from patients with NM-NEB followed up in one specialized center were collected through regular consultations. Patients were evaluated regarding motor, bulbar, and respiratory functions. Results Thirty-three patients with NM-NEB were evaluated consisting of 15 females and 18 males with an average age of 18 (±12) years and a median of 17 (±11) years. 32% of patients with NM-NEB used a G tube, 35% were not able to walk without support, and 55% needed VS. Scoliosis and dysphagia were more common among patients who used VS. Described for the first time, half of the patients presented tongue atrophy in a triple furrow pattern, and the presence of the atrophy was associated with dysphagia. Comparing the patients grouped by age, we found that, proportionally, older patients had more scoliosis and respiratory dysfunction than younger groups, suggesting the progression of the disease in these domains. In addition to that, we showed that VS use was associated with scoliosis and dysphagia. Discussion NM-NEB is a very debilitating disease. There is an association between scoliosis and respiratory dysfunction while patients using VS have more often scoliosis than the no-VS group. Triple furrow tongue atrophy is a novel and frequent finding, which is directly associated with dysphagia. Grouping patients by age suggested disease stability in motor and swallow function, but a progression in respiratory dysfunction and skeletal deformities. All observations are relevant in the management care of patients with NM.
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Affiliation(s)
- Cristiane Araujo Martins Moreno
- Department of Neurology (C.A.M.M., M.C.A., A.T.Q.S.M.F., C.G.C., A.M.S.S., U.C.R., E.Z.), School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Department of Physical Therapy (G.C.M., F.C.S., C.R.F.A.), Speech Language and Hearing Science Adn Occupational Therapy, School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Neuromuscular and Neurogenetic Disorders of Childhood Section (S.D., C.B.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; Department of Neurology, Hospital Santa Marcelina (L.D.J.), São Paulo, Brazil; and Department of Pathology (O.L.A.-N.), Division of Neuropathology, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Mariana Cunha Artilheiro
- Department of Neurology (C.A.M.M., M.C.A., A.T.Q.S.M.F., C.G.C., A.M.S.S., U.C.R., E.Z.), School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Department of Physical Therapy (G.C.M., F.C.S., C.R.F.A.), Speech Language and Hearing Science Adn Occupational Therapy, School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Neuromuscular and Neurogenetic Disorders of Childhood Section (S.D., C.B.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; Department of Neurology, Hospital Santa Marcelina (L.D.J.), São Paulo, Brazil; and Department of Pathology (O.L.A.-N.), Division of Neuropathology, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Alulin Tacio Quadros Santos Monteiro Fonseca
- Department of Neurology (C.A.M.M., M.C.A., A.T.Q.S.M.F., C.G.C., A.M.S.S., U.C.R., E.Z.), School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Department of Physical Therapy (G.C.M., F.C.S., C.R.F.A.), Speech Language and Hearing Science Adn Occupational Therapy, School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Neuromuscular and Neurogenetic Disorders of Childhood Section (S.D., C.B.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; Department of Neurology, Hospital Santa Marcelina (L.D.J.), São Paulo, Brazil; and Department of Pathology (O.L.A.-N.), Division of Neuropathology, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Clara Gontijo Camelo
- Department of Neurology (C.A.M.M., M.C.A., A.T.Q.S.M.F., C.G.C., A.M.S.S., U.C.R., E.Z.), School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Department of Physical Therapy (G.C.M., F.C.S., C.R.F.A.), Speech Language and Hearing Science Adn Occupational Therapy, School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Neuromuscular and Neurogenetic Disorders of Childhood Section (S.D., C.B.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; Department of Neurology, Hospital Santa Marcelina (L.D.J.), São Paulo, Brazil; and Department of Pathology (O.L.A.-N.), Division of Neuropathology, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Gisele Chagas de Medeiros
- Department of Neurology (C.A.M.M., M.C.A., A.T.Q.S.M.F., C.G.C., A.M.S.S., U.C.R., E.Z.), School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Department of Physical Therapy (G.C.M., F.C.S., C.R.F.A.), Speech Language and Hearing Science Adn Occupational Therapy, School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Neuromuscular and Neurogenetic Disorders of Childhood Section (S.D., C.B.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; Department of Neurology, Hospital Santa Marcelina (L.D.J.), São Paulo, Brazil; and Department of Pathology (O.L.A.-N.), Division of Neuropathology, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Fernanda Chiarion Sassi
- Department of Neurology (C.A.M.M., M.C.A., A.T.Q.S.M.F., C.G.C., A.M.S.S., U.C.R., E.Z.), School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Department of Physical Therapy (G.C.M., F.C.S., C.R.F.A.), Speech Language and Hearing Science Adn Occupational Therapy, School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Neuromuscular and Neurogenetic Disorders of Childhood Section (S.D., C.B.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; Department of Neurology, Hospital Santa Marcelina (L.D.J.), São Paulo, Brazil; and Department of Pathology (O.L.A.-N.), Division of Neuropathology, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Claudia Regina Furquim de Andrade
- Department of Neurology (C.A.M.M., M.C.A., A.T.Q.S.M.F., C.G.C., A.M.S.S., U.C.R., E.Z.), School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Department of Physical Therapy (G.C.M., F.C.S., C.R.F.A.), Speech Language and Hearing Science Adn Occupational Therapy, School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Neuromuscular and Neurogenetic Disorders of Childhood Section (S.D., C.B.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; Department of Neurology, Hospital Santa Marcelina (L.D.J.), São Paulo, Brazil; and Department of Pathology (O.L.A.-N.), Division of Neuropathology, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Sandra Donkervoort
- Department of Neurology (C.A.M.M., M.C.A., A.T.Q.S.M.F., C.G.C., A.M.S.S., U.C.R., E.Z.), School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Department of Physical Therapy (G.C.M., F.C.S., C.R.F.A.), Speech Language and Hearing Science Adn Occupational Therapy, School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Neuromuscular and Neurogenetic Disorders of Childhood Section (S.D., C.B.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; Department of Neurology, Hospital Santa Marcelina (L.D.J.), São Paulo, Brazil; and Department of Pathology (O.L.A.-N.), Division of Neuropathology, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Andre Macedo Serafim Silva
- Department of Neurology (C.A.M.M., M.C.A., A.T.Q.S.M.F., C.G.C., A.M.S.S., U.C.R., E.Z.), School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Department of Physical Therapy (G.C.M., F.C.S., C.R.F.A.), Speech Language and Hearing Science Adn Occupational Therapy, School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Neuromuscular and Neurogenetic Disorders of Childhood Section (S.D., C.B.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; Department of Neurology, Hospital Santa Marcelina (L.D.J.), São Paulo, Brazil; and Department of Pathology (O.L.A.-N.), Division of Neuropathology, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Luiz Dalfior-Junior
- Department of Neurology (C.A.M.M., M.C.A., A.T.Q.S.M.F., C.G.C., A.M.S.S., U.C.R., E.Z.), School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Department of Physical Therapy (G.C.M., F.C.S., C.R.F.A.), Speech Language and Hearing Science Adn Occupational Therapy, School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Neuromuscular and Neurogenetic Disorders of Childhood Section (S.D., C.B.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; Department of Neurology, Hospital Santa Marcelina (L.D.J.), São Paulo, Brazil; and Department of Pathology (O.L.A.-N.), Division of Neuropathology, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Osorio Lopes Abath-Neto
- Department of Neurology (C.A.M.M., M.C.A., A.T.Q.S.M.F., C.G.C., A.M.S.S., U.C.R., E.Z.), School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Department of Physical Therapy (G.C.M., F.C.S., C.R.F.A.), Speech Language and Hearing Science Adn Occupational Therapy, School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Neuromuscular and Neurogenetic Disorders of Childhood Section (S.D., C.B.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; Department of Neurology, Hospital Santa Marcelina (L.D.J.), São Paulo, Brazil; and Department of Pathology (O.L.A.-N.), Division of Neuropathology, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Umbertina Conti Reed
- Department of Neurology (C.A.M.M., M.C.A., A.T.Q.S.M.F., C.G.C., A.M.S.S., U.C.R., E.Z.), School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Department of Physical Therapy (G.C.M., F.C.S., C.R.F.A.), Speech Language and Hearing Science Adn Occupational Therapy, School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Neuromuscular and Neurogenetic Disorders of Childhood Section (S.D., C.B.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; Department of Neurology, Hospital Santa Marcelina (L.D.J.), São Paulo, Brazil; and Department of Pathology (O.L.A.-N.), Division of Neuropathology, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Carsten Bönnemann
- Department of Neurology (C.A.M.M., M.C.A., A.T.Q.S.M.F., C.G.C., A.M.S.S., U.C.R., E.Z.), School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Department of Physical Therapy (G.C.M., F.C.S., C.R.F.A.), Speech Language and Hearing Science Adn Occupational Therapy, School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Neuromuscular and Neurogenetic Disorders of Childhood Section (S.D., C.B.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; Department of Neurology, Hospital Santa Marcelina (L.D.J.), São Paulo, Brazil; and Department of Pathology (O.L.A.-N.), Division of Neuropathology, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Edmar Zanoteli
- Department of Neurology (C.A.M.M., M.C.A., A.T.Q.S.M.F., C.G.C., A.M.S.S., U.C.R., E.Z.), School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Department of Physical Therapy (G.C.M., F.C.S., C.R.F.A.), Speech Language and Hearing Science Adn Occupational Therapy, School of Medicine, Universidade de São Paulo (FMUSP), Brazil; Neuromuscular and Neurogenetic Disorders of Childhood Section (S.D., C.B.), National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD; Department of Neurology, Hospital Santa Marcelina (L.D.J.), São Paulo, Brazil; and Department of Pathology (O.L.A.-N.), Division of Neuropathology, University of Pittsburgh Medical Center, Pittsburgh, PA
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Fisher G, Mackels L, Markati T, Sarkozy A, Ochala J, Jungbluth H, Ramdas S, Servais L. Early clinical and pre-clinical therapy development in Nemaline myopathy. Expert Opin Ther Targets 2022; 26:853-867. [PMID: 36524401 DOI: 10.1080/14728222.2022.2157258] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
INTRODUCTION Nemaline myopathies (NM) represent a group of clinically and genetically heterogeneous congenital muscle disorders with the common denominator of nemaline rods on muscle biopsy. NEB and ACTA1 are the most common causative genes. Currently, available treatments are supportive. AREAS COVERED We explored experimental treatments for NM, identifying at least eleven mainly pre-clinical approaches utilizing murine and/or human muscle cells. These approaches target either i) the causative gene or associated genes implicated in the same pathway; ii) pathophysiologically relevant biochemical mechanisms such as calcium/myosin regulation of muscle contraction; iii) myogenesis; iv) other therapies that improve or optimize muscle function more generally; v) and/or combinations of the above. The scope and efficiency of these attempts is diverse, ranging from gene-specific effects to those widely applicable to all NM-associated genes. EXPERT OPINION The wide range of experimental therapies currently under consideration for NM is promising. Potential translation into clinical use requires consideration of additional factors such as the potential muscle type specificity as well as the possibility of gene expression remodeling. Challenges in clinical translation include the rarity and heterogeneity of genotypes, phenotypes, and disease trajectories, as well as the lack of longitudinal natural history data and validated outcomes and biomarkers.
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Affiliation(s)
- Gemma Fisher
- MDUK Neuromuscular Centre, Department of Paediatrics, University of Oxford, Oxford, UK
| | - Laurane Mackels
- MDUK Neuromuscular Centre, Department of Paediatrics, University of Oxford, Oxford, UK.,Neuromuscular Reference Center, University and University Hospital of Liège, Liège, Belgium
| | - Theodora Markati
- MDUK Neuromuscular Centre, Department of Paediatrics, University of Oxford, Oxford, UK
| | - Anna Sarkozy
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Hospital, Institute of Child Health, London, UK
| | - Julien Ochala
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Heinz Jungbluth
- Department of Paediatric Neurology - Neuromuscular Service, Evelina Children's Hospital, Guy's & St Thomas' NHS Foundation Trust, London, UK.,Randall Centre for Cell and Molecular Biophysics, Muscle Signalling Section, Faculty of Life Sciences and Medicine (FoLSM), King's College London, London, UK
| | - Sithara Ramdas
- MDUK Neuromuscular Centre, Department of Paediatrics, University of Oxford, Oxford, UK.,Department of Paediatric Neurology, John Radcliffe Hospital, Oxford, UK
| | - Laurent Servais
- MDUK Neuromuscular Centre, Department of Paediatrics, University of Oxford, Oxford, UK.,Neuromuscular Reference Center, University and University Hospital of Liège, Liège, Belgium
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11
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Removal of MuRF1 Increases Muscle Mass in Nemaline Myopathy Models, but Does Not Provide Functional Benefits. Int J Mol Sci 2022; 23:ijms23158113. [PMID: 35897687 PMCID: PMC9331820 DOI: 10.3390/ijms23158113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 07/18/2022] [Accepted: 07/20/2022] [Indexed: 11/16/2022] Open
Abstract
Nemaline myopathy (NM) is characterized by skeletal muscle weakness and atrophy. No curative treatments exist for this debilitating disease. NM is caused by mutations in proteins involved in thin-filament function, turnover, and maintenance. Mutations in nebulin, encoded by NEB, are the most common cause. Skeletal muscle atrophy is tightly linked to upregulation of MuRF1, an E3 ligase, that targets proteins for proteasome degradation. Here, we report a large increase in MuRF1 protein levels in both patients with nebulin-based NM, also named NEM2, and in mouse models of the disease. We hypothesized that knocking out MuRF1 in animal models of NM with muscle atrophy would ameliorate the muscle deficits. To test this, we crossed MuRF1 KO mice with two NEM2 mouse models, one with the typical form and the other with the severe form. The crosses were viable, and muscles were studied in mice at 3 months of life. Ultrastructural examination of gastrocnemius muscle lacking MuRF1 and with severe NM revealed a small increase in vacuoles, but no significant change in the myofibrillar fractional area. MuRF1 deficiency led to increased weights of various muscle types in the NM models. However, this increase in muscle size was not associated with increased in vivo or in vitro force production. We conclude that knocking out MuRF1 in NEM2 mice increases muscle size, but does not improve muscle function.
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12
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Yin X, Pu C, Wang Z, Li K, Wang H. Clinico-pathological features and mutational spectrum of 16 nemaline myopathy patients from a Chinese neuromuscular center. Acta Neurol Belg 2022; 122:631-639. [PMID: 33742414 PMCID: PMC9170660 DOI: 10.1007/s13760-020-01542-9] [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: 04/16/2020] [Accepted: 10/29/2020] [Indexed: 11/15/2022]
Abstract
Nemaline myopathy (NM) is a congenital myopathy of great heterogeneity, characterized by the presence of rods in the cytoplasm of muscle fibers. The samples of 16 nemaline myopathy patients diagnosed by characteristically pathological features went through whole exon sequencing. Clinico-pathological and genetic features of the cases were systematically analyzed. According to the classification of nemaline myopathy by ENMC, 8 cases are typical congenital subtype, 6 cases are childhood/juvenile onset subtype and 2 case are adult onset subtype. In histological findings, characteristic purple-colored rods are discovered under modified gömöri trichrome staining (MGT). Electron microscopy revealed the presence of high electron-dense nemaline bodies around the submucosa and the nucleus nine patients (9/16 56.3%) were detected pathogenic causative mutations, among whom mutations in the NEB gene were the most frequent (6 patients, 66.7%). KBTBD13 gene mutation was discovered in two patients and ACTA1 gene mutation was discovered in 1 patient. Nemaline myopathy is a congenital myopathy with highly clinico-pathological and genetic heterogeneity. NEB gene mutation is the most common mutation, in which splicing change c.21522 +3A > G is hotspot mutation in Chinese NM patients.
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13
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Sagath L, Lehtokari VL, Wallgren-Pettersson C, Pelin K, Kiiski K. A custom ddPCR method for the detection of copy number variations in the nebulin triplicate region. PLoS One 2022; 17:e0267793. [PMID: 35576196 PMCID: PMC9109913 DOI: 10.1371/journal.pone.0267793] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 04/15/2022] [Indexed: 11/21/2022] Open
Abstract
The human genome contains repetitive regions, such as segmental duplications, known to be prone to copy number variation. Segmental duplications are highly identical and homologous sequences, posing a specific challenge for most mutation detection methods. The giant nebulin gene is expressed in skeletal muscle. It harbors a large segmental duplication region composed of eight exons repeated three times, the so-called triplicate region. Mutations in nebulin are known to cause nemaline myopathy and other congenital myopathies. Using our custom targeted Comparative Genomic Hybridization arrays, we have previously shown that copy number variations in the nebulin triplicate region are pathogenic when the copy number of the segmental duplication block deviates two or more copies from the normal number, which is three per allele. To complement our Comparative Genomic Hybridization arrays, we have established a custom Droplet Digital PCR method for the detection of copy number variations within the nebulin triplicate region. The custom Droplet Digital PCR assays allow sensitive, rapid, high-throughput, and cost-effective detection of copy number variations within this region and is ready for implementation a screening method for disease-causing copy number variations of the nebulin triplicate region. We suggest that Droplet Digital PCR may also be used in the study and diagnostics of other segmental duplication regions of the genome.
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Affiliation(s)
- Lydia Sagath
- Folkhälsan Research Center, Helsinki, Finland
- Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
- * E-mail: , (LS); (KK)
| | - Vilma-Lotta Lehtokari
- Folkhälsan Research Center, Helsinki, Finland
- Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Carina Wallgren-Pettersson
- Folkhälsan Research Center, Helsinki, Finland
- Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Katarina Pelin
- Folkhälsan Research Center, Helsinki, Finland
- Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Kirsi Kiiski
- Folkhälsan Research Center, Helsinki, Finland
- Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
- * E-mail: , (LS); (KK)
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Laitila J, Wallgren-Pettersson C. Recent advances in nemaline myopathy. Neuromuscul Disord 2021; 31:955-967. [PMID: 34561123 DOI: 10.1016/j.nmd.2021.07.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 07/14/2021] [Accepted: 07/16/2021] [Indexed: 11/18/2022]
Abstract
The nemaline myopathies constitute a large proportion of the congenital or structural myopathies. Common to all patients is muscle weakness and the presence in the muscle biopsy of nemaline rods. The causative genes are at least twelve, encoding structural or regulatory proteins of the thin filament, and the clinical picture as well as the histological appearance on muscle biopsy vary widely. Here, we suggest a renewed clinical classification to replace the original one, summarise what is known about the pathogenesis from mutations in each causative gene to the forms of nemaline myopathy described to date, and provide perspectives on pathogenetic mechanisms possibly open to therapeutic modalities.
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Affiliation(s)
- Jenni Laitila
- The Folkhälsan Institute of Genetics, Folkhälsan Research Center, Helsinki, Finland; Department of Medical Genetics, Medicum, University of Helsinki, Finland; Department of Biomedical Sciences, University of Copenhagen, Denmark.
| | - Carina Wallgren-Pettersson
- The Folkhälsan Institute of Genetics, Folkhälsan Research Center, Helsinki, Finland; Department of Medical Genetics, Medicum, University of Helsinki, Finland
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15
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Laflamme N, Lace B, Thonta Setty S, Rioux N, Labrie Y, Droit A, Chrestian N, Rivest S. A Homozygous Deep Intronic Mutation Alters the Splicing of Nebulin Gene in a Patient With Nemaline Myopathy. Front Neurol 2021; 12:660113. [PMID: 34211429 PMCID: PMC8239344 DOI: 10.3389/fneur.2021.660113] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 05/11/2021] [Indexed: 11/19/2022] Open
Abstract
Nemaline myopathy is a rare disorder affecting the muscle sarcomere. Mutations in nebulin gene (NEB) are known to be responsible for about 50% of nemaline myopathy cases. Nebulin is a giant protein which is formed integrally with the sarcomeric thin filament. This complex gene is under extensive alternative splicing giving rise to multiple isoforms. In this study, we report a 6-year-old boy presenting with general muscular weaknesses. Identification of rod-shaped structures in the patient' biopsy raised doubt about the presence of a nemaline myopathy. Next-generation sequencing was used to identify a causative mutation for the patient syndrome. A homozygous deep intronic substitution was found in the intron 144 of the NEB. The variant was predicted by in silico tools to create a new donor splice site. Molecular analysis has shown that the mutation could alter splicing events of the nebulin gene leading to a significant decrease of isoforms level. This change in the expression level of nebulin could give rise to functional consequences in the sarcomere. These results are consistent with the phenotypes observed in the patient. Such a discovery of variants in this gene will allow a better understanding of the involvement of nebulin in neuromuscular diseases and help find new treatments for the nemaline myopathy.
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Affiliation(s)
- Nathalie Laflamme
- Centre de recherche CHU de Québec- Laval University, Quebec City, QC, Canada
| | - Baiba Lace
- Department of Medical Genetics, Centre Mère Enfant Soleil, Laval University, Quebec City, QC, Canada
| | | | - Nadie Rioux
- Centre de recherche CHU de Québec- Laval University, Quebec City, QC, Canada
| | - Yvan Labrie
- Centre de recherche CHU de Québec- Laval University, Quebec City, QC, Canada
| | - Arnaud Droit
- Centre de recherche CHU de Québec- Laval University, Quebec City, QC, Canada
| | - Nicolas Chrestian
- Department of Pediatric Neurology, Pediatric Neuromuscular Disorder, Centre Mère Enfant Soleil, Laval University, Quebec City, QC, Canada
| | - Serge Rivest
- Centre de recherche CHU de Québec- Laval University, Quebec City, QC, Canada
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16
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Sagath L, Lehtokari VL, Välipakka S, Vihola A, Gardberg M, Hackman P, Pelin K, Jokela M, Kiiski K, Udd B, Wallgren-Pettersson C. Congenital asymmetric distal myopathy with hemifacial weakness caused by a heterozygous large de novo mosaic deletion in nebulin. Neuromuscul Disord 2021; 31:539-545. [PMID: 33933294 DOI: 10.1016/j.nmd.2021.03.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 03/10/2021] [Accepted: 03/16/2021] [Indexed: 11/25/2022]
Abstract
We report the first mosaic mutation, a deletion of exons 11-107, identified in the nebulin gene in a Finnish patient presenting with a predominantly distal congenital myopathy and asymmetric muscle weakness. The female patient is ambulant and currently 26 years old. Muscle biopsies showed myopathic features with type 1 fibre predominance, strikingly hypotrophic type 2 fibres and central nuclei, but no nemaline bodies. The deletion was detected in a copy number variation analysis based on next-generation sequencing data. The parents of the patient did not carry the deletion. Mosaicism was detected using a custom, targeted comparative genomic hybridisation array. Expression of the truncated allele, less than half the size of full-length nebulin, was confirmed by Western blotting. The clinical and histological picture resembled that of a family with a slightly smaller deletion, and that in patients with recessively inherited distal forms of nebulin-caused myopathy. Asymmetry, however, was a novel feature.
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Affiliation(s)
- Lydia Sagath
- Folkhälsan Research Center, Helsinki, Finland; Department of Medical Genetics, Medicum, University of Helsinki, Finland.
| | - Vilma-Lotta Lehtokari
- Folkhälsan Research Center, Helsinki, Finland; Department of Medical Genetics, Medicum, University of Helsinki, Finland
| | - Salla Välipakka
- Folkhälsan Research Center, Helsinki, Finland; Department of Medical Genetics, Medicum, University of Helsinki, Finland
| | - Anna Vihola
- Folkhälsan Research Center, Helsinki, Finland; Department of Medical Genetics, Medicum, University of Helsinki, Finland; Neuromuscular Research Centre, Fimlab Laboratories, Tampere University and University Hospital, Tampere, Finland
| | - Maria Gardberg
- Department of Pathology, Turku University Hospital and Institute of Biomedicine, University of Turku, Turku, Finland
| | - Peter Hackman
- Folkhälsan Research Center, Helsinki, Finland; Department of Medical Genetics, Medicum, University of Helsinki, Finland
| | - Katarina Pelin
- Folkhälsan Research Center, Helsinki, Finland; Department of Medical Genetics, Medicum, University of Helsinki, Finland; Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Manu Jokela
- Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland; Laboratory of Genetics, HUS Diagnostic Centre, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Kirsi Kiiski
- Folkhälsan Research Center, Helsinki, Finland; Department of Medical Genetics, Medicum, University of Helsinki, Finland; Laboratory of Genetics, HUS Diagnostic Centre, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Bjarne Udd
- Folkhälsan Research Center, Helsinki, Finland; Department of Medical Genetics, Medicum, University of Helsinki, Finland; Neuromuscular Research Centre, Tampere University and University Hospital, Tampere, Finland; Department of Neurology, Vaasa Central Hospital, Vaasa, Finland
| | - Carina Wallgren-Pettersson
- Folkhälsan Research Center, Helsinki, Finland; Department of Medical Genetics, Medicum, University of Helsinki, Finland
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17
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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: 8] [Impact Index Per Article: 2.7] [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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18
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Pelin K. Nebulin: Size matters for optimal muscle function. J Gen Physiol 2021; 153:211751. [PMID: 33533889 PMCID: PMC7863720 DOI: 10.1085/jgp.202012848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- Katarina Pelin
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
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19
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Rocha ML, Dittmayer C, Uruha A, Korinth D, Chaoui R, Schlembach D, Rossi R, Pelin K, Suk EK, Schmid S, Goebel HH, Schuelke M, Stenzel W, Englert B. A novel mutation in NEB causing foetal nemaline myopathy with arthrogryposis during early gestation. Neuromuscul Disord 2020; 31:239-245. [PMID: 33376055 DOI: 10.1016/j.nmd.2020.11.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 11/27/2020] [Accepted: 11/30/2020] [Indexed: 12/24/2022]
Abstract
Nemaline myopathies are a clinically and genetically heterogeneous group of congenital myopathies, mainly characterized by muscle weakness, hypotonia and respiratory insufficiency. Here, we report a male foetus of consanguineous parents with a severe congenital syndrome characterized by arthrogryposis detected at 13 weeks of gestation. We describe severe complex dysmorphic facial and musculoskeletal features by post mortem fetal examination confirming the prenatal diagnosis. Histomorphological and ultrastructural studies of skeletal muscle reveal mini-rods in myotubes caused by a novel homozygous splice-site mutation in NEB (NM_001164508, chr2:g.152,417,623C>A GRCh37.p11 | c.19,102-1G>T ENST00000397345.3). No rods were seen in the myocardium. We discuss the relevance of this mutation in the context of nemaline myopathies associated with early developmental musculoskeletal disorders.
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Affiliation(s)
- Maria L Rocha
- Department of Pathology, Vivantes Friedrichshain Hospital, Vivantes Hospital Group, Charité Academic Teaching Hospital, Berlin, Germany
| | - Carsten Dittmayer
- Department of Neuropathology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany
| | - Akinori Uruha
- Department of Neuropathology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany
| | - Dirk Korinth
- Private practice of Human Genetics, Berlin, Germany and Private practice of Human Genetics and Molecular Pathology, Rostock, Germany
| | - Rabih Chaoui
- Center for Prenatal Diagnosis-Friedrichstrasse, Berlin, Germany
| | - Dietmar Schlembach
- Clinic for Obstetric Medicine and Center for Prenatal Medicine, Vivantes Neukölln Hospital, Vivantes Hospital Group, Charité Academic Teaching Hospital, Berlin, Germany
| | - Rainer Rossi
- Department of Paediatrics, Vivantes Neukölln Hospital, Vivantes Hospital Group, Charité Academic Teaching Hospital, Berlin, Germany
| | - Katarina Pelin
- Folkhälsan Research Center, Folkhälsan Institute of Genetics, Biomedicum, Helsinki, Finland; Department of Medical and Clinical Genetics, Biomedicum, University of Helsinki, Helsinki, Finland; Faculty of Biological and EnviroNEMental Sciences, Molecular and Integrative Biosciences Research Programme, University of Helsinki, Helsinki, Finland
| | - Eun Kyung Suk
- Private practice of Human Genetics, Berlin, Germany and Private practice of Human Genetics and Molecular Pathology, Rostock, Germany
| | - Simone Schmid
- Department of Neuropathology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany
| | - Hans H Goebel
- Department of Neuropathology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany; Department of Neuropathology, Universitätsmedizin Mainz, Germany
| | - Markus Schuelke
- Department of Neuropediatrics and NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Werner Stenzel
- Department of Neuropathology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany.
| | - Benjamin Englert
- Department of Neuropathology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany; Center for Neuropathology and Prion Research, Ludwig-Maximilians-Universität Munich, Munich, Germany
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20
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Zheng Y, Lv H, Zhang W, Wang Z, Yuan Y. Respiratory Failure as the Presenting Symptom in a Sporadic Case of Cap Myopathy. J Neuropathol Exp Neurol 2020; 79:1382-1384. [PMID: 33064836 DOI: 10.1093/jnen/nlaa117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Yiming Zheng
- Department of Neurology, Peking University First Hospital, Peking, China
| | - He Lv
- Department of Neurology, Peking University First Hospital, Peking, China
| | - Wei Zhang
- Department of Neurology, Peking University First Hospital, Peking, China
| | - Zhaoxia Wang
- Department of Neurology, Peking University First Hospital, Peking, China
| | - Yun Yuan
- Department of Neurology, Peking University First Hospital, Peking, China
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21
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A childhood-onset nemaline myopathy caused by novel heterozygote variants in the nebulin gene with literature review. Acta Neurol Belg 2020; 120:1351-1360. [PMID: 31696431 DOI: 10.1007/s13760-019-01230-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 10/17/2019] [Indexed: 10/25/2022]
Abstract
Nemaline myopathy, a rare congenital myopathy, is characterized by generalized muscle weakness, hypotonia, respiratory insufficiency, and the presence of rod structures on muscle biopsy, which is caused by mutations in at least 13 known genes. A patient showing gradually deteriorated proximal muscle weakness and rod-shaped structures found in muscle fibers was suspected of having nemaline myopathy, following by the next-generation sequencing. We report two novel compound heterozygous variants in nebulin gene in a family residing in China. One is an intron event caused by an underlying variant at the + 3 position of the donor site. Another is a novel nonsense variant, which may lead to the end of protein translation and have a significant impact on protein function. The pathogenicity of this novel compound heterozygous variant remains to be verified. Variants reported here could help to diagnose NM for clinicians.
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22
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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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23
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Triggering typical nemaline myopathy with compound heterozygous nebulin mutations reveals myofilament structural changes as pathomechanism. Nat Commun 2020; 11:2699. [PMID: 32483185 PMCID: PMC7264197 DOI: 10.1038/s41467-020-16526-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 05/06/2020] [Indexed: 12/26/2022] Open
Abstract
Nebulin is a giant protein that winds around the actin filaments in the skeletal muscle sarcomere. Compound-heterozygous mutations in the nebulin gene (NEB) cause typical nemaline myopathy (NM), a muscle disorder characterized by muscle weakness with limited treatment options. We created a mouse model with a missense mutation p.Ser6366Ile and a deletion of NEB exon 55, the Compound-Het model that resembles typical NM. We show that Compound-Het mice are growth-retarded and have muscle weakness. Muscles have a reduced myofibrillar fractional-area and sarcomeres are disorganized, contain rod bodies, and have longer thin filaments. In contrast to nebulin-based severe NM where haplo-insufficiency is the disease driver, Compound-Het mice express normal amounts of nebulin. X-ray diffraction revealed that the actin filament is twisted with a larger radius, that tropomyosin and troponin behavior is altered, and that the myofilament spacing is increased. The unique disease mechanism of nebulin-based typical NM reveals novel therapeutic targets. Nebulin-based nemaline myopathy is a heterogenous disease with unclear pathological mechanisms. Here, the authors generate a mouse model that mimics the most common genetic cause of the disease and demonstrate that muscle weakness in this model is associated with twisted actin filaments and altered tropomyosin and troponin behaviour.
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24
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Laitila JM, McNamara EL, Wingate CD, Goullee H, Ross JA, Taylor RL, van der Pijl R, Griffiths LM, Harries R, Ravenscroft G, Clayton JS, Sewry C, Lawlor MW, Ottenheijm CAC, Bakker AJ, Ochala J, Laing NG, Wallgren-Pettersson C, Pelin K, Nowak KJ. Nebulin nemaline myopathy recapitulated in a compound heterozygous mouse model with both a missense and a nonsense mutation in Neb. Acta Neuropathol Commun 2020; 8:18. [PMID: 32066503 PMCID: PMC7027239 DOI: 10.1186/s40478-020-0893-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 02/05/2020] [Indexed: 12/31/2022] Open
Abstract
Nemaline myopathy (NM) caused by mutations in the gene encoding nebulin (NEB) accounts for at least 50% of all NM cases worldwide, representing a significant disease burden. Most NEB-NM patients have autosomal recessive disease due to a compound heterozygous genotype. Of the few murine models developed for NEB-NM, most are Neb knockout models rather than harbouring Neb mutations. Additionally, some models have a very severe phenotype that limits their application for evaluating disease progression and potential therapies. No existing murine models possess compound heterozygous Neb mutations that reflect the genotype and resulting phenotype present in most patients. We aimed to develop a murine model that more closely matched the underlying genetics of NEB-NM, which could assist elucidation of the pathogenetic mechanisms underlying the disease. Here, we have characterised a mouse strain with compound heterozygous Neb mutations; one missense (p.Tyr2303His), affecting a conserved actin-binding site and one nonsense mutation (p.Tyr935*), introducing a premature stop codon early in the protein. Our studies reveal that this compound heterozygous model, NebY2303H, Y935X, has striking skeletal muscle pathology including nemaline bodies. In vitro whole muscle and single myofibre physiology studies also demonstrate functional perturbations. However, no reduction in lifespan was noted. Therefore, NebY2303H,Y935X mice recapitulate human NEB-NM and are a much needed addition to the NEB-NM mouse model collection. The moderate phenotype also makes this an appropriate model for studying NEB-NM pathogenesis, and could potentially be suitable for testing therapeutic applications.
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25
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Li F, Kolb J, Crudele J, Tonino P, Hourani Z, Smith JE, Chamberlain JS, Granzier H. Expressing a Z-disk nebulin fragment in nebulin-deficient mouse muscle: effects on muscle structure and function. Skelet Muscle 2020; 10:2. [PMID: 31992366 PMCID: PMC6986074 DOI: 10.1186/s13395-019-0219-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 12/17/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Nebulin is a critical thin filament-binding protein that spans from the Z-disk of the skeletal muscle sarcomere to near the pointed end of the thin filament. Its massive size and actin-binding property allows it to provide the thin filaments with structural and regulatory support. When this protein is lost, nemaline myopathy occurs. Nemaline myopathy causes severe muscle weakness as well as structural defects on a sarcomeric level. There is no known cure for this disease. METHODS We studied whether sarcomeric structure and function can be improved by introducing nebulin's Z-disk region into a nebulin-deficient mouse model (Neb cKO) through adeno-associated viral (AAV) vector therapy. Following this treatment, the structural and functional characteristics of both vehicle-treated and AAV-treated Neb cKO and control muscles were studied. RESULTS Intramuscular injection of this AAV construct resulted in a successful expression of the Z-disk fragment within the target muscles. This expression was significantly higher in Neb cKO mice than control mice. Analysis of protein expression revealed that the nebulin fragment was localized exclusively to the Z-disks and that Neb cKO expressed the nebulin fragment at levels comparable to the level of full-length nebulin in control mice. Additionally, the Z-disk fragment displaced full-length nebulin in control mice, resulting in nemaline rod body formation and a worsening of muscle function. Neb cKO mice experienced a slight functional benefit from the AAV treatment, with a small increase in force and fatigue resistance. Disease progression was also slowed as indicated by improved muscle structure and myosin isoform expression. CONCLUSIONS This study reveals that nebulin fragments are well-received by nebulin-deficient mouse muscles and that limited functional benefits are achievable.
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Affiliation(s)
- Frank Li
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, 85721, USA
| | - Justin Kolb
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, 85721, USA
| | - Julie Crudele
- Department of Neurology, University of Washington, Seattle, WA, 98109-8055, USA
| | - Paola Tonino
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, 85721, USA
| | - Zaynab Hourani
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, 85721, USA
| | - John E Smith
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, 85721, USA
| | | | - Henk Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, 85721, USA.
- Medical Research Building, RM 325, 1656 E Mabel St, Tucson, AZ, 85721, USA.
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26
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Välipakka S, Savarese M, Sagath L, Arumilli M, Giugliano T, Udd B, Hackman P. Improving Copy Number Variant Detection from Sequencing Data with a Combination of Programs and a Predictive Model. J Mol Diagn 2020; 22:40-49. [DOI: 10.1016/j.jmoldx.2019.08.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 06/25/2019] [Accepted: 08/08/2019] [Indexed: 12/18/2022] Open
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27
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Sewry CA, Laitila JM, Wallgren-Pettersson C. Nemaline myopathies: a current view. J Muscle Res Cell Motil 2019; 40:111-126. [PMID: 31228046 PMCID: PMC6726674 DOI: 10.1007/s10974-019-09519-9] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 05/29/2019] [Indexed: 12/13/2022]
Abstract
Nemaline myopathies are a heterogenous group of congenital myopathies caused by de novo, dominantly or recessively inherited mutations in at least twelve genes. The genes encoding skeletal α-actin (ACTA1) and nebulin (NEB) are the commonest genetic cause. Most patients have congenital onset characterized by muscle weakness and hypotonia, but the spectrum of clinical phenotypes is broad, ranging from severe neonatal presentations to onset of a milder disorder in childhood. Most patients with adult onset have an autoimmune-related myopathy with a progressive course. The wide application of massively parallel sequencing methods is increasing the number of known causative genes and broadening the range of clinical phenotypes. Nemaline myopathies are identified by the presence of structures that are rod-like or ovoid in shape with electron microscopy, and with light microscopy stain red with the modified Gömöri trichrome technique. These rods or nemaline bodies are derived from Z lines (also known as Z discs or Z disks) and have a similar lattice structure and protein content. Their shape in patients with mutations in KLHL40 and LMOD3 is distinctive and can be useful for diagnosis. The number and distribution of nemaline bodies varies between fibres and different muscles but does not correlate with severity or prognosis. Additional pathological features such as caps, cores and fibre type disproportion are associated with the same genes as those known to cause the presence of rods. Animal models are advancing the understanding of the effects of various mutations in different genes and paving the way for the development of therapies, which at present only manage symptoms and are aimed at maintaining muscle strength, joint mobility, ambulation, respiration and independence in the activities of daily living.
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Affiliation(s)
- Caroline A Sewry
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health and Great Ormond Street Hospital, 30 Guilford Street, London, WC1N 1EH, UK. .,Wolfson Centre of Inherited Neuromuscular Disorders, RJAH Orthopaedic Hospital, Oswestry, SY10 7AG, UK.
| | - Jenni M Laitila
- Folkhälsan Institute of Genetics, Folkhälsan Research Center, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Carina Wallgren-Pettersson
- Folkhälsan Institute of Genetics, Folkhälsan Research Center, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland
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