1
|
Periviita V, Palmio J, Jokela M, Hartikainen P, Vihola A, Rauramaa T, Udd B. CACNA1S Variant Associated With a Myalgic Myopathy Phenotype. Neurology 2023; 101:e1779-e1786. [PMID: 37679049 PMCID: PMC10634652 DOI: 10.1212/wnl.0000000000207639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 05/30/2023] [Indexed: 09/09/2023] Open
Abstract
BACKGROUND AND OBJECTIVES This study aimed to characterize the phenotype of a novel myalgic myopathy encountered in a Finnish family. METHODS Four symptomatic and 3 asymptomatic individuals from 2 generations underwent clinical, neurophysiologic, imaging, and muscle biopsy examinations. Targeted sequencing of all known myopathy genes was performed. RESULTS A very rare CACNA1S gene variant c.2893G>C (p.E965Q) was identified in the family. The symptomatic patients presented with exercise-induced myalgia, cramping, muscle stiffness, and fatigue and eventually developed muscle weakness. Examinations revealed mild ptosis and unusual muscle hypertrophy in the upper limbs. In the most advanced disease stage, muscle weakness and muscle atrophy of the limbs were evident. In some patients, muscle biopsy showed mild myopathic findings and creatine kinase levels were slightly elevated. DISCUSSION Myalgia is a very common symptom affecting quality of life. Widespread myalgia may be confused with other myalgic syndromes such as fibromyalgia. In this study, we show that variants in CACNA1S gene may be one cause of severe exercise-induced myalgia.
Collapse
Affiliation(s)
- Vesa Periviita
- From the Department of Neurology (V.P., P.H.), Kuopio University Hospital; Tampere Neuromuscular Center (J.P., M.J., A.V., B.U.); Tampere University Hospital (J.P.); Tampere University (J.P.); Neurology (M.J.), Clinical Medicine, University of Turku; Neurocenter (M.J.), Turku University Hospital; Folkhälsan Research Center (A.V., B.U.), Helsinki; Medicum (A.V., B.U.), University of Helsinki; Fimlab Laboratories (A.V.), Tampere; Department of Pathology (T.R.), Kuopio University Hospital; and Unit of Pathology (T.R.), Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland.
| | - Johanna Palmio
- From the Department of Neurology (V.P., P.H.), Kuopio University Hospital; Tampere Neuromuscular Center (J.P., M.J., A.V., B.U.); Tampere University Hospital (J.P.); Tampere University (J.P.); Neurology (M.J.), Clinical Medicine, University of Turku; Neurocenter (M.J.), Turku University Hospital; Folkhälsan Research Center (A.V., B.U.), Helsinki; Medicum (A.V., B.U.), University of Helsinki; Fimlab Laboratories (A.V.), Tampere; Department of Pathology (T.R.), Kuopio University Hospital; and Unit of Pathology (T.R.), Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Manu Jokela
- From the Department of Neurology (V.P., P.H.), Kuopio University Hospital; Tampere Neuromuscular Center (J.P., M.J., A.V., B.U.); Tampere University Hospital (J.P.); Tampere University (J.P.); Neurology (M.J.), Clinical Medicine, University of Turku; Neurocenter (M.J.), Turku University Hospital; Folkhälsan Research Center (A.V., B.U.), Helsinki; Medicum (A.V., B.U.), University of Helsinki; Fimlab Laboratories (A.V.), Tampere; Department of Pathology (T.R.), Kuopio University Hospital; and Unit of Pathology (T.R.), Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Paivi Hartikainen
- From the Department of Neurology (V.P., P.H.), Kuopio University Hospital; Tampere Neuromuscular Center (J.P., M.J., A.V., B.U.); Tampere University Hospital (J.P.); Tampere University (J.P.); Neurology (M.J.), Clinical Medicine, University of Turku; Neurocenter (M.J.), Turku University Hospital; Folkhälsan Research Center (A.V., B.U.), Helsinki; Medicum (A.V., B.U.), University of Helsinki; Fimlab Laboratories (A.V.), Tampere; Department of Pathology (T.R.), Kuopio University Hospital; and Unit of Pathology (T.R.), Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Anna Vihola
- From the Department of Neurology (V.P., P.H.), Kuopio University Hospital; Tampere Neuromuscular Center (J.P., M.J., A.V., B.U.); Tampere University Hospital (J.P.); Tampere University (J.P.); Neurology (M.J.), Clinical Medicine, University of Turku; Neurocenter (M.J.), Turku University Hospital; Folkhälsan Research Center (A.V., B.U.), Helsinki; Medicum (A.V., B.U.), University of Helsinki; Fimlab Laboratories (A.V.), Tampere; Department of Pathology (T.R.), Kuopio University Hospital; and Unit of Pathology (T.R.), Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Tuomas Rauramaa
- From the Department of Neurology (V.P., P.H.), Kuopio University Hospital; Tampere Neuromuscular Center (J.P., M.J., A.V., B.U.); Tampere University Hospital (J.P.); Tampere University (J.P.); Neurology (M.J.), Clinical Medicine, University of Turku; Neurocenter (M.J.), Turku University Hospital; Folkhälsan Research Center (A.V., B.U.), Helsinki; Medicum (A.V., B.U.), University of Helsinki; Fimlab Laboratories (A.V.), Tampere; Department of Pathology (T.R.), Kuopio University Hospital; and Unit of Pathology (T.R.), Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Bjarne Udd
- From the Department of Neurology (V.P., P.H.), Kuopio University Hospital; Tampere Neuromuscular Center (J.P., M.J., A.V., B.U.); Tampere University Hospital (J.P.); Tampere University (J.P.); Neurology (M.J.), Clinical Medicine, University of Turku; Neurocenter (M.J.), Turku University Hospital; Folkhälsan Research Center (A.V., B.U.), Helsinki; Medicum (A.V., B.U.), University of Helsinki; Fimlab Laboratories (A.V.), Tampere; Department of Pathology (T.R.), Kuopio University Hospital; and Unit of Pathology (T.R.), Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| |
Collapse
|
2
|
Zhang Y, Yan H, Liu J, Yan H, Ma Y, Wei C, Wang Z, Xiong H, Chang X. Clinical and genetic features of infancy-onset congenital myopathies from a Chinese paediatric centre. BMC Pediatr 2022; 22:65. [PMID: 35081925 PMCID: PMC8790871 DOI: 10.1186/s12887-021-03024-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 11/18/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Congenital myopathies are a group of rare neuromuscular diseases characterized by specific histopathological features. The relationship between the pathologies and the genetic causes is complex, and the prevalence of myopathy-causing genes varies among patients from different ethnic groups. The aim of the present study was to characterize congenital myopathies with infancy onset among patients registered at our institution. METHOD This retrospective study enrolled 56 patients based on the pathological and/or genetic diagnosis. Clinical, histopathological and genetic features of the patients were analysed with long-term follow-up. RESULTS Twenty-six out of 43 patients who received next-generation sequencing had genetic confirmation, and RYR1 variations (12/26) were the most prevalent. Eighteen novel variations were identified in 6 disease-causing genes, including RYR1, NEB, TTN, TNNT1, DNM2 and ACTA1. Nemaline myopathy (17/55) was the most common histopathology. The onset ages ranged from birth to 1 year. Thirty-one patients were followed for 3.83 ± 3.05 years (ranging from 3 months to 11 years). No patient died before 1 year. Two patients died at 5 years and 8 years respectively. The motor abilities were stable or improved in 23 patients and deteriorated in 6 patients. Ten (10/31) patients developed respiratory involvement, and 9 patients (9/31) had mildly abnormal electrocardiograms and/or echocardiograms. CONCLUSION The severity of congenital myopathies in the neonatal/infantile period may vary in patients from different ethnic groups. More concern should be given to cardiac monitoring in patients with congenital myopathies even in those with static courses.
Collapse
Affiliation(s)
- Yu Zhang
- Department of Paediatrics, Peking University First Hospital, No.1 Xianmen Street, Xicheng District, 100034, Beijing, PR China.,Department of Paediatrics, Peking University International Hospital, 102206, Beijing, PR China
| | - Hui Yan
- Department of Paediatrics, Peking University First Hospital, No.1 Xianmen Street, Xicheng District, 100034, Beijing, PR China
| | - Jieyu Liu
- Department of Paediatrics, Peking University First Hospital, No.1 Xianmen Street, Xicheng District, 100034, Beijing, PR China
| | - Huifang Yan
- Department of Paediatrics, Peking University First Hospital, No.1 Xianmen Street, Xicheng District, 100034, Beijing, PR China
| | - Yinan Ma
- Department of Central Laboratory, Peking University First Hospital, 100034, Beijing, PR China
| | - Cuijie Wei
- Department of Paediatrics, Peking University First Hospital, No.1 Xianmen Street, Xicheng District, 100034, Beijing, PR China
| | - Zhaoxia Wang
- Department of Neurology, Peking University First Hospital, 100034, Beijing, PR China
| | - Hui Xiong
- Department of Paediatrics, Peking University First Hospital, No.1 Xianmen Street, Xicheng District, 100034, Beijing, PR China
| | - Xingzhi Chang
- Department of Paediatrics, Peking University First Hospital, No.1 Xianmen Street, Xicheng District, 100034, Beijing, PR China.
| |
Collapse
|
3
|
Nicolau S, Milone M, Liewluck T. Guidelines for genetic testing of muscle and neuromuscular junction disorders. Muscle Nerve 2021; 64:255-269. [PMID: 34133031 DOI: 10.1002/mus.27337] [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: 05/28/2021] [Accepted: 05/28/2021] [Indexed: 12/24/2022]
Abstract
Despite recent advances in the understanding of inherited muscle and neuromuscular junction diseases, as well as the advent of a wide range of genetic tests, patients continue to face delays in diagnosis of sometimes treatable disorders. These guidelines outline an approach to genetic testing in such disorders. Initially, a patient's phenotype is evaluated to identify myopathies requiring directed testing, including myotonic dystrophies, facioscapulohumeral muscular dystrophy, oculopharyngeal muscular dystrophy, mitochondrial myopathies, dystrophinopathies, and oculopharyngodistal myopathy. Initial investigation in the remaining patients is generally a comprehensive gene panel by next-generation sequencing. Broad panels have a higher diagnostic yield and can be cost-effective. Due to extensive phenotypic overlap and treatment implications, genes responsible for congenital myasthenic syndromes should be included when evaluating myopathy patients. For patients whose initial genetic testing is negative or inconclusive, phenotypic re-evaluation is warranted, along with consideration of genes and variants not included initially, as well as their acquired mimickers.
Collapse
Affiliation(s)
- Stefan Nicolau
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Teerin Liewluck
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
Truong KM, Cherednichenko G, Pessah IN. Interactions of Dichlorodiphenyltrichloroethane (DDT) and Dichlorodiphenyldichloroethylene (DDE) With Skeletal Muscle Ryanodine Receptor Type 1. Toxicol Sci 2020; 170:509-524. [PMID: 31127943 DOI: 10.1093/toxsci/kfz120] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Dichlorodiphenyltrichloroethane (DDT) and its metabolite dichlorodiphenyldichloroethylene (DDE) are ubiquitous in the environment and detected in tissues of living organisms. Although DDT owes its insecticidal activity to impeding closure of voltage-gated sodium channels, it mediates toxicity in mammals by acting as an endocrine disruptor (ED). Numerous studies demonstrate DDT/DDE to be EDs, but studies examining muscle-specific effects mediated by nonhormonal receptors in mammals are lacking. Therefore, we investigated whether o,p'-DDT, p,p'-DDT, o,p'-DDE, and p,p'-DDE (DDx, collectively) alter the function of ryanodine receptor type 1 (RyR1), a protein critical for skeletal muscle excitation-contraction coupling and muscle health. DDx (0.01-10 µM) elicited concentration-dependent increases in [3H]ryanodine ([3H]Ry) binding to RyR1 with o,p'-DDE showing highest potency and efficacy. DDx also showed sex differences in [3H]Ry-binding efficacy toward RyR1, where [3H]Ry-binding in female muscle preparations was greater than male counterparts. Measurements of Ca2+ transport across sarcoplasmic reticulum (SR) membrane vesicles further confirmed DDx can selectively engage with RyR1 to cause Ca2+ efflux from SR stores. DDx also disrupts RyR1-signaling in HEK293T cells stably expressing RyR1 (HEK-RyR1). Pretreatment with DDx (0.1-10 µM) for 100 s, 12 h, or 24 h significantly sensitized Ca2+-efflux triggered by RyR agonist caffeine in a concentration-dependent manner. o,p'-DDE (24 h; 1 µM) significantly increased Ca2+-transient amplitude from electrically stimulated mouse myotubes compared with control and displayed abnormal fatigability. In conclusion, our study demonstrates DDx can directly interact and modulate RyR1 conformation, thereby altering SR Ca2+-dynamics and sensitize RyR1-expressing cells to RyR1 activators, which may ultimately contribute to long-term impairments in muscle health.
Collapse
Affiliation(s)
- Kim M Truong
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, California 95616-5270
| | - Gennady Cherednichenko
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, California 95616-5270
| | - Isaac N Pessah
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, California 95616-5270
| |
Collapse
|
6
|
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.
Collapse
|
7
|
Chagovetz AA, Klatt Shaw D, Ritchie E, Hoshijima K, Grunwald DJ. Interactions among ryanodine receptor isotypes contribute to muscle fiber type development and function. Dis Model Mech 2019; 13:dmm.038844. [PMID: 31383689 PMCID: PMC6906632 DOI: 10.1242/dmm.038844] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 07/17/2019] [Indexed: 12/14/2022] Open
Abstract
Mutations affecting ryanodine receptor (RyR) calcium release channels commonly underlie congenital myopathies. Although these channels are known principally for their essential roles in muscle contractility, mutations in the human RYR1 gene result in a broad spectrum of phenotypes, including muscle weakness, altered proportions of fiber types, anomalous muscle fibers with cores or centrally placed nuclei, and dysmorphic craniofacial features. Currently, it is unknown which phenotypes directly reflect requirements for RyRs and which result secondarily to aberrant muscle function. To identify biological processes requiring RyR function, skeletal muscle development was analyzed in zebrafish embryos harboring protein-null mutations. RyR channels contribute to both muscle fiber development and function. Loss of some RyRs had modest effects, altering muscle fiber-type specification in the embryo without compromising viability. In addition, each RyR-encoding gene contributed to normal swimming behavior and muscle function. The RyR channels do not function in a simple additive manner. For example, although isoform RyR1a is sufficient for muscle contraction in the absence of RyR1b, RyR1a normally attenuates the activity of the co-expressed RyR1b channel in slow muscle. RyR3 also acts to modify the functions of other RyR channels. Furthermore, diminished RyR-dependent contractility affects both muscle fiber maturation and craniofacial development. These findings help to explain some of the heterogeneity of phenotypes that accompany RyR1 mutations in humans.
Collapse
Affiliation(s)
- Alexis A Chagovetz
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Dana Klatt Shaw
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Erin Ritchie
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Kazuyuki Hoshijima
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - David J Grunwald
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| |
Collapse
|
8
|
Nicolau S, Liewluck T, Tracy JA, Laughlin RS, Milone M. Congenital myopathies in the adult neuromuscular clinic: Diagnostic challenges and pitfalls. NEUROLOGY-GENETICS 2019; 5:e341. [PMID: 31321302 PMCID: PMC6563518 DOI: 10.1212/nxg.0000000000000341] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 04/29/2019] [Indexed: 01/28/2023]
Abstract
Objective To investigate the spectrum of undiagnosed congenital myopathies (CMs) in adults presenting to our neuromuscular clinic and to identify the pitfalls responsible for diagnostic delays. Methods We conducted a retrospective review of patients diagnosed with CM in adulthood in our neuromuscular clinic between 2008 and 2018. Patients with an established diagnosis of CM before age 18 years were excluded. Results We identified 26 patients with adult-onset CM and 18 patients with pediatric-onset CM who were only diagnosed in adulthood. Among patients with adult onset, the median age at onset was 47 years, and the causative genes were RYR1 (11 families), MYH7 (3 families) and ACTA1 (2 families), and SELENON, MYH2, DNM2, and CACNA1S (1 family each). Of 33 patients who underwent muscle biopsy, only 18 demonstrated histologic abnormalities characteristic of CM. Before their diagnosis of CM, 23 patients had received other diagnoses, most commonly non-neurologic disorders. The main causes of diagnostic delays were mildness of the symptoms delaying neurologic evaluation and attribution of the symptoms to coexisting comorbidities, particularly among pediatric-onset patients. Conclusions CMs in adulthood represent a diagnostic challenge, as they may lack the clinical and myopathologic features classically associated with CM. Our findings underscore the need for a revision of the terminology and current classification of these disorders.
Collapse
|
9
|
Milone M, Liewluck T. The unfolding spectrum of inherited distal myopathies. Muscle Nerve 2018; 59:283-294. [PMID: 30171629 DOI: 10.1002/mus.26332] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 08/26/2018] [Accepted: 08/28/2018] [Indexed: 12/30/2022]
Abstract
Distal myopathies are a group of rare muscle diseases characterized by distal weakness at onset. Although acquired myopathies can occasionally present with distal weakness, the majority of distal myopathies have a genetic etiology. Their age of onset varies from early-childhood to late-adulthood while the predominant muscle weakness can affect calf, ankle dorsiflexor, or distal upper limb muscles. A spectrum of muscle pathological changes, varying from nonspecific myopathic changes to rimmed vacuoles to myofibrillar pathology to nuclei centralization, have been noted. Likewise, the underlying molecular defect is heterogeneous. In addition, there is emerging evidence that distal myopathies can result from defective proteins encoded by genes causative of neurogenic disorders, be manifestation of multisystem proteinopathies or the result of the altered interplay between different genes. In this review, we provide an overview on the clinical, electrophysiological, pathological, and molecular aspects of distal myopathies, focusing on the most recent developments in the field. Muscle Nerve 59:283-294, 2019.
Collapse
Affiliation(s)
| | - Teerin Liewluck
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
| |
Collapse
|
10
|
Abstract
Ryanodine receptor type 1-related myopathies (RYR1-RM) are the most common class of congenital myopathies. Historically, RYR1-RM classification and diagnosis have been guided by histopathologic findings on muscle biopsy. Main histological subtypes of RYR1-RM include central core disease, multiminicore disease, core-rod myopathy, centronuclear myopathy, and congenital fiber-type disproportion. A range of RYR1-RM clinical phenotypes has also emerged more recently and includes King Denborough syndrome, RYR1 rhabdomyolysis-myalgia syndrome, atypical periodic paralysis, congenital neuromuscular disease with uniform type 1 fibers, and late-onset axial myopathy. This expansion of the RYR1-RM disease spectrum is due, in part, to implementation of next-generation sequencing methods, which include the entire RYR1 coding sequence rather than being restricted to hotspot regions. These methods enhance diagnostic capabilities, especially given historic limitations of histopathologic and clinical overlap across RYR1-RM. Both dominant and recessive modes of inheritance have been documented, with the latter typically associated with a more severe clinical phenotype. As with all congenital myopathies, no FDA-approved treatments exist to date. Here, we review histopathologic, clinical, imaging, and genetic diagnostic features of the main RYR1-RM subtypes. We also discuss the current state of treatments and focus on disease-modulating (nongenetic) therapeutic strategies under development for RYR1-RM. Finally, perspectives for future approaches to treatment development are broached.
Collapse
Affiliation(s)
- Tokunbor A Lawal
- Neuromuscular Symptoms Unit, National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA
| | - Joshua J Todd
- Neuromuscular Symptoms Unit, National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA
| | - Katherine G Meilleur
- Neuromuscular Symptoms Unit, National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA.
| |
Collapse
|
11
|
Kushnir A, Wajsberg B, Marks AR. Ryanodine receptor dysfunction in human disorders. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1687-1697. [PMID: 30040966 DOI: 10.1016/j.bbamcr.2018.07.011] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 07/13/2018] [Accepted: 07/14/2018] [Indexed: 01/07/2023]
Abstract
Regulation of intracellular calcium (Ca2+) is critical in all cell types. The ryanodine receptor (RyR), an intracellular Ca2+ release channel located on the sarco/endoplasmic reticulum (SR/ER), releases Ca2+ from intracellular stores to activate critical functions including muscle contraction and neurotransmitter release. Dysfunctional RyR-mediated Ca2+ handling has been implicated in the pathogenesis of inherited and non-inherited conditions including heart failure, cardiac arrhythmias, skeletal myopathies, diabetes, and neurodegenerative diseases. Here we have reviewed the evidence linking human disorders to RyR dysfunction and describe novel approaches to RyR-targeted therapeutics.
Collapse
Affiliation(s)
- Alexander Kushnir
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA; Department of Medicine, Division of Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA
| | - Benjamin Wajsberg
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA
| | - Andrew R Marks
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA.
| |
Collapse
|
12
|
Laughlin RS, Niu Z, Wieben E, Milone M. RYR1 causing distal myopathy. Mol Genet Genomic Med 2017; 5:800-804. [PMID: 29178655 PMCID: PMC5702567 DOI: 10.1002/mgg3.338] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 08/25/2017] [Accepted: 08/29/2017] [Indexed: 12/31/2022] Open
Abstract
Background Congenital myopathies due to ryanodine receptor (RYR1) mutations are increasingly identified and correlate with a wide range of phenotypes, most commonly that of malignant hyperthermia susceptibility and central cores on muscle biopsy with rare reports of distal muscle weakness, but in the setting of early onset global weakness. Methods We report a case of a patient presenting with childhood onset hand stiffness and adult onset progressive hand weakness and jaw contractures discovered to have two variants in the RYR1 gene. Results The patient manifested with distal upper limb weakness which progressed to involve the distal lower limb, proximal upper limb, as well as the face in addition to limited jaw opening. Creatine kinase was mildly elevated with EMG findings supporting a myopathy. Muscle biopsy showed features consistent with centronuclear myopathy. Whole exome sequencing revealed a novel heterozygous pathogenic variant in RYR1 (c.12315_12328delAGAAATCCAGTTCC, p.Glu4106Alafs*8), and a heterozygous missense variant (c.10648C>T, p.Arg3550Trp) of unknown significance in compound heterozygous state. Conclusion We expand the spectrum of RYR1‐related myopathy with the description of a novel phenotype in an adult patient presenting with hand weakness and suggest considering RYR1 analysis in the diagnosis of distal myopathies.
Collapse
Affiliation(s)
| | - Zhiyv Niu
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota.,Department of Clinical Genomics, Mayo Clinic, Rochester, Minnesota
| | - Eric Wieben
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota
| | | |
Collapse
|