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O'Brien K, Nguo K, Yiu EM, Woodcock IR, Billich N, Davidson ZE. Nutrition outcomes of disease modifying therapies in spinal muscular atrophy: A systematic review. Muscle Nerve 2024; 70:890-902. [PMID: 39129236 DOI: 10.1002/mus.28224] [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: 03/06/2024] [Revised: 07/17/2024] [Accepted: 07/19/2024] [Indexed: 08/13/2024]
Abstract
The nutritional implications of spinal muscular atrophy (SMA) are profound. Disease modifying therapies (DMT) have improved clinical outcomes. This review describes the impact of DMT on nutrition outcomes. A systematic search strategy was applied across seven databases until May 2023. Eligible studies measured nutrition outcomes in individuals with SMA on DMT (nusinersen, risdiplam or onasemnogene abeparvovec [OA]) compared to untreated comparators. Nutrition outcomes included anthropometry, feeding route, swallowing dysfunction, dietary intake, dietetic intervention, nutritional biochemistry, metabolism, gastrointestinal issues and energy expenditure. Articles retrieved were screened in duplicate, data were extracted and appraised systematically. Sixty three articles from 54 studies were included; 41% (n = 22) investigated nusinersen in pediatric participants with SMA type 1. Anthropometry (n = 18), feeding route (n = 39), and swallowing dysfunction (n = 18) were the most commonly reported outcomes. In combined pediatric and adult cohorts, BMI z-score remained stable post nusinersen therapy. The proportion of children with SMA requiring enteral nutrition was stable post nusinersen therapy. Ability to thrive at age 1.5 years was higher in children treated in early infancy with OA compared to historical controls. Significant heterogeneity existed across study population characteristics and outcome measures. Nusinersen may prevent deterioration in some nutrition outcomes; and OA in early infancy may be associated with improved nutrition outcomes. Timing of DMT initiation is an important consideration for future nutrition research. Studies investigating nutrition as a primary outcome of DMT, using consistent outcome measures are required for nutritional management strategies for this cohort to be appropriately tailored.
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Affiliation(s)
- Katie O'Brien
- Department of Nutrition, Dietetics and Food, Monash University, Faculty of Medicine Nursing and Health Sciences, Melbourne, Australia
- Department of Nutrition and Food Services, Royal Children's Hospital, Melbourne, Australia
| | - Kay Nguo
- Department of Nutrition, Dietetics and Food, Monash University, Faculty of Medicine Nursing and Health Sciences, Melbourne, Australia
| | - Eppie M Yiu
- Department of Neurology, Royal Children's Hospital, Melbourne, Australia
- Neurosciences Research, Murdoch Children's Research Institute, Melbourne, Australia
- Department of Paediatrics, Faculty of Medicine Dentistry and Health Sciences, University of Melbourne, Melbourne, Australia
| | - Ian R Woodcock
- Department of Neurology, Royal Children's Hospital, Melbourne, Australia
- Neurosciences Research, Murdoch Children's Research Institute, Melbourne, Australia
- Department of Paediatrics, Faculty of Medicine Dentistry and Health Sciences, University of Melbourne, Melbourne, Australia
| | - Natassja Billich
- Molecular Therapies Research, Murdoch Children's Research Institute, Melbourne, Australia
- The University of Queensland School of Human Movement and Nutrition Sciences, St Lucia, Australia
| | - Zoe E Davidson
- Department of Nutrition, Dietetics and Food, Monash University, Faculty of Medicine Nursing and Health Sciences, Melbourne, Australia
- Department of Neurology, Royal Children's Hospital, Melbourne, Australia
- Neurosciences Research, Murdoch Children's Research Institute, Melbourne, Australia
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2
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McPheron MA, Felker MV. Clinical perspectives: Treating spinal muscular atrophy. Mol Ther 2024; 32:2489-2504. [PMID: 38894541 PMCID: PMC11405177 DOI: 10.1016/j.ymthe.2024.06.020] [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: 12/05/2023] [Revised: 04/26/2024] [Accepted: 06/14/2024] [Indexed: 06/21/2024] Open
Abstract
Spinal muscular atrophy is a rare and progressive neuromuscular disease that, without treatment, leads to progressive weakness and often death. A plethora of studies have led to the approval of three high-cost and effective treatments since 2016. These treatments, nusinersen, onasemnogene abeparvovec, and risdiplam, have not been directly compared and have varying challenges in administration. In this review, we discuss the evidence supporting the use of these medications, the process of treatment selection, monitoring after treatment, the limited data comparing treatments, as well as future directions for investigation and therapy.
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Affiliation(s)
- Molly A McPheron
- Department of Medical and Molecular Genetics, Indiana University, Indianapolis, IN 46202, USA
| | - Marcia V Felker
- Department of Neurology, Indiana University, Indianapolis, IN 46202, USA.
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3
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Ahmed F, Islam A, Akter S, Al Zubayer MA, Mahmud MN, Yeasmin H, Mawa Z. Multidisciplinary physical rehabilitation program of individuals with spinal muscular atrophy in an inclusive school setting. J Pediatr Rehabil Med 2024; 17:247-252. [PMID: 38007681 PMCID: PMC11307014 DOI: 10.3233/prm-230008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Accepted: 07/26/2023] [Indexed: 11/27/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular ailment that leads to the deprivation of motor neurons in the spinal cord, producing denervation and muscle weakness. This case report explains how a patient with type 2 SMA used a therapeutic exercise rehabilitation program in a school environment. Motor functions were assessed by Gross Motor Function Measure-88 (GMFM-88), Manual Muscle Testing (MMT), and Hammersmith Functional Motor Scale (HFMS), which is validated and reliable. This study employed a repeated pre-test post-test measures design. During a year of treatment sessions, the child underwent twice weekly 45-minute physical therapy sessions for 48 weeks. The research was carried out between March 2022 and February 2023. The purpose of the intervention, which comprised a variety of therapeutic workouts, was to enhance physical function and gross motor abilities in an age-appropriate manner. The intervention utilized in this study led to improvements in GMFM-88, HFMS, and MMT total scores. The results of this case study showed that a child with type 2 SMA aged nine had successfully improved their gross motor skills and muscle strength.
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Affiliation(s)
- Faruq Ahmed
- William and Marie Taylor School, Centre for the Rehabilitation of the Paralyzed (CRP), Savar, Dhaka, Bangladesh
| | - Asma Islam
- Department of Physiotherapy, Bangladesh Health Professions Institute (BHPI), CRP, Savar, Dhaka, Bangladesh
| | - Suria Akter
- William and Marie Taylor School, Centre for the Rehabilitation of the Paralyzed (CRP), Savar, Dhaka, Bangladesh
| | - Md Abdullah Al Zubayer
- William and Marie Taylor School, Centre for the Rehabilitation of the Paralyzed (CRP), Savar, Dhaka, Bangladesh
| | - Md Nasim Mahmud
- Department of Physiotherapy, Centre for the Rehabilitation of the Paralyzed (CRP), Savar, Dhaka, Bangladesh
| | - Hosneara Yeasmin
- William and Marie Taylor School, Centre for the Rehabilitation of the Paralyzed (CRP), Savar, Dhaka, Bangladesh
| | - Zannatul Mawa
- Department of Physiotherapy, Centre for the Rehabilitation of the Paralyzed (CRP), Savar, Dhaka, Bangladesh
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Li L, Perera L, Varghese SA, Shiloh-Malawsky Y, Hunter SE, Sneddon TP, Powell CM, Matera AG, Fan Z. A homozygous missense variant in the YG box domain in an individual with severe spinal muscular atrophy: a case report and variant characterization. Front Cell Neurosci 2023; 17:1259380. [PMID: 37841286 PMCID: PMC10571918 DOI: 10.3389/fncel.2023.1259380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Accepted: 09/04/2023] [Indexed: 10/17/2023] Open
Abstract
The vast majority of severe (Type 0) spinal muscular atrophy (SMA) cases are caused by homozygous deletions of survival motor neuron 1 (SMN1). We report a case in which the patient has two copies of SMN1 but clinically presents as Type 0 SMA. The patient is an African American male carrying a homozygous maternally inherited missense variant (c.796T>C) in a cis-oriented SMN1 duplication on one chromosome and an SMN1 deletion on the other chromosome (genotype: 2*+0). Initial extensive genetic workups including exome sequencing were negative. Deletion analysis used in the initial testing for SMA also failed to detect SMA as the patient has two copies of SMN1. Because of high clinical suspicion, SMA diagnosis was finally confirmed based on full-length SMN1 sequencing. The patient was initially treated with risdiplam and later gene therapy with onasemnogene abeparvovec at 5 months without complications. The patient's muscular weakness has stabilized with mild improvement. The patient is now 28 months old and remains stable and diffusely weak, with stable respiratory ventilatory support. This case highlights challenges in the diagnosis of SMA with a non-deletion genotype and provides a clinical example demonstrating that disruption of functional SMN protein polymerization through an amino acid change in the YG-box domain represents a little known but important pathogenic mechanism for SMA. Clinicians need to be mindful about the limitations of the current diagnostic approach for SMA in detecting non-deletion genotypes.
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Affiliation(s)
- Leping Li
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, Durham, NC, United States
| | - Lalith Perera
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, Durham, NC, United States
| | - Sonia A. Varghese
- Division of Pediatric Neurology, Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Yael Shiloh-Malawsky
- Division of Pediatric Neurology, Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Senyene E. Hunter
- Division of Pediatric Neurology, Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Tam P. Sneddon
- Department of Pathology and Lab Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Cynthia M. Powell
- Division of Genetics and Metabolism, Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - A. Gregory Matera
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Zheng Fan
- Division of Pediatric Neurology, Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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5
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Sagerer E, Wirner C, Schoser B, Wenninger S. Nociceptive pain in adult patients with 5q-spinal muscular atrophy type 3: a cross-sectional clinical study. J Neurol 2023; 270:250-261. [PMID: 36036285 PMCID: PMC9813071 DOI: 10.1007/s00415-022-11351-0] [Citation(s) in RCA: 1] [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: 06/13/2022] [Revised: 08/19/2022] [Accepted: 08/21/2022] [Indexed: 01/09/2023]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder caused by mutations in the SMN gene, leading to progressive muscular weakness, atrophy and so far neglected musculoskeletal pain. This study is the first to characterize nociceptive pain in patients living with SMA type 3 by assessing whether muscle pain is associated with alterations in muscle strength, function, stiffness, frequency, decrement, relaxation, or creep. METHODS We performed a cross-sectional pilot study on 20 SMA3 patients. We evaluated motor function and muscle strength (dynamometry, quick motor function test and 6-min-walk test), nociceptive pain (pressure algometer evaluating muscular pressure pain threshold (PPT)) and non-invasive measurement of muscle stiffness, frequency, decrement, relaxation, or creep (myotonometry with the MyotonPro®). For statistical analysis, we used t tests, Mann-Whitney U tests and linear regression. RESULTS Significantly more women than men reported musculoskeletal pain (p = 0.003). A lower score in dynamometry was associated with lower scores in PPT in all extremities reflecting a higher sensitivity of these muscles to pressure. We did not find significant correlations between the PPT values and the MyotonPro values in the corresponding muscles. Assessments of PPT before and after the 6-min walk test did not show clinical meaningful changes. Besides nociceptive pain, fatigue was prevalent in 50% and pain in 55% of the patients. CONCLUSIONS Muscle pain in SMA3 is associated with muscular weakness in the arms and legs, but not with changes in muscular stiffness, frequency, decrement, relaxation, or creep. This shows that muscle pain in SMA3 is mainly caused by changes in the dysbalanced musculoskeletal system due to muscle weakness.
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Affiliation(s)
- Elena Sagerer
- Department of Neurology, Friedrich-Baur-Institute, Ludwig-Maximilians University Munich, Ziemssenstr. 1, 80336, Munich, Germany
| | - Corinna Wirner
- Department of Neurology, Friedrich-Baur-Institute, Ludwig-Maximilians University Munich, Ziemssenstr. 1, 80336, Munich, Germany
| | - Benedikt Schoser
- Department of Neurology, Friedrich-Baur-Institute, Ludwig-Maximilians University Munich, Ziemssenstr. 1, 80336, Munich, Germany
| | - Stephan Wenninger
- Department of Neurology, Friedrich-Baur-Institute, Ludwig-Maximilians University Munich, Ziemssenstr. 1, 80336, Munich, Germany.
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6
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Detering NT, Schüning T, Hensel N, Claus P. The phospho-landscape of the survival of motoneuron protein (SMN) protein: relevance for spinal muscular atrophy (SMA). Cell Mol Life Sci 2022; 79:497. [PMID: 36006469 PMCID: PMC11071818 DOI: 10.1007/s00018-022-04522-9] [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: 03/21/2022] [Revised: 07/27/2022] [Accepted: 08/09/2022] [Indexed: 11/03/2022]
Abstract
Spinal muscular atrophy (SMA) is caused by low levels of the survival of motoneuron (SMN) Protein leading to preferential degeneration of lower motoneurons in the ventral horn of the spinal cord and brain stem. However, the SMN protein is ubiquitously expressed and there is growing evidence of a multisystem phenotype in SMA. Since a loss of SMN function is critical, it is important to decipher the regulatory mechanisms of SMN function starting on the level of the SMN protein itself. Posttranslational modifications (PTMs) of proteins regulate multiple functions and processes, including activity, cellular trafficking, and stability. Several PTM sites have been identified within the SMN sequence. Here, we map the identified SMN PTMs highlighting phosphorylation as a key regulator affecting localization, stability and functions of SMN. Furthermore, we propose SMN phosphorylation as a crucial factor for intracellular interaction and cellular distribution of SMN. We outline the relevance of phosphorylation of the spinal muscular atrophy (SMA) gene product SMN with regard to basic housekeeping functions of SMN impaired in this neurodegenerative disease. Finally, we compare SMA patient mutations with putative and verified phosphorylation sites. Thus, we emphasize the importance of phosphorylation as a cellular modulator in a clinical perspective as a potential additional target for combinatorial SMA treatment strategies.
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Affiliation(s)
- Nora Tula Detering
- SMATHERIA gGmbH - Non-Profit Biomedical Research Institute, Hannover, Germany
- Center for Systems Neuroscience (ZSN), Hannover, Germany
| | - Tobias Schüning
- SMATHERIA gGmbH - Non-Profit Biomedical Research Institute, Hannover, Germany
- Center for Systems Neuroscience (ZSN), Hannover, Germany
| | - Niko Hensel
- Ottawa Hospital Research Institute (OHRI), Ottawa, Canada
- Center for Systems Neuroscience (ZSN), Hannover, Germany
| | - Peter Claus
- SMATHERIA gGmbH - Non-Profit Biomedical Research Institute, Hannover, Germany.
- Center for Systems Neuroscience (ZSN), Hannover, Germany.
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7
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Butchbach MER. Genomic Variability in the Survival Motor Neuron Genes ( SMN1 and SMN2): Implications for Spinal Muscular Atrophy Phenotype and Therapeutics Development. Int J Mol Sci 2021; 22:ijms22157896. [PMID: 34360669 PMCID: PMC8348669 DOI: 10.3390/ijms22157896] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 07/14/2021] [Accepted: 07/21/2021] [Indexed: 02/07/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a leading genetic cause of infant death worldwide that is characterized by loss of spinal motor neurons leading to muscle weakness and atrophy. SMA results from the loss of survival motor neuron 1 (SMN1) gene but retention of its paralog SMN2. The copy numbers of SMN1 and SMN2 are variable within the human population with SMN2 copy number inversely correlating with SMA severity. Current therapeutic options for SMA focus on increasing SMN2 expression and alternative splicing so as to increase the amount of SMN protein. Recent work has demonstrated that not all SMN2, or SMN1, genes are equivalent and there is a high degree of genomic heterogeneity with respect to the SMN genes. Because SMA is now an actionable disease with SMN2 being the primary target, it is imperative to have a comprehensive understanding of this genomic heterogeneity with respect to hybrid SMN1–SMN2 genes generated by gene conversion events as well as partial deletions of the SMN genes. This review will describe this genetic heterogeneity in SMA and its impact on disease phenotype as well as therapeutic efficacy.
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Affiliation(s)
- Matthew E. R. Butchbach
- Center for Applied Clinical Genomics, Nemours Children’s Health Delaware, Wilmington, DE 19803, USA;
- Center for Pediatric Research, Nemours Children’s Health Delaware, Wilmington, DE 19803, USA
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
- Department of Pediatrics, Thomas Jefferson University, Philadelphia, PA 19107, USA
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8
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Spinal Muscular Atrophy: Inheritance, Screening, and Counseling for the Obstetric Provider. Obstet Gynecol Surv 2021; 76:166-169. [PMID: 33783545 DOI: 10.1097/ogx.0000000000000870] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Importance Spinal muscular atrophy (SMA) confers significant risk of neonatal and infant morbidity and mortality. Screening women during or before pregnancy for carrier status of SMA presents an opportunity to identify pregnancies at risk for this potentially devastating condition. Objective The objective of this review is to describe the different forms of SMA and their inheritance. In addition, this review guides obstetric providers in interpreting results of carrier screening. Evidence Acquisition A MEDLINE search of "prenatal genetic testing," "spinal muscular atrophy," and "inheritance of spinal muscular atrophy" in the review was performed. Results The evidence cited in this review includes 4 medical society committee opinions and 14 additional peer-reviewed journal articles that were original research or expert opinion summaries. Conclusions and Relevance Spinal muscular atrophy is a severe, heterogeneous neurodegenerative disorder. The American College of Obstetricians and Gynecologists recommends that obstetricians offer carrier screening for SMA to all pregnant women. Given the different types and inheritance of SMA, understanding of the disease and interpreting carrier screening results is of paramount importance to the prenatal care provider.
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9
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Dual Mechanism of a New SMN1 Variant (c.835G>C, p.Gly279Arg) by Interrupting Exon 7 Skipping and YG Oligomerization in Causation of Spinal Muscular Atrophy. J Mol Neurosci 2020; 71:112-121. [PMID: 32812185 DOI: 10.1007/s12031-020-01631-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 06/08/2020] [Indexed: 10/23/2022]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder caused by deletion or subtle variant of survival motor neuron 1 (SMN1) gene. By multiplex ligation-dependent probe amplification, genomic sequencing, and T-A cloning on cDNA level, we identified one novel SMN1 subtle variant c.835G>C (p.Gly279Arg) in a non-homozygous patient with type 1 SMA. Full-length SMN1 (fl-SMN1) transcripts in the peripheral bloods of the patient were significantly decreased compared with those in healthy individuals and the carries (p < 0.05). And two fragments of SMN1 transcripts including fl-SMN1 and △7-SMN1 were observed by RT-PCR, which indicated Exon 7 skipping of SMN1 gene. To further evaluate its splicing effects on Exon 7, we performed ex vivo splicing analysis, which showed that the mutant mini gene with c.835G>C reduced Exon 7 inclusion to 54%. In addition, self-oligomerization between mutant SMN protein with the c.835G>C (p.Gly279Arg) and wild SMN was decreased in self-interaction assays. Our study clearly demonstrates that the c.835G>C (p.Gly279Arg) variant can lead to a decrease in fl-SMN1 transcripts by interrupting correct splicing of SMN1. What is more, the variant also affects SMN self-oligomerization via amino acid substitution from Gly to Arg at amino acid position of 279. This work presents the first evidence that it does exit double-hit events for the novel variant, which is crucial to understanding a severe SMA phenotype (type 1).
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10
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Chang Y, Kim J, Park H, Choi H, Kim J. Modelling neurodegenerative diseases with 3D brain organoids. Biol Rev Camb Philos Soc 2020; 95:1497-1509. [PMID: 32568450 DOI: 10.1111/brv.12626] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 05/25/2020] [Accepted: 05/28/2020] [Indexed: 02/06/2023]
Abstract
Neurodegenerative diseases are incurable and debilitating conditions characterized by the deterioration of brain function. Most brain disease models rely on human post-mortem brain tissue, non-human primate tissue, or in vitro two-dimensional (2D) experiments. Resource limitations and the complexity of the human brain are some of the reasons that make suitable human neurodegenerative disease models inaccessible. However, recently developed three-dimensional (3D) brain organoids derived from pluripotent stem cells (PSCs), including embryonic stem cells and induced PSCs, may provide suitable models for the study of the pathological features of neurodegenerative diseases. In this review, we provide an overview of existing 3D brain organoid models and discuss recent advances in organoid technology that have increased our understanding of brain development. Moreover, we explain how 3D organoid models recapitulate aspects of specific neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and Huntington's disease, and explore the utility of these models, for therapeutic applications.
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Affiliation(s)
- Yujung Chang
- Department of Biomedical Engineering, Dongguk University, Seoul, 04620, Republic of Korea
| | - Junyeop Kim
- Department of Biomedical Engineering, Dongguk University, Seoul, 04620, Republic of Korea
| | - Hanseul Park
- Department of Biomedical Engineering, Dongguk University, Seoul, 04620, Republic of Korea
| | - Hwan Choi
- Department of Biomedical Engineering, Dongguk University, Seoul, 04620, Republic of Korea
| | - Jongpil Kim
- Department of Biomedical Engineering, Dongguk University, Seoul, 04620, Republic of Korea.,Department of Chemistry, Dongguk University, Seoul, 04620, Republic of Korea
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11
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Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease caused by deletions or mutations in the survival motor neuron (SMN1) gene. SMA is characterized by loss of lower motor neurons (anterior horn cells) in the spinal cord and brainstem nuclei, leading to progressive symmetrical muscle weakness and atrophy. It affects approximately 1 in 6,000 to 1 in 10,000 individuals and is the most common inherited cause of childhood mortality, but this may soon change given recent developments. In December 2016, nusinersen, an antisense oligonucleotide drug, was approved by the United States Food and Drug Administration for the treatment of SMA, and in July 2018, SMA was added to the recommended uniform screening panel, a list of conditions that all states are encouraged to include in their newborn screening (NBS) panels. In this review, we begin with a brief clinical history of the diagnosis of SMA, discuss the current SMA clinical classification system, describe the current treatment, and discuss evolving treatment guidelines. We then discuss the path to include SMA in NBS programs as well as the controversies it engenders because the variability in age at symptom onset means early identification of asymptomatic patients who will not require therapy for years or decades. We also consider alternate population screening opportunities. Next, we consider experimental treatments. We conclude by supporting NBS for SMA with the caveat that a long-term follow-up registry is ethically essential to ensure that the benefits outweigh the harms for all screened infants, including those with milder and/or later-onset forms of SMA.
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Affiliation(s)
- Lainie Friedman Ross
- Departments of Pediatrics, Medicine, Surgery and the College; MacLean Center for Clinical Medical Ethics, University of Chicago, Chicago, IL
| | - Jennifer M Kwon
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, WI
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12
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Lomonte P, Baklouti F, Binda O. The Biochemistry of Survival Motor Neuron Protein Is Paving the Way to Novel Therapies for Spinal Muscle Atrophy. Biochemistry 2020; 59:1391-1397. [PMID: 32227847 DOI: 10.1021/acs.biochem.9b01124] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Spinal muscle atrophy (SMA) is the leading genetic cause of infant mortality. SMA originates from the loss of functional survival motor neuron (SMN) protein. In most SMA cases, the SMN1 gene is deleted. However, in some cases, SMN is mutated, impairing its biological functions. SMN mutants could provide clues about the biological functions of SMN and the specific impact on SMA, potentially leading to the identification of new pathways and thus providing novel treatment alternatives, and even personalized care. Here, we discuss the biochemistry of SMN and the most recent SMA treatment strategies.
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Affiliation(s)
- Patrick Lomonte
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène (INMG), 69008 Lyon, France
| | - Faouzi Baklouti
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène (INMG), 69008 Lyon, France
| | - Olivier Binda
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène (INMG), 69008 Lyon, France
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13
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Xu Y, Xiao B, Liu Y, Qu XX, Dai MY, Ying XM, Jiang WT, Zhang JM, Liu XQ, Chen YW, Ji X. Identification of novel SMN1 subtle mutations using an allelic-specific RT-PCR. Neuromuscul Disord 2019; 30:219-226. [PMID: 32169315 DOI: 10.1016/j.nmd.2019.11.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 11/12/2019] [Accepted: 11/22/2019] [Indexed: 01/18/2023]
Abstract
Spinal muscular atrophy (SMA) is caused by homozygous deletions of the SMN1 gene in approximately 95% of patients. The remaining 5% of patients with SMA retain at least one copy of the SMN1 gene carrying insertions, deletions, or point mutations. Although molecular genetic testing for most SMA patients is quite easy, diagnosing "nondeletion" SMA patients is still compromised by the presence of a highly homologous SMN2 gene. In this study, we analyzed the SMN1/SMN2 copy number by quantitative PCR and multiplex ligation-dependent probe amplification (MLPA). Further, common primers for both SMN1 and SMN2 sequences were used to screen DNA intragenic mutations. To confirm whether the identified mutations occurred in SMN1 or SMN2, we improved the traditional RT-PCR method by only amplifying SMN1 transcripts using an allelic-specific PCR (AS-RT-PCR) strategy. We identified six SMN1 point mutations and small indels in 8 families, which included c.683T>A, c.22dupA, c.815A>G, c.19delG, c.551_552insA and c.401_402delAG. To the best of our knowledge, the latter three have never been previously reported. The most common mutation in Chinese patients is c.22dupA, which was identified in three families. In this work, we demonstrated AS-RT-PCR to be reliable for identifying SMN1 subtle mutations, especially the prevalent mutation c.22dupA in Chinese SMA patients. By reviewing published papers and summarizing reported SMN1 mutations, a distinct ethnic specificity was found in SMA patients from China. Our research extends the SMN1 mutation spectrum.
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Affiliation(s)
- Yan Xu
- Department of Genetic Counseling, Shanghai Institute for Pediatric Research, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, 1665 Kongjiang Road, Shanghai 200092, China; Department of Endocrinology and Genetics, Shanghai Institute for Pediatric Research, Shanghai, China
| | - Bing Xiao
- Department of Genetic Counseling, Shanghai Institute for Pediatric Research, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, 1665 Kongjiang Road, Shanghai 200092, China; Department of Endocrinology and Genetics, Shanghai Institute for Pediatric Research, Shanghai, China
| | - Yu Liu
- Department of Genetic Counseling, Shanghai Institute for Pediatric Research, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, 1665 Kongjiang Road, Shanghai 200092, China; Department of Endocrinology and Genetics, Shanghai Institute for Pediatric Research, Shanghai, China
| | - Xiao-Xing Qu
- Department of Fetal Medicine Center, Shanghai First Maternity and Infant Hospital Affiliated to Shanghai Tongji University, Shanghai, China
| | - Meng-Yao Dai
- Department of Genetic Counseling, Shanghai Institute for Pediatric Research, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, 1665 Kongjiang Road, Shanghai 200092, China; Department of Endocrinology and Genetics, Shanghai Institute for Pediatric Research, Shanghai, China
| | - Xiao-Min Ying
- Department of Genetic Counseling, Shanghai Institute for Pediatric Research, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, 1665 Kongjiang Road, Shanghai 200092, China; Department of Endocrinology and Genetics, Shanghai Institute for Pediatric Research, Shanghai, China
| | - Wen-Ting Jiang
- Department of Genetic Counseling, Shanghai Institute for Pediatric Research, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, 1665 Kongjiang Road, Shanghai 200092, China; Department of Endocrinology and Genetics, Shanghai Institute for Pediatric Research, Shanghai, China
| | - Jing-Min Zhang
- Department of Genetic Counseling, Shanghai Institute for Pediatric Research, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, 1665 Kongjiang Road, Shanghai 200092, China; Department of Endocrinology and Genetics, Shanghai Institute for Pediatric Research, Shanghai, China
| | - Xiao-Qing Liu
- Department of Genetic Counseling, Shanghai Institute for Pediatric Research, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, 1665 Kongjiang Road, Shanghai 200092, China; Department of Endocrinology and Genetics, Shanghai Institute for Pediatric Research, Shanghai, China
| | - Ying-Wei Chen
- Department of Genetic Counseling, Shanghai Institute for Pediatric Research, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, 1665 Kongjiang Road, Shanghai 200092, China
| | - Xing Ji
- Department of Genetic Counseling, Shanghai Institute for Pediatric Research, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, 1665 Kongjiang Road, Shanghai 200092, China.
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14
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Carrier frequency of spinal muscular atrophy in Thailand. Neurol Sci 2019; 40:1729-1732. [DOI: 10.1007/s10072-019-03885-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 04/04/2019] [Indexed: 01/20/2023]
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15
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Ruhno C, McGovern VL, Avenarius MR, Snyder PJ, Prior TW, Nery FC, Muhtaseb A, Roggenbuck JS, Kissel JT, Sansone VA, Siranosian JJ, Johnstone AJ, Nwe PH, Zhang RZ, Swoboda KJ, Burghes AHM. Complete sequencing of the SMN2 gene in SMA patients detects SMN gene deletion junctions and variants in SMN2 that modify the SMA phenotype. Hum Genet 2019; 138:241-256. [PMID: 30788592 PMCID: PMC6503527 DOI: 10.1007/s00439-019-01983-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 02/14/2019] [Indexed: 12/11/2022]
Abstract
Spinal muscular atrophy (SMA) is a progressive motor neuron disease caused by loss or mutation of the survival motor neuron 1 (SMN1) gene and retention of SMN2. We performed targeted capture and sequencing of the SMN2, CFTR, and PLS3 genes in 217 SMA patients. We identified a 6.3 kilobase deletion that occurred in both SMN1 and SMN2 (SMN1/2) and removed exons 7 and 8. The deletion junction was flanked by a 21 bp repeat that occurred 15 times in the SMN1/2 gene. We screened for its presence in 466 individuals with the known SMN1 and SMN2 copy numbers. In individuals with 1 SMN1 and 0 SMN2 copies, the deletion occurred in 63% of cases. We modeled the deletion junction frequency and determined that the deletion occurred in both SMN1 and SMN2. We have identified the first deletion junction where the deletion removes exons 7 and 8 of SMN1/2. As it occurred in SMN1, it is a pathogenic mutation. We called variants in the PLS3 and SMN2 genes, and tested for association with mild or severe exception patients. The variants A-44G, A-549G, and C-1897T in intron 6 of SMN2 were significantly associated with mild exception patients, but no PLS3 variants correlated with severity. The variants occurred in 14 out of 58 of our mild exception patients, indicating that mild exception patients with an intact SMN2 gene and without modifying variants occur. This sample set can be used in the association analysis of candidate genes outside of SMN2 that modify the SMA phenotype.
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Affiliation(s)
- Corey Ruhno
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, USA
| | - Vicki L McGovern
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, USA
| | | | - Pamela J Snyder
- Department of Pathology, The Ohio State University, Columbus, OH, USA
| | - Thomas W Prior
- Department of Pathology, Case Western Reserve Medical Center, Cleveland, OH, USA
| | - Flavia C Nery
- Department of Neurology, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Abdurrahman Muhtaseb
- Department of Neurology, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | | | - John T Kissel
- Department of Neurology, The Ohio State University, Columbus, OH, USA
| | | | - Jennifer J Siranosian
- Department of Neurology, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Alec J Johnstone
- Department of Neurology, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Pann H Nwe
- Department of Neurology, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Ren Z Zhang
- Department of Neurology, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Kathryn J Swoboda
- Department of Neurology, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Arthur H M Burghes
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, USA.
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16
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Silvinato A, Bernardo WM. Spinal muscular atrophy 5Q - Treatment with nusinersen. ACTA ACUST UNITED AC 2018; 64:484-491. [PMID: 30304304 DOI: 10.1590/1806-9282.64.06.484] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The Guidelines Project, an initiative of the Brazilian Medical Association, aims to combine information from the medical field in order to standardize producers to assist the reasoning and decision-making of doctors. The information provided through this project must be assessed and criticized by the physician responsible for the conduct that will be adopted, depending on the conditions and the clinical status of each patient.
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Affiliation(s)
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- Brazilian Medical Association, São Paulo, SP, Brasil
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17
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Falsaperla R, Vitaliti G, Collotta AD, Fiorillo C, Pulvirenti A, Alaimo S, Romano C, Ruggieri M. Electrocardiographic Evaluation in Patients With Spinal Muscular Atrophy: A Case-Control Study. J Child Neurol 2018; 33:487-492. [PMID: 29687752 DOI: 10.1177/0883073818767170] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND This study aimed to show the impairment of autonomic cardiac conduction causing bradycardia and/or electrocardiographic alterations in children affected by spinal muscular atrophy type 1 and 2 (SMA 1 and 2). METHODS We included 25 spinal muscular atrophy patients, admitted from November 2016 to May 2017. All patients underwent an electrocardiographic examination and we studied PR and QRS intervals, P-waves and QRS amplitudes, and heart rate in spinal muscular atrophy patients compared to a control group. RESULTS In all patients, we found longer PRi and QRSi ( P < .05), lower P-wave and QRS complex amplitudes ( P < .01), and a decreased heart rate ( P < .01) with respect to controls. When we divided our patients into SMA1 and SMA2 subgroups, we found that statistical differences were maintained for P-wave and QRS complex amplitudes and heart rate, but not for PRi and QRSi with respect to controls. CONCLUSION We suggest the hypothesis of SMN expression on cardiac tissue condition and/or autonomic cardiac conduction.
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Affiliation(s)
- Raffaele Falsaperla
- 1 General Pediatrics and Pediatric Acute and Emergency Complex Unit, Policlinico-Vittorio-Emanuele University Hospital, University of Catania, Italy
| | - Giovanna Vitaliti
- 1 General Pediatrics and Pediatric Acute and Emergency Complex Unit, Policlinico-Vittorio-Emanuele University Hospital, University of Catania, Italy
| | - Ausilia Desiree Collotta
- 1 General Pediatrics and Pediatric Acute and Emergency Complex Unit, Policlinico-Vittorio-Emanuele University Hospital, University of Catania, Italy
| | - Chiara Fiorillo
- 2 Unit of Paediatric Neurology and Muscle Diseases, G. Gaslini Institute, Genoa, Italy
| | - Alfredo Pulvirenti
- 3 Department of Clinical and Experimental Medicine, Section of Bioinformatics, University of Catania, Italy
| | - Salvatore Alaimo
- 3 Department of Clinical and Experimental Medicine, Section of Bioinformatics, University of Catania, Italy
| | - Catia Romano
- 1 General Pediatrics and Pediatric Acute and Emergency Complex Unit, Policlinico-Vittorio-Emanuele University Hospital, University of Catania, Italy
| | - Martino Ruggieri
- 4 Unit of Rare Diseases of the Nervous System in Childhood, Policlinico-Vittorio-Emanuele University Hospital, University of Catania, Italy
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18
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Lin X, Li JJ, Qian WJ, Zhang QJ, Wang ZF, Lu YQ, Dong EL, He J, Wang N, Ma LX, Chen WJ. Modeling the differential phenotypes of spinal muscular atrophy with high-yield generation of motor neurons from human induced pluripotent stem cells. Oncotarget 2018; 8:42030-42042. [PMID: 28159932 PMCID: PMC5522047 DOI: 10.18632/oncotarget.14925] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 12/27/2016] [Indexed: 12/14/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a devastating motor neuron disease caused by mutations of the survival motor neuron 1 (SMN1) gene. SMN2, a paralogous gene to SMN1, can partially compensate for the loss of SMN1. On the basis of age at onset, highest motor function and SMN2 copy numbers, childhood-onset SMA can be divided into three types (SMA I-III). An inverse correlation was observed between SMN2 copies and the differential phenotypes of SMA. Interestingly, this correlation is not always absolute. Using SMA induced pluripotent stem cells (iPSCs), we found that the SMN was significantly decreased in both SMA III and SMA I iPSCs derived postmitotic motor neurons (pMNs) and γ-aminobutyric acid (GABA) neurons. Moreover, the significant differences of SMN expression level between SMA III (3 copies of SMN2) and SMA I (2 copies of SMN2) were observed only in pMNs culture, but not in GABA neurons or iPSCs. From these findings, we further discovered that the neurite outgrowth was suppressed in both SMA III and SMA I derived MNs. Meanwhile, the significant difference of neurite outgrowth between SMA III and SMA I group was also found in long-term cultures. However, significant hyperexcitability was showed only in SMA I derived mature MNs, but not in SMA III group. Above all, we propose that SMN protein is a major factor of phenotypic modifier. Our data may provide a new insight into recognition for differential phenotypes of SMA disease.
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Affiliation(s)
- Xiang Lin
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China
| | - Jin-Jing Li
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China
| | - Wen-Jing Qian
- Institutes of Brain Science, Institute of Neurobiology, State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Qi-Jie Zhang
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China
| | - Zhong-Feng Wang
- Institutes of Brain Science, Institute of Neurobiology, State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Ying-Qian Lu
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China
| | - En-Lin Dong
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China
| | - Jin He
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China
| | - Ning Wang
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China
| | - Li-Xiang Ma
- Department of Anatomy, Histology & Embryology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Wan-Jin Chen
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China.,Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou 350005, China
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19
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Krosschell KJ, Bosch M, Nelson L, Duong T, Lowes LP, Alfano LN, Benjamin D, Carry TB, Devine G, Kelley C, Gadekan R, Malkus EC, Pasternak A, Provance-Orr S, Roemeiser-Logan L, Nicorici A, Trussell D, Young SD, Fetterman JR, Montes J, Powers PJ, Quinones R, Quigley J, Coffey CS, Yankey JW, Bartlett A, Kissel JT, Kolb SJ. Motor Function Test Reliability During the NeuroNEXT Spinal Muscular Atrophy Infant Biomarker Study. J Neuromuscul Dis 2018; 5:509-521. [PMID: 30223401 PMCID: PMC8112280 DOI: 10.3233/jnd-180327] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND The NeuroNEXT SMA Infant Biomarker Study, a two year, longitudinal, multi-center study of infants with SMA type 1 and healthy infants, presented a unique opportunity to assess multi-site rater reliability on three infant motor function tests (MFTs) commonly used to assess infants with SMA type 1. OBJECTIVE To determine the effect of prospective MFT rater training and the effect of rater experience on inter-rater and intra-rater reliability for the Test of Infant Motor Performance Screening Items (TIMPSI), the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND) and the Alberta Infant Motor Scale (AIMS). METHODS Training was conducted utilizing a novel set of motor function test (MFT) videos to optimize accurate MFT administration and reliability for the study duration. Inter- and intra-rater reliability of scoring for the TIMPSI and inter-rater reliability of scoring for the CHOP INTEND and the AIMS was assessed using intraclass correlation coefficients (ICC). Effect of rater experience on reliability was examined using ICC. Agreement with 'expert' consensus scores was examined using Pearson's correlation coefficients. RESULTS Inter-rater reliability on all MFTs was good to excellent. Intra-rater reliability for the primary MFT, the TIMPSI, was excellent for the study duration. Agreement with 'expert' consensus was within predetermined limits (≥85%) after training. Evaluator experience with SMA and MFTs did not affect reliability. CONCLUSIONS Reliability of scores across evaluators was demonstrated for all three study MFTs and scores were reproducible on repeated administration. Evaluator experience had no effect on reliability.
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Affiliation(s)
- Kristin J. Krosschell
- Department of Physical Therapy and Human Movement Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Michael Bosch
- Department of Biostatistics, NeuroNEXT Data Coordinating Center, University of Iowa, Iowa City, IA, USA
| | - Leslie Nelson
- Physical Therapy, UT Southwestern Medical Center, Dallas, TX, USA
| | - Tina Duong
- Department of Neurology, Stanford University, Palo Alto, CA, USA
| | - Linda P. Lowes
- Neurology, Nationwide Children’s Hospital, Columbus, OH, USA
| | | | - Danielle Benjamin
- Physical Therapy, Oregon Health and Science University, Portland, OR, USA
| | - Terri B. Carry
- Physical Therapy, Children’s Hospital Colorado, Aurora, CO, USA
| | - Ginger Devine
- Pi Beta Phi Rehabilitation Institute, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Carolyn Kelley
- Physical Therapy, Children’s Hospital Colorado, Aurora, CO, USA
| | - Rebecca Gadekan
- Neuromuscular Division, Washington University School of Medicine, St. Louis, MO, USA
| | | | - Amy Pasternak
- The Department of Physical Therapy and Occupational Therapy Services, Boston Children’s Hospital, Boston, MA, USA
- The Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | | | | | - Alina Nicorici
- Physical Medicine and Rehabilitation, University of California – Davis, Davis, CA, USA
| | | | - Sally Dunaway Young
- Departments of Neurology and Rehabilitation and Regenerative Medicine, Columbia University Medical Center, New York, NY, USA
| | | | - Jacqueline Montes
- Departments of Neurology and Rehabilitation and Regenerative Medicine, Columbia University Medical Center, New York, NY, USA
| | - Penny J. Powers
- Pi Beta Phi Rehabilitation Institute, Vanderbilt University Medical Center, Nashville, TN, USA
| | | | - Janet Quigley
- The Department of Physical Therapy and Occupational Therapy Services, Boston Children’s Hospital, Boston, MA, USA
- The Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | - Christopher S. Coffey
- Department of Biostatistics, NeuroNEXT Data Coordinating Center, University of Iowa, Iowa City, IA, USA
| | - Jon W. Yankey
- Department of Biostatistics, NeuroNEXT Data Coordinating Center, University of Iowa, Iowa City, IA, USA
| | - Amy Bartlett
- Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - John T. Kissel
- Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Stephen J. Kolb
- Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
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20
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Gao K, Zhang Y, Zhang L, Kong W, Xie H, Wang J, Wu Y, Wu X, Liu X, Zhang Y, Zhang F, Yu ACH, Jiang Y. Large De Novo Microdeletion in Epilepsy with Intellectual and Developmental Disabilities, with a Systems Biology Analysis. ADVANCES IN NEUROBIOLOGY 2018; 21:247-266. [DOI: 10.1007/978-3-319-94593-4_9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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21
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Dominguez CE, Cunningham D, Chandler DS. SMN regulation in SMA and in response to stress: new paradigms and therapeutic possibilities. Hum Genet 2017; 136:1173-1191. [PMID: 28852871 PMCID: PMC6201753 DOI: 10.1007/s00439-017-1835-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 08/07/2017] [Indexed: 12/12/2022]
Abstract
Low levels of the survival of motor neuron (SMN) protein cause the neurodegenerative disease spinal muscular atrophy (SMA). SMA is a pediatric disease characterized by spinal motor neuron degeneration. SMA exhibits several levels of severity ranging from early antenatal fatality to only mild muscular weakness, and disease prognosis is related directly to the amount of functional SMN protein that a patient is able to express. Current therapies are being developed to increase the production of functional SMN protein; however, understanding the effect that natural stresses have on the production and function of SMN is of critical importance to ensuring that these therapies will have the greatest possible effect for patients. Research has shown that SMN, both on the mRNA and protein level, is highly affected by cellular stress. In this review we will summarize the research that highlights the roles of SMN in the disease process and the response of SMN to various environmental stresses.
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Affiliation(s)
- Catherine E Dominguez
- Molecular, Cellular and Developmental Biology Graduate Program and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA
- Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA
| | - David Cunningham
- Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA
| | - Dawn S Chandler
- Molecular, Cellular and Developmental Biology Graduate Program and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA.
- Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA.
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.
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22
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Hwang H, Lee JH, Choi YC. Clinical Characteristics of Spinal Muscular Atrophy in Korea Confirmed by Genetic Analysis. Yonsei Med J 2017; 58:1051-1054. [PMID: 28792153 PMCID: PMC5552634 DOI: 10.3349/ymj.2017.58.5.1051] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 06/05/2017] [Accepted: 06/22/2017] [Indexed: 11/27/2022] Open
Abstract
The objective of this study was to review the clinical characteristics of patients with spinal muscular atrophy and to emphasize the importance of performing genetic mutational analysis at initial patient assessment. This is a single center oriented, retrospective, and descriptive study conducted in Seoul, South Korea. Genetic mutational analysis to detect the deletion of exon 7 of the SMN1 gene on chromosome 5q13 was performed by multiplex ligation-dependent probe amplification. Clinical features, electrodiagnostic study results, muscle biopsy results, and laboratory test results were reviewed from patient medical records. Of all 28 patients (15 males and 13 females), all showed bilateral symmetric proximal dominant weakness. Among them, 3 patients were classified as type I, 14 patients as type II, and 11 patients as type III. Twenty-five patients had scoliosis and eight of these patients received surgical treatment for scoliosis with improvement in clinical outcomes. Ventilator support was used in 15 patients. In terms of the diagnostic process, 15 patients had completed an electrodiagnostic study and muscle biopsy before genetic testing, and six of these patients were initially misdiagnosed with myopathy. Owing to the similar clinical features of SMA and congenital myopathy, an electrodiagnostic study and muscle biopsy could create confusion in the correct diagnosis in some cases. Therefore, it is recommended that genetic mutation analysis should be conducted along with an electrodiagnostic study or muscle biopsy in the diagnostic process for spinal muscular atrophy.
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Affiliation(s)
- Heewon Hwang
- Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Jung Hwan Lee
- Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Young Chul Choi
- Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
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23
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Howell MD, Ottesen EW, Singh NN, Anderson RL, Seo J, Sivanesan S, Whitley EM, Singh RN. TIA1 is a gender-specific disease modifier of a mild mouse model of spinal muscular atrophy. Sci Rep 2017; 7:7183. [PMID: 28775379 PMCID: PMC5543135 DOI: 10.1038/s41598-017-07468-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 06/26/2017] [Indexed: 02/08/2023] Open
Abstract
Spinal muscular atrophy (SMA) is caused by deletions or mutations of Survival Motor Neuron 1 (SMN1) gene. The nearly identical SMN2 cannot compensate for SMN1 loss due to exon 7 skipping. The allele C (C +/+) mouse recapitulates a mild SMA-like phenotype and offers an ideal system to monitor the role of disease-modifying factors over a long time. T-cell-restricted intracellular antigen 1 (TIA1) regulates SMN exon 7 splicing. TIA1 is reported to be downregulated in obese patients, although it is not known if the effect is gender-specific. We show that female Tia1-knockout (Tia1 -/-) mice gain significant body weight (BW) during early postnatal development. We next examined the effect of Tia1 deletion in novel C +/+/Tia1 -/- mice. Underscoring the opposing effects of Tia1 deletion and low SMN level on BW gain, both C +/+ and C +/+/Tia1 -/- females showed similar BW gain trajectory at all time points during our study. We observed early tail necrosis in C +/+/Tia1 -/- females but not in males. We show enhanced impairment of male reproductive organ development and exacerbation of the C +/+/Tia1 -/- testis transcriptome. Our findings implicate a protein factor as a gender-specific modifier of a mild mouse model of SMA.
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Affiliation(s)
- Matthew D Howell
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, 50011, USA
| | - Eric W Ottesen
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, 50011, USA
| | - Natalia N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, 50011, USA
| | - Rachel L Anderson
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, 50011, USA
| | - Joonbae Seo
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, 50011, USA
- Division of Endocrinology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | | | - Elizabeth M Whitley
- Department of Veterinary Pathology, Iowa State University, Ames, IA, 50011-1250, USA
- Pathogenesis, LLC, Gainesville, Florida, 32614, USA
| | - Ravindra N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, 50011, USA.
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24
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Li W. How do SMA-linked mutations of SMN1 lead to structural/functional deficiency of the SMA protein? PLoS One 2017; 12:e0178519. [PMID: 28570645 PMCID: PMC5453535 DOI: 10.1371/journal.pone.0178519] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 05/15/2017] [Indexed: 11/19/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease with dysfunctional α-motor neurons in the anterior horn of the spinal cord. SMA is caused by loss (∼95% of SMA cases) or mutation (∼5% of SMA cases) of the survival motor neuron 1 gene SMN1. As the product of SMN1, SMN is a component of the SMN complex, and is also involved in the biosynthesis of the small nuclear ribonucleoproteins (snRNPs), which play critical roles in pre-mRNA splicing in the pathogenesis of SMA. To investigate how SMA-linked mutations of SMN1 lead to structural/functional deficiency of SMN, a set of computational analysis of SMN-related structures were conducted and are described in this article. Of extraordinary interest, the structural analysis highlights three SMN residues (Asp44, Glu134 and Gln136) with SMA-linked missense mutations, which cause disruptions of electrostatic interactions for Asp44, Glu134 and Gln136, and result in three functionally deficient SMA-linked SMN mutants, Asp44Val, Glu134Lys and Gln136Glu. From the computational analysis, it is also possible that SMN’s Lys45 and Asp36 act as two electrostatic clips at the SMN-Gemin2 complex structure interface.
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Affiliation(s)
- Wei Li
- Medical College, Shantou University, Shantou City, Guangdong Province, China
- * E-mail:
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25
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Singh RN, Howell MD, Ottesen EW, Singh NN. Diverse role of survival motor neuron protein. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2017; 1860:299-315. [PMID: 28095296 PMCID: PMC5325804 DOI: 10.1016/j.bbagrm.2016.12.008] [Citation(s) in RCA: 195] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 12/23/2016] [Accepted: 12/30/2016] [Indexed: 02/07/2023]
Abstract
The multifunctional Survival Motor Neuron (SMN) protein is required for the survival of all organisms of the animal kingdom. SMN impacts various aspects of RNA metabolism through the formation and/or interaction with ribonucleoprotein (RNP) complexes. SMN regulates biogenesis of small nuclear RNPs, small nucleolar RNPs, small Cajal body-associated RNPs, signal recognition particles and telomerase. SMN also plays an important role in DNA repair, transcription, pre-mRNA splicing, histone mRNA processing, translation, selenoprotein synthesis, macromolecular trafficking, stress granule formation, cell signaling and cytoskeleton maintenance. The tissue-specific requirement of SMN is dictated by the variety and the abundance of its interacting partners. Reduced expression of SMN causes spinal muscular atrophy (SMA), a leading genetic cause of infant mortality. SMA displays a broad spectrum ranging from embryonic lethality to an adult onset. Aberrant expression and/or localization of SMN has also been associated with male infertility, inclusion body myositis, amyotrophic lateral sclerosis and osteoarthritis. This review provides a summary of various SMN functions with implications to a better understanding of SMA and other pathological conditions.
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Affiliation(s)
- Ravindra N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States.
| | - Matthew D Howell
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States
| | - Eric W Ottesen
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States
| | - Natalia N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States
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Mechanistic principles of antisense targets for the treatment of spinal muscular atrophy. Future Med Chem 2015; 7:1793-808. [PMID: 26381381 DOI: 10.4155/fmc.15.101] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a major neurodegenerative disorder of children and infants. SMA is primarily caused by low levels of SMN protein owing to deletions or mutations of the SMN1 gene. SMN2, a nearly identical copy of SMN1, fails to compensate for the loss of the production of the functional SMN protein due to predominant skipping of exon 7. Several compounds, including antisense oligonucleotides (ASOs) that elevate SMN protein from SMN2 hold the promise for treatment. An ASO-based drug currently under Phase III clinical trial employs intronic splicing silencer N1 (ISS-N1) as its target. Cumulative studies on ISS-N1 reveal a wealth of information with significance to the overall therapeutic development for SMA. Here, the authors summarize the mechanistic principles behind various antisense targets currently available for SMA therapy.
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Carré A, Empey C. Review of Spinal Muscular Atrophy (SMA) for Prenatal and Pediatric Genetic Counselors. J Genet Couns 2015; 25:32-43. [DOI: 10.1007/s10897-015-9859-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 06/30/2015] [Indexed: 11/29/2022]
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Abstract
Spinal muscular atrophies (SMAs) are hereditary degenerative disorders of lower motor neurons associated with progressive muscle weakness and atrophy. Proximal 5q SMA is caused by decreased levels of the survival of motor neuron (SMN) protein and is the most common genetic cause of infant mortality. Its inheritance pattern is autosomal recessive, resulting from mutations involving the SMN1 gene on chromosome 5q13. Unlike other autosomal recessive diseases, the SMN gene has a unique structure (an inverted duplication) that presents potential therapeutic targets. Although there is currently no effective treatment of SMA, the field of translational research in this disorder is active and clinical trials are ongoing. Advances in the multidisciplinary supportive care of children with SMA also offer hope for improved life expectancy and quality of life.
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Affiliation(s)
- Basil T Darras
- Division of Clinical Neurology, Department of Neurology, Boston Children's Hospital, 300 Longwood Avenue, Fegan 11, Boston, MA 02115, USA.
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29
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Abstract
Spinal muscular atrophy (SMA) is a leading genetic cause of infant mortality. The disease originates from low levels of SMN protein due to deletion and/or mutations of SMN1 coupled with the inability of SMN2 to compensate for the loss of SMN1. While SMN1 and SMN2 are nearly identical, SMN2 predominantly generates a truncated protein (SMNΔ7) due to skipping of exon 7, the last coding exon. Several avenues for SMA therapy are being explored, including means to enhance SMN2 transcription, correct SMN2 exon 7 splicing, stabilize SMN/SMNΔ7 protein, manipulate SMN-regulated pathways and SMN1 gene delivery by viral vectors. This review focuses on the aspects of target discovery, validations and outcome measures for a promising therapy of SMA.
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Fang P, Li L, Zeng J, Zhou WJ, Wu WQ, Zhong ZY, Yan TZ, Xie JS, Huang J, Lin L, Zhao Y, Xu XM. Molecular characterization and copy number of SMN1, SMN2 and NAIP in Chinese patients with spinal muscular atrophy and unrelated healthy controls. BMC Musculoskelet Disord 2015; 16:11. [PMID: 25888055 PMCID: PMC4328246 DOI: 10.1186/s12891-015-0457-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 01/12/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is caused by SMN1 dysfunction, and the copy number of SMN2 and NAIP can modify the phenotype of SMA. The aim of this study was to analyze the copy numbers and gene structures of SMA-related genes in Chinese SMA patients and unrelated healthy controls. METHODS Forty-two Chinese SMA patients and two hundred and twelve unrelated healthy Chinese individuals were enrolled in our study. The copy numbers and gene structures of SMA-related genes were measured by MLPA assay. RESULTS We identified a homozygous deletion of SMN1 in exons 7 and 8 in 37 of 42 patients (88.1%); the other 5 SMA patients (11.9%) had a single copy of SMN1 exon 8. The proportions of the 212 unrelated healthy controls with different copy numbers for the normal SMN1 gene were 1 copy in 4 individuals (1.9%), 2 copies in 203 (95.7%) and 3 copies in 5 (2.4%). Three hybrid SMN genes and five genes that lack partial sequences were found in SMA patients and healthy controls. Distributions of copy numbers for normal SMN2 and NAIP were significantly different (P < 0.001) in people with and without SMA. CONCLUSION The copy numbers and gene structures of SMA-related genes were different in Chinese SMA patients and healthy controls.
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Affiliation(s)
- Ping Fang
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Avenue North1838, Guangzhou, Guangdong, People's Republic of China.
| | - Liang Li
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Avenue North1838, Guangzhou, Guangdong, People's Republic of China.
| | - Jian Zeng
- Department of Clinical Laboratory, The Fuzhou General Hospital, Nanjing Military Command, Fuzhou, Fujian, People's Republic of China.
| | - Wan-Jun Zhou
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Avenue North1838, Guangzhou, Guangdong, People's Republic of China.
| | - Wei-Qing Wu
- Prenatal Diagnosis Center, Shenzhen Maternity and Child Healthcare Hospital, Shenzhen, Guangdong, People's Republic of China.
| | - Ze-Yan Zhong
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Avenue North1838, Guangzhou, Guangdong, People's Republic of China.
| | - Ti-Zhen Yan
- Liuzhou Key Laboratory of birth defects prevention and control, Liuzhou Municipal Maternity and Child Healthcare Hospital, Liuzhou, Guangxi, People's Republic of China.
| | - Jian-Sheng Xie
- Prenatal Diagnosis Center, Shenzhen Maternity and Child Healthcare Hospital, Shenzhen, Guangdong, People's Republic of China.
| | - Jing Huang
- The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong, People's Republic of China.
| | - Li Lin
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Avenue North1838, Guangzhou, Guangdong, People's Republic of China.
| | - Ying Zhao
- Prenatal Diagnostic Center, Dongguan Maternal and Children Health Hospital, Dongguan, Guangdong, People's Republic of China.
| | - Xiang-Min Xu
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Avenue North1838, Guangzhou, Guangdong, People's Republic of China.
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Arnold WD, Kassar D, Kissel JT. Spinal muscular atrophy: diagnosis and management in a new therapeutic era. Muscle Nerve 2014; 51:157-67. [PMID: 25346245 DOI: 10.1002/mus.24497] [Citation(s) in RCA: 203] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/20/2014] [Indexed: 12/13/2022]
Abstract
Spinal muscular atrophy (SMA) describes a group of disorders associated with spinal motor neuron loss. In this review we provide an update regarding the most common form of SMA, proximal or 5q-SMA, and discuss the contemporary approach to diagnosis and treatment. Electromyography and muscle biopsy features of denervation were once the basis for diagnosis, but molecular testing for homozygous deletion or mutation of the SMN1 gene allows efficient and specific diagnosis. In combination with loss of SMN1, patients retain variable numbers of copies of a second similar gene, SMN2, which produces reduced levels of the survival motor neuron (SMN) protein that are insufficient for normal motor neuron function. Despite the fact that understanding of how ubiquitous reduction of SMN protein leads to motor neuron loss remains incomplete, several promising therapeutics are now being tested in early-phase clinical trials.
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Affiliation(s)
- W David Arnold
- Division of Neuromuscular Disorders, Department of Neurology, Wexner Medical Center, The Ohio State University, 395 West 12th Avenue, Columbus, Ohio, 43210, USA; Department of Physical Medicine and Rehabilitation, Wexner Medical Center, The Ohio State University, Columbus, Ohio, USA
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Martínez Carrasco C, Villa Asensi JR, Luna Paredes MC, Osona Rodríguez de Torres FB, Peña Zarza JA, Larramona Carrera H, Costa Colomer J. [Neuromuscular disease: respiratory clinical assessment and follow-up]. An Pediatr (Barc) 2014; 81:258.e1-258.e17. [PMID: 24709048 DOI: 10.1016/j.anpedi.2014.02.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 01/18/2014] [Accepted: 02/25/2014] [Indexed: 10/25/2022] Open
Abstract
Patients with neuromuscular disease are an important group at risk of frequently suffering acute or chronic respiratory failure, which is their main cause of death. They require follow-up by a pediatric respiratory medicine specialist from birth or diagnosis in order to confirm the diagnosis and treat any respiratory complications within a multidisciplinary context. The ventilatory support and the cough assistance have improved the quality of life and long-term survival for many of these patients. In this paper, the authors review the pathophysiology, respiratory function evaluation, sleep disorders, and the most frequent respiratory complications in neuromuscular diseases. The various treatments used, from a respiratory medicine point of view, will be analyzed in a next paper.
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Affiliation(s)
- C Martínez Carrasco
- Sección de Neumología Pediátrica, Hospital Universitario La Paz, Madrid, España.
| | - J R Villa Asensi
- Sección de Neumología Pediátrica, Hospital Universitario del Niño Jesús, Madrid, España
| | - M C Luna Paredes
- Sección de Neumología Pediátrica, Hospital Materno Infantil Doce de Octubre, Madrid, España
| | | | - J A Peña Zarza
- Sección de Neumología Pediátrica, Hospital Universitario Son Espases, Palma de Mallorca, España
| | - H Larramona Carrera
- Sección de Neumología Pediátrica, Hospital Parc Taulí, Sabadell, Barcelona, España
| | - J Costa Colomer
- Sección de Neumología Pediátrica, Hospital Sant Joan de Déu, Barcelona, España
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Seo J, Howell MD, Singh NN, Singh RN. Spinal muscular atrophy: an update on therapeutic progress. Biochim Biophys Acta Mol Basis Dis 2013; 1832:2180-90. [PMID: 23994186 DOI: 10.1016/j.bbadis.2013.08.005] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 07/27/2013] [Accepted: 08/14/2013] [Indexed: 12/24/2022]
Abstract
Humans have two nearly identical copies of survival motor neuron gene: SMN1 and SMN2. Deletion or mutation of SMN1 combined with the inability of SMN2 to compensate for the loss of SMN1 results in spinal muscular atrophy (SMA), a leading genetic cause of infant mortality. SMA affects 1 in ~6000 live births, a frequency much higher than in several genetic diseases. The major known defect of SMN2 is the predominant exon 7 skipping that leads to production of a truncated protein (SMNΔ7), which is unstable. Therefore, SMA has emerged as a model genetic disorder in which almost the entire disease population could be linked to the aberrant splicing of a single exon (i.e. SMN2 exon 7). Diverse treatment strategies aimed at improving the function of SMN2 have been envisioned. These strategies include, but are not limited to, manipulation of transcription, correction of aberrant splicing and stabilization of mRNA, SMN and SMNΔ7. This review summarizes up to date progress and promise of various in vivo studies reported for the treatment of SMA.
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Affiliation(s)
- Joonbae Seo
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA
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Nurputra DK, Lai PS, Harahap NIF, Morikawa S, Yamamoto T, Nishimura N, Kubo Y, Takeuchi A, Saito T, Takeshima Y, Tohyama Y, Tay SKH, Low PS, Saito K, Nishio H. Spinal muscular atrophy: from gene discovery to clinical trials. Ann Hum Genet 2013; 77:435-63. [PMID: 23879295 DOI: 10.1111/ahg.12031] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 04/26/2013] [Indexed: 12/25/2022]
Abstract
Spinal muscular atrophy (SMA) is a common neuromuscular disorder with autosomal recessive inheritance, resulting in the degeneration of motor neurons. The incidence of the disease has been estimated at 1 in 6000-10,000 newborns with a carrier frequency of 1 in 40-60. SMA is caused by mutations of the SMN1 gene, located on chromosome 5q13. The gene product, survival motor neuron (SMN) plays critical roles in a variety of cellular activities. SMN2, a homologue of SMN1, is retained in all SMA patients and generates low levels of SMN, but does not compensate for the mutated SMN1. Genetic analysis demonstrates the presence of homozygous deletion of SMN1 in most patients, and allows screening of heterozygous carriers in affected families. Considering high incidence of carrier frequency in SMA, population-wide newborn and carrier screening has been proposed. Although no effective treatment is currently available, some treatment strategies have already been developed based on the molecular pathophysiology of this disease. Current treatment strategies can be classified into three major groups: SMN2-targeting, SMN1-introduction, and non-SMN targeting. Here, we provide a comprehensive and up-to-date review integrating advances in molecular pathophysiology and diagnostic testing with therapeutic developments for this disease including promising candidates from recent clinical trials.
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Affiliation(s)
- Dian K Nurputra
- Department of Community Medicine and Social Health Care, Kobe University Graduate School of Medicine, Kobe, Japan
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Sivanesan S, Howell MD, DiDonato CJ, Singh RN. Antisense oligonucleotide mediated therapy of spinal muscular atrophy. Transl Neurosci 2013; 4:10.2478/s13380-013-0109-2. [PMID: 24265944 PMCID: PMC3832262 DOI: 10.2478/s13380-013-0109-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Spinal muscular atrophy (SMA) is the leading genetic cause of infant mortality. SMA results from deletions or mutations of survival motor neuron 1 (SMN1), an essential gene. SMN2, a nearly identical copy, can compensate for SMN1 loss if SMN2 exon 7 skipping is prevented. Among the many cis-elements involved in the splicing regulation of SMN exon 7, intronic splicing silencer N1 (ISS-N1) has emerged as the most effective target for an antisense oligonucleotide (ASO)-mediated splicing correction of SMN2 exon 7. Blocking of ISS-N1 by an ASO has been shown to fully restore SMN2 exon 7 inclusion in SMA patient cells as well as in vivo. Here we review how ISS-N1 targeting ASOs that use different chemistries respond differently in the various SMA mouse models. We also compare other ASO-based strategies for therapeutic splicing correction in SMA. Given that substantial progress on ASO-based strategies to promote SMN2 exon 7 inclusion in SMA has been made, and that similar approaches in a growing number of genetic diseases are possible, this report has wide implications.
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Affiliation(s)
- Senthilkumar Sivanesan
- Department of Biomedical Sciences, College of Veterinary Medicine (2034 Vet Med Bld.), Iowa State University, Ames, IA 50011
| | - Matthew D. Howell
- Department of Biomedical Sciences, College of Veterinary Medicine (2034 Vet Med Bld.), Iowa State University, Ames, IA 50011
| | - Christine J. DiDonato
- Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
- Human Molecular Genetics Program, Ann & Robert H. Lurie Children’s Hospital of Chicago, Research Center, Chicago, IL 60614
| | - Ravindra N. Singh
- Department of Biomedical Sciences, College of Veterinary Medicine (2034 Vet Med Bld.), Iowa State University, Ames, IA 50011
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Abstract
In the field of regenerative medicine, the development of induced pluripotent stem (iPS) cells may represent a potential strategy to overcome the limitations of human embryonic stem cells (ESCs). iPS cells have the potential to mimic human disease, since they carry the genome of the donor. Hypothetically, with iPS cell technology it is possible to screen patients for a genetic cause of disease (genetic mutation), develop cell lines, reprogram them back to iPS cells, finally differentiate them into one or more cell types that develop the disease. Although the creation of multiple lineages with iPS cells can seem limitless, a number of challenges need to be addressed in order to effectively use these cell lines for disease modeling. These include the low efficiency of iPS cell generation without genetic alterations, the possibility of tumor formation in vivo, the random integration of retroviral-based delivery vectors into the genome, and unregulated growth of the remaining cells that are partially reprogrammed and refractory to differentiation. The establishment of protein or RNA-based reprogramming strategies will help generate human iPS cells without permanent genetic alterations. Finally, direct reprogramming strategies can provide rapid production of models of human "diseases in a dish", without first passing the cells through a pluripotent state, so avoiding the challenges of time-consumming and labor-intensive iPS cell line generation. This review will overview methods to develop iPS cells, current strategies for direct reprogramming, and main applications of iPS cells as human disease model, focusing on human cardiovascular diseases, with the aim to be a potential information resource for biomedical scientists and clinicians who exploit or intend to exploit iPS cell technology in a range of applications.
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Affiliation(s)
- Rosalinda Madonna
- Institute of Cardiology, G. d'Annunzio University-Chieti, C/o Ospedale SS. Annunziata Via dei Vestini, 66013 Chieti, Italy.
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Brumback RA. "3 . . 2 . . 1 . . Impact [factor]: target [academic career] destroyed!": just another statistical casualty. J Child Neurol 2012. [PMID: 23183597 DOI: 10.1177/0883073812465014] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
"Publish or perish" is the time-honored "principle" for academicians who race to accumulate lines under the "publications" section of a curriculum vitae. The original intent of publication-to inform others of findings and further scientific knowledge-has been corrupted by factors including (1) exponential growth of journals and the journal industry, fueled in part by intrusion of the Internet into all aspects of academic life; and (2) adoption of journal metrics (rather than written content) as the measure of scientific quality. The proprietary Thomson Reuters Impact Factor is the most pernicious metric, having caused editors and publishers to change editorial practices to boost the number. At the same time, gullible administrators and government agencies have been persuaded that metrics for the journal in which materials are published can be used as a measure of the worth of individual investigators (and institutions) and their research efforts: simple numbers can be substituted for the burdensome effort required to read and assess research quality. Thus, granting of research funds, awarding of academic rank and tenure, and determination of salaries (including bonus payments) have become tied to manipulable journal metrics rather than the significance or quality of reported research. Therefore, it is no wonder that the integrity of science is more often being questioned. How should a young investigator approach the "publish or perish" dilemma? Performing sound research and preparing optimal materials for publication must remain the overriding goals: properly articulate the question addressed by the study; thoroughly document all methods and case information; carefully describe results including any conflicting or negative findings; discuss the importance of the findings along with how the results address the initial question and whether findings refute or confirm previous studies; prepare properly cited bibliographic references; list all author contributions, potential conflicts of interest, financial support, and required ethical approvals; and provide a catchy title and an abstract containing sufficient information that other investigators perusing scientific indices will be enticed to read the published article. Submit the completed manuscript to the most appropriate journal based on that journal's previously published content and relevance to the field of study regardless of journal metrics. On publication, notify investigators in the same field to ask for their comments on the work. Thus, an individual will become known for the quality of his or her work product and the worshiping of publication metrics will be unnecessary.
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Winters JP, Weisleder P. A young man with spinal muscular atrophy and impending respiratory arrest. Continuum (Minneap Minn) 2012; 17:148-51. [PMID: 22810793 DOI: 10.1212/01.con.0000394681.97867.b3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
From a statutory standpoint, the decision-making capacity of adolescents differs significantly from that of adults because adolescents are considered to lack the experience and judgment necessary to make legally binding decisions. Furthermore, in the case of minors, the principle of protection of life tends to outweigh the principle of autonomy. Here we present the hypothetical case of a 16-year-old boy with spinalmuscular atrophy type II who was admitted to the intensive care unit for severe respiratory distress. We focus on the tension that developed among the patient, his parents, and his physicians when the need for emergency mechanical ventilation became apparent. We review the legal and ethical premises under which adolescents are permitted to make legally binding decisions, ie, the emancipated minor and the mature minor doctrines. Finally, we discuss the concepts of protectionism and liberationism as they apply to adolescents' decision-making capacity.
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Yu-Jin Q, Juan D, Er-zhen L, Jin-li B, Yu-wei J, Hong W, Fang S. Subtle mutations in the SMN1 gene in Chinese patients with SMA: p.Arg288Met mutation causing SMN1 transcript exclusion of exon7. BMC MEDICAL GENETICS 2012; 13:86. [PMID: 22994313 PMCID: PMC3523059 DOI: 10.1186/1471-2350-13-86] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 09/14/2012] [Indexed: 11/17/2022]
Abstract
Background Proximal spinal muscular atrophy (SMA) is a common neuromuscular disorder resulting in death during childhood. Around 81 ~ 95% of SMA cases are a result of homozygous deletions of survival motor neuron gene 1 (SMN1) gene or gene conversions from SMN1 to SMN2. Less than 5% of cases showed rare subtle mutations in SMN1. Our aim was to identify subtle mutations in Chinese SMA patients carrying a single SMN1 copy. Methods We examined 14 patients from 13 unrelated families. Multiplex ligation-dependent probe amplification analysis was carried out to determine the copy numbers of SMN1 and SMN2. Reverse transcription polymerase chain reaction (RT-PCR) and clone sequencing were used to detect subtle mutations in SMN1. SMN transcript levels were determined using quantitative RT-PCR. Results Six subtle mutations (p.Ser8LysfsX23, p.Glu134Lys, p.Leu228X, p.Ser230Leu, p.Tyr277Cys, and p.Arg288Met) were identified in 12 patients. The p.Tyr277Cys mutation has not been reported previously. The p.Ser8LysfsX23, p.Leu228X, and p.Tyr277Cys mutations have only been reported in Chinese SMA patients and the first two mutations seem to be the common ones. Levels of full length SMN1 (fl-SMN1) transcripts were very low in patients carrying p.Ser8LysfsX23, p.Leu228X or p.Arg288Met compared with healthy carriers. In patients carrying p.Glu134Lys or p.Ser230Leu, levels of fl-SMN1 transcripts were reduced but not significant. The SMN1 transcript almost skipped exon 7 entirely in patients with the p.Arg288Met mutation. Conclusions Our study reveals a distinct spectrum of subtle mutations in SMN1 of Chinese SMA patients from that of other ethnicities. The p.Arg288Met missense mutation possibly influences the correct splicing of exon 7 in SMN1. Mutation analysis of the SMN1 gene in Chinese patients may contribute to the identification of potential ethnic differences and enrich the SMN1 subtle mutation database.
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Affiliation(s)
- Qu Yu-Jin
- Department of Medical Genetics, Capital Institute of Pediatrics, Beijing, China
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Ekici B, Bozkurt B, Tatlı B, Calışkan M, Aydınlı N, Ozmen M. Demographic characteristics of SMA type 1 patients at a tertiary center in Turkey. Eur J Pediatr 2012; 171:549-52. [PMID: 22016262 DOI: 10.1007/s00431-011-1607-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 10/07/2011] [Indexed: 12/01/2022]
Abstract
UNLABELLED The aim of this study was to demonstrate demographics of 39 consecutive Spinal Muscular Atrophy (SMA) type 1 patients diagnosed genetically in a tertiary center between June 2006 and June 2009. There was history of consanguineous marriage in 27 (69%) patients. The average patient lifespan was 251 days (30-726 days). The average patient age at diagnosis was 129 days (33-297 days). A statistically significant correlation was found between the age at diagnosis and the lifespan (p = 0.00). No significant correlation was found between the time spent in intensive care and the lifespan (p = 0.43). Routine physical therapy was found to have no significant impact on the lifespan average (p = 0.17). The cause of death in all of our patients was respiratory issues. Genetic counseling was given to 35 families. A second child with SMA was born in three out of the 14 families who declined prenatal diagnosis. CONCLUSION A national program is needed in Turkey for SMA prevention and creation of expert teams for the management of these patients.
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Affiliation(s)
- Barış Ekici
- Department of Pediatric Neurology, Istanbul Medical Faculty, Ortaköy Dereboyu cad. Arkeon sitesi A 5 blok D 3, Beşiktaş, Fatih, Istanbul, Turkey.
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Abstract
Spinal muscular atrophy, a hereditary degenerative disorder of lower motor neurons associated with progressive muscle weakness and atrophy, is the most common genetic cause of infant mortality. It is caused by decreased levels of the "survival of motor neuron" (SMN) protein. Its inheritance pattern is autosomal recessive, resulting from mutations involving the SMN1 gene on chromosome 5q13. However, unlike many other autosomal recessive diseases, the SMN gene involves a unique structure (an inverted duplication) that presents potential therapeutic targets. Although no effective treatment for spinal muscular atrophy exists, the field of translational research in spinal muscular atrophy is active, and clinical trials are ongoing. Advances in the multidisciplinary supportive care of children with spinal muscular atrophy also offer hope for improved life expectancy and quality of life.
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Brumback RA. Neurobiology of disease in children: a decade of successful symposia and a robust partnership with the Journal of Child Neurology. J Child Neurol 2011; 26:1475-9. [PMID: 22114242 DOI: 10.1177/0883073811426934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Abstract
Spinal muscular atrophy (SMA), a potentially devastating disease marked by progressive weakness and muscle atrophy resulting from the dysfunction and loss of motor neurons of the spinal cord, has emerged in recent years as an attractive target for therapeutic intervention. Caused by a homozygous mutation to the Survival of Motor Neurons 1 (SMN1) gene on chromosome 5q, the severity of the clinical phenotype in SMA is modulated by the function of a related protein, Survival of Motor Neurons 2 (SMN2). SMN2 predominantly produces an unstable SMN transcript lacking exon 7; only about 10% of the transcription product produces a full-length, functional SMN protein. Several therapeutic strategies have targeted this gene with the goal of producing increased full-length SMN transcript, thereby modifying the underlying mechanism. Drugs that have increased SMN2 function, in vitro, are now explored for potential therapeutic benefit in this disease. Alternative approaches, including neuroprotective, muscle anabolic, gene and cell replacement strategies, also hold promise. The recent advances in preclinical research and the development of a wider range of animal models for SMA continue to provide cautious optimism that effective treatments for SMA will eventually emerge.
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Affiliation(s)
- Douglas M Sproule
- Division of Pediatric Neurosciences, Department of Neurology, SMA Clinical Research Center, Columbia University Medical Center, Harkness Pavilion, HP-514, 180 Fort Washington Avenue, New York, NY 10032-3791, USA.
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Maranda B, Fan L, Soucy JF, Simard L, Mitchell GA. Spinal muscular atrophy: clinical validation of a single-tube multiplex real time PCR assay for determination of SMN1 and SMN2 copy numbers. Clin Biochem 2011; 45:88-91. [PMID: 22085534 DOI: 10.1016/j.clinbiochem.2011.10.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Revised: 10/22/2011] [Accepted: 10/30/2011] [Indexed: 01/07/2023]
Abstract
OBJECTIVES To describe and validate a new protocol for molecular diagnosis of spinal muscular atrophy (SMA), a frequent neuromuscular disease of childhood. DESIGN AND METHODS SMA is caused in most cases by homozygous deletion of the SMN1 gene. We describe a triplex quantitative real-time PCR method in which fragments of SMN1, SMN2 (a nearly-identical neighboring gene with markedly reduced function) and of a control gene, CFTR, are amplified in the same tube. RESULTS We validated this method in three ways. First, testing the same samples ten times yielded CV values <4.6%. Second, in 104 previously-genotyped individuals, SMN copy numbers identical to those of the previously-determined genotype was unambiguously obtained in all cases. Finally, results using the technique in practice are described and analyzed for reproducibility of amplification efficiency and for inter-run variability. CONCLUSIONS In over 1200 samples, this technique has proven accurate, fast, economical and reproducible.
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Affiliation(s)
- Bruno Maranda
- Department of Genetics, CHUS and Université de Sherbrooke, Sherbrooke, Québec, Canada
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Pandey R, Chandratre S, Roberts A, Dwyer JSM, Sewry C, Quinlivan R. Central core myopathy with RYR1 mutation masks 5q spinal muscular atrophy. Eur J Paediatr Neurol 2011; 15:70-3. [PMID: 20452790 DOI: 10.1016/j.ejpn.2010.04.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2009] [Revised: 04/01/2010] [Accepted: 04/07/2010] [Indexed: 10/19/2022]
Abstract
We report the case of a male who presented in infancy with motor delay and muscle weakness. Typical muscle biopsy features and heterozygous RYR1 mutation confirmed a diagnosis of central core disease. Family studies showed this to be a de-novo mutation. Some years later, his two older teenage brothers presented with proximal muscle weakness. Neurophysiology, muscle biopsy and DNA studies confirmed spinal muscular atrophy. Subsequent genetic studies in the index case also confirmed homozygous deletions of exon 7 and 8 in the SMN gene. Review of the original muscle biopsy showed classical features of central core disease with no evidence to suggest denervation, such that the diagnosis of spinal muscular atrophy could not have been suspected in the absence of the family history.
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Affiliation(s)
- R Pandey
- Sandwell and West Birmingham NHS Trust, Sandwell General Hospital, Lyndon, West Bromwich, West Midlands B71 4HJ, UK.
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Sun X, Fontaine JM, Hoppe AD, Carra S, DeGuzman C, Martin JL, Simon S, Vicart P, Welsh MJ, Landry J, Benndorf R. Abnormal interaction of motor neuropathy-associated mutant HspB8 (Hsp22) forms with the RNA helicase Ddx20 (gemin3). Cell Stress Chaperones 2010; 15:567-82. [PMID: 20157854 PMCID: PMC3006614 DOI: 10.1007/s12192-010-0169-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Revised: 01/07/2010] [Accepted: 01/08/2010] [Indexed: 01/16/2023] Open
Abstract
A number of missense mutations in the two related small heat shock proteins HspB8 (Hsp22) and HspB1 (Hsp27) have been associated with the inherited motor neuron diseases (MND) distal hereditary motor neuropathy and Charcot-Marie-Tooth disease. HspB8 and HspB1 interact with each other, suggesting that these two etiologic factors may act through a common biochemical mechanism. However, their role in neuron biology and in MND is not understood. In a yeast two-hybrid screen, we identified the DEAD box protein Ddx20 (gemin3, DP103) as interacting partner of HspB8. Using co-immunoprecipitation, chemical cross-linking, and in vivo quantitative fluorescence resonance energy transfer, we confirmed this interaction. We also show that the two disease-associated mutant HspB8 forms have abnormally increased binding to Ddx20. Ddx20 itself binds to the survival-of-motor-neurons protein (SMN protein), and mutations in the SMN1 gene cause spinal muscular atrophy, another MND and one of the most prevalent genetic causes of infant mortality. Thus, these protein interaction data have linked the three etiologic factors HspB8, HspB1, and SMN protein, and mutations in any of their genes cause the various forms of MND. Ddx20 and SMN protein are involved in spliceosome assembly and pre-mRNA processing. RNase treatment affected the interaction of the mutant HspB8 with Ddx20 suggesting RNA involvement in this interaction and a potential role of HspB8 in ribonucleoprotein processing.
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Affiliation(s)
- Xiankui Sun
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109 USA
| | - Jean-Marc Fontaine
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109 USA
| | - Adam D. Hoppe
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109 USA
| | - Serena Carra
- Le Centre de recherche en cancérologie, l’Université Laval, L’Hôtel-Dieu de Québec, Laval, Québec Canada G1R 2J6
- Section for Radiation and Stress Cell Biology, Department of Cell Biology, University Medical Center Groningen, 9713 AV Groningen, The Netherlands
| | - Cheryl DeGuzman
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109 USA
| | - Jody L. Martin
- Department of Medicine, Cardiovascular Institute, Loyola University Medical Center, Maywood, IL 60153 USA
| | - Stephanie Simon
- Laboratory BFA, University Paris Diderot/CNRS, 75013 Paris, France
| | - Patrick Vicart
- Laboratory BFA, University Paris Diderot/CNRS, 75013 Paris, France
| | - Michael J. Welsh
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109 USA
| | - Jacques Landry
- Le Centre de recherche en cancérologie, l’Université Laval, L’Hôtel-Dieu de Québec, Laval, Québec Canada G1R 2J6
| | - Rainer Benndorf
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109 USA
- Department of Pediatrics, Ohio State University, Columbus, OH 43205 USA
- The Center for Clinical and Translational Research, The Research Institute at Nationwide Children’s Hospital, Research Building II, Room WA2109, 700 Children’s Drive, Columbus, OH 43205 USA
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Abstract
During the past five years, copy number variation (CNV) has emerged as a highly prevalent form of genomic variation, bridging the interval between long-recognised microscopic chromosomal alterations and single-nucleotide changes. These genomic segmental differences among humans reflect the dynamic nature of genomes, and account for both normal variations among us and variations that predispose to conditions of medical consequence. Here, we place CNVs into their historical and medical contexts, focusing on how these variations can be recognised, documented, characterised and interpreted in clinical diagnostics. We also discuss how they can cause disease or influence adaptation to an environment. Various clinical exemplars are drawn out to illustrate salient characteristics and residual enigmas of CNVs, particularly the complexity of the data and information associated with CNVs relative to that of single-nucleotide variation. The potential is immense for CNVs to explain and predict disorders and traits that have long resisted understanding. However, creative solutions are needed to manage the sudden and overwhelming burden of expectation for laboratories and clinicians to assay and interpret these complex genomic variations as awareness permeates medical practice. Challenges remain for understanding the relationship between genomic changes and the phenotypes that might be predicted and prevented by such knowledge.
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de Resende MAC, Vaz da Silva E, Nascimento OJM, Gemal AE, Quintanilha G, Vasconcelos EM. Total Intravenous Anesthesia (TIVA) in an Infant with Werdnig-Hoffmann Disease. Case Report. Braz J Anesthesiol 2010. [DOI: 10.1016/s0034-7094(10)70022-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Acsadi G, Lee I, Li X, Khaidakov M, Pecinova A, Parker GC, Hüttemann M. Mitochondrial dysfunction in a neural cell model of spinal muscular atrophy. J Neurosci Res 2010; 87:2748-56. [PMID: 19437551 DOI: 10.1002/jnr.22106] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Mutations of the survival motor neuron (SMN) gene in spinal muscular atrophy (SMA) lead to anterior horn cell death. The cause is unknown, but motor neurons depend substantially on mitochondrial oxidative phosphorylation (OxPhos) for normal function. Therefore, mitochondrial parameters were analyzed in an SMA cell culture model using small interfering RNA (siRNA) transfection that decreased Smn expression in NSC-34 cells to disease levels. Smn siRNA knock-down resulted in 35% and 66% reduced Smn protein levels 48 and 72 hr posttransfection, respectively. ATP levels were reduced by 14% and 26% at 48 and 72 hr posttransfection, respectively, suggesting decreased ATP production or increased energy demand in neural cells. Smn knock-down resulted in increased mitochondrial membrane potential and increased free radical production. Changes in activity of cytochrome c oxidase (CcO), a key OxPhos component, were observed at 72 hr with a 26% increase in oxygen consumption. This suggests a compensatory activation of the aerobic pathway, resulting in increased mitochondrial membrane potentials, a condition known to lead to the observed increase in free radical production. Further testing suggested that changes in ATP at 24 hr precede observable indices of cell injury at 48 hr. We propose that energy paucity and increased mitochondrial free radical production lead to accumulated cell damage and eventual cell death in Smn-depleted neural cells. Mitochondrial dysfunction may therefore be important in SMA pathology and may represent a new therapeutic target.
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Affiliation(s)
- Gyula Acsadi
- Children's Hospital of Michigan, Carman and Ann Adams Department of Pediatrics, Detroit, Michigan, USA
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50
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Brumback RA. Child neurologists should be interested in brain tumors! J Child Neurol 2009; 24:1338-40. [PMID: 19841422 DOI: 10.1177/0883073809343317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Roger A. Brumback
- Journal of Child Neurology, Creighton University School of Medicine, Omaha, Nebraska
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