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Genetic Insights into Primary Restrictive Cardiomyopathy. J Clin Med 2022; 11:jcm11082094. [PMID: 35456187 PMCID: PMC9027761 DOI: 10.3390/jcm11082094] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 04/05/2022] [Accepted: 04/06/2022] [Indexed: 12/04/2022] Open
Abstract
Restrictive cardiomyopathy is a rare cardiac disease causing severe diastolic dysfunction, ventricular stiffness and dilated atria. In consequence, it induces heart failure often with preserved ejection fraction and is associated with a high mortality. Since it is a poor clinical prognosis, patients with restrictive cardiomyopathy frequently require heart transplantation. Genetic as well as non-genetic factors contribute to restrictive cardiomyopathy and a significant portion of cases are of unknown etiology. However, the genetic forms of restrictive cardiomyopathy and the involved molecular pathomechanisms are only partially understood. In this review, we summarize the current knowledge about primary genetic restrictive cardiomyopathy and describe its genetic landscape, which might be of interest for geneticists as well as for cardiologists.
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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.
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Affiliation(s)
- Stefan Nicolau
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Teerin Liewluck
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
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Williams ZJ, Velez-Irizarry D, Petersen JL, Ochala J, Finno CJ, Valberg SJ. Candidate gene expression and coding sequence variants in Warmblood horses with myofibrillar myopathy. Equine Vet J 2021; 53:306-315. [PMID: 32453872 PMCID: PMC7864122 DOI: 10.1111/evj.13286] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 03/18/2020] [Accepted: 05/02/2020] [Indexed: 12/19/2022]
Abstract
BACKGROUND Myofibrillar myopathy (MFM) of unknown aetiology has recently been identified in Warmblood (WB) horses. In humans, 16 genes have been implicated in various MFM-like disorders. OBJECTIVES To identify variants in 16 MFM candidate genes and compare allele frequencies of all variants between MFM WB and non-MFM WB and coding variants with moderate or severe predicted effects in MFM WB with publicly available data of other breeds. To compare differential gene expression and muscle fibre contractile force between MFM and non-MFM WB. STUDY DESIGN Case-control. ANIMALS 8 MFM WB, 8 non-MFM WB, 33 other WB, 32 Thoroughbreds, 80 Quarter Horses and 77 horses of other breeds in public databases. METHODS Variants were called within transcripts of 16 candidate genes using gluteal muscle mRNA sequences aligned to EquCab3.0 and allele frequencies compared by Fisher's exact test among MFM WB, non-MFM WB and public sequences across breeds. Candidate gene differential expression was determined between MFM and non-MFM WB by fitting a negative binomial generalised log-linear model per gene (false discovery rate <0.05). The maximal isometric force/cross-sectional area generated by isolated membrane-permeabilised muscle fibres was determined. RESULTS None of the 426 variants identified in 16 candidate genes were associated with MFM including 26 missense variants. Breed-specific differences existed in allele frequencies. Candidate gene differential expression and muscle fibre-specific force did not differ between MFM WB (143.1 ± 34.7 kPa) and non-MFM WB (140.2 ± 43.7 kPa) (P = .8). MAIN LIMITATIONS RNA-seq-only assays transcripts expressed in skeletal muscle. Other possible candidate genes were not evaluated. CONCLUSIONS Evidence for association of variants with a disease is essential because coding sequence variants are common in the equine genome. Variants identified in MFM candidate genes, including two coding variants offered as commercial MFM equine genetic tests, did not associate with the WB MFM phenotype.
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Affiliation(s)
- Zoë J. Williams
- Large Animal Clinical Sciences, Michigan State University, College of Veterinary Medicine, East Lansing, MI, USA
| | - Deborah Velez-Irizarry
- Large Animal Clinical Sciences, Michigan State University, College of Veterinary Medicine, East Lansing, MI, USA
| | - Jessica L. Petersen
- Department of Animal Science, University of Nebraska Lincoln, Lincoln, NE, USA
| | - Julien Ochala
- Faculty of Life Sciences and Medicine, King’s College London, London, UK
| | - Carrie J. Finno
- University of California at Davis, School of Veterinary Medicine, Davis, CA, USA
| | - Stephanie J. Valberg
- Large Animal Clinical Sciences, Michigan State University, College of Veterinary Medicine, East Lansing, MI, USA
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Whole-exome sequencing in patients with protein aggregate myopathies reveals causative mutations associated with novel atypical phenotypes. Neurol Sci 2020; 42:2819-2827. [PMID: 33170376 PMCID: PMC7654353 DOI: 10.1007/s10072-020-04876-7] [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: 05/04/2020] [Accepted: 11/01/2020] [Indexed: 11/19/2022]
Abstract
Background Myofibrillar myopathies (MFM) are a subgroup of protein aggregate myopathies (PAM) characterized by a common histological picture of myofibrillar dissolution, Z-disk disintegration, and accumulation of degradation products into inclusions. Mutations in genes encoding components of the Z-disk or Z-disk-associated proteins occur in some patients whereas in most of the cases, the causative gene defect is still unknown. We aimed to search for pathogenic mutations in genes not previously associated with MFM phenotype. Methods We performed whole-exome sequencing in four patients from three unrelated families who were diagnosed with PAM without aberrations in causative genes for MFM. Results In the first patient and her affected daughter, we identified a heterozygous p.(Arg89Cys) missense mutation in LMNA gene which has not been linked with PAM pathology before. In the second patient, a heterozygous p.(Asn4807Phe) mutation in RYR1 not previously described in PAM represents a novel, candidate gene with a possible causative role in the disease. Finally, in the third patient and his symptomatic daughter, we found a previously reported heterozygous p.(Cys30071Arg) mutation in TTN gene that was clinically associated with cardiac involvement. Conclusions Our study identifies a new genetic background in PAM pathology and expands the clinical phenotype of known pathogenic mutations. Supplementary Information The online version contains supplementary material available at 10.1007/s10072-020-04876-7.
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Luo YB, Peng Y, Lu Y, Li Q, Duan H, Bi F, Yang H. Expanding the Clinico-Genetic Spectrum of Myofibrillar Myopathy: Experience From a Chinese Neuromuscular Center. Front Neurol 2020; 11:1014. [PMID: 33041974 PMCID: PMC7522348 DOI: 10.3389/fneur.2020.01014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 07/31/2020] [Indexed: 12/14/2022] Open
Abstract
Background: Myofibrillar myopathy is a group of hereditary neuromuscular disorders characterized by dissolution of myofibrils and abnormal intracellular accumulation of Z disc-related proteins. We aimed to characterize the clinical, physiological, pathohistological, and genetic features of Chinese myofibrillar myopathy patients from a single neuromuscular center. Methods: A total of 18 patients were enrolled. Demographic and clinical data were collected. Laboratory investigations, electromyography, and cardiac evaluation was performed. Routine and immunohistochemistry stainings against desmin, αB-crystallin, and BAG3 of muscle specimen were carried out. Finally, next-generation sequencing panel array for genes associated with hereditary neuromuscular disorders were performed. Results: Twelve pathogenic variants in DES, BAG3, FLNC, FHL1, and TTN were identified, of which seven were novel mutations. The novel DES c.1256C>T substitution is a high frequency mutation. The combined recessively/dominantly transmitted c.19993G>T and c.107545delG mutations in TTN gene cause a limb girdle muscular dystrophy phenotype with the classical myofibrillar myopathy histological changes. Conclusions: We report for the first time that hereditary myopathy with early respiratory failure patient can have peripheral nerve and severe spine involvement. The mutation in Ig-like domain 16 of FLNC is associated with the limb girdle type of filaminopathy, and the mutation in Ig-like domain 18 with distal myopathy type. These findings expand the phenotypic and genotypic correlation spectrum of myofibrillar myopathy.
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Affiliation(s)
- Yue-Bei Luo
- Department of Neurology, Xiangya Hospital, Central South Hospital, Changsha, China
| | - Yuyao Peng
- Department of Neurology, Xiangya Hospital, Central South Hospital, Changsha, China
| | - Yuling Lu
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Qiuxiang Li
- Department of Neurology, Xiangya Hospital, Central South Hospital, Changsha, China
| | - Huiqian Duan
- Department of Neurology, Xiangya Hospital, Central South Hospital, Changsha, China
| | - Fangfang Bi
- Department of Neurology, Xiangya Hospital, Central South Hospital, Changsha, China
| | - Huan Yang
- Department of Neurology, Xiangya Hospital, Central South Hospital, Changsha, China
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Carvalho AADS, Lacene E, Brochier G, Labasse C, Madelaine A, Silva VGD, Corazzini R, Papadopoulos K, Behin A, Laforêt P, Stojkovic T, Eymard B, Fardeau M, Romero N. Genetic Mutations and Demographic, Clinical, and Morphological Aspects of Myofibrillar Myopathy in a French Cohort. Genet Test Mol Biomarkers 2018; 22:374-383. [PMID: 29924655 DOI: 10.1089/gtmb.2018.0004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Protein aggregate myopathies (PAM) represent a group of familial or sporadic neuromuscular conditions with marked clinical and genetic heterogeneity that occur in children and adults. Familial PAM includes myofibrillar myopathies defined by the presence of desmin-positive protein aggregates and degenerative intermyofibrillar network changes. PAM is often caused by dysfunctional genes, such as DES, PLEC 1, CRYAB, FLNC, MYOT, ZASP, BAG3, FHL1, and DNAJB6. OBJECTIVE To retrospectively analyze genetic mutations and demographic, clinical, and morphological aspects of PAM in a French population. METHODS Forty-eight PAM patients (29 men, 19 women) were divided into two groups, those with genetically (GIM) and nongenetically identified (NGIM) mutations associated with myofibrillar myopathy. RESULTS Age of myopathy onset ranged from 13 to 68 years. GIM group mutations (81.25%) included DES (14), ZASP (8), FLNC (4), MYOT (4), BAG3 (1), CRYAB (2), and DNAJB6 (6). The MYOT subgroup displayed a significantly older onset age (p = 0.029). Autosomal dominant inheritance was found in 74.3% of GIM and 44.4% of NGIM subjects. Overall, 22.9% had Maghrebian heritage, 72.9% Caucasian, and 4.2% Asian. The most common clinical sign was distal muscle weakness (66%) followed by simultaneous distal and proximal weakness in 49%. Eleven patients had contractures, one had a rigid spine, and five had respiratory dysfunction. GIM subjects had greater cardiac involvement (51.7%) versus the NGIM group (33.3%). The average serum creatine kinase level was 393 U/L in GIM and 382 U/L in NGIM subjects. Morphological analysis showed significant differences among GIM subgroups, including the number of vacuoles and regenerated fibers (ZASP), group atrophy (ZASP), and rubbed out fibers (MYOT). Ultrastructural findings showed significant differences in intranuclear rods, Z-disc thickness, and intranuclear inclusions between gene mutation subgroups. Paracrystalline inclusions were present in three patients (DNAJB6). The most frequent mutation in was in DES, followed by ZASP. CONCLUSIONS GIM and NGIM PAM subjects showed similar results, suggesting that any unknown genes, which cause this disease have characteristics similar to those already described. Considering the complexity of clinical, morphological, and genetic data related to PAM, particularly myofibrillar myopathies, physicians should be careful when diagnosing patients with sporadic PAM.
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Affiliation(s)
- Alzira Alves de Siqueira Carvalho
- 1 Laboratório de Doenças Neuromusculares da Faculdade de Medicina do ABC , Departamento de Neurociências, Santo André, Brazil .,2 Laboratoire de Pathologie Musculaire Risler, Groupe Hospitalier Pitié-Salpêtrière , Paris, France
| | - Emmanuele Lacene
- 2 Laboratoire de Pathologie Musculaire Risler, Groupe Hospitalier Pitié-Salpêtrière , Paris, France
| | - Guy Brochier
- 2 Laboratoire de Pathologie Musculaire Risler, Groupe Hospitalier Pitié-Salpêtrière , Paris, France
| | - Clémance Labasse
- 2 Laboratoire de Pathologie Musculaire Risler, Groupe Hospitalier Pitié-Salpêtrière , Paris, France
| | - Angeline Madelaine
- 2 Laboratoire de Pathologie Musculaire Risler, Groupe Hospitalier Pitié-Salpêtrière , Paris, France
| | - Vinicius Gomes da Silva
- 3 Laboratório de Doenças Neuromusculares da Faculdade de Medicina do ABC , Departamento de Neurociências, Santo André, Brazil
| | - Roseli Corazzini
- 3 Laboratório de Doenças Neuromusculares da Faculdade de Medicina do ABC , Departamento de Neurociências, Santo André, Brazil
| | - Konstantinos Papadopoulos
- 4 Centre de Référence de Pathologie Neuromusculaire Paris-Est, Groupe Hospitalier Pitié-Salpêtrière , Institut de Myologie, Paris, France
| | - Anthony Behin
- 4 Centre de Référence de Pathologie Neuromusculaire Paris-Est, Groupe Hospitalier Pitié-Salpêtrière , Institut de Myologie, Paris, France
| | - Pascal Laforêt
- 4 Centre de Référence de Pathologie Neuromusculaire Paris-Est, Groupe Hospitalier Pitié-Salpêtrière , Institut de Myologie, Paris, France
| | - Tania Stojkovic
- 4 Centre de Référence de Pathologie Neuromusculaire Paris-Est, Groupe Hospitalier Pitié-Salpêtrière , Institut de Myologie, Paris, France
| | - Bruno Eymard
- 4 Centre de Référence de Pathologie Neuromusculaire Paris-Est, Groupe Hospitalier Pitié-Salpêtrière , Institut de Myologie, Paris, France
| | - Michel Fardeau
- 2 Laboratoire de Pathologie Musculaire Risler, Groupe Hospitalier Pitié-Salpêtrière , Paris, France
| | - Norma Romero
- 2 Laboratoire de Pathologie Musculaire Risler, Groupe Hospitalier Pitié-Salpêtrière , Paris, France
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Fichna JP, Maruszak A, Żekanowski C. Myofibrillar myopathy in the genomic context. J Appl Genet 2018; 59:431-439. [PMID: 30203143 DOI: 10.1007/s13353-018-0463-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 08/30/2018] [Indexed: 12/31/2022]
Abstract
Myofibrillar myopathy (MFM) is a group of inherited muscular disorders characterized by myofibril dissolution and abnormal accumulation of degradation products. The diagnosis of muscular disorders based on clinical presentation is difficult due to phenotypic heterogeneity and overlapping symptoms. In addition, precise diagnosis does not always explain the disease etiopathology or the highly variable clinical course even among patients diagnosed with the same type of myopathy. The advent of high-throughput next-generation sequencing (NGS) has provided a successful and cost-effective strategy for identification of novel causative genes in myopathies, including MFM. So far, pathogenic mutations associated with MFM phenotype, including atypical MFM-like cases, have been identified in 17 genes: DES, CRYAB, MYOT, ZASP, FLNC, BAG3, FHL1, TTN, DNAJB6, PLEC, LMNA, ACTA1, HSPB8, KY, PYROXD1, and SQSTM + TIA1 (digenic). Most of these genes are also associated with other forms of muscle diseases. In addition, in many MFM patients, numerous genomic variants in muscle-related genes have been identified. The various myopathies and muscular dystrophies seem to form a single disease continuum; therefore, gene identification in one disease impacts the genetic etiology of the others. In this review, we describe the heterogeneity of the MFM genetic background focusing on the role of rare variants, the importance of whole genome sequencing in the identification of novel disease-associated mutations, and the emerging concept of variant load as the basis of the phenotypic heterogeneity.
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Affiliation(s)
- Jakub Piotr Fichna
- Department of Neurodegenerative Disorders, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego St., 02-106, Warsaw, Poland.
| | - Aleksandra Maruszak
- Department of Neurodegenerative Disorders, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego St., 02-106, Warsaw, Poland
| | - Cezary Żekanowski
- Department of Neurodegenerative Disorders, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego St., 02-106, Warsaw, Poland
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