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Rzepnikowska W, Kaminska J, Kochański A. The molecular mechanisms that underlie IGHMBP2-related diseases. Neuropathol Appl Neurobiol 2024; 50:e13005. [PMID: 39119929 DOI: 10.1111/nan.13005] [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: 01/31/2024] [Revised: 07/18/2024] [Accepted: 07/20/2024] [Indexed: 08/10/2024]
Abstract
Immunoglobulin Mu-binding protein 2 (IGHMBP2) pathogenic variants result in the fatal, neurodegenerative disease spinal muscular atrophy with respiratory distress type 1 (SMARD1) and the milder, Charcot-Marie-Tooth (CMT) type 2S (CMT2S) neuropathy. More than 20 years after the link between IGHMBP2 and SMARD1 was revealed, and 10 years after the discovery of the association between IGHMBP2 and CMT2S, the pathogenic mechanism of these diseases is still not well defined. The discovery that IGHMBP2 functions as an RNA/DNA helicase was an important step, but it did not reveal the pathogenic mechanism. Helicases are enzymes that use ATP hydrolysis to catalyse the separation of nucleic acid strands. They are involved in numerous cellular processes, including DNA repair and transcription; RNA splicing, transport, editing and degradation; ribosome biogenesis; translation; telomere maintenance; and homologous recombination. IGHMBP2 appears to be a multifunctional factor involved in several cellular processes that regulate gene expression. It is difficult to determine which processes, when dysregulated, lead to pathology. Here, we summarise our current knowledge of the clinical presentation of IGHMBP2-related diseases. We also overview the available models, including yeast, mice and cells, which are used to study the function of IGHMBP2 and the pathogenesis of the related diseases. Further, we discuss the structure of the IGHMBP2 protein and its postulated roles in cellular functioning. Finally, we present potential anomalies that may result in the neurodegeneration observed in IGHMBP2-related disease and highlight the most prominent ones.
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Affiliation(s)
- Weronika Rzepnikowska
- Neuromuscular Unit, Mossakowski Medical Research Institute Polish Academy of Sciences, Warsaw, 02-106, Poland
| | - Joanna Kaminska
- Institute of Biochemistry and Biophysics Polish Academy of Sciences, Warsaw, 02-106, Poland
| | - Andrzej Kochański
- Neuromuscular Unit, Mossakowski Medical Research Institute Polish Academy of Sciences, Warsaw, 02-106, Poland
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Liu L, Zeng S, Li X, Xie Y, Xu K, Yang H, Huang S, Zhao H, Zhang R. Genotype-phenotype correlations of AR-CMT2S in a cohort of axonal Charcot-Marie-Tooth patients from Central South China. J Peripher Nerv Syst 2024; 29:243-251. [PMID: 38772550 DOI: 10.1111/jns.12633] [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: 04/03/2024] [Revised: 05/07/2024] [Accepted: 05/08/2024] [Indexed: 05/23/2024]
Abstract
BACKGROUND AND AIMS This study aimed to report nine Charcot-Marie-Tooth disease (CMT) families with six novel IGHMBP2 mutations in our CMT2 cohort and to summarize the genetic and clinical features of all AR-CMT2S patients reported worldwide. METHODS General information, clinical and neurophysiological data of 275 axonal CMT families were collected. Genetic screening was performed by inherited peripheral neuropathy related genes panel or whole exome sequencing. The published papers reporting AR-CMT2S from 2014 to 2023 were searched in Pubmed and Wanfang databases. RESULTS In our CMT2 cohort, we detected 17 AR-CMT2S families carrying IGHMBP2 mutations and eight were published previously. Among these, c.743 T > A (p.Val248Glu), c.884A > G (p.Asp295Gly), c.1256C > A (p.Ser419*), c.2598_2599delGA (p.Lys868Sfs*16), c.1694_1696delATG (p.Asp565del) and c.2509A > T (p.Arg837*) were firstly reported. These patients prominently presented with early-onset typical axonal neuropathy and without respiratory dysfunction. So far, 56 AR-CMT2S patients and 57 different mutations coming from 43 families have been reported in the world. Twenty-nine of 32 missense mutations were clustered in helicase domain and ATPase region. The age at onset ranged from 0.11to 20 years (Mean ± SD: 3.43 ± 3.88 years) and the majority was infantile-onset (<2 years). The initial symptoms included weakness of limbs (19, 29.7%), delayed milestones (12, 18.8%), gait disturbance (11, 17.2%), feet deformity (8, 12.5%), feet drop (8, 12.5%), etc. INTERPRETATION: AR-CMT2S accounted for 6.2% in our CMT2 cohort. We firstly reported six novel IGHMBP2 mutations which expanded the genotypic spectrum of AR-CMT2S. Furthermore, 17 AR-CMT2S families could provide more resources for natural history study, drug research and development.
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Affiliation(s)
- Lei Liu
- Health Management Center, The Third Xiangya Hospital, Central South University, Changsha, People's Republic of China
| | - Sen Zeng
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, People's Republic of China
| | - Xiaobo Li
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, People's Republic of China
| | - Yongzhi Xie
- Department of Radiology, The Third Xiangya Hospital, Central South University, Changsha, People's Republic of China
| | - Ke Xu
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, People's Republic of China
| | - Honglan Yang
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, People's Republic of China
| | - Shunxiang Huang
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, People's Republic of China
| | - Huadong Zhao
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, People's Republic of China
| | - Ruxu Zhang
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, People's Republic of China
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Figueiredo FB, Tomaselli PJ, Hallak J, Mattiello-Sverzut AC, Covaleski APPM, Sobreira CFDR, de Paula Gouvêa S, Marques W. Genetic diversity in hereditary axonal neuropathy: Analyzing 53 Brazilian children. J Peripher Nerv Syst 2024; 29:97-106. [PMID: 38375759 DOI: 10.1111/jns.12617] [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: 01/21/2023] [Revised: 01/24/2024] [Accepted: 01/31/2024] [Indexed: 02/21/2024]
Abstract
BACKGROUND AND AIMS The genetic epidemiology of inherited neuropathies in children remains largely unknown. In this study, we specifically investigated the genetic profile of a Brazilian cohort of pediatric patients with pure or complex axonal neuropathies, a crucial knowledge in the near future for establishing treatment priorities and perspectives for this group of patients. METHODS Fifty-three pediatric patients who were assessed prior to reaching the age of 20, and who had clinical diagnoses of axonal hereditary neuropathy or presented with axonal neuropathy as the primary clinical feature, were included in the study. The recruitment of these cases took place from January 1, 2018, to December 31, 2020. The diagnosis was based on clinical and electrophysiological data. A molecular assessment was made using target-gene panel or whole-exome sequencing. Subsequently, segregation analysis was performed on available family members, and all candidate variants found were confirmed through Sanger. RESULTS A molecular diagnosis was reached in 68% of the patients (n = 36/53), considering only pathogenic and probably pathogenic variants. Variants in MFN2 (n = 15) and GJB1 (n = 3) accounted for half of the genetically confirmed patients (50%; n = 18/36). The other 18 genetically diagnosed patients had variants in several less common genes. INTERPRETATION Apart from MFN2 and GJB1 genes, universally recognized as a frequent cause of axonal neuropathies in most studied population, our Brazilian cohort of children with axonal neuropathies showed an important genetic heterogeneity, probably reflecting the multi ethnicity of the Brazilian population. Diagnostic, counseling, and future interventions should consider this characteristic.
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Affiliation(s)
- Fernanda Barbosa Figueiredo
- Neuroscience and Behavior Sciences Department, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Pedro José Tomaselli
- Neuroscience and Behavior Sciences Department, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Jaime Hallak
- Neuroscience and Behavior Sciences Department, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
- National Institute of Sciences and Technology-INCT-Translational Medicine-CNPq/FAPESP, Ribeirao Preto, Brazil
| | | | | | | | - Silmara de Paula Gouvêa
- Neuroscience and Behavior Sciences Department, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Wilson Marques
- Neuroscience and Behavior Sciences Department, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
- National Institute of Sciences and Technology-INCT-Translational Medicine-CNPq/FAPESP, Ribeirao Preto, Brazil
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Tian Y, Xing J, Shi Y, Yuan E. Exploring the relationship between IGHMBP2 gene mutations and spinal muscular atrophy with respiratory distress type 1 and Charcot-Marie-Tooth disease type 2S: a systematic review. Front Neurosci 2023; 17:1252075. [PMID: 38046662 PMCID: PMC10690808 DOI: 10.3389/fnins.2023.1252075] [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: 07/03/2023] [Accepted: 11/03/2023] [Indexed: 12/05/2023] Open
Abstract
Background IGHMBP2 is a crucial gene for the development and maintenance of the nervous system, especially in the survival of motor neurons. Mutations in this gene have been associated with spinal muscular atrophy with respiratory distress type 1 (SMARD1) and Charcot-Marie-Tooth disease type 2S (CMT2S). Methods We conducted a systematic literature search using the PubMed database to identify studies published up to April 1st, 2023, that investigated the association between IGHMBP2 mutations and SMARD1 or CMT2S. We compared the non-truncating mutations and truncating mutations of the IGHMBP2 gene and selected high-frequency mutations of the IGHMBP2 gene. Results We identified 52 articles that investigated the association between IGHMBP2 mutations and SMARD1/CMT2S. We found 6 hotspot mutations of the IGHMBP2 gene. The truncating mutations in trans were all associated with SMARD1. Conclusion This study provides evidence that the complete LOF mechanism of the IGHMBP2 gene defect may be an important cause of SMARD1.
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Affiliation(s)
- Yuan Tian
- Department of Clinical Laboratory, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Jinfang Xing
- Department of Clinical Laboratory, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Ying Shi
- Screening Center, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Enwu Yuan
- Department of Clinical Laboratory, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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Vadla GP, Ricardez Hernandez SM, Mao J, Garro-Kacher MO, Lorson ZC, Rice RP, Hansen SA, Lorson CL, Singh K, Lorson MA. ABT1 modifies SMARD1 pathology via interactions with IGHMBP2 and stimulation of ATPase and helicase activity. JCI Insight 2023; 8:e164608. [PMID: 36480289 PMCID: PMC9977310 DOI: 10.1172/jci.insight.164608] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 12/07/2022] [Indexed: 12/13/2022] Open
Abstract
SMA with respiratory distress type 1 (SMARD1) and Charcot-Marie-Tooth type 2S (CMT2S) are results of mutations in immunoglobulin mu DNA binding protein 2 (IGHMBP2). IGHMBP2 is a UPF1-like helicase with proposed roles in several cellular processes, including translation. This study examines activator of basal transcription 1 (ABT1), a modifier of SMARD1-nmd disease pathology. Microscale thermophoresis and dynamic light scattering demonstrate that IGHMBP2 and ABT1 proteins directly interact with high affinity. The association of ABT1 with IGHMBP2 significantly increases the ATPase and helicase activity as well as the processivity of IGHMBP2. The IGHMBP2/ABT1 complex interacts with the 47S pre-rRNA 5' external transcribed spacer and U3 small nucleolar RNA (snoRNA), suggesting that the IGHMBP2/ABT1 complex is important for pre-rRNA processing. Intracerebroventricular injection of scAAV9-Abt1 decreases FVB-Ighmbp2nmd/nmd disease pathology, significantly increases lifespan, and substantially decreases neuromuscular junction denervation. To our knowledge, ABT1 is the first disease-modifying gene identified for SMARD1. We provide a mechanism proposing that ABT1 decreases disease pathology in FVB-Ighmbp2nmd/nmd mutants by optimizing IGHMBP2 biochemical activity (ATPase and helicase activity). Our studies provide insight into SMARD1 pathogenesis, suggesting that ABT1 modifies IGHMBP2 activity as a means to regulate pre-rRNA processing.
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Affiliation(s)
- Gangadhar P. Vadla
- Department of Veterinary Pathobiology, College of Veterinary Medicine, and
- Bond Life Sciences Center, University of Missouri, Columbia, Missouri, USA
| | - Sara M. Ricardez Hernandez
- Department of Veterinary Pathobiology, College of Veterinary Medicine, and
- Bond Life Sciences Center, University of Missouri, Columbia, Missouri, USA
| | - Jiude Mao
- Department of Veterinary Pathobiology, College of Veterinary Medicine, and
- Bond Life Sciences Center, University of Missouri, Columbia, Missouri, USA
| | - Mona O. Garro-Kacher
- Department of Veterinary Pathobiology, College of Veterinary Medicine, and
- Bond Life Sciences Center, University of Missouri, Columbia, Missouri, USA
| | - Zachary C. Lorson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, and
- Bond Life Sciences Center, University of Missouri, Columbia, Missouri, USA
| | - Ronin P. Rice
- Department of Veterinary Pathobiology, College of Veterinary Medicine, and
- Bond Life Sciences Center, University of Missouri, Columbia, Missouri, USA
| | - Sarah A. Hansen
- Bond Life Sciences Center, University of Missouri, Columbia, Missouri, USA
| | - Christian L. Lorson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, and
- Bond Life Sciences Center, University of Missouri, Columbia, Missouri, USA
| | - Kamal Singh
- Department of Veterinary Pathobiology, College of Veterinary Medicine, and
- Bond Life Sciences Center, University of Missouri, Columbia, Missouri, USA
| | - Monique A. Lorson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, and
- Bond Life Sciences Center, University of Missouri, Columbia, Missouri, USA
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Zambon AA, Pini V, Bosco L, Falzone YM, Munot P, Muntoni F, Previtali SC. Early onset hereditary neuronopathies: an update on non-5q motor neuron diseases. Brain 2022; 146:806-822. [PMID: 36445400 PMCID: PMC9976982 DOI: 10.1093/brain/awac452] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 10/21/2022] [Accepted: 11/12/2022] [Indexed: 11/30/2022] Open
Abstract
Hereditary motor neuropathies (HMN) were first defined as a group of neuromuscular disorders characterized by lower motor neuron dysfunction, slowly progressive length-dependent distal muscle weakness and atrophy, without sensory involvement. Their cumulative estimated prevalence is 2.14/100 000 and, to date, around 30 causative genes have been identified with autosomal dominant, recessive,and X-linked inheritance. Despite the advances of next generation sequencing, more than 60% of patients with HMN remain genetically uncharacterized. Of note, we are increasingly aware of the broad range of phenotypes caused by pathogenic variants in the same gene and of the considerable clinical and genetic overlap between HMN and other conditions, such as Charcot-Marie-Tooth type 2 (axonal), spinal muscular atrophy with lower extremities predominance, neurogenic arthrogryposis multiplex congenita and juvenile amyotrophic lateral sclerosis. Considering that most HMN present during childhood, in this review we primarily aim to summarize key clinical features of paediatric forms, including recent data on novel phenotypes, to help guide differential diagnosis and genetic testing. Second, we describe newly identified causative genes and molecular mechanisms, and discuss how the discovery of these is changing the paradigm through which we approach this group of conditions.
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Affiliation(s)
- Alberto A Zambon
- Correspondence to: Alberto A. Zambon Neuromuscular Repair Unit InSpe and Division of Neuroscience IRCCS Ospedale San Raffaele, Milan, Italy E-mail:
| | - Veronica Pini
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health and Great Ormond Street Hospital, London, WC1N 1EH, UK
| | - Luca Bosco
- Neuromuscular Repair Unit, Institute of Experimental Neurology (InSpe), Division of Neuroscience, IRCCS Ospedale San Raffaele, 20132 Milan, Italy
| | - Yuri M Falzone
- Neuromuscular Repair Unit, Institute of Experimental Neurology (InSpe), Division of Neuroscience, IRCCS Ospedale San Raffaele, 20132 Milan, Italy
| | - Pinki Munot
- NIHR Great Ormond Street Hospital Biomedical Research Centre, London, WC1N 1EH, UK
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health and Great Ormond Street Hospital, London, WC1N 1EH, UK,NIHR Great Ormond Street Hospital Biomedical Research Centre, London, WC1N 1EH, UK
| | - Stefano C Previtali
- Neuromuscular Repair Unit, Institute of Experimental Neurology (InSpe), Division of Neuroscience, IRCCS Ospedale San Raffaele, 20132 Milan, Italy
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Rzepnikowska W, Kaminska J, Kochański A. Validation of the Pathogenic Effect of IGHMBP2 Gene Mutations Based on Yeast S. cerevisiae Model. Int J Mol Sci 2022; 23:ijms23179913. [PMID: 36077311 PMCID: PMC9456350 DOI: 10.3390/ijms23179913] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/28/2022] [Accepted: 08/29/2022] [Indexed: 11/29/2022] Open
Abstract
Spinal muscular atrophy with respiratory distress type 1 (SMARD1) is a heritable neurodegenerative disease characterized by rapid respiratory failure within the first months of life and progressive muscle weakness and wasting. Although the causative gene, IGHMBP2, is well defined, information on IGHMBP2 mutations is not always sufficient to diagnose particular patients, as the gene is highly polymorphic and the pathogenicity of many gene variants is unknown. In this study, we generated a simple yeast model to establish the significance of IGHMBP2 variants for disease development, especially those that are missense mutations. We have shown that cDNA of the human gene encodes protein which is functional in yeast cells and different pathogenic mutations affect this functionality. Furthermore, there is a correlation between the phenotype estimated in in vitro studies and our results, indicating that our model may be used to quickly and simply distinguish between pathogenic and non-pathogenic mutations identified in IGHMBP2 in patients.
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Affiliation(s)
- Weronika Rzepnikowska
- Neuromuscular Unit, Mossakowski Medical Research Institute, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Joanna Kaminska
- Institute of Biochemistry and Biophysics Polish Academy of Sciences, 02-106 Warsaw, Poland
- Correspondence:
| | - Andrzej Kochański
- Neuromuscular Unit, Mossakowski Medical Research Institute, Polish Academy of Sciences, 02-106 Warsaw, Poland
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8
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Clinical and genetic features of Charcot-Marie-Tooth disease patients with IGHMBP2 mutations. Neuromuscul Disord 2022; 32:564-571. [DOI: 10.1016/j.nmd.2022.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 05/07/2022] [Accepted: 05/09/2022] [Indexed: 11/18/2022]
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Rzepnikowska W, Kochański A. Models for IGHMBP2-associated diseases: an overview and a roadmap for the future. Neuromuscul Disord 2021; 31:1266-1278. [PMID: 34785121 DOI: 10.1016/j.nmd.2021.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 07/16/2021] [Accepted: 08/06/2021] [Indexed: 12/13/2022]
Abstract
Models are practical tools with which to establish the basic aspects of a diseases. They allow systematic research into the significance of mutations, of cellular and molecular pathomechanisms, of therapeutic options and of functions of diseases associated proteins. Thus, disease models are an integral part of the study of enigmatic proteins such as immunoglobulin mu-binding protein 2 (IGHMBP2). IGHMBP2 has been well defined as a helicase, however there is little known about its role in cellular processes. Notably, it is unclear why changes in such an abundant protein lead to specific neuronal disorders including spinal muscular atrophy with respiratory distress type 1 (SMARD1) and Charcot-Marie-Tooth type 2S (CMT2S). SMARD1 is caused by a loss of motor neurons in the spinal cord that results in muscle atrophy and is accompanied by rapid respiratory failure. In contrast, CMT2S manifests as a severe neuropathy, but typically without critical breathing problems. Here, we present the clinical manifestation of IGHMBP2 mutations, function of protein and models that may be used for the study of IGHMBP2-associated disorders. We highlight the strengths and weaknesses of specific models and discuss the orthologs of IGHMBP2 that are found in different systems with regard to their similarity to human IGHMBP2.
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Affiliation(s)
- Weronika Rzepnikowska
- Neuromuscular Unit, Mossakowski Medical Research Institute Polish Academy of Sciences, Warsaw 02-106, Poland.
| | - Andrzej Kochański
- Neuromuscular Unit, Mossakowski Medical Research Institute Polish Academy of Sciences, Warsaw 02-106, Poland
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10
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Bodle EE, Zhu W, Velez-Bartolomei F, Tesi-Rocha A, Liu P, Bernstein JA. Combined Genome Sequencing and RNA Analysis Reveals and Characterizes a Deep Intronic Variant in IGHMBP2 in a Patient With Spinal Muscular Atrophy With Respiratory Distress Type 1. Pediatr Neurol 2021; 114:16-20. [PMID: 33189025 DOI: 10.1016/j.pediatrneurol.2020.09.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 09/21/2020] [Accepted: 09/23/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND Pathogenic variants in the IGHMBP2 gene cause recessive spinal motor neuropathies of variable phenotype, including a predominantly distal motor impairment of Charcot-Marie-Tooth type 2S and the more severe condition of spinal muscular atrophy with respiratory distress type 1 in which infantile respiratory failure predominates. METHODS We describe the first reported case of spinal muscular atrophy with respiratory distress type 1 caused by a novel deep intronic variant in IGHMBP2 (NM_002180c.712-610A>G). RESULTS The variant was detected by whole genome sequencing. Reverse transcription-polymerase chain reaction and complimentary DNA sequencing were used to characterize the impact of the novel variant. CONCLUSIONS This report illustrates the utility in clinical practice of genome sequencing and RNA analysis, compared with exome sequencing alone.
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Affiliation(s)
- Ethan E Bodle
- Division of Medical Genetics, Department of Pediatrics, Stanford University School of Medicine, Stanford, California.
| | | | - Frances Velez-Bartolomei
- Division of Medical Genetics, Department of Pediatrics, Stanford University School of Medicine, Stanford, California
| | - Ana Tesi-Rocha
- Department of Neurology, Stanford University School of Medicine, Stanford, California
| | - Pengfei Liu
- Baylor Genetics, Houston, Texas; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Jonathan A Bernstein
- Division of Medical Genetics, Department of Pediatrics, Stanford University School of Medicine, Stanford, California
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11
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Guimarães-Costa R, Villar-Quiles RN, Latour P, Sole G, Husson I, Lacour A, Leonard-Louis S, Stojkovic T. Confounding clinical presentation and different disease progression in CMT4B1. Neuromuscul Disord 2020; 30:576-582. [DOI: 10.1016/j.nmd.2020.05.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 04/30/2020] [Accepted: 05/07/2020] [Indexed: 11/27/2022]
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12
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Morelli KH, Hatton CL, Harper SQ, Burgess RW. Gene therapies for axonal neuropathies: Available strategies, successes to date, and what to target next. Brain Res 2020; 1732:146683. [PMID: 32001243 DOI: 10.1016/j.brainres.2020.146683] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 01/23/2020] [Accepted: 01/24/2020] [Indexed: 12/20/2022]
Abstract
Nearly one-hundred loci in the human genome have been associated with different forms of Charcot-Marie-Tooth disease (CMT) and related inherited neuropathies. Despite this wealth of gene targets, treatment options are still extremely limited, and clear "druggable" pathways are not obvious for many of these mutations. However, recent advances in gene therapies are beginning to circumvent this challenge. Each type of CMT is a monogenic disorder, and the cellular targets are usually well-defined and typically include peripheral neurons or Schwann cells. In addition, the genetic mechanism is often also clear, with loss-of-function mutations requiring restoration of gene expression, and gain-of-function or dominant-negative mutations requiring silencing of the mutant allele. These factors combine to make CMT a good target for developing genetic therapies. Here we will review the state of relatively established gene therapy approaches, including viral vector-mediated gene replacement and antisense oligonucleotides for exon skipping, altering splicing, and gene knockdown. We will also describe earlier stage approaches for allele-specific knockdown and CRIPSR/Cas9 gene editing. We will next describe how these various approaches have been deployed in clinical and preclinical studies. Finally, we will evaluate various forms of CMT as candidates for gene therapy based on the current understanding of their genetics, cellular/tissue targets, validated animal models, and availability of patient populations and natural history data.
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Affiliation(s)
- Kathryn H Morelli
- The Jackson Laboratory, Bar Harbor, ME 04609, USA; The Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469, USA
| | | | - Scott Q Harper
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Robert W Burgess
- The Jackson Laboratory, Bar Harbor, ME 04609, USA; The Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469, USA.
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Cortese A, Wilcox JE, Polke JM, Poh R, Skorupinska M, Rossor AM, Laura M, Tomaselli PJ, Houlden H, Shy ME, Reilly MM. Targeted next-generation sequencing panels in the diagnosis of Charcot-Marie-Tooth disease. Neurology 2019; 94:e51-e61. [PMID: 31827005 PMCID: PMC7011687 DOI: 10.1212/wnl.0000000000008672] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 06/24/2019] [Indexed: 12/22/2022] Open
Abstract
OBJECTIVE To investigate the effectiveness of targeted next-generation sequencing (NGS) panels in achieving a molecular diagnosis in Charcot-Marie-Tooth disease (CMT) and related disorders in a clinical setting. METHODS We prospectively enrolled 220 patients from 2 tertiary referral centers, one in London, United Kingdom (n = 120), and one in Iowa (n = 100), in whom a targeted CMT NGS panel had been requested as a diagnostic test. PMP22 duplication/deletion was previously excluded in demyelinating cases. We reviewed the genetic and clinical data upon completion of the diagnostic process. RESULTS After targeted NGS sequencing, a definite molecular diagnosis, defined as a pathogenic or likely pathogenic variant, was reached in 30% of cases (n = 67). The diagnostic rate was similar in London (32%) and Iowa (29%). Variants of unknown significance were found in an additional 33% of cases. Mutations in GJB1, MFN2, and MPZ accounted for 39% of cases that received genetic confirmation, while the remainder of positive cases had mutations in diverse genes, including SH3TC2, GDAP1, IGHMBP2, LRSAM1, FDG4, and GARS, and another 12 less common genes. Copy number changes in PMP22, MPZ, MFN2, SH3TC2, and FDG4 were also accurately detected. A definite genetic diagnosis was more likely in cases with an early onset, a positive family history of neuropathy or consanguinity, and a demyelinating neuropathy. CONCLUSIONS NGS panels are effective tools in the diagnosis of CMT, leading to genetic confirmation in one-third of cases negative for PMP22 duplication/deletion, thus highlighting how rarer and previously undiagnosed subtypes represent a relevant part of the genetic landscape of CMT.
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Affiliation(s)
- Andrea Cortese
- From the MRC Centre for Neuromuscular Diseases (A.C., J.M.P., R.P., M.S., A.M.R., M.L., P.J.T., H.H., M.M.R.), Department of Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Queen Square Institute of Neurology, London, UK; Department of Brain and Behavioral Sciences (A.C.), University of Pavia, Italy; and the Department of Neurology (J.E.W., M.E.S.), University of Iowa Carver College of Medicine, Iowa City
| | - Janel E Wilcox
- From the MRC Centre for Neuromuscular Diseases (A.C., J.M.P., R.P., M.S., A.M.R., M.L., P.J.T., H.H., M.M.R.), Department of Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Queen Square Institute of Neurology, London, UK; Department of Brain and Behavioral Sciences (A.C.), University of Pavia, Italy; and the Department of Neurology (J.E.W., M.E.S.), University of Iowa Carver College of Medicine, Iowa City
| | - James M Polke
- From the MRC Centre for Neuromuscular Diseases (A.C., J.M.P., R.P., M.S., A.M.R., M.L., P.J.T., H.H., M.M.R.), Department of Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Queen Square Institute of Neurology, London, UK; Department of Brain and Behavioral Sciences (A.C.), University of Pavia, Italy; and the Department of Neurology (J.E.W., M.E.S.), University of Iowa Carver College of Medicine, Iowa City
| | - Roy Poh
- From the MRC Centre for Neuromuscular Diseases (A.C., J.M.P., R.P., M.S., A.M.R., M.L., P.J.T., H.H., M.M.R.), Department of Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Queen Square Institute of Neurology, London, UK; Department of Brain and Behavioral Sciences (A.C.), University of Pavia, Italy; and the Department of Neurology (J.E.W., M.E.S.), University of Iowa Carver College of Medicine, Iowa City
| | - Mariola Skorupinska
- From the MRC Centre for Neuromuscular Diseases (A.C., J.M.P., R.P., M.S., A.M.R., M.L., P.J.T., H.H., M.M.R.), Department of Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Queen Square Institute of Neurology, London, UK; Department of Brain and Behavioral Sciences (A.C.), University of Pavia, Italy; and the Department of Neurology (J.E.W., M.E.S.), University of Iowa Carver College of Medicine, Iowa City
| | - Alexander M Rossor
- From the MRC Centre for Neuromuscular Diseases (A.C., J.M.P., R.P., M.S., A.M.R., M.L., P.J.T., H.H., M.M.R.), Department of Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Queen Square Institute of Neurology, London, UK; Department of Brain and Behavioral Sciences (A.C.), University of Pavia, Italy; and the Department of Neurology (J.E.W., M.E.S.), University of Iowa Carver College of Medicine, Iowa City
| | - Matilde Laura
- From the MRC Centre for Neuromuscular Diseases (A.C., J.M.P., R.P., M.S., A.M.R., M.L., P.J.T., H.H., M.M.R.), Department of Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Queen Square Institute of Neurology, London, UK; Department of Brain and Behavioral Sciences (A.C.), University of Pavia, Italy; and the Department of Neurology (J.E.W., M.E.S.), University of Iowa Carver College of Medicine, Iowa City
| | - Pedro J Tomaselli
- From the MRC Centre for Neuromuscular Diseases (A.C., J.M.P., R.P., M.S., A.M.R., M.L., P.J.T., H.H., M.M.R.), Department of Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Queen Square Institute of Neurology, London, UK; Department of Brain and Behavioral Sciences (A.C.), University of Pavia, Italy; and the Department of Neurology (J.E.W., M.E.S.), University of Iowa Carver College of Medicine, Iowa City
| | - Henry Houlden
- From the MRC Centre for Neuromuscular Diseases (A.C., J.M.P., R.P., M.S., A.M.R., M.L., P.J.T., H.H., M.M.R.), Department of Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Queen Square Institute of Neurology, London, UK; Department of Brain and Behavioral Sciences (A.C.), University of Pavia, Italy; and the Department of Neurology (J.E.W., M.E.S.), University of Iowa Carver College of Medicine, Iowa City
| | - Michael E Shy
- From the MRC Centre for Neuromuscular Diseases (A.C., J.M.P., R.P., M.S., A.M.R., M.L., P.J.T., H.H., M.M.R.), Department of Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Queen Square Institute of Neurology, London, UK; Department of Brain and Behavioral Sciences (A.C.), University of Pavia, Italy; and the Department of Neurology (J.E.W., M.E.S.), University of Iowa Carver College of Medicine, Iowa City
| | - Mary M Reilly
- From the MRC Centre for Neuromuscular Diseases (A.C., J.M.P., R.P., M.S., A.M.R., M.L., P.J.T., H.H., M.M.R.), Department of Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Queen Square Institute of Neurology, London, UK; Department of Brain and Behavioral Sciences (A.C.), University of Pavia, Italy; and the Department of Neurology (J.E.W., M.E.S.), University of Iowa Carver College of Medicine, Iowa City.
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