1
|
Rashid S, Dimitriadi M. Autophagy in spinal muscular atrophy: from pathogenic mechanisms to therapeutic approaches. Front Cell Neurosci 2024; 17:1307636. [PMID: 38259504 PMCID: PMC10801191 DOI: 10.3389/fncel.2023.1307636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 12/14/2023] [Indexed: 01/24/2024] Open
Abstract
Spinal muscular atrophy (SMA) is a devastating neuromuscular disorder caused by the depletion of the ubiquitously expressed survival motor neuron (SMN) protein. While the genetic cause of SMA has been well documented, the exact mechanism(s) by which SMN depletion results in disease progression remain elusive. A wide body of evidence has highlighted the involvement and dysregulation of autophagy in SMA. Autophagy is a highly conserved lysosomal degradation process which is necessary for cellular homeostasis; defects in the autophagic machinery have been linked with a wide range of neurodegenerative disorders, including amyotrophic lateral sclerosis, Alzheimer's disease and Parkinson's disease. The pathway is particularly known to prevent neurodegeneration and has been suggested to act as a neuroprotective factor, thus presenting an attractive target for novel therapies for SMA patients. In this review, (a) we provide for the first time a comprehensive summary of the perturbations in the autophagic networks that characterize SMA development, (b) highlight the autophagic regulators which may play a key role in SMA pathogenesis and (c) propose decreased autophagic flux as the causative agent underlying the autophagic dysregulation observed in these patients.
Collapse
Affiliation(s)
| | - Maria Dimitriadi
- School of Life and Medical Science, University of Hertfordshire, Hatfield, United Kingdom
| |
Collapse
|
2
|
Thimm A, Brakemeier S, Dag M, Munoz Rosales J, Stolte B, Kleinschnitz C, Stettner M, Hagenacker T. Corneal confocal microscopy reveals small nerve fibre loss correlating with motor function in adult spinal muscular atrophy. Eur J Neurol 2023; 30:2821-2827. [PMID: 37159488 DOI: 10.1111/ene.15852] [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: 03/10/2023] [Revised: 04/20/2023] [Accepted: 05/04/2023] [Indexed: 05/11/2023]
Abstract
BACKGROUND 5q Spinal muscular atrophy (SMA) is a progressive, inherited, and severely disabling - yet treatable - motor neuron disease. Although treatment options have evolved in recent years, biomarkers for treatment monitoring and prognosis prediction remain elusive. Here, we investigated the utility of corneal confocal microscopy (CCM), a non-invasive imaging technique to quantify small corneal nerve fibres in vivo, as a diagnostic tool in adult SMA. METHODS In this cross-sectional study, 19 patients with SMA type 3 and 19 healthy controls underwent CCM to measure corneal nerve fibre density (CNFD), corneal nerve fibre length (CNFL), and corneal nerve branch density (CNBD), as well as corneal immune cell infiltration. Hammersmith Functional Motor Scale Expanded (HFMSE) and Revised Upper Limb Module (RULM) scores and a 6-Minute Walk Test (6MWT) were conducted to explore any correlation between CCM findings and motor function. RESULTS Corneal nerve fibre parameters were decreased in SMA patients versus healthy controls (CNFD: p = 0.030; CNFL: p = 0.013; CNBD: p = 0.020) in the absence of relevant immune cell infiltration. CNFD and CNFL correlated with HFMSE scores (CNFD: r = 0.492, p = 0.038; CNFL: r = 0.484, p = 0.042) and distance covered in the 6MWT (CNFD: r = 0.502, p = 0.042; CNFL: r = 0.553, p = 0.023). CONCLUSIONS Corneal confocal microscopy CCM reveals sensory neurodegeneration in SMA, thereby supporting a multisystem view of the disorder. Subclinical small nerve fibre damage correlated with motor function. Thus, CCM may be ideally suited for treatment monitoring and prognosis.
Collapse
Affiliation(s)
- Andreas Thimm
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Essen, Germany
| | - Svenja Brakemeier
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Essen, Germany
| | - Merve Dag
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Essen, Germany
| | - Juan Munoz Rosales
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Essen, Germany
| | - Benjamin Stolte
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Essen, Germany
| | - Christoph Kleinschnitz
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Essen, Germany
| | - Mark Stettner
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Essen, Germany
| | - Tim Hagenacker
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Essen, Germany
| |
Collapse
|
3
|
Messina S, Sframeli M, Maggi L, D'Amico A, Bruno C, Comi G, Mercuri E. Spinal muscular atrophy: state of the art and new therapeutic strategies. Neurol Sci 2022; 43:615-624. [PMID: 33871750 DOI: 10.1007/s10072-021-05258-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 04/12/2021] [Indexed: 12/27/2022]
Abstract
Spinal muscular atrophy (SMA) is a severe disorder of motor neurons and the most frequent cause of genetic mortality, due to respiratory complications. We are facing an exciting era with three available therapeutic options in a disease considered incurable for more than a century. However, the availability of effective approaches has raised up ethical, medical, and financial issues that are routinely faced by the SMA community. Each therapeutic strategy has its weaknesses and strengths and clinicians need to know them to optimize clinical care. In this review, the state of the art and the results and challenges of the new SMA therapeutic strategies are highlighted.
Collapse
Affiliation(s)
- Sonia Messina
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy. .,NEuroMuscular Omnicentre (NEMO) Sud Clinical Centre, University Hospital "G. Martino", Messina, Italy.
| | - Maria Sframeli
- NEuroMuscular Omnicentre (NEMO) Sud Clinical Centre, University Hospital "G. Martino", Messina, Italy
| | - Lorenzo Maggi
- Neuroimmunology and Neuromuscular Disease Unit, Foundation IRCCS Carlo Besta Neurological Institute, Milan, Italy
| | - Adele D'Amico
- Unit of Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, Bambino Gesù Children's Hospital, Rome, Italy
| | - Claudio Bruno
- Center of Translational and Experimental Myology, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Giacomo Comi
- Neuromuscular and Rare Disease Unit, La Fondazione IRCCS Ca' Granda Ospedale Maggiore di Milano Policlinico, Milan, Italy.,Department of Pathophysiology and Transplantation (DEPT), Dino Ferrari Centre, University of Milan, Milan, Italy
| | - Eugenio Mercuri
- Department of Child Neurology, University Policlinico Gemelli, Rome, Italy
| |
Collapse
|
4
|
Thimm A, Brakemeier S, Kizina K, Munoz Rosales J, Stolte B, Totzeck A, Deuschl C, Kleinschnitz C, Hagenacker T. Assessment of Health-Related Quality of Life in Adult Spinal Muscular Atrophy Under Nusinersen Treatment—A Pilot Study. Front Neurol 2022; 12:812063. [PMID: 35140677 PMCID: PMC8818760 DOI: 10.3389/fneur.2021.812063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 12/27/2021] [Indexed: 01/16/2023] Open
Abstract
5q-Spinal muscular atrophy (SMA) is a severely disabling inherited neuromuscular disease that progressively reduces the motor abilities of affected individuals. The approval of the antisense oligonucleotide nusinersen, which has been shown to improve motor function in adult SMA patients, changed the treatment landscape. However, little is known about its impact on patients' quality of life (QoL), and there is still a need for adequate patient-reported outcome measures. In this study, we used the short form of the Neuro-QoL (Quality of Life in Neurological Disorders) for upper/lower extremity function to prospectively assess the health-related QoL of 17 adult SMA patients prior to initiation of nusinersen treatment and 2, 6, 10, and 14 months afterwards. At baseline, Neuro-QoL scores strongly correlated with motor function scores (Hammersmith Functional Motor Scale Expanded, HFMSE; Revised Upper Limb Module, RULM), but QoL did not increase significantly during the 14-month treatment period despite significant motor improvement as measured by HFMSE. Our results underline the need for novel, disease-specific assessments of QoL in SMA.
Collapse
Affiliation(s)
- Andreas Thimm
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences, University Hospital Essen, Essen, Germany
- *Correspondence: Andreas Thimm
| | - Svenja Brakemeier
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences, University Hospital Essen, Essen, Germany
| | - Kathrin Kizina
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences, University Hospital Essen, Essen, Germany
| | - Juan Munoz Rosales
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences, University Hospital Essen, Essen, Germany
| | - Benjamin Stolte
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences, University Hospital Essen, Essen, Germany
| | - Andreas Totzeck
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences, University Hospital Essen, Essen, Germany
| | - Cornelius Deuschl
- Institute for Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany
| | - Christoph Kleinschnitz
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences, University Hospital Essen, Essen, Germany
| | - Tim Hagenacker
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences, University Hospital Essen, Essen, Germany
| |
Collapse
|
5
|
In Search of a Cure: The Development of Therapeutics to Alter the Progression of Spinal Muscular Atrophy. Brain Sci 2021; 11:brainsci11020194. [PMID: 33562482 PMCID: PMC7915832 DOI: 10.3390/brainsci11020194] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/29/2021] [Accepted: 02/01/2021] [Indexed: 12/19/2022] Open
Abstract
Until the recent development of disease-modifying therapeutics, spinal muscular atrophy (SMA) was considered a devastating neuromuscular disease with a poor prognosis for most affected individuals. Symptoms generally present during early childhood and manifest as muscle weakness and progressive paralysis, severely compromising the affected individual’s quality of life, independence, and lifespan. SMA is most commonly caused by the inheritance of homozygously deleted SMN1 alleles with retention of one or more copies of a paralog gene, SMN2, which inversely correlates with disease severity. The recent advent and use of genetically targeted therapies have transformed SMA into a prototype for monogenic disease treatment in the era of genetic medicine. Many SMA-affected individuals receiving these therapies achieve traditionally unobtainable motor milestones and survival rates as medicines drastically alter the natural progression of this disease. This review discusses historical SMA progression and underlying disease mechanisms, highlights advances made in therapeutic research, clinical trials, and FDA-approved medicines, and discusses possible second-generation and complementary medicines as well as optimal temporal intervention windows in order to optimize motor function and improve quality of life for all SMA-affected individuals.
Collapse
|
6
|
Kim JK, Jha NN, Feng Z, Faleiro MR, Chiriboga CA, Wei-Lapierre L, Dirksen RT, Ko CP, Monani UR. Muscle-specific SMN reduction reveals motor neuron-independent disease in spinal muscular atrophy models. J Clin Invest 2020; 130:1271-1287. [PMID: 32039917 DOI: 10.1172/jci131989] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 11/26/2019] [Indexed: 12/12/2022] Open
Abstract
Paucity of the survival motor neuron (SMN) protein triggers the oft-fatal infantile-onset motor neuron disorder, spinal muscular atrophy (SMA). Augmenting the protein is one means of treating SMA and recently led to FDA approval of an intrathecally delivered SMN-enhancing oligonucleotide currently in use. Notwithstanding the advent of this and other therapies for SMA, it is unclear whether the paralysis associated with the disease derives solely from dysfunctional motor neurons that may be efficiently targeted by restricted delivery of SMN-enhancing agents to the nervous system, or stems from broader defects of the motor unit, arguing for systemic SMN repletion. We investigated the disease-contributing effects of low SMN in one relevant peripheral organ - skeletal muscle - by selectively depleting the protein in only this tissue. We found that muscle deprived of SMN was profoundly damaged. Although a disease phenotype was not immediately obvious, persistent low levels of the protein eventually resulted in muscle fiber defects, neuromuscular junction abnormalities, compromised motor performance, and premature death. Importantly, restoring SMN after the onset of muscle pathology reversed disease. Our results provide the most compelling evidence yet for a direct contributing role of muscle in SMA and argue that an optimal therapy for the disease must be designed to treat this aspect of the dysfunctional motor unit.
Collapse
Affiliation(s)
- Jeong-Ki Kim
- Department of Pathology and Cell Biology and.,Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, New York, USA
| | - Narendra N Jha
- Department of Pathology and Cell Biology and.,Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, New York, USA
| | - Zhihua Feng
- Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
| | - Michelle R Faleiro
- Department of Pathology and Cell Biology and.,Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, New York, USA
| | - Claudia A Chiriboga
- Department of Neurology and.,Department of Pediatrics, Columbia University Medical Center, New York, New York, USA
| | - Lan Wei-Lapierre
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York, USA
| | - Robert T Dirksen
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York, USA
| | - Chien-Ping Ko
- Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
| | - Umrao R Monani
- Department of Pathology and Cell Biology and.,Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, New York, USA.,Department of Neurology and
| |
Collapse
|
7
|
Glascock J, Sampson J, Haidet-Phillips A, Connolly A, Darras B, Day J, Finkel R, Howell RR, Klinger K, Kuntz N, Prior T, Shieh PB, Crawford TO, Kerr D, Jarecki J. Treatment Algorithm for Infants Diagnosed with Spinal Muscular Atrophy through Newborn Screening. J Neuromuscul Dis 2018; 5:145-158. [PMID: 29614695 PMCID: PMC6004919 DOI: 10.3233/jnd-180304] [Citation(s) in RCA: 130] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Background: Spinal muscular atrophy (SMA) is an autosomal recessive disease characterized by the degeneration of alpha motor neurons in the spinal cord, leading to muscular atrophy. SMA is caused by deletions or mutations in the survival motor neuron 1 gene (SMN1). In humans, a nearly identical copy gene, SMN2, is present. Because SMN2 has been shown to decrease disease severity in a dose-dependent manner, SMN2 copy number is predictive of disease severity. Objective: To develop a treatment algorithm for SMA-positive infants identified through newborn screening based upon SMN2 copy number. Methods: A working group comprised of 15 SMA experts participated in a modified Delphi process, moderated by a neutral third-party expert, to develop treatment guidelines. Results: The overarching recommendation is that all infants with two or three copies of SMN2 should receive immediate treatment (n = 13). For those infants in which immediate treatment is not recommended, guidelines were developed that outline the timing and appropriate screens and tests to be used to determine the timing of treatment initiation. Conclusions: The identification SMA affected infants via newborn screening presents an unprecedented opportunity for achievement of maximal therapeutic benefit through the administration of treatment pre-symptomatically. The recommendations provided here are intended to help formulate treatment guidelines for infants who test positive during the newborn screening process.
Collapse
Affiliation(s)
| | | | | | - Anne Connolly
- Washington University School of Medicine, St. Louis, MO, USA
| | - Basil Darras
- Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - John Day
- Stanford University, Stanford, CA, USA
| | - Richard Finkel
- Nemours Children's Hospital, University of Central Florida College of Medicine, Orlando, FL, USA
| | - R Rodney Howell
- Miller School of Medicine, University of Miami, Miami, FL, USA
| | | | - Nancy Kuntz
- Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Thomas Prior
- Department of Molecular Pathology, Ohio State Wexner Medical Center, Columbus, OH, USA
| | - Perry B Shieh
- University of California Los Angeles, Los Angeles, CA, USA
| | - Thomas O Crawford
- Departments of Neurology and Pediatrics, Johns Hopkins University, Baltimore, MD, USA
| | | | | |
Collapse
|
8
|
Nash LA, McFall ER, Perozzo AM, Turner M, Poulin KL, De Repentigny Y, Burns JK, McMillan HJ, Warman Chardon J, Burger D, Kothary R, Parks RJ. Survival Motor Neuron Protein is Released from Cells in Exosomes: A Potential Biomarker for Spinal Muscular Atrophy. Sci Rep 2017; 7:13859. [PMID: 29066780 PMCID: PMC5655039 DOI: 10.1038/s41598-017-14313-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 10/06/2017] [Indexed: 11/09/2022] Open
Abstract
Spinal muscular atrophy (SMA) is caused by homozygous mutation of the survival motor neuron 1 (SMN1) gene. Disease severity inversely correlates to the amount of SMN protein produced from the homologous SMN2 gene. We show that SMN protein is naturally released in exosomes from all cell types examined. Fibroblasts from patients or a mouse model of SMA released exosomes containing reduced levels of SMN protein relative to normal controls. Cells overexpressing SMN protein released exosomes with dramatically elevated levels of SMN protein. We observed enhanced quantities of exosomes in the medium from SMN-depleted cells, and in serum from a mouse model of SMA and a patient with Type 3 SMA, suggesting that SMN-depletion causes a deregulation of exosome release or uptake. The quantity of SMN protein contained in the serum-derived exosomes correlated with the genotype of the animal, with progressively less protein in carrier and affected animals compared to wildtype mice. SMN protein was easily detectable in exosomes isolated from human serum, with a reduction in the amount of SMN protein in exosomes from a patient with Type 3 SMA compared to a normal control. Our results suggest that exosome-derived SMN protein may serve as an effective biomarker for SMA.
Collapse
Affiliation(s)
- Leslie A Nash
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada.,University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
| | - Emily R McFall
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada.,University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
| | - Amanda M Perozzo
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Maddison Turner
- Kidney Research Centre, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Kathy L Poulin
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Yves De Repentigny
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Joseph K Burns
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada.,University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
| | - Hugh J McMillan
- University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada.,Department of Pediatrics, Children's Hospital of Eastern Ontario, University of Ottawa, Ottawa, Canada.,Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada
| | - Jodi Warman Chardon
- University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada.,Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada.,Division of Neurogenetics, Department of Genetics, Children's Hospital of Eastern Ontario, Ottawa, Canada.,Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Dylan Burger
- Kidney Research Centre, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Rashmi Kothary
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada.,Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Robin J Parks
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada. .,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada. .,University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada. .,Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
| |
Collapse
|
9
|
Wijngaarde CA, Blank AC, Stam M, Wadman RI, van den Berg LH, van der Pol WL. Cardiac pathology in spinal muscular atrophy: a systematic review. Orphanet J Rare Dis 2017; 12:67. [PMID: 28399889 PMCID: PMC5387385 DOI: 10.1186/s13023-017-0613-5] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Accepted: 03/14/2017] [Indexed: 01/09/2023] Open
Abstract
Background Hereditary proximal spinal muscular atrophy (SMA) is a severe neuromuscular disease of childhood caused by homozygous loss of function of the survival motor neuron (SMN) 1 gene. The presence of a second, nearly identical SMN gene (SMN2) in the human genome ensures production of residual levels of the ubiquitously expressed SMN protein. Alpha-motor neurons in the ventral horns of the spinal cord are most vulnerable to reduced SMN concentrations but the development or function of other tissues may also be affected, and cardiovascular abnormalities have frequently been reported both in patients and SMA mouse models. Methods We systematically reviewed reported cardiac pathology in relation to SMN deficiency. To investigate the relevance of the possible association in more detail, we used clinical classification systems to characterize structural cardiac defects and arrhythmias. Conclusions Seventy-two studies with a total of 264 SMA patients with reported cardiac pathology were identified, along with 14 publications on SMA mouse models with abnormalities of the heart. Structural cardiac pathology, mainly septal defects and abnormalities of the cardiac outflow tract, was reported predominantly in the most severely affected patients (i.e. SMA type 1). Cardiac rhythm disorders were most frequently reported in patients with milder SMA types (e.g. SMA type 3). All included studies lacked control groups and a standardized approach for cardiac evaluation. The convergence to specific abnormalities of cardiac structure and function may indicate vulnerability of specific cell types or developmental processes relevant for cardiogenesis. Future studies would benefit from a controlled and standardized approach for cardiac evaluation in patients with SMA. Electronic supplementary material The online version of this article (doi:10.1186/s13023-017-0613-5) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- C A Wijngaarde
- Department of Neurology and Neurosurgery, F02.230, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands.
| | - A C Blank
- Department of Pediatric Cardiology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - M Stam
- Department of Neurology and Neurosurgery, F02.230, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands
| | - R I Wadman
- Department of Neurology and Neurosurgery, F02.230, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands
| | - L H van den Berg
- Department of Neurology and Neurosurgery, F02.230, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands
| | - W L van der Pol
- Department of Neurology and Neurosurgery, F02.230, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands.
| |
Collapse
|
10
|
Kaifer KA, Villalón E, Osman EY, Glascock JJ, Arnold LL, Cornelison DDW, Lorson CL. Plastin-3 extends survival and reduces severity in mouse models of spinal muscular atrophy. JCI Insight 2017; 2:e89970. [PMID: 28289706 PMCID: PMC5333955 DOI: 10.1172/jci.insight.89970] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a leading genetic cause of infantile death and is caused by the loss of survival motor neuron-1 (SMN1). Importantly, a nearly identical gene is present called SMN2; however, the majority of SMN2-derived transcripts are alternatively spliced and encode a truncated, dysfunctional protein. Recently, several compounds designed to increase SMN protein have entered clinical trials, including antisense oligonucleotides (ASOs), traditional small molecules, and gene therapy. Expanding beyond SMN-centric therapeutics is important, as it is likely that the breadth of the patient spectrum and the inherent complexity of the disease will be difficult to address with a single therapeutic strategy. Several SMN-independent pathways that could impinge upon the SMA phenotype have been examined with varied success. To identify disease-modifying pathways that could serve as stand-alone therapeutic targets or could be used in combination with an SMN-inducing compound, we investigated adeno-associated virus-mediated (AAV-mediated) gene therapy using plastin-3 (PLS3). Here, we report that AAV9-PLS3 extends survival in an intermediate model of SMA mice as well as in a pharmacologically induced model of SMA using a splice-switching ASO that increases SMN production. PLS3 coadministration improves the phenotype beyond the ASO, demonstrating the potential utility of combinatorial therapeutics in SMA that target SMN-independent and SMN-dependent pathways.
Collapse
Affiliation(s)
- Kevin A Kaifer
- Molecular Pathogeneses and Therapeutics Program.,Bond Life Sciences Center
| | - Eric Villalón
- Bond Life Sciences Center.,Department of Veterinary Pathobiology, College of Veterinary Medicine
| | - Erkan Y Osman
- Bond Life Sciences Center.,Department of Veterinary Pathobiology, College of Veterinary Medicine
| | | | - Laura L Arnold
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, USA
| | - D D W Cornelison
- Bond Life Sciences Center.,Division of Biological Sciences, University of Missouri, Columbia, Missouri, USA
| | - Christian L Lorson
- Molecular Pathogeneses and Therapeutics Program.,Bond Life Sciences Center.,Department of Veterinary Pathobiology, College of Veterinary Medicine
| |
Collapse
|
11
|
Abstract
This case report describes a rare phenotype of very severe spinal muscular atrophy (SMA) in a newborn who presented with reduced fetal movements in utero and significant respiratory distress at birth. The patient was homozygously deleted for exon 7 and exon 8 of the survival motor neuron gene 1. Very severe SMA should be considered in the differential diagnosis of respiratory distress at birth, and more research should be dedicated to investigate the genetic determinants of its widely variable phenotypes.
Collapse
Affiliation(s)
- Suleiman Al Dakhoul
- Department Neonatal Unit, Leeds Teaching Hospitals NHS Trust, Children's Hospital, UK
| |
Collapse
|
12
|
Liu Z, Zhang P, He X, Liu S, Tang S, Zhang R, Wang X, Tan J, Peng B, Jiang L, Hong S, Zou L. New multiplex real-time PCR approach to detect gene mutations for spinal muscular atrophy. BMC Neurol 2016; 16:141. [PMID: 27534852 PMCID: PMC4989483 DOI: 10.1186/s12883-016-0651-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 07/29/2016] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is the most common autosomal recessive disease in children, and the diagnosis is complicated and difficult, especially at early stage. Early diagnosis of SMA is able to improve the outcome of SMA patients. In our study, Real-time PCR was developed to measure the gene mutation or deletion of key genes for SMA and to further analyse genotype-phenotype correlation. METHODS The multiple real-time PCR for detecting the mutations of survival of motor neuron (SMN), apoptosis inhibitory protein (NAIP) and general transcription factor IIH, polypeptide 2 gene (GTF2H2) was established and confirmed by DNA sequencing and multiplex ligation-dependent probe amplification (MLPA). The diagnosis and prognosis of 141 hospitalized children, 100 normal children and further 2000 cases of dry blood spot (DBS) samples were analysed by this multiple real-time PCR. RESULTS The multiple real-time PCR was established and the accuracy of it to detect the mutations of SMN, NAIP and GTF2H2 was at least 98.8 % comparing with DNA sequencing and MLPA. Among 141 limb movement disorders children, 75 cases were SMA. 71 cases of SMA (94.67 %) were with SMN c.840 mutation, 9 cases (12 %) with NAIP deletion and 3 cases (4 %) with GTF2H2 deletion. The multiple real-time PCR was able to diagnose and predict the prognosis of SMA patients. Simultaneously, the real-time PCR was applied to detect trace DNA from DBS and able to make an early diagnosis of SMA. CONCLUSION The clinical and molecular characteristics of SMA in Southwest of China were presented. Our work provides a novel way for detecting SMA in children by using real-time PCR and the potential usage in newborn screening for early diagnosis of SMA.
Collapse
Affiliation(s)
- Zhidai Liu
- Center for Clinical Molecular Medicine, Children's Hospital, Chongqing Medical University, 136 Zhongshan Er Road, Yuzhong District, Chongqing, 400014, China.,Ministry of Education Key Laboratory of Development and Disorders, Children's Hospital, Chongqing Medical University, Yuzhong District, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Children's Hospital, Chongqing Medical University, Chongqing, China
| | - Penghui Zhang
- Center for Clinical Laboratory, Children's Hospital, Chongqing Medical University, Yuzhong District, Chongqing, China.,Ministry of Education Key Laboratory of Development and Disorders, Children's Hospital, Chongqing Medical University, Yuzhong District, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Children's Hospital, Chongqing Medical University, Chongqing, China
| | - Xiaoyan He
- Center for Clinical Molecular Medicine, Children's Hospital, Chongqing Medical University, 136 Zhongshan Er Road, Yuzhong District, Chongqing, 400014, China.,Ministry of Education Key Laboratory of Development and Disorders, Children's Hospital, Chongqing Medical University, Yuzhong District, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Children's Hospital, Chongqing Medical University, Chongqing, China
| | - Shan Liu
- Center for Clinical Molecular Medicine, Children's Hospital, Chongqing Medical University, 136 Zhongshan Er Road, Yuzhong District, Chongqing, 400014, China.,Ministry of Education Key Laboratory of Development and Disorders, Children's Hospital, Chongqing Medical University, Yuzhong District, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Children's Hospital, Chongqing Medical University, Chongqing, China
| | - Shi Tang
- Center for Clinical Molecular Medicine, Children's Hospital, Chongqing Medical University, 136 Zhongshan Er Road, Yuzhong District, Chongqing, 400014, China.,Ministry of Education Key Laboratory of Development and Disorders, Children's Hospital, Chongqing Medical University, Yuzhong District, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Children's Hospital, Chongqing Medical University, Chongqing, China
| | - Rong Zhang
- Center for Clinical Molecular Medicine, Children's Hospital, Chongqing Medical University, 136 Zhongshan Er Road, Yuzhong District, Chongqing, 400014, China.,Ministry of Education Key Laboratory of Development and Disorders, Children's Hospital, Chongqing Medical University, Yuzhong District, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Children's Hospital, Chongqing Medical University, Chongqing, China
| | - Xinbin Wang
- Center for Clinical Molecular Medicine, Children's Hospital, Chongqing Medical University, 136 Zhongshan Er Road, Yuzhong District, Chongqing, 400014, China.,Ministry of Education Key Laboratory of Development and Disorders, Children's Hospital, Chongqing Medical University, Yuzhong District, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Children's Hospital, Chongqing Medical University, Chongqing, China
| | - Junjie Tan
- Center for Clinical Molecular Medicine, Children's Hospital, Chongqing Medical University, 136 Zhongshan Er Road, Yuzhong District, Chongqing, 400014, China.,Ministry of Education Key Laboratory of Development and Disorders, Children's Hospital, Chongqing Medical University, Yuzhong District, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Children's Hospital, Chongqing Medical University, Chongqing, China
| | - Bin Peng
- Department of Health Statistics, School of Public Health, Chongqing Medical University, Yuzhong District, Chongqing, China
| | - Li Jiang
- Department of Neurology, Children's Hospital, Chongqing Medical University, Yuzhong District, Chongqing, China.,Ministry of Education Key Laboratory of Development and Disorders, Children's Hospital, Chongqing Medical University, Yuzhong District, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Children's Hospital, Chongqing Medical University, Chongqing, China
| | - Siqi Hong
- Department of Neurology, Children's Hospital, Chongqing Medical University, Yuzhong District, Chongqing, China.,Ministry of Education Key Laboratory of Development and Disorders, Children's Hospital, Chongqing Medical University, Yuzhong District, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Children's Hospital, Chongqing Medical University, Chongqing, China
| | - Lin Zou
- Center for Clinical Molecular Medicine, Children's Hospital, Chongqing Medical University, 136 Zhongshan Er Road, Yuzhong District, Chongqing, 400014, China. .,Ministry of Education Key Laboratory of Development and Disorders, Children's Hospital, Chongqing Medical University, Yuzhong District, Chongqing, China. .,Key Laboratory of Pediatrics in Chongqing, Children's Hospital, Chongqing Medical University, Chongqing, China.
| |
Collapse
|
13
|
Abstract
Spinal muscular atrophy is an autosomal-recessive disorder characterized by degeneration of motor neurons in the spinal cord and caused by mutations in the survival motor neuron 1 gene, SMN1. The severity of SMA is variable. The SMN2 gene produces a fraction of the SMN messenger RNA (mRNA) transcript produced by the SMN1 gene. There is an inverse correlation between SMN2 gene copy number and clinical severity. Clinical management focuses on multidisciplinary care. Preclinical models of SMA have led to an explosion of SMA clinical trials that hold great promise of effective therapy in the future.
Collapse
|
14
|
Fayzullina S, Martin LJ. DNA Damage Response and DNA Repair in Skeletal Myocytes From a Mouse Model of Spinal Muscular Atrophy. J Neuropathol Exp Neurol 2016; 75:889-902. [PMID: 27452406 DOI: 10.1093/jnen/nlw064] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We studied DNA damage response (DDR) and DNA repair capacities of skeletal muscle cells from a mouse model of infantile spinal muscular atrophy (SMA) caused by loss-of-function mutation of survival of motor neuron (Smn). Primary myocyte cultures derived from skeletal muscle satellite cells of neonatal control and mutant SMN mice had similar myotube length, myonuclei, satellite cell marker Pax7 and differentiated myotube marker myosin, and acetylcholine receptor clustering. DNA damage was induced in differentiated skeletal myotubes by γ-irradiation, etoposide, and methyl methanesulfonate (MMS). Unexposed control and SMA myotubes had stable genome integrity. After γ-irradiation and etoposide, myotubes repaired most DNA damage equally. Control and mutant myotubes exposed to MMS exhibited equivalent DNA damage without repair. Control and SMA myotube nuclei contained DDR proteins phospho-p53 and phospho-H2AX foci that, with DNA damage, dispersed and then re-formed similarly after recovery. We conclude that mouse primary satellite cell-derived myotubes effectively respond to and repair DNA strand-breaks, while DNA alkylation repair is underrepresented. Morphological differentiation, genome stability, genome sensor, and DNA strand-break repair potential are preserved in mouse SMA myocytes; thus, reduced SMN does not interfere with myocyte differentiation, genome integrity, and DNA repair, and faulty DNA repair is unlikely pathogenic in SMA.
Collapse
Affiliation(s)
- Saniya Fayzullina
- From the Department of Pathology, Division of Neuropathology, and the Pathobiology Graduate Training Program, Johns Hopkins School of Medicine, Baltimore, Maryland, USA (SF, LJM)
| | - Lee J Martin
- From the Department of Pathology, Division of Neuropathology, and the Pathobiology Graduate Training Program, Johns Hopkins School of Medicine, Baltimore, Maryland, USA (SF, LJM)
| |
Collapse
|
15
|
Abstract
Motor neuron diseases are neurological disorders characterized primarily by the degeneration of spinal motor neurons, skeletal muscle atrophy, and debilitating and often fatal motor dysfunction. Spinal muscular atrophy (SMA) is an autosomal-recessive motor neuron disease of high incidence and severity and the most common genetic cause of infant mortality. SMA is caused by homozygous mutations in the survival motor neuron 1 (SMN1) gene and retention of at least one copy of the hypomorphic gene paralog SMN2. Early studies established a loss-of-function disease mechanism involving ubiquitous SMN deficiency and suggested SMN upregulation as a possible therapeutic approach. In recent years, greater knowledge of the central role of SMN in RNA processing combined with deep characterization of animal models of SMA has significantly advanced our understanding of the cellular and molecular basis of the disease. SMA is emerging as an RNA disease not limited to motor neurons, but one that involves dysfunction of motor circuits that comprise multiple neuronal subpopulations and possibly other cell types. Advances in SMA research have also led to the development of several potential therapeutics shown to be effective in animal models of SMA that are now in clinical trials. These agents offer unprecedented promise for the treatment of this still incurable neurodegenerative disease.
Collapse
|
16
|
Abstract
Neuropathologic findings within the central and peripheral nervous systems in patients with spinal muscular atrophy type I (SMA-I) were examined in relation to genetic, clinical, and electrophysiologic features. Five infants representing the full clinical spectrum of SMA-I were examined clinically for compound motor action potential amplitude and SMN2 gene copy number; morphologic analyses of postmortem central nervous system, neuromuscular junction, and muscle tissue samples were performed and SMN protein was assessed in muscle samples. The 2 clinically most severely affected patients had a single copy of the SMN2 gene; in addition to anterior horn cells, dorsal root ganglia, and thalamus, neuronal degeneration in them was widespread in the cerebral cortex, basal ganglia, pigmented nuclei, brainstem, and cerebellum. Two typical SMA-I patients and a milder case each had 2 copies of the SMN2 gene and more restricted neuropathologic abnormalities. Maturation of acetylcholine receptor subunits was delayed and the neuromuscular junctions were abnormally formed in the SMA-I patients. Thus, the neuropathologic findings in human SMA-I are similar to many findings in animal models; factors other than SMN2 copy number modify disease severity. We present a pathophysiologic model for SMA-I as a protein deficiency disease affecting a neuronal network with variable clinical thresholds. Because new treatment strategies improve survival of infants with SMA-I, a better understanding of these factors will guide future treatments.
Collapse
|
17
|
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.
Collapse
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
| | | | | |
Collapse
|
18
|
Gathwala G, Silayach J, Bhakhari BK, Narwal V. Very severe spinal muscular atrophy: Type 0 with Dandy-Walker variant. J Pediatr Neurosci 2014; 9:55-6. [PMID: 24891907 PMCID: PMC4040036 DOI: 10.4103/1817-1745.131488] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease characterized by degeneration of alpha motor neurons in the spinal cord, resulting in progressive proximal muscle weakness and paralysis. In addition to the three classical SMA types, a new form known as type 0 with intrauterine onset, profound hypotonia and a progressive and early fatal course has been described. Herein we report a case of type 0 SMA with a Dandy Walker variant anomaly, which has not hitherto been reported in the world literature.
Collapse
Affiliation(s)
- Geeta Gathwala
- Department of Pediatrics, The Division of Neonatal Services, Pandit Bhagwat Dayal Sharma Post Graduate Institute of Medical Sciences, Rohtak, Haryana, India
| | - Joginder Silayach
- Department of Pediatrics, The Division of Neonatal Services, Pandit Bhagwat Dayal Sharma Post Graduate Institute of Medical Sciences, Rohtak, Haryana, India
| | - Bhanu Kiran Bhakhari
- Department of Pediatrics, The Division of Neonatal Services, Pandit Bhagwat Dayal Sharma Post Graduate Institute of Medical Sciences, Rohtak, Haryana, India
| | - Varun Narwal
- Department of Pediatrics, The Division of Neonatal Services, Pandit Bhagwat Dayal Sharma Post Graduate Institute of Medical Sciences, Rohtak, Haryana, India
| |
Collapse
|
19
|
Fayzullina S, Martin LJ. Skeletal muscle DNA damage precedes spinal motor neuron DNA damage in a mouse model of Spinal Muscular Atrophy (SMA). PLoS One 2014; 9:e93329. [PMID: 24667816 PMCID: PMC3965546 DOI: 10.1371/journal.pone.0093329] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 03/03/2014] [Indexed: 12/27/2022] Open
Abstract
Spinal Muscular Atrophy (SMA) is a hereditary childhood disease that causes paralysis by progressive degeneration of skeletal muscles and spinal motor neurons. SMA is associated with reduced levels of full-length Survival of Motor Neuron (SMN) protein, due to mutations in the Survival of Motor Neuron 1 gene. The mechanisms by which lack of SMN causes SMA pathology are not known, making it very difficult to develop effective therapies. We investigated whether DNA damage is a perinatal pathological event in SMA, and whether DNA damage and cell death first occur in skeletal muscle or spinal cord of SMA mice. We used a mouse model of severe SMA to ascertain the extent of cell death and DNA damage throughout the body of prenatal and newborn mice. SMA mice at birth (postnatal day 0) exhibited internucleosomal fragmentation in genomic DNA from hindlimb skeletal muscle, but not in genomic DNA from spinal cord. SMA mice at postnatal day 5, compared with littermate controls, exhibited increased apoptotic cell death profiles in skeletal muscle, by hematoxylin and eosin, terminal deoxynucleotidyl transferase dUTP nick end labeling, and electron microscopy. SMA mice had no increased cell death, no loss of choline acetyl transferase (ChAT)-positive motor neurons, and no overt pathology in the ventral horn of the spinal cord. At embryonic days 13 and 15.5, SMA mice did not exhibit statistically significant increases in cell death profiles in spinal cord or skeletal muscle. Motor neuron numbers in the ventral horn, as identified by ChAT immunoreactivity, were comparable in SMA mice and control littermates at embryonic day 15.5 and postnatal day 5. These observations demonstrate that in SMA, disease in skeletal muscle emerges before pathology in spinal cord, including loss of motor neurons. Overall, this work identifies DNA damage and cell death in skeletal muscle as therapeutic targets for SMA.
Collapse
Affiliation(s)
- Saniya Fayzullina
- Division of Neuropathology, Department of Pathology, and the Pathobiology Graduate Program, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
| | - Lee J. Martin
- Division of Neuropathology, Department of Pathology, and the Pathobiology Graduate Program, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
| |
Collapse
|
20
|
Haaker G, Fujak A. Proximal spinal muscular atrophy: current orthopedic perspective. APPLICATION OF CLINICAL GENETICS 2013; 6:113-20. [PMID: 24399883 PMCID: PMC3876556 DOI: 10.2147/tacg.s53615] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Spinal muscular atrophy (SMA) is a hereditary neuromuscular disease of lower motor neurons that is caused by a defective “survival motor neuron” (SMN) protein that is mainly associated with proximal progressive muscle weakness and atrophy. Although SMA involves a wide range of disease severity and a high mortality and morbidity rate, recent advances in multidisciplinary supportive care have enhanced quality of life and life expectancy. Active research for possible treatment options has become possible since the disease-causing gene defect was identified in 1995. Nevertheless, a causal therapy is not available at present, and therapeutic management of SMA remains challenging; the prolonged survival is increasing, especially orthopedic, respiratory and nutritive problems. This review focuses on orthopedic management of the disease, with discussion of key aspects that include scoliosis, muscular contractures, hip joint disorders, fractures, technical devices, and a comparative approach of conservative and surgical treatment. Also emphasized are associated complications including respiratory involvement, perioperative care and anesthesia, nutrition problems, and rehabilitation. The SMA disease course can be greatly improved with adequate therapy with established orthopedic procedures in a multidisciplinary therapeutic approach.
Collapse
Affiliation(s)
- Gerrit Haaker
- Department of Orthopaedic Surgery, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Albert Fujak
- Department of Orthopaedic Surgery, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| |
Collapse
|
21
|
D'Amico A, Mercuri E, Tiziano FD, Bertini E. Spinal muscular atrophy. Orphanet J Rare Dis 2011; 6:71. [PMID: 22047105 PMCID: PMC3231874 DOI: 10.1186/1750-1172-6-71] [Citation(s) in RCA: 292] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Accepted: 11/02/2011] [Indexed: 01/11/2023] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease characterized by degeneration of alpha motor neurons in the spinal cord, resulting in progressive proximal muscle weakness and paralysis. Estimated incidence is 1 in 6,000 to 1 in 10,000 live births and carrier frequency of 1/40-1/60. This disease is characterized by generalized muscle weakness and atrophy predominating in proximal limb muscles, and phenotype is classified into four grades of severity (SMA I, SMAII, SMAIII, SMA IV) based on age of onset and motor function achieved. This disease is caused by homozygous mutations of the survival motor neuron 1 (SMN1) gene, and the diagnostic test demonstrates in most patients the homozygous deletion of the SMN1 gene, generally showing the absence of SMN1 exon 7. The test achieves up to 95% sensitivity and nearly 100% specificity. Differential diagnosis should be considered with other neuromuscular disorders which are not associated with increased CK manifesting as infantile hypotonia or as limb girdle weakness starting later in life. Considering the high carrier frequency, carrier testing is requested by siblings of patients or of parents of SMA children and are aimed at gaining information that may help with reproductive planning. Individuals at risk should be tested first and, in case of testing positive, the partner should be then analyzed. It is recommended that in case of a request on carrier testing on siblings of an affected SMA infant, a detailed neurological examination should be done and consideration given doing the direct test to exclude SMA. Prenatal diagnosis should be offered to couples who have previously had a child affected with SMA (recurrence risk 25%). The role of follow-up coordination has to be managed by an expert in neuromuscular disorders and in SMA who is able to plan a multidisciplinary intervention that includes pulmonary, gastroenterology/nutrition, and orthopedic care. Prognosis depends on the phenotypic severity going from high mortality within the first year for SMA type 1 to no mortality for the chronic and later onset forms.
Collapse
Affiliation(s)
- Adele D'Amico
- Department of Neurosciences, Unit of Molecular Medicine for Neuromuscular and Neurodegenerative Disorders, Bambino Gesu' Children's Research Hospital, P.za S. Onofrio, 4, Rome (00165), Italy
| | | | | | | |
Collapse
|
22
|
Sasongko TH, Salmi AR, Zilfalil BA, Albar MA, Mohd Hussin ZA. Permissibility of prenatal diagnosis and abortion for fetuses with severe genetic disorder: type 1 spinal muscular atrophy. Ann Saudi Med 2010; 30:427-31. [PMID: 21060155 PMCID: PMC2994156 DOI: 10.4103/0256-4947.72259] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Abortion has been largely avoided in Muslim communities. However, Islamic jurists have established rigorous parameters enabling abortion of fetuses with severe congenital abnormalities. This decision-making process has been hindered by an inability to predict the severity of such prenatally-diagnosed conditions, especially in genetic disorders with clinical heterogeneity, such as spinal muscular atrophy (SMA). Heterogeneous phenotypes of SMA range from extremely severe type 1 to very mild type 4. Advances in molecular genetics have made it possible to perform prenatal diagnosis and to predict the types of SMA with its potential subsequent severity. Such techniques will make it possible for clinicians working in predominantly Muslim countries to counsel their patients accurately and in harmony with their religious beliefs. In this paper, we discuss and postulate that with our current knowledge of determining SMA types and severity with great accuracy, abortion is legally applicable for type 1 SMA.
Collapse
Affiliation(s)
- Teguh H Sasongko
- Department of Pediatrics, School of Medical Sciences, University Sains Malaysia, Kelantan, Malaysia
| | | | | | | | | |
Collapse
|
23
|
Abstract
Spinal muscular atrophy (SMA) is a hereditary neurodegenerative disease caused by homozygous deletions or mutations in the SMN1 gene on Chr.5q13. SMA spans from severe Werdnig-Hoffmann disease (SMA 1) to relatively benign Kugelberg-Welander disease (SMA 3). Onset before birth possibly aggravates the clinical course, because immature motoneurons do not show compensatory sprouting and collateral reinnervation, and motor units in SMA 1, in contrast to those in SMA 3, are not enlarged. Genetic evidence indicates that SMN2, a gene 99% identical to SMN1, can attenuate SMA severity: in patients, more SMN2 copies and higher SMN protein levels are correlated with milder SMA. There is evidence that SMN plays a role in motoneuron RNA metabolism, but it has also been linked to apoptosis. Several mouse models with motoneuron disease have been successfully treated with neurotrophic factors. None of these models is, however, homologous to SMA. Recently, genetic mouse models of SMA have been created by introducing human SMN2 transgenes into Smn knockout mice or by targeting the Smn gene knockout to neurons. These mice not only provide important insights into the pathogenesis of SMA but are also crucial for testing new therapeutic strategies. These include SMN gene transfer, molecules capable to up-regulate SMN expression and trophic or antiapoptotic factors.
Collapse
Affiliation(s)
- H Schmalbruch
- Department of Medical Physiology, University of Copenhagen, Denmark.
| | | |
Collapse
|
24
|
Affiliation(s)
- M K M Hardart
- Department of Anesthesia, Children's Hospital, Harvard Medical School, Boston, MA, USA.
| | | |
Collapse
|