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Mao B, Yang J, Zhao X, Jia X, Shi X, Zhao L, Banerjee S, Zhang L, Ma X. Identification and functional characterization of a novel heterozygous splice‑site mutation in the calpain 3 gene causes rare autosomal dominant limb‑girdle muscular dystrophy. Exp Ther Med 2024; 27:97. [PMID: 38356676 PMCID: PMC10865457 DOI: 10.3892/etm.2024.12385] [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: 08/30/2022] [Accepted: 11/03/2023] [Indexed: 02/16/2024] Open
Abstract
Limb-girdle muscular dystrophies are a group of extremely heterogenous neuromuscular disorders that manifest with gradual and progressive weakness of both proximal and distal muscles. Autosomal dominant limb-girdle muscular dystrophy (LGMDD4) or calpainopathy is a very rare form of myopathy characterized by weakness and atrophy of both proximal and distal muscles with a variable age of onset. LGMDD4 is caused by germline heterozygous mutations of the calpain 3 (CAPN3) gene. Patients with LGMDD4 often show extreme phenotypic heterogeneity; however, most patients present with gait difficulties, increased levels of serum creatine kinase, myalgia and back pain. In the present study, a 16-year-old male patient, clinically diagnosed with LGMDD4, was investigated. The proband had been suffering from weakness and atrophy of both of their proximal and distal muscles, and had difficulty walking and standing independently. The serum creatine kinase levels (4,754 IU/l; normal, 35-232 IU/l) of the patient were markedly elevated. The younger sister and mother of the proband were also clinically diagnosed with LGMDD4, while the father was phenotypically normal. Whole exome sequencing identified a heterozygous novel splice-site (c.2440-1G>A) mutation in intron 23 of the CAPN3 gene in the proband. Sanger sequencing confirmed that this mutation was also present in both the younger sister and mother of the proband, but the father was not a carrier of this mutation. This splice-site (c.2440-1G>A) mutation causes aberrant splicing of CAPN3 mRNA, leading to the skipping of the last exon (exon 24) of CAPN3 mRNA and resulting in the removal of eight amino acids from the C-terminal of domain IV of the CAPN3 protein. Hence, this splice site mutation causes the formation of a truncated CAPN3 protein (p.Trp814*) of 813 amino acids instead of the wild-type CAPN3 protein that consists of 821 amino acids. This mutation causes partial loss of domain IV (PEF domain) in the CAPN3 protein, which is involved in calcium binding and homodimerization; therefore, this is a loss-of-function mutation. Relative expression of the mutated CAPN3 mRNA was reduced in comparison with the wild-type CAPN3 mRNA in the proband, and their younger sister and mother. This mutation was also not present in 100 normal healthy control individuals of the same ethnicity. The present study reported the first case of CAPN3 gene-associated LGMDD4 in the Chinese population.
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Affiliation(s)
- Bin Mao
- The Reproductive Medicine Centre, The First Hospital of Lanzhou University, Lanzhou, Gansu 730000, P.R. China
| | - Jie Yang
- The Reproductive Medicine Centre, The First Hospital of Lanzhou University, Lanzhou, Gansu 730000, P.R. China
| | - Xiaodong Zhao
- The Reproductive Medicine Centre, The First Hospital of Lanzhou University, Lanzhou, Gansu 730000, P.R. China
| | - Xueling Jia
- The Reproductive Medicine Centre, The First Hospital of Lanzhou University, Lanzhou, Gansu 730000, P.R. China
| | - Xin Shi
- The Reproductive Medicine Centre, The First Hospital of Lanzhou University, Lanzhou, Gansu 730000, P.R. China
| | - Lihui Zhao
- The Reproductive Medicine Centre, The First Hospital of Lanzhou University, Lanzhou, Gansu 730000, P.R. China
| | - Santasree Banerjee
- Department of Genetics, College of Basic Medical Sciences, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Lili Zhang
- The Reproductive Medicine Centre, The First Hospital of Lanzhou University, Lanzhou, Gansu 730000, P.R. China
| | - Xiaoling Ma
- The Reproductive Medicine Centre, The First Hospital of Lanzhou University, Lanzhou, Gansu 730000, P.R. China
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Chung Tran N, Lien NTK, Ta TD, Nguyen VH, Tran HT, Van Tung N, Xuan NT, Huy Hoang N, Tran VK. Novel mutations in the SGCA gene in unrelated Vietnamese patients with limb-girdle muscular dystrophies disease. Front Genet 2023; 14:1248338. [PMID: 37900180 PMCID: PMC10611451 DOI: 10.3389/fgene.2023.1248338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 09/18/2023] [Indexed: 10/31/2023] Open
Abstract
Background: Limb-girdle muscular dystrophy (LGMD) is a group of inherited neuromuscular disorders characterized by atrophy and weakness in the shoulders and hips. Over 30 subtypes have been described in five dominant (LGMD type 1 or LGMDD) and 27 recessive (LGMD type 2 or LGMDR). Each subtype involves a mutation in a single gene and has high heterogeneity in age of onset, expression, progression, and prognosis. In addition, the lack of understanding of the disease and the vague, nonspecific symptoms of LGMD subtypes make diagnosis difficult. Even as next-generation sequencing (NGS) genetic testing has become commonplace, some patients remain undiagnosed for many years. Methods: To identify LGMD-associated mutations, Targeted sequencing was performed in the patients and Sanger sequencing was performed in patients and family members. The in silico analysis tools such as Fathmm, M-CAP, Mutation Taster, PolyPhen 2, PROVEAN, REVEL, SIFT, MaxEntScan, Spliceailookup, Human Splicing Finder, NetGene2, and Fruitfly were used to predict the influence of the novel mutations. The pathogenicity of the mutation was interpreted according to the ACMG guidelines. Results: In this study, six patients from four different Vietnamese families were collected for genetic analysis at The Center for Gene and Protein Research and The Department of Molecular Pathology Faculty of Medical Technology, Hanoi Medical University, Hanoi, Vietnam. Based on clinical symptoms and serum creatine kinase (CK) levels, the patients were diagnosed with limb-girdle muscular dystrophies. Five mutations, including four (c.229C>T, p.Arg77Cys; exon one to three deletion; c.983 + 5G>C; and c.257_258insTGGCT, p.Phe88Leufs*125) in the SGCA gene and one (c.946-4_946-1delACAG) in the CAPN3 gene, were detected in six LGMD patients from four unrelated Vietnamese families. Two homozygous mutations (c.983 + 5G>C and c.257_258insTGGCT) in the SGCA gene were novel. These mutations were identified as the cause of the disease in the patients. Conclusion: Our results contribute to the general understanding of the etiology of the disease and provide the basis for definitive diagnosis and support genetic counseling and prenatal screening.
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Affiliation(s)
- Nam Chung Tran
- Center for Gene and Protein Research, Department of Molecular Pathology, Faculty of Medical Technology, Hanoi Medical University, Hanoi, Vietnam
- Hanoi Medical University, Hanoi, Vietnam
| | - Nguyen Thi Kim Lien
- Institute of Genome Research, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - Thanh Dat Ta
- Center for Gene and Protein Research, Department of Molecular Pathology, Faculty of Medical Technology, Hanoi Medical University, Hanoi, Vietnam
| | | | | | - Nguyen Van Tung
- Institute of Genome Research, Vietnam Academy of Science and Technology, Hanoi, Vietnam
- Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - Nguyen Thi Xuan
- Institute of Genome Research, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - Nguyen Huy Hoang
- Institute of Genome Research, Vietnam Academy of Science and Technology, Hanoi, Vietnam
- Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - Van Khanh Tran
- Center for Gene and Protein Research, Department of Molecular Pathology, Faculty of Medical Technology, Hanoi Medical University, Hanoi, Vietnam
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A Novel Homozygous Variant in DYSF Gene Is Associated with Autosomal Recessive Limb Girdle Muscular Dystrophy R2/2B. Int J Mol Sci 2022; 23:ijms23168932. [PMID: 36012197 PMCID: PMC9408934 DOI: 10.3390/ijms23168932] [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] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/04/2022] [Accepted: 08/09/2022] [Indexed: 11/16/2022] Open
Abstract
Mutations in the DYSF gene, encoding dysferlin, are responsible for Limb Girdle Muscular Dystrophy type R2/2B (LGMDR2/2B), Miyoshi myopathy (MM), and Distal Myopathy with Anterior Tibialis onset (MDAT). The size of the gene and the reported inter and intra familial phenotypic variability make early diagnosis difficult. Genetic analysis was conducted using Next Gene Sequencing (NGS), with a panel of 40 Muscular Dystrophies associated genes we designed. In the present study, we report a new missense variant c.5033G>A, p.Cys1678Tyr (NM_003494) in the exon 45 of DYSF gene related to Limb Girdle Muscular Dystrophy type R2/2B in a 57-year-old patient affected with LGMD from a consanguineous family of south Italy. Both healthy parents carried this variant in heterozygosity. Genetic analysis extended to two moderately affected sisters of the proband, showed the presence of the variant c.5033G>A in both in homozygosity. These data indicate a probable pathological role of the variant c.5033G>A never reported before in the onset of LGMDR2/2B, pointing at the NGS as powerful tool for identifying LGMD subtypes. Moreover, the collection and the networking of genetic data will increase power of genetic-molecular investigation, the management of at-risk individuals, the development of new therapeutic targets and a personalized medicine.
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Late-onset camptocormia caused by a heterozygous in-frame CAPN3 deletion. Neuromuscul Disord 2021; 31:450-455. [PMID: 33741228 DOI: 10.1016/j.nmd.2021.02.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 12/09/2020] [Accepted: 02/11/2021] [Indexed: 02/06/2023]
Abstract
Camptocormia is defined by a pathological involuntary flexion of the thoracic and lumbar spine that is fully reducible in the supine position. Although originally described as a manifestation of conversion disorder, it is more commonly caused by a wide range of neurological diseases, in particular movement and neuromuscular disorders. We describe here a rare case of late onset camptocormia caused by autosomal dominant calpainopathy due to a heterozygous in-frame deletion in CAPN3 leading to loss of a single lysin amino acid in the catalytic domain of calpain-3. Creatine kinase levels, electromyography, and thigh muscle MRI were normal. Muscle biopsy did not show lobulated fibers and calpain-3 protein expression was not decreased, but in vitro functional assays showed impaired proteolytic function of. Lys254del CAPN3. Autosomal dominant calpainopathy should be considered in the differential diagnosis of late onset camptocormia and unexplained paravertebral myopathies even in presence of normal creatine kinase levels, and in absence of lobulated fibers, of decreased calpain-3 protein expression, and of muscle limb involvement.
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Cerino M, Campana-Salort E, Salvi A, Cintas P, Renard D, Juntas Morales R, Tard C, Leturcq F, Stojkovic T, Bonello-Palot N, Gorokhova S, Mortreux J, Maues De Paula A, Lévy N, Pouget J, Cossée M, Bartoli M, Krahn M, Attarian S. Novel CAPN3 variant associated with an autosomal dominant calpainopathy. Neuropathol Appl Neurobiol 2020; 46:564-578. [PMID: 32342993 DOI: 10.1111/nan.12624] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 04/09/2020] [Indexed: 12/15/2022]
Abstract
AIMS The most common autosomal recessive limb girdle muscular dystrophy is associated with the CAPN3 gene. The exclusively recessive inheritance of this disorder has been recently challenged by the description of the recurrent variants, c.643_663del21 [p.(Ser215_Gly221del)] and c.598_612del15 [p.(Phe200_Leu204del)], associated with autosomal dominant inheritance. Our objective was to confirm the existence of autosomal dominant calpainopathies. METHODS Through our activity as one of the reference centres for genetic diagnosis of calpainopathies in France and the resulting collaborations through the French National Network for Rare Neuromuscular Diseases (FILNEMUS), we identified four families harbouring the same CAPN3 heterozygous variant with supposedly autosomal dominant inheritance. RESULTS We identified a novel dominantly inherited CAPN3 variant, c.1333G>A [p.(Gly445Arg)] in 14 affected patients from four unrelated families. The complementary phenotypic, functional and genetic findings correlate with an autosomal dominant inheritance in these families, emphasizing the existence of this novel transmission mode for calpainopathies. The mild phenotype associated with these autosomal dominant cases widens the phenotypic spectrum of calpainopathies and should therefore be considered in clinical practice. CONCLUSIONS We confirm the existence of autosomal dominant calpainopathies as an entity beyond the cases related to the in-frame deletions c.643_663del21 and c.598_612del15, with the identification of a novel dominantly inherited and well-documented CAPN3 missense variant, c.1333G>A [p.(Gly445Arg)]. In addition to the consequences for genetic counselling, the confirmation of an autosomal dominant transmission mode for calpainopathies underlines the importance of re-assessing other myopathies for which the inheritance is considered as strictly autosomal recessive.
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Affiliation(s)
- M Cerino
- Aix Marseille Univ, Inserm, U1251-MMG, Marseille Medical Genetics, Marseille, France.,APHM, Hôpital Timone Enfants, Département de Génétique Médicale, Marseille, France.,APHM, Laboratoire de Biochimie, Hôpital de la Conception, Marseille, France
| | - E Campana-Salort
- Aix Marseille Univ, Inserm, U1251-MMG, Marseille Medical Genetics, Marseille, France.,APHM, centre de référence des maladies neuromusculaires et de la SLA, CHU La Timone, Marseille, France
| | - A Salvi
- Aix Marseille Univ, Inserm, U1251-MMG, Marseille Medical Genetics, Marseille, France
| | - P Cintas
- Centre de référence de pathologie neuromusculaires, Hôpital Purpan, CHU de Toulouse, Toulouse, France
| | - D Renard
- Service de Neurologie, CHU de Nîmes, Univ. Montpellier, Nîmes, France
| | - R Juntas Morales
- Laboratoire de Génétique de Maladies Rares, Université de Montpellier, Montpellier, France.,Service de Neurologie, CHU de Montpellier, Montpellier, France
| | - C Tard
- U1172, Service de Neurologie, CHU de Lille, Lille, France.,Centre de référence des maladies neuromusculaires Nord/Est/Ile de France, Paris, France
| | - F Leturcq
- APHP, Laboratoire de génétique et biologie moléculaires, HUPC Cochin, Paris, France
| | - T Stojkovic
- APHP, Centre de référence des maladies neuromusculaires Nord/Est/Ile de France, Hôpital Pitié-Salpêtrière, Paris, France
| | - N Bonello-Palot
- Aix Marseille Univ, Inserm, U1251-MMG, Marseille Medical Genetics, Marseille, France.,APHM, Hôpital Timone Enfants, Département de Génétique Médicale, Marseille, France
| | - S Gorokhova
- Aix Marseille Univ, Inserm, U1251-MMG, Marseille Medical Genetics, Marseille, France.,APHM, Hôpital Timone Enfants, Département de Génétique Médicale, Marseille, France
| | - J Mortreux
- Aix Marseille Univ, Inserm, U1251-MMG, Marseille Medical Genetics, Marseille, France.,APHM, Hôpital Timone Enfants, Département de Génétique Médicale, Marseille, France
| | - A Maues De Paula
- Aix Marseille Univ, Inserm, U1251-MMG, Marseille Medical Genetics, Marseille, France.,APHM, Service d'anatomie pathologique et de neuropathologie, CHU La Timone, Marseille, France
| | - N Lévy
- Aix Marseille Univ, Inserm, U1251-MMG, Marseille Medical Genetics, Marseille, France.,APHM, Hôpital Timone Enfants, Département de Génétique Médicale, Marseille, France
| | - J Pouget
- APHM, centre de référence des maladies neuromusculaires et de la SLA, CHU La Timone, Marseille, France
| | - M Cossée
- Laboratoire de Génétique de Maladies Rares, Université de Montpellier, Montpellier, France.,Laboratoire de Génétique moléculaire, CHRU Montpellier, Montpellier, France
| | - M Bartoli
- Aix Marseille Univ, Inserm, U1251-MMG, Marseille Medical Genetics, Marseille, France
| | - M Krahn
- Aix Marseille Univ, Inserm, U1251-MMG, Marseille Medical Genetics, Marseille, France.,APHM, Hôpital Timone Enfants, Département de Génétique Médicale, Marseille, France
| | - S Attarian
- Aix Marseille Univ, Inserm, U1251-MMG, Marseille Medical Genetics, Marseille, France.,APHM, centre de référence des maladies neuromusculaires et de la SLA, CHU La Timone, Marseille, France
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Lasa-Elgarresta J, Mosqueira-Martín L, Naldaiz-Gastesi N, Sáenz A, López de Munain A, Vallejo-Illarramendi A. Calcium Mechanisms in Limb-Girdle Muscular Dystrophy with CAPN3 Mutations. Int J Mol Sci 2019; 20:E4548. [PMID: 31540302 PMCID: PMC6770289 DOI: 10.3390/ijms20184548] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 09/10/2019] [Accepted: 09/11/2019] [Indexed: 12/22/2022] Open
Abstract
Limb-girdle muscular dystrophy recessive 1 (LGMDR1), previously known as LGMD2A, is a rare disease caused by mutations in the CAPN3 gene. It is characterized by progressive weakness of shoulder, pelvic, and proximal limb muscles that usually appears in children and young adults and results in loss of ambulation within 20 years after disease onset in most patients. The pathophysiological mechanisms involved in LGMDR1 remain mostly unknown, and to date, there is no effective treatment for this disease. Here, we review clinical and experimental evidence suggesting that dysregulation of Ca2+ homeostasis in the skeletal muscle is a significant underlying event in this muscular dystrophy. We also review and discuss specific clinical features of LGMDR1, CAPN3 functions, novel putative targets for therapeutic strategies, and current approaches aiming to treat LGMDR1. These novel approaches may be clinically relevant not only for LGMDR1 but also for other muscular dystrophies with secondary calpainopathy or with abnormal Ca2+ homeostasis, such as LGMD2B/LGMDR2 or sporadic inclusion body myositis.
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Affiliation(s)
- Jaione Lasa-Elgarresta
- Biodonostia, Neurosciences Area, Group of Neuromuscular Diseases, 20014 San Sebastian, Spain.
- CIBERNED, Instituto de Salud Carlos III, Ministry of Science, Innovation and Universities, 28031 Madrid, Spain.
| | - Laura Mosqueira-Martín
- Biodonostia, Neurosciences Area, Group of Neuromuscular Diseases, 20014 San Sebastian, Spain.
- CIBERNED, Instituto de Salud Carlos III, Ministry of Science, Innovation and Universities, 28031 Madrid, Spain.
| | - Neia Naldaiz-Gastesi
- Biodonostia, Neurosciences Area, Group of Neuromuscular Diseases, 20014 San Sebastian, Spain.
- CIBERNED, Instituto de Salud Carlos III, Ministry of Science, Innovation and Universities, 28031 Madrid, Spain.
| | - Amets Sáenz
- Biodonostia, Neurosciences Area, Group of Neuromuscular Diseases, 20014 San Sebastian, Spain.
- CIBERNED, Instituto de Salud Carlos III, Ministry of Science, Innovation and Universities, 28031 Madrid, Spain.
| | - Adolfo López de Munain
- Biodonostia, Neurosciences Area, Group of Neuromuscular Diseases, 20014 San Sebastian, Spain.
- CIBERNED, Instituto de Salud Carlos III, Ministry of Science, Innovation and Universities, 28031 Madrid, Spain.
- Departmento de Neurosciencias, Universidad del País Vasco UPV/EHU, 20014 San Sebastian, Spain.
- Osakidetza Basque Health Service, Donostialdea Integrated Health Organisation, Neurology Department, 20014 San Sebastian, Spain.
| | - Ainara Vallejo-Illarramendi
- Biodonostia, Neurosciences Area, Group of Neuromuscular Diseases, 20014 San Sebastian, Spain.
- CIBERNED, Instituto de Salud Carlos III, Ministry of Science, Innovation and Universities, 28031 Madrid, Spain.
- Grupo Neurociencias, Departmento de Pediatría, Hospital Universitario Donostia, UPV/EHU, 20014 San Sebastian, Spain.
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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: 34] [Impact Index Per Article: 5.7] [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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Fichna JP, Macias A, Piechota M, Korostyński M, Potulska-Chromik A, Redowicz MJ, Zekanowski C. Whole-exome sequencing identifies novel pathogenic mutations and putative phenotype-influencing variants in Polish limb-girdle muscular dystrophy patients. Hum Genomics 2018; 12:34. [PMID: 29970176 PMCID: PMC6029161 DOI: 10.1186/s40246-018-0167-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 06/25/2018] [Indexed: 12/16/2022] Open
Abstract
Background Limb girdle muscular dystrophies (LGMD) are a group of heterogeneous hereditary myopathies with similar clinical symptoms. Disease onset and progression are highly variable, with an elusive genetic background, and around 50% cases lacking molecular diagnosis. Methods Whole exome sequencing (WES) was performed in 73 patients with clinically diagnosed LGMD. A filtering strategy aimed at identification of variants related to the disease included integrative analysis of WES data and human phenotype ontology (HPO) terms, analysis of genes expressed in muscle, analysis of the disease-associated interactome and copy number variants analysis. Results Genetic diagnosis was possible in 68.5% of cases. On average, 36.3 rare variants in genes associated with various muscle diseases per patient were found that could relate to the clinical phenotype. The putative causative mutations were mostly in LGMD-associated genes, but also in genes not included in the current LGMD classification (DMD, COL6A2, and COL6A3). In three patients, mutations in two genes were suggested as the joint cause of the disease (CAPN3+MYH7, COL6A3+CACNA1S, DYSF+MYH7). Moreover, a variety of phenotype-influencing variants were postulated, including in patients with an identified already known primary pathogenic mutation. Conclusions We hypothesize that LGMD could be better described as oligogenic disorders in which dominant clinical presentation can result from the combined effect of mutations in a set of genes. In this view, the inter- and intrafamilial variability could reflect a specific genetic background and the presence of sets of phenotype-influencing or co-causative mutations in genes that either interact with the known LGMD-associated genes or are a part of the same pathways or structures. Electronic supplementary material The online version of this article (10.1186/s40246-018-0167-1) contains supplementary material, which is available to authorized users.
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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.
| | - Anna Macias
- Department of Neurology, Medical University of Warsaw, 1a Banacha St., 02-097, Warsaw, Poland
| | - Marcin Piechota
- Department of Molecular Neuropharmacology, Institute of Pharmacology, Polish Academy of Sciences, 31-344, Krakow, Poland
| | - Michał Korostyński
- Department of Molecular Neuropharmacology, Institute of Pharmacology, Polish Academy of Sciences, 31-344, Krakow, Poland
| | - Anna Potulska-Chromik
- Department of Neurology, Medical University of Warsaw, 1a Banacha St., 02-097, Warsaw, Poland
| | - Maria Jolanta Redowicz
- Laboratory of Molecular Basis of Cell Motility, Department of Biochemistry, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093, Warsaw, Poland
| | - Cezary Zekanowski
- Department of Neurodegenerative Disorders, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego St., 02-106, Warsaw, Poland
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