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Tapken I, Kuhn D, Hoffmann N, Detering NT, Schüning T, Billaud JN, Tugendreich S, Schlüter N, Green J, Krämer A, Claus P. From data to discovery: AI-guided analysis of disease-relevant molecules in spinal muscular atrophy (SMA). Hum Mol Genet 2024:ddae076. [PMID: 38704739 DOI: 10.1093/hmg/ddae076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 04/04/2024] [Accepted: 04/22/2024] [Indexed: 05/07/2024] Open
Abstract
Spinal Muscular Atrophy is caused by partial loss of survival of motoneuron (SMN) protein expression. The numerous interaction partners and mechanisms influenced by SMN loss result in a complex disease. Current treatments restore SMN protein levels to a certain extent, but do not cure all symptoms. The prolonged survival of patients creates an increasing need for a better understanding of SMA. Although many SMN-protein interactions, dysregulated pathways, and organ phenotypes are known, the connections among them remain largely unexplored. Monogenic diseases are ideal examples for the exploration of cause-and-effect relationships to create a network describing the disease-context. Machine learning tools can utilize such knowledge to analyze similarities between disease-relevant molecules and molecules not described in the disease so far. We used an artificial intelligence-based algorithm to predict new genes of interest. The transcriptional regulation of 8 out of 13 molecules selected from the predicted set were successfully validated in an SMA mouse model. This bioinformatic approach, using the given experimental knowledge for relevance predictions, enhances efficient targeted research in SMA and potentially in other disease settings.
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Affiliation(s)
- Ines Tapken
- SMATHERIA gGmbH - Non-Profit Biomedical Research Institute, Feodor-Lynen-Str. 31, Hannover 30625, Germany
- Center for Systems Neuroscience (ZSN), Bünteweg 2, Hannover 30559, Germany
| | - Daniela Kuhn
- SMATHERIA gGmbH - Non-Profit Biomedical Research Institute, Feodor-Lynen-Str. 31, Hannover 30625, Germany
- Hannover Medical School, Department of Conservative Dentistry, Periodontology and Preventive Dentistry, Carl-Neuberg-Str. 1, Hannover 30625, Germany
| | - Nico Hoffmann
- SMATHERIA gGmbH - Non-Profit Biomedical Research Institute, Feodor-Lynen-Str. 31, Hannover 30625, Germany
| | - Nora T Detering
- SMATHERIA gGmbH - Non-Profit Biomedical Research Institute, Feodor-Lynen-Str. 31, Hannover 30625, Germany
- Center for Systems Neuroscience (ZSN), Bünteweg 2, Hannover 30559, Germany
| | - Tobias Schüning
- SMATHERIA gGmbH - Non-Profit Biomedical Research Institute, Feodor-Lynen-Str. 31, Hannover 30625, Germany
| | - Jean-Noël Billaud
- QIAGEN Digital Insights, 1001 Marshall Street,Redwood City, CA 94063, United States
| | - Stuart Tugendreich
- QIAGEN Digital Insights, 1001 Marshall Street,Redwood City, CA 94063, United States
| | - Nadine Schlüter
- Hannover Medical School, Department of Conservative Dentistry, Periodontology and Preventive Dentistry, Carl-Neuberg-Str. 1, Hannover 30625, Germany
| | - Jeff Green
- QIAGEN Digital Insights, 1001 Marshall Street,Redwood City, CA 94063, United States
| | - Andreas Krämer
- QIAGEN Digital Insights, 1001 Marshall Street,Redwood City, CA 94063, United States
| | - Peter Claus
- SMATHERIA gGmbH - Non-Profit Biomedical Research Institute, Feodor-Lynen-Str. 31, Hannover 30625, Germany
- Center for Systems Neuroscience (ZSN), Bünteweg 2, Hannover 30559, Germany
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Andrea ZA, Matteo FY, Alessandra B, Carlo PS. Molecular mechanisms and therapeutic strategies for neuromuscular diseases. Cell Mol Life Sci 2024; 81:198. [PMID: 38678519 PMCID: PMC11056344 DOI: 10.1007/s00018-024-05229-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 03/14/2024] [Accepted: 04/07/2024] [Indexed: 05/01/2024]
Abstract
Neuromuscular diseases encompass a heterogeneous array of disorders characterized by varying onset ages, clinical presentations, severity, and progression. While these conditions can stem from acquired or inherited causes, this review specifically focuses on disorders arising from genetic abnormalities, excluding metabolic conditions. The pathogenic defect may primarily affect the anterior horn cells, the axonal or myelin component of peripheral nerves, the neuromuscular junction, or skeletal and/or cardiac muscles. While inherited neuromuscular disorders have been historically deemed not treatable, the advent of gene-based and molecular therapies is reshaping the treatment landscape for this group of condition. With the caveat that many products still fail to translate the positive results obtained in pre-clinical models to humans, both the technological development (e.g., implementation of tissue-specific vectors) as well as advances on the knowledge of pathogenetic mechanisms form a collective foundation for potentially curative approaches to these debilitating conditions. This review delineates the current panorama of therapies targeting the most prevalent forms of inherited neuromuscular diseases, emphasizing approved treatments and those already undergoing human testing, offering insights into the state-of-the-art interventions.
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Affiliation(s)
- Zambon Alberto Andrea
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Institute for Experimental Neurology, Inspe, Milan, Italy
- Neurology Department, San Raffaele Scientific Institute, Milan, Italy
- Vita-Salute San Raffaele University, Milan, Italy
| | - Falzone Yuri Matteo
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Institute for Experimental Neurology, Inspe, Milan, Italy
- Neurology Department, San Raffaele Scientific Institute, Milan, Italy
| | - Bolino Alessandra
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Institute for Experimental Neurology, Inspe, Milan, Italy
- Vita-Salute San Raffaele University, Milan, Italy
| | - Previtali Stefano Carlo
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Institute for Experimental Neurology, Inspe, Milan, Italy.
- Neurology Department, San Raffaele Scientific Institute, Milan, Italy.
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Sun H, Zheng J, Zhang Q, Ying F, Fu Y, Guan Y, Wu J, Zhou Y, Dong J, Xu M, Yang F, An N, Shi N, Zhang L, Zhu S, Liu J, Li M. Screening of Spinal Muscular Atrophy Carriers and Prenatal Diagnosis in Pregnant Women in Yancheng, China. Biochem Genet 2024:10.1007/s10528-024-10775-9. [PMID: 38581475 DOI: 10.1007/s10528-024-10775-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 03/06/2024] [Indexed: 04/08/2024]
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disorder with an autosomal recessive inheritance pattern. Patients with severe symptoms may suffer respiratory failure, leading to death. The homozygous deletion of exon 7 in the SMN1 gene accounts for nearly 95% of all cases. Population carrier screening for SMA and prenatal diagnosis by amniocentesis for high-risk couples can assist in identifying the risk of fetal disease. We provided the SMA carrier screening process to 55,447 pregnant women in Yancheng from October 2020 to December 2022. Among them, 8185 participated in this process, with a participation rate of around 14.76% (95% CI 14.47-15.06%). Quantitative real-time polymerase chain reaction (qPCR) was used to detect deletions of SMN1 exons 7 and 8 (E7, E8) in screened pregnant women. 127 were identified as carriers (111 cases of E7 and E8 heterozygous deletions, 15 cases of E7 heterozygous deletions, and 1 case of E7 heterozygous deletions and E8 homozygous deletions), resulting in a carrying rate of around 1.55% (95% CI 1.30-1.84%). After genetic counseling, 114 spouses of pregnant women who tested positive underwent SMA carrier screening; three of them were screened as SMA carriers. Multiplexed ligation-dependent probe amplification (MLPA) was used for the prenatal diagnosis of the fetuses of high-risk couples. Two of them exhibited two copies of SMN1 exon 7 (normal), and the pregnancy was continued; one exhibited no copies of SMN1 exon 7 and exon 8 (SMA patient), and the pregnancy was terminated. Analyzing SMN1 mutations in Yancheng and provide clinical evidence for SMA genetic counseling and birth defect prevention. Interventional prenatal diagnosis for high-risk families can promote informed reproductive selection and prepare for the fetus's early treatment.
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Affiliation(s)
- Huilin Sun
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Jianli Zheng
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Qing'e Zhang
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Feifei Ying
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Yadong Fu
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Yongjuan Guan
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Jing Wu
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Yueyun Zhou
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Jingjing Dong
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Mengjun Xu
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Fangfang Yang
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Ning An
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Ning Shi
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Lu Zhang
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Shu Zhu
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Jianbing Liu
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China.
| | - Min Li
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China.
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Dosi C, Masson R. The impact of three SMN2 gene copies on clinical characteristics and effect of disease-modifying treatment in patients with spinal muscular atrophy: a systematic literature review. Front Neurol 2024; 15:1308296. [PMID: 38487326 PMCID: PMC10937544 DOI: 10.3389/fneur.2024.1308296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 02/12/2024] [Indexed: 03/17/2024] Open
Abstract
Objective To review the clinical characteristics and effect of treatment in patients with spinal muscular atrophy (SMA) and three copies of the SMN2 gene. Methods We conducted a literature search in October 2022 to identify English-language clinical research on SMA that included SMN2 copy number according to PRISMA guidelines. Results Our search identified 44 studies examining the impact of three SMN2 copies on clinical characteristics (21 on phenotype, 13 on natural history, and 15 on functional status and other signs/symptoms). In children with type I SMA or presymptomatic infants with an SMN1 deletion, three SMN2 copies was associated with later symptom onset, slower decline in motor function and longer survival compared with two SMN2 copies. In patients with SMA type II or III, three SMN2 copies is associated with earlier symptom onset, loss of ambulation, and ventilator dependence compared with four SMN2 copies. Eleven studies examined treatment effects with nusinersen (nine studies), onasemnogene abeparvovec (one study), and a range of treatments (one study) in patients with three SMN2 copies. In presymptomatic infants, early treatment delayed the onset of symptoms and maintained motor function in those with three SMN2 copies. The impact of copy number on treatment response in symptomatic patients is still unclear. Conclusion SMN2 copy number is strongly correlated with SMA phenotype in patients with SMN1 deletion, while no correlation was found in patients with an SMN1 mutation. Patients with three SMN2 copies show a highly variable clinical phenotype. Early initiation of treatment is highly effective in presymptomatic patients with three SMN2 copies.
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Affiliation(s)
| | - Riccardo Masson
- Fondazione IRCCS Istituto Neurologico Carlo Besta, Developmental Neurology Unit, Milan, Italy
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Abiusi E, Costa-Roger M, Bertini ES, Tiziano FD, Tizzano EF, Abiusi E, Baranello G, Bertini E, Boemer F, Burghes A, Codina-Solà M, Costa-Roger M, Dangouloff T, Groen E, Gos M, Jędrzejowska M, Kirschner J, Lemmink HH, Müller-Felber W, Ouillade MC, Quijano-Roy S, Rucinski K, Saugier-Veber P, Tiziano FD, Tizzano EF, Wirth B. 270th ENMC International Workshop: Consensus for SMN2 genetic analysis in SMA patients 10-12 March, 2023, Hoofddorp, the Netherlands. Neuromuscul Disord 2024; 34:114-122. [PMID: 38183850 DOI: 10.1016/j.nmd.2023.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2024]
Abstract
The 270th ENMC workshop aimed to develop a common procedure to optimize the reliability of SMN2 gene copy number determination and to reinforce collaborative networks between molecular scientists and clinicians. The workshop involved neuromuscular and clinical experts and representatives of patient advocacy groups and industry. SMN2 copy number is currently one of the main determinants for therapeutic decision in SMA patients: participants discussed the issues that laboratories may encounter in this molecular test and the cruciality of the accurate determination, due the implications as prognostic factor in symptomatic patients and in individuals identified through newborn screening programmes. At the end of the workshop, the attendees defined a set of recommendations divided into four topics: SMA molecular prognosis assessment, newborn screening for SMA, SMN2 copies and treatments, and modifiers and biomarkers. Moreover, the group draw up a series of recommendations for the companies manufacturing laboratory kits, that will help to minimize the risk of errors, regardless of the laboratories' expertise.
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Affiliation(s)
- Emanuela Abiusi
- Section of Genomic Medicine, Department of Public Health and Life Sciences, Università Cattolica del Sacro Cuore, Roma, Italy
| | - Mar Costa-Roger
- Clinical and Molecular Genetics Area, Vall d'Hebron Hospital; Medicine Genetics Group, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain
| | - Enrico Silvio Bertini
- Research Unit of Neuromuscular Disease, Bambino Gesu’ Children's Hospital, IRCCS, Roma, Italy
| | - Francesco Danilo Tiziano
- Section of Genomic Medicine, Department of Public Health and Life Sciences, Università Cattolica del Sacro Cuore, Roma, Italy
- Complex Unit of Medical Genetics, Fondazione Policlinico Universitario IRCCS “A. Gemelli”, Roma, Italy
| | - Eduardo F Tizzano
- Clinical and Molecular Genetics Area, Vall d'Hebron Hospital; Medicine Genetics Group, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain
| | - Emanuela Abiusi
- Section of Genomic Medicine, Dept. of Life Sciences and Public Health, Catholic University of the Sacred Heart, Roma, Italy
| | - Giovanni Baranello
- The Dubowitz Neuromuscular Centre, Developmental Neuroscience Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, NIHR Great Ormond Street Hospital Biomedical Research Centre & Great Ormond Street Hospital NHS Foundation Trust, 30 Guilford Street, London WC1N 1EH, UK
| | - Enrico Bertini
- Italy, Research Unit of Neuromuscular Disease, Bambino Gesù Children's Hospital, IRCCS, Roma, Italy
| | - François Boemer
- Biochemical Genetics Lab, Department of Human Genetics, University Hospital, University of Liège, 4000 Liège, Belgium
| | - Arthur Burghes
- Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Marta Codina-Solà
- Neuromuscular Reference Center, Department of Paediatrics, University Hospital Liege & University of Liege, Belgium
| | - Mar Costa-Roger
- Department of Neurology & Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Tamara Dangouloff
- Department of Medical Genetics, Institute of Mother and Child, Warsaw, Poland
| | - Ewout Groen
- Department of Neurology, Medical University of Warsaw, Warsaw, Poland
| | - Monika Gos
- Department of Neuropediatrics and Muscle Disorders, Medical Center University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Maria Jędrzejowska
- Department of Genetics, University of Groningen, University Medical Center Groningen, 9700 RB Groningen, The Netherlands
| | - Janbernd Kirschner
- Centre for Neuromuscular Disorders, Center for Translational Neuro and Behavioral Sciences, Department of Pediatric Neurology, University Duisburg-Essen, 45147 Essen, Germany
| | - Henny H Lemmink
- AFM Téléthon, Évry, France; SMA Europe; European Alliance for Newborn Screening in Spinal Muscular Atrophy
| | - Wolfgang Müller-Felber
- Pediatric Neuromuscular Unit (NEIDF Reference Center at FILNEMUS & Euro-NMD), Child Neurology Department, Raymond Poincaré Hospital (UVSQ), APHP Université Paris Saclay, Garches France
| | - Marie-Christine Ouillade
- Fundacja SMA, Warsaw, Poland; SMA Europe; European Alliance for Newborn Screening in Spinal Muscular Atrophy
| | - Susana Quijano-Roy
- Univ Rouen Normandie, Inserm U1245, Normandie Univ and CHU Rouen, Department of Genetics and Nord/Est/Ile de France Neuromuscular Reference Center, F-76000 Rouen, France
| | - Kacper Rucinski
- Institute of Medical Genomics, Dept. of Life Sciences and Public Health, Catholic University of the Sacred Heart, and Complex Unit of Medical Genetics, Fondazione Policlinico Universitario IRCCS “A. Gemelli”, Roma, Italy
| | - Pascale Saugier-Veber
- Institute of Human Genetics, University Hospital of Cologne, Center for Molecular Medicine, University of Cologne and Center for Rare Diseases Cologne, University Hopsital of Cologne, Cologne, Germany
| | - Francesco Danilo Tiziano
- Institute of Medical Genomics, Dept. of Life Sciences and Public Health, Catholic University of the Sacred Heart, and Complex Unit of Medical Genetics, Fondazione Policlinico Universitario IRCCS “A. Gemelli”, Roma, Italy
| | - Eduardo Fidel Tizzano
- Clinical and Molecular Genetics Area, Vall d'Hebron Hospital; Medicine Genetics Group, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain
| | - Brunhilde Wirth
- Institute of Human Genetics, University Hospital of Cologne, Center for Molecular Medicine, University of Cologne and Center for Rare Diseases Cologne, University Hopsital of Cologne, Cologne, Germany
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Signoria I, van der Pol WL, Groen EJN. Innovating spinal muscular atrophy models in the therapeutic era. Dis Model Mech 2023; 16:dmm050352. [PMID: 37787662 PMCID: PMC10565113 DOI: 10.1242/dmm.050352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a severe, monogenetic, neuromuscular disease. A thorough understanding of its genetic cause and the availability of robust models has led to the development and approval of three gene-targeting therapies. This is a unique and exciting development for the field of neuromuscular diseases, many of which remain untreatable. The development of therapies for SMA not only opens the door to future therapeutic possibilities for other genetic neuromuscular diseases, but also informs us about the limitations of such treatments. For example, treatment response varies widely and, for many patients, significant disability remains. Currently available SMA models best recapitulate the severe types of SMA, and these models are genetically and phenotypically more homogeneous than patients. Furthermore, treating patients is leading to a shift in phenotypes with increased variability in SMA clinical presentation. Therefore, there is a need to generate model systems that better reflect these developments. Here, we will first discuss current animal models of SMA and their limitations. Next, we will discuss the characteristics required to future-proof models to assist the field in the development of additional, novel therapies for SMA.
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Affiliation(s)
- Ilaria Signoria
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - W. Ludo van der Pol
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Ewout J. N. Groen
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
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Ros LA, Sleutjes BT, Stikvoort García DJ, Goedee HS, Asselman FL, van den Berg LH, van der Pol WL, Wadman RI. Feasibility and tolerability of multimodal peripheral electrophysiological techniques in a cohort of patients with spinal muscular atrophy. Clin Neurophysiol Pract 2023; 8:123-131. [PMID: 37554725 PMCID: PMC10404501 DOI: 10.1016/j.cnp.2023.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 05/27/2023] [Accepted: 06/17/2023] [Indexed: 08/10/2023] Open
Abstract
OBJECTIVE Electrophysiological techniques are emerging as an aid in identifying prognostic or therapeutic biomarkers in patients with spinal muscular atrophy (SMA), but electrophysiological assessments may be burdensome for patients. We, therefore, assessed feasibility and tolerability of multimodal peripheral non-invasive electrophysiological techniques in a cohort of patients with SMA. METHODS We conducted a single center, longitudinal cohort study investigating the feasibility and tolerability of applying multimodal electrophysiological techniques to the median nerve unilaterally. Techniques consisted of the compound muscle action potential scan, motor nerve excitability tests, repetitive nerve stimulation and sensory nerve action potential. We assessed tolerability using the numeric rating scale (NRS), ranging from 0 (no pain) to 10 (worst possible pain), and defined the protocol to be tolerable if the NRS score ≤ 3. The protocol was considered feasible if it could be performed according to test and quality standards. RESULTS We included 71 patients with SMA types 1-4 (median 39 years; range 13-67) and 63 patients at follow-up. The protocol was feasible in 98% of patients and was well-tolerated in up to 90% of patients. Median NRS score was 2 (range 0-6 at baseline and range 0-4 at follow-up (p < 0.01)). None of the patients declined follow-up assessment. CONCLUSIONS Multimodal, peripheral, non-invasive, electrophysiological techniques applied to the median nerve are feasible and well-tolerated in adolescents and adults with SMA types 1-4. SIGNIFICANCE Our study supports the use of non-invasive multimodal electrophysiological assessments in adolescents and adults with SMA types 1-4.
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Affiliation(s)
- Leandra A.A. Ros
- Department of Neurology, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Boudewijn T.H.M. Sleutjes
- Department of Neurology, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Diederik J.L. Stikvoort García
- Department of Neurology, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - H. Stephan Goedee
- Department of Neurology, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Fay-Lynn Asselman
- Department of Neurology, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Leonard H. van den Berg
- Department of Neurology, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | | | - Renske I. Wadman
- Corresponding author at: Department of Neurology, University Medical Center Utrecht, UMC Utrecht Brain Center, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands.
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8
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René CA, Parks RJ. Expanding the Availability of Onasemnogene Abeparvovec to Older Patients: The Evolving Treatment Landscape for Spinal Muscular Atrophy. Pharmaceutics 2023; 15:1764. [PMID: 37376212 DOI: 10.3390/pharmaceutics15061764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 06/06/2023] [Accepted: 06/15/2023] [Indexed: 06/29/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a devastating neuromuscular disorder caused by mutations in the survival of motor neuron 1 (SMN1) gene, which leads to a reduced level in the SMN protein within cells. Patients with SMA suffer from a loss of alpha motor neurons in the spinal cord leading to skeletal muscle atrophy in addition to deficits in other tissues and organs. Patients with severe forms of the disease require ventilator assistance and typically succumb to the disease due to respiratory failure. Onasemnogene abeparvovec is an adeno-associated virus (AAV)-based gene therapeutic that has been approved for infants and young children with SMA, and it is delivered through intravenous administration using a dose based on the weight of the patient. While excellent outcomes have been observed in treated patients, the greater viral dose necessary to treat older children and adults raises legitimate safety concerns. Recently, onasemnogene abeparvovec use was investigated in older children through a fixed dose and intrathecal administration, a route that provides a more direct delivery to affected cells in the spinal cord and central nervous system. The promising results observed in the STRONG trial may support approval of onasemnogene abeparvovec for a greater proportion of patients with SMA.
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Affiliation(s)
- Charlotte A René
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Centre for Neuromuscular Disease, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Robin J Parks
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Centre for Neuromuscular Disease, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Department of Medicine, The Ottawa Hospital, Ottawa, ON K1H 8L6, Canada
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Zhang H, Qi G, Wang K, Yang J, Shen Y, Yang X, Chen X, Yao X, Gu X, Qi L, Zhou C, Sun H. Oxidative stress: roles in skeletal muscle atrophy. Biochem Pharmacol 2023:115664. [PMID: 37331636 DOI: 10.1016/j.bcp.2023.115664] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 06/12/2023] [Accepted: 06/13/2023] [Indexed: 06/20/2023]
Abstract
Oxidative stress, inflammation, mitochondrial dysfunction, reduced protein synthesis, and increased proteolysis are all critical factors in the process of muscle atrophy. In particular, oxidative stress is the key factor that triggers skeletal muscle atrophy. It is activated in the early stages of muscle atrophy and can be regulated by various factors. The mechanisms of oxidative stress in the development of muscle atrophy have not been completely elucidated. This review provides an overview of the sources of oxidative stress in skeletal muscle and the correlation of oxidative stress with inflammation, mitochondrial dysfunction, autophagy, protein synthesis, proteolysis, and muscle regeneration in muscle atrophy. Additionally, the role of oxidative stress in skeletal muscle atrophy caused by several pathological conditions, including denervation, unloading, chronic inflammatory diseases (diabetes mellitus, chronic kidney disease, chronic heart failure, and chronic obstructive pulmonary disease), sarcopenia, hereditary neuromuscular diseases (spinal muscular atrophy, amyotrophic lateral sclerosis, and Duchenne muscular dystrophy), and cancer cachexia, have been discussed. Finally, this review proposes the alleviation oxidative stress using antioxidants, Chinese herbal extracts, stem cell and extracellular vesicles as a promising therapeutic strategy for muscle atrophy. This review will aid in the development of novel therapeutic strategies and drugs for muscle atrophy.
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Affiliation(s)
- Han Zhang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Medical College, Nantong University, Nantong, Jiangsu Province, 226001, PR China
| | - Guangdong Qi
- Department of Endocrinology, Binhai County People's Hospital, Yancheng, Jiangsu Province, 224500, PR China
| | - Kexin Wang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Medical College, Nantong University, Nantong, Jiangsu Province, 226001, PR China
| | - Jiawen Yang
- Department of Clinical Medicine, Medical College, Nantong University, Nantong 226001, China
| | - Yuntian Shen
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Medical College, Nantong University, Nantong, Jiangsu Province, 226001, PR China
| | - Xiaoming Yang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Medical College, Nantong University, Nantong, Jiangsu Province, 226001, PR China
| | - Xin Chen
- Department of Neurology, Affiliated Hospital of Nantong University, Nantong, Jiangsu Province, 226001, PR China
| | - Xinlei Yao
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Medical College, Nantong University, Nantong, Jiangsu Province, 226001, PR China
| | - Xiaosong Gu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Medical College, Nantong University, Nantong, Jiangsu Province, 226001, PR China
| | - Lei Qi
- Department of Emergency Medicine, Affiliated Hospital of Nantong University, Nantong, Jiangsu Province, 226001, PR China.
| | - Chun Zhou
- Department of Neurology, Affiliated Hospital of Nantong University, Nantong, Jiangsu Province, 226001, PR China.
| | - Hualin Sun
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Medical College, Nantong University, Nantong, Jiangsu Province, 226001, PR China; Research and Development Center for E-Learning, Ministry of Education, Beijing 100816, PR China.
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Núñez-Moreno G, Tamayo A, Ruiz-Sánchez C, Cortón M, Mínguez P. VIsoQLR: an interactive tool for the detection, quantification and fine-tuning of isoforms in selected genes using long-read sequencing. Hum Genet 2023; 142:495-506. [PMID: 36881176 DOI: 10.1007/s00439-023-02539-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 02/23/2023] [Indexed: 03/08/2023]
Abstract
DNA variants altering the pre-mRNA splicing process represent an underestimated cause of human genetic diseases. Their association with disease traits should be confirmed using functional assays from patient cell lines or alternative models to detect aberrant mRNAs. Long-read sequencing is a suitable technique to identify and quantify mRNA isoforms. Available isoform detection and/or quantification tools are generally designed for the whole transcriptome analysis. However experiments focusing on genes of interest need more precise data fine-tuning and visualization tools.Here we describe VIsoQLR, an interactive analyzer, viewer and editor for the semi-automated identification and quantification of known and novel isoforms using long-read sequencing data. VIsoQLR is tailored to thoroughly analyze mRNA expression in splicing assays of selected genes. Our tool takes sequences aligned to a reference, and for each gene, it defines consensus splice sites and quantifies isoforms. VIsoQLR introduces features to edit the splice sites through dynamic and interactive graphics and tables, allowing accurate manual curation. Known isoforms detected by other methods can also be imported as references for comparison. A benchmark against two other popular transcriptome-based tools shows VIsoQLR accurate performance on both detection and quantification of isoforms. Here, we present VIsoQLR principles and features and its applicability in a case study example using nanopore-based long-read sequencing. VIsoQLR is available at https://github.com/TBLabFJD/VIsoQLR .
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Affiliation(s)
- Gonzalo Núñez-Moreno
- Department of Genetics and Genomics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.
- Bioinformatics Unit, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.
- Center for Biomedical Network Research On Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.
| | - Alejandra Tamayo
- Department of Genetics and Genomics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
- Center for Biomedical Network Research On Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
- Department of Surgery, Medical and Social Sciences, Faculty of Medicine and Health Sciences, Science and Technology Campus, University of Alcalá, 28871, Alcalá de Henares, Spain
| | - Carolina Ruiz-Sánchez
- Department of Genetics and Genomics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
| | - Marta Cortón
- Department of Genetics and Genomics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
- Center for Biomedical Network Research On Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Pablo Mínguez
- Department of Genetics and Genomics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
- Bioinformatics Unit, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
- Center for Biomedical Network Research On Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
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11
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Riboldi GM, Faravelli I, Rinchetti P, Lotti F. SMN post-translational modifications in spinal muscular atrophy. Front Cell Neurosci 2023; 17:1092488. [PMID: 36874214 PMCID: PMC9981653 DOI: 10.3389/fncel.2023.1092488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 01/26/2023] [Indexed: 02/19/2023] Open
Abstract
Since its first identification as the gene responsible for spinal muscular atrophy (SMA), the range of survival motor neuron (SMN) protein functions has increasingly expanded. This multimeric complex plays a crucial role in a variety of RNA processing pathways. While its most characterized function is in the biogenesis of ribonucleoproteins, several studies have highlighted the SMN complex as an important contributor to mRNA trafficking and translation, axonal transport, endocytosis, and mitochondria metabolism. All these multiple functions need to be selectively and finely modulated to maintain cellular homeostasis. SMN has distinct functional domains that play a crucial role in complex stability, function, and subcellular distribution. Many different processes were reported as modulators of the SMN complex activities, although their contribution to SMN biology still needs to be elucidated. Recent evidence has identified post-translational modifications (PTMs) as a way to regulate the pleiotropic functions of the SMN complex. These modifications include phosphorylation, methylation, ubiquitination, acetylation, sumoylation, and many other types. PTMs can broaden the range of protein functions by binding chemical moieties to specific amino acids, thus modulating several cellular processes. Here, we provide an overview of the main PTMs involved in the regulation of the SMN complex with a major focus on the functions that have been linked to SMA pathogenesis.
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Affiliation(s)
| | | | | | - Francesco Lotti
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY, United States
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12
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Abstract
There are more than 7,000 paediatric genetic diseases (PGDs) but less than 5% have treatment options. Treatment strategies targeting different levels of the biological process of the disease have led to optimal health outcomes in a subset of patients with PGDs, where treatment is available. In the past 3 decades, there has been rapid advancement in the development of novel therapies, including gene therapy, for many PGDs. The therapeutic success of treatment relies heavily on knowledge of the genetic basis and the disease mechanism. Specifically, gene therapy has been shown to be effective in various clinical trials, and indeed, these trials have led to regulatory approvals, paving the way for gene therapies for other types of PGDs. In this review, we provide an overview of the treatment strategies and focus on some of the recent advancements in therapeutics for PGDs.
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Affiliation(s)
- Ai Ling Koh
- Genetics Service, Department of Paediatrics, KK Women's and Children's Hospital, Singapore,SingHealth Duke-NUS Genomic Medicine Centre, Nanyang Technological University, Singapore,Duke-NUS Medical School, Nanyang Technological University, Singapore,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore,Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Saumya Shekhar Jamuar
- Genetics Service, Department of Paediatrics, KK Women's and Children's Hospital, Singapore,SingHealth Duke-NUS Genomic Medicine Centre, Nanyang Technological University, Singapore,Duke-NUS Medical School, Nanyang Technological University, Singapore,Yong Loo Lin School of Medicine, National University of Singapore, Singapore,SingHealth Duke-NUS Institute of Precision Medicine, Singapore,Correspondence: Dr. Saumya Shekhar Jamuar, Senior Consultant, Genetics Service, Department of Paediatrics, KK Women's and Children's Hospital, 100 Bukit Timah Road, 229899, Singapore. E-mail:
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Scheijmans FEV, Cuppen I, Zwartkruis MM, Signoria I, van Ekris C, Asselman F, Wadman RI, Knol EF, van der Pol WL, Groen EJN. Inflammatory markers in cerebrospinal fluid of paediatric spinal muscular atrophy patients receiving nusinersen treatment. Eur J Paediatr Neurol 2023; 42:34-41. [PMID: 36525882 DOI: 10.1016/j.ejpn.2022.12.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 11/01/2022] [Accepted: 12/05/2022] [Indexed: 12/12/2022]
Abstract
Spinal muscular atrophy (SMA) is a progressive motor neuron disease with onset during infancy or early childhood. Recent therapeutic advances targeting the genetic defect that underlies SMA improved survival in patients with infantile onset SMA (type 1) and improved motor function in SMA type 1-3. The most commonly used therapy for SMA, the antisense oligonucleotide nusinersen, is delivered by repeated intrathecal injections. The long-term safety effects of this procedure, however, have not yet been investigated in detail. We here present case reports of three children with SMA in which routine laboratory investigation revealed increased leukocyte counts in cerebrospinal fluid (CSF) collected during the course of nusinersen treatment. To further characterize this observation, we used a multiplex method to analyse a broad spectrum of inflammatory markers in the CSF of these patients. We found that interleukin-10 (IL10) was consistently elevated in CSF with increased leukocyte counts, but other inflammatory markers were not. Based on this analysis we selected 7 markers for further analysis in a cohort of 38 children with SMA and determined their expression during the course of nusinersen therapy. No consistent association was found between levels of inflammatory markers and the duration of nusinersen therapy in individual patients. However, monocyte chemoactive protein 1 (MCP1/CCL2) -a neuroprotective protein secreted by astrocytes and previously associated with SMA- levels increased over the course of nusinersen treatment, indicating a possible neuroprotective mechanism associated with nusinersen therapy. In summary, our findings confirm that repeated intrathecal injections are safe and do not trigger unwanted immune responses.
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Affiliation(s)
- F E V Scheijmans
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht, the Netherlands
| | - I Cuppen
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht, the Netherlands
| | - M M Zwartkruis
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht, the Netherlands; Department of Genetics, University Medical Center Utrecht, Utrecht, the Netherlands
| | - I Signoria
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht, the Netherlands
| | - C van Ekris
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht, the Netherlands
| | - F Asselman
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht, the Netherlands
| | - R I Wadman
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht, the Netherlands
| | - E F Knol
- Department of Dermatology and Allergology, Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - W L van der Pol
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht, the Netherlands.
| | - E J N Groen
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht, the Netherlands.
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Belter L, Mazzella A, O’Brien S, Jarecki J. Knowledge of genetic test results among caregivers and individuals with spinal muscular atrophy. PLoS One 2022; 17:e0276756. [PMID: 36346824 PMCID: PMC9642888 DOI: 10.1371/journal.pone.0276756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 10/12/2022] [Indexed: 11/11/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a progressive recessive genetic disease. Early identification is critical for achieving maximal treatment benefit. Survival motor neuron (SMN) 2 copy number may be a needed descriptor of disease severity than SMA type. Therefore, we assessed knowledge of SMN2 copy number among those with SMA and their caregivers via a phone survey. Only patients with SMA (or their caregivers) registered in the Cure SMA database with no SMN2 copy number on file were eligible. Descriptive results are reported. Backward stepwise multinomial logistic regressions determined if specific factors predicted knowledge of SMN2 copy number. Engagement with the SMA community (odds ratio [OR] 1.82; p<0.0001), ability to walk (OR 1.74; p = 0.006), and current age at time of survey (OR = 0.98; p<0.0001) each positively predicted knowledge of SMN2 copy number. Of 806 completed surveys, the majority (n = 452; 56.3%) did not know SMN2 copy numbers for themselves (n = 190; 62.5%) or their loved ones (n = 261; 52.4%). Of these, 66 respondents (8.2%) said genetic testing had not been done. Motor function increased linearly with increasing SMN2 copy number. SMN2 copy number is emerging as a critical descriptor of severity for SMA as type becomes more obsolete with early drug treatment. Communication of SMN2 copy numbers is recommended as a standard part of the treatment plan.
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Affiliation(s)
- Lisa Belter
- Research Department, Cure SMA, Elk Grove Village, IL, United States of America
- * E-mail:
| | - Allison Mazzella
- Research Department, Cure SMA, Elk Grove Village, IL, United States of America
- Division of Penn Translational Medicine and Human Genetics, Perleman Center for Advanced Medicine, Philadelphia, PA, United States of America
| | - Shannon O’Brien
- Community Support Department, Cure SMA, Elk Grove Village, IL, United States of America
| | - Jill Jarecki
- Research Department, Cure SMA, Elk Grove Village, IL, United States of America
- Department of Strategic Risk Management, BioMarin Pharmaceutical Inc., San Rafael, CA, United States of America
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15
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Blasco-Pérez L, Costa-Roger M, Leno-Colorado J, Bernal S, Alias L, Codina-Solà M, Martínez-Cruz D, Castiglioni C, Bertini E, Travaglini L, Millán JM, Aller E, Sotoca J, Juntas R, Hoei-Hansen CE, Moreno-Escribano A, Guillén-Navarro E, Costa-Comellas L, Munell F, Boronat S, Rojas-García R, Povedano M, Cuscó I, Tizzano EF. Deep Molecular Characterization of Milder Spinal Muscular Atrophy Patients Carrying the c.859G>C Variant in SMN2. Int J Mol Sci 2022; 23. [PMID: 35955418 DOI: 10.3390/ijms23158289] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/20/2022] [Accepted: 07/22/2022] [Indexed: 02/01/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a severe neuromuscular disorder caused by biallelic loss or pathogenic variants in the SMN1 gene. Copy number and modifier intragenic variants in SMN2, an almost identical paralog gene of SMN1, are known to influence the amount of complete SMN proteins. Therefore, SMN2 is considered the main phenotypic modifier of SMA, although genotype−phenotype correlation is not absolute. We present eleven unrelated SMA patients with milder phenotypes carrying the c.859G>C-positive modifier variant in SMN2. All were studied by a specific NGS method to allow a deep characterization of the entire SMN region. Analysis of two homozygous cases for the variant allowed us to identify a specific haplotype, Smn2-859C.1, in association with c.859G>C. Two other cases with the c.859G>C variant in their two SMN2 copies showed a second haplotype, Smn2-859C.2, in cis with Smn2-859C.1, assembling a more complex allele. We also identified a previously unreported variant in intron 2a exclusively linked to the Smn2-859C.1 haplotype (c.154-1141G>A), further suggesting that this region has been ancestrally conserved. The deep molecular characterization of SMN2 in our cohort highlights the importance of testing c.859G>C, as well as accurately assessing the SMN2 region in SMA patients to gain insight into the complex genotype−phenotype correlations and improve prognostic outcomes.
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16
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Jin W, Yang Z, Tang X, Wang X, Huang Y, Hui C, Yao J, Luan J, Tang S, Wu S, Jin S, Ding C. Simultaneous quantification of SMN1 and SMN2 copy numbers by MALDI-TOF mass spectrometry for spinal muscular atrophy genetic testing. Clin Chim Acta 2022; 532:45-52. [DOI: 10.1016/j.cca.2022.05.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 05/22/2022] [Indexed: 11/25/2022]
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Habets LE, Bartels B, Asselman FL, Hooijmans MT, van den Berg S, Nederveen AJ, van der Pol WL, Jeneson JAL. Magnetic resonance reveals mitochondrial dysfunction and muscle remodelling in spinal muscular atrophy. Brain 2021; 145:1422-1435. [PMID: 34788410 PMCID: PMC9128825 DOI: 10.1093/brain/awab411] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 09/24/2021] [Accepted: 10/08/2021] [Indexed: 11/14/2022] Open
Abstract
Genetic therapy has changed the prognosis of hereditary proximal spinal muscular atrophy, although treatment efficacy has been variable. There is a clear need for deeper understanding of underlying causes of muscle weakness and exercise intolerance in patients with this disease to further optimize treatment strategies. Animal models suggest that in addition to motor neuron and associated musculature degeneration, intrinsic abnormalities of muscle itself including mitochondrial dysfunction contribute to the disease aetiology. To test this hypothesis in patients, we conducted the first in vivo clinical investigation of muscle bioenergetics. We recruited 15 patients and 15 healthy age and gender-matched control subjects in this cross-sectional clinico-radiological study. MRI and 31P magnetic resonance spectroscopy, the modality of choice to interrogate muscle energetics and phenotypic fibre-type makeup, was performed of the proximal arm musculature in combination with fatiguing arm-cycling exercise and blood lactate testing. We derived bioenergetic parameter estimates including: blood lactate, intramuscular pH and inorganic phosphate accumulation during exercise, and muscle dynamic recovery constants. A linear correlation was used to test for associations between muscle morphological and bioenergetic parameters and clinico-functional measures of muscle weakness. MRI showed significant atrophy of triceps but not biceps muscles in patients. Maximal voluntary contraction force normalized to muscle cross-sectional area for both arm muscles was 1.4-fold lower in patients than in controls, indicating altered intrinsic muscle properties other than atrophy contributed to muscle weakness in this cohort. In vivo31P magnetic resonance spectroscopy identified white-to-red remodelling of residual proximal arm musculature in patients on the basis of altered intramuscular inorganic phosphate accumulation during arm-cycling in red versus white and intermediate myofibres. Blood lactate rise during arm-cycling was blunted in patients and correlated with muscle weakness and phenotypic muscle makeup. Post-exercise metabolic recovery was slower in residual intramuscular white myofibres in patients demonstrating mitochondrial ATP synthetic dysfunction in this particular fibre type. This study provides the first in vivo evidence in patients that degeneration of motor neurons and associated musculature causing atrophy and muscle weakness in 5q spinal muscular atrophy type 3 and 4 is aggravated by disproportionate depletion of myofibres that contract fastest and strongest. Our finding of decreased mitochondrial ATP synthetic function selectively in residual white myofibres provides both a possible clue to understanding the apparent vulnerability of this particular fibre type in 5q spinal muscular atrophy types 3 and 4 as well as a new biomarker and target for therapy.
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Affiliation(s)
- Laura E Habets
- Centre for Child Development, Exercise and Physical Literacy, Wilhelmina Children's Hospital, University Medical Centre Utrecht, P.O. Box 85090 3508 AB Utrecht, The Netherlands
| | - Bart Bartels
- Centre for Child Development, Exercise and Physical Literacy, Wilhelmina Children's Hospital, University Medical Centre Utrecht, P.O. Box 85090 3508 AB Utrecht, The Netherlands
| | - Fay-Lynn Asselman
- UMC Utrecht Brain Centre, Department of Neurology and Neurosurgery, University Medical Centre Utrecht Brain Center, Utrecht University, P.O. Box 85500, 3508 GA Utrecht, The Netherlands
| | - Melissa T Hooijmans
- Department of Radiology & Nuclear Medicine, Amsterdam Movement Sciences, Amsterdam University Medical Centre, location AMC, 1105 AZ Amsterdam, The Netherlands
| | - Sandra van den Berg
- Department of Radiology & Nuclear Medicine, Amsterdam Movement Sciences, Amsterdam University Medical Centre, location AMC, 1105 AZ Amsterdam, The Netherlands
| | - Aart J Nederveen
- Department of Radiology & Nuclear Medicine, Amsterdam Movement Sciences, Amsterdam University Medical Centre, location AMC, 1105 AZ Amsterdam, The Netherlands
| | - W Ludo van der Pol
- UMC Utrecht Brain Centre, Department of Neurology and Neurosurgery, University Medical Centre Utrecht Brain Center, Utrecht University, P.O. Box 85500, 3508 GA Utrecht, The Netherlands
| | - Jeroen A L Jeneson
- Centre for Child Development, Exercise and Physical Literacy, Wilhelmina Children's Hospital, University Medical Centre Utrecht, P.O. Box 85090 3508 AB Utrecht, The Netherlands
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18
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van der Pol L. Buying time for infants with spinal muscular atrophy. Lancet Neurol 2021; 20:777-9. [PMID: 34536396 DOI: 10.1016/S1474-4422(21)00291-X] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 08/26/2021] [Indexed: 11/23/2022]
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Costa-Roger M, Blasco-Pérez L, Cuscó I, Tizzano EF. The Importance of Digging into the Genetics of SMN Genes in the Therapeutic Scenario of Spinal Muscular Atrophy. Int J Mol Sci 2021; 22:9029. [PMID: 34445733 DOI: 10.3390/ijms22169029] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/13/2021] [Accepted: 08/19/2021] [Indexed: 12/12/2022] Open
Abstract
After 26 years of discovery of the determinant survival motor neuron 1 and the modifier survival motor neuron 2 genes (SMN1 and SMN2, respectively), three SMN-dependent specific therapies are already approved by FDA and EMA and, as a consequence, worldwide SMA patients are currently under clinical investigation and treatment. Bi-allelic pathogenic variants (mostly deletions) in SMN1 should be detected in SMA patients to confirm the disease. Determination of SMN2 copy number has been historically employed to correlate with the phenotype, predict disease evolution, stratify patients for clinical trials and to define those eligible for treatment. In view that discordant genotype-phenotype correlations are present in SMA, besides technical issues with detection of SMN2 copy number, we have hypothesized that copy number determination is only the tip of the iceberg and that more deepen studies of variants, sequencing and structures of the SMN2 genes are necessary for a better understanding of the disease as well as to investigate possible influences in treatment responses. Here, we highlight the importance of a comprehensive approach of SMN1 and SMN2 genetics with the perspective to apply for better prediction of SMA in positive neonatal screening cases and early diagnosis to start treatments.
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Baker MW, Mochal ST, Dawe SJ, Wiberley-Bradford AE, Cogley MF, Zeitler BR, Piro ZD, Harmelink MM, Kwon JM. Newborn screening for spinal muscular atrophy: The Wisconsin first year experience. Neuromuscul Disord 2021; 32:135-141. [PMID: 35120759 DOI: 10.1016/j.nmd.2021.07.398] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 07/10/2021] [Accepted: 07/20/2021] [Indexed: 11/27/2022]
Abstract
Spinal muscular atrophy was recently added to the Wisconsin newborn screening panel. Here we report our screening methods, algorithm, and outcomes. A multiplex real-time PCR assay was used to identify newborns with homozygous SMN1 exon 7 deletion, and those newborns' specimens further underwent a droplet digital PCR assay for SMN2 copy number assessment. An independent dried blood spot specimen was collected and tested to confirm the initial screening results for SMN1 and SMN2. From October 15, 2019 to October 14, 2020, a total of 60,984 newborns were screened for spinal muscular atrophy. Six newborns screened positive for and were confirmed to have spinal muscular atrophy, making the Wisconsin spinal muscular atrophy birth prevalence 1 in 10,164. Of these six infants, two have two copies of SMN2, two have three copies of SMN2, and two have four copies of SMN2. Five newborns received Zolgensma therapy, and one newborn received Spinraza therapy. Our screening method's positive predictive value is 100%. This comprehensive approach, providing both timely SMN2 information and SMN1 and SMN2 confirmation as parts of the algorithm for spinal muscular atrophy newborn screening, facilitated timely clinical follow-up, family counseling, and treatment planning.
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Affiliation(s)
- Mei W Baker
- Newborn Screening Laboratory, Wisconsin State Laboratory of Hygiene, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States; Genetics and Metabolism Division, Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States.
| | - Sean T Mochal
- Newborn Screening Laboratory, Wisconsin State Laboratory of Hygiene, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Sandra J Dawe
- Office of Information Systems, Wisconsin State Laboratory of Hygiene University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Amy E Wiberley-Bradford
- Newborn Screening Laboratory, Wisconsin State Laboratory of Hygiene, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Michael F Cogley
- Newborn Screening Laboratory, Wisconsin State Laboratory of Hygiene, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Bethany R Zeitler
- Newborn Screening Laboratory, Wisconsin State Laboratory of Hygiene, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Zachary D Piro
- Newborn Screening Laboratory, Wisconsin State Laboratory of Hygiene, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Mathew M Harmelink
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Jennifer M Kwon
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
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21
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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: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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22
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Chaytow H, Faller KME, Huang YT, Gillingwater TH. Spinal muscular atrophy: From approved therapies to future therapeutic targets for personalized medicine. Cell Rep Med 2021; 2:100346. [PMID: 34337562 DOI: 10.1016/j.xcrm.2021.100346] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Spinal muscular atrophy (SMA) is a devastating childhood motor neuron disease that, in the most severe cases and when left untreated, leads to death within the first two years of life. Recent therapeutic advances have given hope to families and patients by compensating for the deficiency in survival motor neuron (SMN) protein via gene therapy or other genetic manipulation. However, it is now apparent that none of these therapies will cure SMA alone. In this review, we discuss the three currently licensed therapies for SMA, briefly highlighting their respective advantages and disadvantages, before considering alternative approaches to increasing SMN protein levels. We then explore recent preclinical research that is identifying and targeting dysregulated pathways secondary to, or independent of, SMN deficiency that may provide adjunctive opportunities for SMA. These additional therapies are likely to be key for the development of treatments that are effective across the lifespan of SMA patients. Three licensed SMA therapies increase SMN levels, but are not a cure Other strategies to increase SMN levels are still under development Alternatives target the correction of dysregulated pathways following SMN loss Ultimately, a range of therapies may allow for a tailored treatment
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23
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Bos JW, Groen EJN, Wadman RI, Curial CAD, Molleman NN, Zegers M, van Vught PWJ, Snetselaar R, Vijzelaar R, van der Pol WL, van den Berg LH. SMN1 Duplications Are Associated With Progressive Muscular Atrophy, but Not With Multifocal Motor Neuropathy and Primary Lateral Sclerosis. Neurol Genet 2021; 7:e598. [PMID: 34169148 PMCID: PMC8220964 DOI: 10.1212/nxg.0000000000000598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 04/02/2021] [Indexed: 11/30/2022]
Abstract
Objective To assess the association between copy number (CN) variation in the survival motor neuron (SMN) locus and multifocal motor neuropathy (MMN), progressive muscular atrophy (PMA), and primary lateral sclerosis (PLS) susceptibility and to determine the association of SMN1 and SMN2 CN with MMN, PMA, and PLS disease course. Methods In this monocenter study, we used multiplex ligation-dependent probe amplification to determine SMN1 and SMN2 CN in Dutch patients with MMN, PMA, and PLS and controls. We stratified clinical parameters for SMN1 and SMN2 CN. We analyzed SMN1 and SMN2 exons 1–6, intron 6, and exon 8 CN to study the genetic architecture of SMN1 duplications. Results SMN1 and SMN2 CN were determined in 132 patients with MMN, 150 patients with PMA, 104 patients with PLS, and 956 control subjects. MMN and PLS were not associated with CN variation in SMN1 or SMN2. By contrast, patients with PMA more often than controls carried SMN1 duplications (≥3 SMN1 copies, 12.0% vs 5.0%, odds ratio 2.69 (1.43–4.91), p 0.0020). SMN1 and SMN2 CN status was not associated with MMN, PLS, or PMA disease course. In case of SMN1 exon 7 duplications, exons 1–6, exon 8, and introns 6 and 7 were also duplicated, suggesting full SMN1 duplications. Conclusions SMN1 duplications are associated with PMA, but not with PLS and MMN. SMN1 duplications in PMA are balanced duplications. The results of this study highlight the primary effect of altered SMN CN on lower motor neurons.
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Affiliation(s)
- Jeroen W Bos
- Department of Neurology and Neurosurgery (J.W.B., E.J.N.G., R.I.W., C.A.D.C., W.L.v.d.P., L.H.v.d.B.), UMC Utrecht Brain Center, Utrecht University, Utrecht, the Netherlands; and MRC Holland (N.N.M., M.Z., P.W.J.v.V., R.S., R.V.), Amsterdam, the Netherlands
| | - Ewout J N Groen
- Department of Neurology and Neurosurgery (J.W.B., E.J.N.G., R.I.W., C.A.D.C., W.L.v.d.P., L.H.v.d.B.), UMC Utrecht Brain Center, Utrecht University, Utrecht, the Netherlands; and MRC Holland (N.N.M., M.Z., P.W.J.v.V., R.S., R.V.), Amsterdam, the Netherlands
| | - Renske I Wadman
- Department of Neurology and Neurosurgery (J.W.B., E.J.N.G., R.I.W., C.A.D.C., W.L.v.d.P., L.H.v.d.B.), UMC Utrecht Brain Center, Utrecht University, Utrecht, the Netherlands; and MRC Holland (N.N.M., M.Z., P.W.J.v.V., R.S., R.V.), Amsterdam, the Netherlands
| | - Chantall A D Curial
- Department of Neurology and Neurosurgery (J.W.B., E.J.N.G., R.I.W., C.A.D.C., W.L.v.d.P., L.H.v.d.B.), UMC Utrecht Brain Center, Utrecht University, Utrecht, the Netherlands; and MRC Holland (N.N.M., M.Z., P.W.J.v.V., R.S., R.V.), Amsterdam, the Netherlands
| | - Naomi N Molleman
- Department of Neurology and Neurosurgery (J.W.B., E.J.N.G., R.I.W., C.A.D.C., W.L.v.d.P., L.H.v.d.B.), UMC Utrecht Brain Center, Utrecht University, Utrecht, the Netherlands; and MRC Holland (N.N.M., M.Z., P.W.J.v.V., R.S., R.V.), Amsterdam, the Netherlands
| | - Marinka Zegers
- Department of Neurology and Neurosurgery (J.W.B., E.J.N.G., R.I.W., C.A.D.C., W.L.v.d.P., L.H.v.d.B.), UMC Utrecht Brain Center, Utrecht University, Utrecht, the Netherlands; and MRC Holland (N.N.M., M.Z., P.W.J.v.V., R.S., R.V.), Amsterdam, the Netherlands
| | - Paul W J van Vught
- Department of Neurology and Neurosurgery (J.W.B., E.J.N.G., R.I.W., C.A.D.C., W.L.v.d.P., L.H.v.d.B.), UMC Utrecht Brain Center, Utrecht University, Utrecht, the Netherlands; and MRC Holland (N.N.M., M.Z., P.W.J.v.V., R.S., R.V.), Amsterdam, the Netherlands
| | - Reinier Snetselaar
- Department of Neurology and Neurosurgery (J.W.B., E.J.N.G., R.I.W., C.A.D.C., W.L.v.d.P., L.H.v.d.B.), UMC Utrecht Brain Center, Utrecht University, Utrecht, the Netherlands; and MRC Holland (N.N.M., M.Z., P.W.J.v.V., R.S., R.V.), Amsterdam, the Netherlands
| | - Raymon Vijzelaar
- Department of Neurology and Neurosurgery (J.W.B., E.J.N.G., R.I.W., C.A.D.C., W.L.v.d.P., L.H.v.d.B.), UMC Utrecht Brain Center, Utrecht University, Utrecht, the Netherlands; and MRC Holland (N.N.M., M.Z., P.W.J.v.V., R.S., R.V.), Amsterdam, the Netherlands
| | - W Ludo van der Pol
- Department of Neurology and Neurosurgery (J.W.B., E.J.N.G., R.I.W., C.A.D.C., W.L.v.d.P., L.H.v.d.B.), UMC Utrecht Brain Center, Utrecht University, Utrecht, the Netherlands; and MRC Holland (N.N.M., M.Z., P.W.J.v.V., R.S., R.V.), Amsterdam, the Netherlands
| | - Leonard H van den Berg
- Department of Neurology and Neurosurgery (J.W.B., E.J.N.G., R.I.W., C.A.D.C., W.L.v.d.P., L.H.v.d.B.), UMC Utrecht Brain Center, Utrecht University, Utrecht, the Netherlands; and MRC Holland (N.N.M., M.Z., P.W.J.v.V., R.S., R.V.), Amsterdam, the Netherlands
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24
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James R, Chaytow H, Ledahawsky LM, Gillingwater TH. Revisiting the role of mitochondria in spinal muscular atrophy. Cell Mol Life Sci 2021; 78:4785-4804. [PMID: 33821292 PMCID: PMC8195803 DOI: 10.1007/s00018-021-03819-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/22/2021] [Accepted: 03/23/2021] [Indexed: 02/07/2023]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive motor neuron disease of variable clinical severity that is caused by mutations in the survival motor neuron 1 (SMN1) gene. Despite its name, SMN is a ubiquitous protein that functions within and outside the nervous system and has multiple cellular roles in transcription, translation, and proteostatic mechanisms. Encouragingly, several SMN-directed therapies have recently reached the clinic, albeit this has highlighted the increasing need to develop combinatorial therapies for SMA to achieve full clinical efficacy. As a subcellular site of dysfunction in SMA, mitochondria represents a relevant target for a combinatorial therapy. Accordingly, we will discuss our current understanding of mitochondrial dysfunction in SMA, highlighting mitochondrial-based pathways that offer further mechanistic insights into the involvement of mitochondria in SMA. This may ultimately facilitate translational development of targeted mitochondrial therapies for SMA. Due to clinical and mechanistic overlaps, such strategies may also benefit other motor neuron diseases and related neurodegenerative disorders.
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Affiliation(s)
- Rachel James
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Helena Chaytow
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Leire M Ledahawsky
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Thomas H Gillingwater
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK.
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK.
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25
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Blasco-Pérez L, Paramonov I, Leno J, Bernal S, Alias L, Fuentes-Prior P, Cuscó I, Tizzano EF. Beyond copy number: A new, rapid, and versatile method for sequencing the entire SMN2 gene in SMA patients. Hum Mutat 2021; 42:787-795. [PMID: 33739559 PMCID: PMC8252042 DOI: 10.1002/humu.24200] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 01/13/2021] [Accepted: 03/11/2021] [Indexed: 01/16/2023]
Abstract
Spinal muscular atrophy (SMA) is caused by bi‐allelic loss or pathogenic variants in the SMN1 gene. SMN2, the highly homologous copy of SMN1, is considered the major phenotypic modifier of the disease. Determination of SMN2 copy number is essential to establish robust genotype–phenotype correlations and predict disease evolution, to stratify patients for clinical trials, as well as to define those eligible for treatment. Discordant genotype–phenotype correlations are not uncommon in SMA, some of which are due to intragenic SMN2 variants that may influence the amount of complete SMN transcripts and, therefore, of full‐length SMN protein. Detection of these variants is crucial to predict SMA phenotypes in the present scenario of therapeutic advances and with the perspective of SMA neonatal screening and early diagnosis to start treatments. Here, we present a novel, affordable, and versatile method for complete sequencing of the SMN2 gene based on long‐range polymerase chain reaction and next‐generation sequencing. The method was validated by analyzing samples from 53 SMA patients who lack SMN1, allowing to characterize paralogous, rare variants, and single‐nucleotide polymorphisms of SMN2 as well as SMN2–SMN1 hybrid genes. The method identifies partial deletions and can be adapted to determine rare pathogenic variants in patients with at least one SMN1 copy.
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Affiliation(s)
- Laura Blasco-Pérez
- Medicine Genetics Group, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain.,Department of Clinical and Molecular Genetics, Hospital Vall d'Hebron, Barcelona, Spain
| | - Ida Paramonov
- Medicine Genetics Group, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain.,Department of Clinical and Molecular Genetics, Hospital Vall d'Hebron, Barcelona, Spain
| | - Jordi Leno
- Medicine Genetics Group, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain.,Department of Clinical and Molecular Genetics, Hospital Vall d'Hebron, Barcelona, Spain
| | - Sara Bernal
- Genetics Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER)
| | - Laura Alias
- Genetics Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER)
| | - Pablo Fuentes-Prior
- Molecular Bases of Disease, Biomedical Research Institute Sant Pau (IIB Sant Pau), Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Ivon Cuscó
- Medicine Genetics Group, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain.,Department of Clinical and Molecular Genetics, Hospital Vall d'Hebron, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER)
| | - Eduardo F Tizzano
- Medicine Genetics Group, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain.,Department of Clinical and Molecular Genetics, Hospital Vall d'Hebron, Barcelona, Spain
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26
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Baranello G, Gorni K, Daigl M, Kotzeva A, Evans R, Hawkins N, Scott DA, Mahajan A, Muntoni F, Servais L. Prognostic Factors and Treatment-Effect Modifiers in Spinal Muscular Atrophy. Clin Pharmacol Ther 2021; 110:1435-1454. [PMID: 33792051 PMCID: PMC9292571 DOI: 10.1002/cpt.2247] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 02/21/2021] [Indexed: 12/20/2022]
Abstract
Spinal muscular atrophy (SMA) is a rare, progressive neuromuscular disease characterized by loss of motor neurons and muscle atrophy. Untreated infants with type 1 SMA do not achieve major motor milestones, and death from respiratory failure typically occurs before 2 years of age. Individuals with types 2 and 3 SMA exhibit milder phenotypes and have better functional and survival outcomes. Herein, a systematic literature review was conducted to identify factors that influence the prognosis of types 1, 2, and 3 SMA. In untreated infants with type 1 SMA, absence of symptoms at birth, a later symptom onset, and a higher survival of motor neuron 2 (SMN2) copy number are all associated with increased survival. Disease duration, age at treatment initiation, and, to a lesser extent, baseline function were identified as potential treatment‐modifying factors for survival, emphasizing that early treatment with disease‐modifying therapies (DMT) is essential in type 1 SMA. In patients with types 2 and 3 SMA, factors considered prognostic of changes in motor function were SMN2 copy number, age, and ambulatory status. Individuals aged 6–15 years were particularly vulnerable to developing complications (scoliosis and progressive joint contractures) which negatively influence functional outcomes and may also affect the therapeutic response in patients. Age at the time of treatment initiation emerged as a treatment‐effect modifier on the outcome of DMTs. Factors identified in this review should be considered prior to designing or analyzing studies in an SMA population, conducting population matching, or summarizing results from different studies on the treatments for SMA.
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Affiliation(s)
- Giovanni Baranello
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health, London, United Kingdom.,Developmental Neurology Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Istituto Neurologico Carlo Besta, Milan, Italy
| | | | | | | | | | | | | | | | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health, London, United Kingdom.,National Institute for Health Research Biomedical Research Centre, University College of London Great Ormond Street Institute of Child Health, Great Ormond Street Hospital National Health Service Trust, London, UK
| | - Laurent Servais
- Division of Child Neurology Reference Center for Neuromuscular Disease, Department of Pediatrics, Centre Hospitalier Régional de Références des Maladies Neuromusculaires, University Hospital Liège & University of La Citadelle, Liège, Belgium.,Department of Paediatrics, Muscular Dystrophy UK Oxford Neuromuscular Centre, University of Oxford, Oxford, UK
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27
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Milligan JN, Larson JL, Filipovic-Sadic S, Laosinchai-Wolf W, Huang YW, Ko TM, Abbott KM, Lemmink HH, Toivonen M, Schleutker J, Gentile C, Van Deerlin VM, Zhu H, Latham GJ. Multisite Evaluation and Validation of a Sensitive Diagnostic and Screening System for Spinal Muscular Atrophy that Reports SMN1 and SMN2 Copy Number, along with Disease Modifier and Gene Duplication Variants. J Mol Diagn 2021; 23:753-764. [PMID: 33798739 DOI: 10.1016/j.jmoldx.2021.03.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 02/17/2021] [Accepted: 03/16/2021] [Indexed: 11/24/2022] Open
Abstract
Spinal muscular atrophy is a severe autosomal recessive disease caused by disruptions in the SMN1 gene. The nearly identical SMN2 gene copy number is associated with disease severity. SMN1 duplication markers, such as c.∗3+80T>G and c.∗211_∗212del, can assess residual carrier risk. An SMN2 disease modifier (c.859G>C) can help inform prognostic outcomes. The emergence of multiple precision gene therapies for spinal muscular atrophy requires accurate and rapid detection of SMN1 and SMN2 copy numbers to enable early treatment and optimal patient outcomes. We developed and evaluated a single-tube PCR/capillary electrophoresis assay system that quantifies SMN1/2 copy numbers and genotypes three additional clinically relevant variants. Analytical validation was performed with human cell lines and whole blood representing varying SMN1/2 copies on four capillary electrophoresis instrument models. In addition, four independent laboratories used the assay to test 468 residual clinical genomic DNA samples. The results were ≥98.3% concordant with consensus SMN1/2 exon 7 copy numbers, determined using multiplex ligation-dependent probe amplification and droplet digital PCR, and were 100% concordant with Sanger sequencing for the three variants. Furthermore, copy number values were 98.6% (SMN1) and 97.1% (SMN2) concordant to each laboratory's own reference results.
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Affiliation(s)
| | | | | | | | - Ya-Wen Huang
- GenePhile Bioscience Laboratory, Ko's Obstetrics and Gynecology Clinic, Taipei City, Taiwan
| | - Tsang-Ming Ko
- GenePhile Bioscience Laboratory, Ko's Obstetrics and Gynecology Clinic, Taipei City, Taiwan
| | - Kristin M Abbott
- Department of Genetics, University Medical Center Groningen, Groningen, the Netherlands
| | - Henny H Lemmink
- Department of Genetics, University Medical Center Groningen, Groningen, the Netherlands
| | - Minna Toivonen
- Department of Medical Genetics, Genomics, Laboratory Division, Turku University Hospital, Turku, Finland
| | - Johanna Schleutker
- Department of Medical Genetics, Genomics, Laboratory Division, Turku University Hospital, Turku, Finland; Institute of Biomedicine, University of Turku, Turun yliopisto, Finland
| | - Caren Gentile
- Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
| | | | - Huiping Zhu
- Research and Development, Asuragen Inc., Austin, Texas
| | - Gary J Latham
- Research and Development, Asuragen Inc., Austin, Texas
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28
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Kucera KS, Taylor JL, Robles VR, Clinard K, Migliore B, Boyea BL, Okoniewski KC, Duparc M, Rehder CW, Shone SM, Fan Z, Raspa M, Peay HL, Wheeler AC, Powell CM, Bailey DB Jr, Gehtland LM. A Voluntary Statewide Newborn Screening Pilot for Spinal Muscular Atrophy: Results from Early Check. Int J Neonatal Screen 2021; 7. [PMID: 33801060 DOI: 10.3390/ijns7010020] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 03/06/2021] [Accepted: 03/15/2021] [Indexed: 02/07/2023] Open
Abstract
Prior to statewide newborn screening (NBS) for spinal muscular atrophy (SMA) in North Carolina, U.S.A., we offered voluntary screening through the Early Check (EC) research study. Here, we describe the EC experience from October 2018 through December 2020. We enrolled a total of 12,065 newborns and identified one newborn with 0 copies of SMN1 and two copies of SMN2, consistent with severe early onset of SMA. We also detected one false positive result, likely stemming from an unrelated blood disorder associated with a low white blood cell count. We evaluated the timing of NBS for babies enrolled prenatally (n = 932) and postnatally (n = 11,133) and reasons for delays in screening and reporting. Although prenatal enrollment led to faster return of results (median = 13 days after birth), results for babies enrolled postnatally were still available within a timeframe (median = 21 days after birth) that allowed the opportunity to receive essential treatment early in life. We evaluated an SMA q-PCR screening method at two separate time points, confirming the robustness of the assay. The pilot project provided important information about SMA screening in anticipation of forthcoming statewide expansion as part of regular NBS.
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