1
|
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] [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.
Collapse
Affiliation(s)
| | - Riccardo Masson
- Fondazione IRCCS Istituto Neurologico Carlo Besta, Developmental Neurology Unit, Milan, Italy
| |
Collapse
|
2
|
Shell RD, McGrattan KE, Hurst-Davis R, Young SD, Baranello G, Lavrov A, O'Brien E, Wallach S, LaMarca N, Reyna SP, Darras BT. Onasemnogene abeparvovec preserves bulbar function in infants with presymptomatic spinal muscular atrophy: a post-hoc analysis of the SPR1NT trial. Neuromuscul Disord 2023; 33:670-676. [PMID: 37455203 DOI: 10.1016/j.nmd.2023.06.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 06/08/2023] [Accepted: 06/14/2023] [Indexed: 07/18/2023]
Abstract
Bulbar function in spinal muscular atrophy has been defined as the ability to meet nutritional needs by mouth while maintaining airway protection and communicate verbally. The effects of disease-modifying treatment on bulbar function are not clear. A multidisciplinary team conducted post-hoc analyses of phase 3 SPR1NT trial data to evaluate bulbar function of infants at risk for spinal muscular atrophy who received one-time gene replacement therapy (onasemnogene abeparvovec) before symptom onset. Three endpoints represented adequate bulbar function in SPR1NT: (1) absence of physiologic swallowing impairment, (2) full oral nutrition, and (3) absence of adverse events indicating pulmonary instability. Communication was not assessed in SPR1NT. We descriptively assessed numbers/percentages of children who achieved each endpoint and all three collectively. SPR1NT included infants <6 postnatal weeks with two (n = 14) or three (n = 15) copies of the survival motor neuron 2 gene. At study end (18 [two-copy cohort] or 24 [three-copy cohort] months of age), 100% (29/29) of patients swallowed normally, achieved full oral nutrition, maintained pulmonary stability, and achieved the composite endpoint. When administered to infants before clinical symptom onset, onasemnogene abeparvovec allowed children at risk for spinal muscular atrophy to achieve milestones within published normal ranges of development and preserve bulbar function.
Collapse
Affiliation(s)
- Richard D Shell
- Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, The Ohio State University, Columbus, OH, USA.
| | | | | | | | - Giovanni Baranello
- The Dubowitz Neuromuscular Centre, Developmental Neuroscience Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK; NIHR Great Ormond Street Hospital Biomedical Research Centre & Great Ormond Street Hospital NHS Foundation Trust, London, UK
| | | | | | | | | | | | | |
Collapse
|
3
|
Coratti G, Pera MC, D'Amico A, Bruno C, Bovis F, Gullì C, Brolatti N, Pedemonte M, Apicella M, Antonaci L, Ricci M, Capasso A, Cicala G, Cutrona C, de Sanctis R, Carnicella S, Forcina N, Catteruccia M, Damasio MB, Labianca L, Leone A, Bertini E, Pane M, Mercuri E. Long term follow-up of scoliosis progression in type II SMA patients. Neuromuscul Disord 2022; 32:879-885. [PMID: 36456406 DOI: 10.1016/j.nmd.2022.11.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 10/27/2022] [Accepted: 11/15/2022] [Indexed: 11/18/2022]
Abstract
The aim of this study is to retrospectively assess onset and progression of scoliosis in type II SMA patients not treated with the approved disease modifying treatments. Scoliosis was evaluated by measuring the scoliosis angle on X-ray obtained in the anteroposterior view in sitting position (Cobb's angle method). Eighty-four patients had at least one assessment of scoliosis angle (287 assessments). There was a positive correlation between age and scoliosis angles (p<0.001) with a progressive increase of scoliosis with age. When subdividing the population by HFMSE score (<10; 11-22;> 22), there was a progressive increase in scoliosis angles with decreasing HFMSE scores. The difference between HFMSE categories was significant (p<0.001). Fifty-four patients had at least two assessments at 6-month distance and were retained for the longitudinal analysis. Using a mixed model, age, functional status and scoliosis angle at baseline were predictive on scoliosis progression. The mean annual rate of increase of scoliosis angle was 5.63 (95%CI: 4.74-6.52). Our results confirm the progression of scoliosis in untreated type II SMA providing details of the progression in relation to different variables. With different therapeutical options being available in many countries, our findings will provide reference data for establishing possible differences in the trajectories of progression with treated type II individuals.
Collapse
Affiliation(s)
- Giorgia Coratti
- Pediatric Neurology, Università Cattolica del Sacro Cuore, Rome, Italy; Centro Clinico Nemo, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome
| | - Maria Carmela Pera
- Pediatric Neurology, Università Cattolica del Sacro Cuore, Rome, Italy; Centro Clinico Nemo, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome
| | - Adele D'Amico
- Department of Neurosciences, Unit of Neuromuscular and Neurodegenerative Disorders, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Claudio Bruno
- Center of Translational and Experimental Myology, and Dept. of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Francesca Bovis
- Biostatistics Unit, Department of Health Sciences, University of Genoa, Genoa, Italy
| | - Consolato Gullì
- Department of Radiological and Hematological Sciences Fondazione, Policlinico Universitario A. Gemelli, IRCCS Università Cattolica del Sacro Cuore, Largo A. Gemelli, 100168, Rome, Italy
| | - Noemi Brolatti
- Center of Translational and Experimental Myology, and Dept. of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Marina Pedemonte
- Center of Translational and Experimental Myology, and Dept. of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Massimo Apicella
- Pediatric Neurology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Laura Antonaci
- Pediatric Neurology, Università Cattolica del Sacro Cuore, Rome, Italy; Centro Clinico Nemo, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome
| | - Martina Ricci
- Pediatric Neurology, Università Cattolica del Sacro Cuore, Rome, Italy; Centro Clinico Nemo, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome
| | - Anna Capasso
- Pediatric Neurology, Università Cattolica del Sacro Cuore, Rome, Italy; Centro Clinico Nemo, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome
| | - Gianpaolo Cicala
- Pediatric Neurology, Università Cattolica del Sacro Cuore, Rome, Italy; Centro Clinico Nemo, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome
| | - Costanza Cutrona
- Pediatric Neurology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Roberto de Sanctis
- Centro Clinico Nemo, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome
| | - Sara Carnicella
- Centro Clinico Nemo, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome
| | - Nicola Forcina
- Centro Clinico Nemo, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome
| | - Michela Catteruccia
- Department of Neurosciences, Unit of Neuromuscular and Neurodegenerative Disorders, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | | | - Luca Labianca
- Department of Trauma and Orthopaedics, Sant'Andrea Hospital, Sapienza University of Rome, Rome, Italy; Unicamillus, Saint Camillus International University of Health Sciences, Rome, Italy
| | - Antonio Leone
- Department of Radiological and Hematological Sciences Fondazione, Policlinico Universitario A. Gemelli, IRCCS Università Cattolica del Sacro Cuore, Largo A. Gemelli, 100168, Rome, Italy
| | - Enrico Bertini
- Department of Neurosciences, Unit of Neuromuscular and Neurodegenerative Disorders, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Marika Pane
- Pediatric Neurology, Università Cattolica del Sacro Cuore, Rome, Italy; Centro Clinico Nemo, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome
| | - Eugenio Mercuri
- Pediatric Neurology, Università Cattolica del Sacro Cuore, Rome, Italy; Centro Clinico Nemo, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome.
| |
Collapse
|
4
|
Wu JW, Pepler L, Maturi B, Afonso ACF, Sarmiento J, Haldenby R. Systematic Review of Motor Function Scales and Patient-Reported Outcomes in Spinal Muscular Atrophy. Am J Phys Med Rehabil 2022; 101:590-608. [PMID: 34483260 DOI: 10.1097/phm.0000000000001869] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
ABSTRACT Spinal muscular atrophy is a heterogeneous disease that results in loss of motor function. In an evolving treatment landscape, establishing the suitability and limitations of existing motor function scales and patient-reported outcomes used to monitor patients with this disease is important. A systematic review was conducted to examine utility of motor function scales and patient-reported outcomes in evaluating patients with spinal muscular atrophy. Published literature was reviewed up to June 2021 with no start date restriction. Of the reports screened, 122 were deemed appropriate for inclusion and are discussed in this review (including 24 validation studies for motor function scales or patient-reported outcomes). Fifteen motor function scales and patient-reported outcomes were identified to be commonly used (≥5 studies), of which 11 had available validation assessments. Each instrument has its strengths and limitations. It is imperative that the patient population (e.g., age, mobility), goals of treatment, and outcomes or endpoints of interest be considered when selecting the appropriate motor function scales and patient-reported outcomes for clinical studies.
Collapse
Affiliation(s)
- Jennifer W Wu
- From the Hoffmann-La Roche Limited, Mississauga, Ontario, Canada (JWW, LP, BM, RH); and Synapse Medical Communications, Inc, Oakville, Ontario, Canada (ACFA, JS)
| | | | | | | | | | | |
Collapse
|
5
|
McMillan HJ, Proud CM, Farrar MA, Alexander IE, Muntoni F, Servais L. Onasemnogene abeparvovec for the treatment of spinal muscular atrophy. Expert Opin Biol Ther 2022; 22:1075-1090. [PMID: 35437095 DOI: 10.1080/14712598.2022.2066471] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Gene therapy for spinal muscular atrophy (SMA) represents a significant milestone in the treatment of neurologic diseases. SMA is a neurodegenerative disease that results in motor neuron loss because of mutations of the survival motor neuron 1 gene, which directs survival motor neuron (SMN) protein production. Onasemnogene abeparvovec, a one-time gene replacement therapy, delivers a functional transgene to restore SMN protein expression. Onasemnogene abeparvovec has demonstrated improved survival and motor milestone achievements for presymptomatic infants and patients with SMA type 1. AREAS COVERED This expert review describes the current state of gene therapy for SMA, reviews the mechanism of and clinical experience with onasemnogene abeparvovec, explains future efforts to expand applications of gene therapy for SMA, and provides context for developing gene therapy for other conditions. EXPERT OPINION Onasemnogene abeparvovec has demonstrated efficacy in clinical trials and, because of this, is a valuable treatment option for patients with symptomatic infantile SMA and those identified by newborn screening. Gene therapy is still in its infancy, and challenges and uncertainties associated with transgene delivery must be addressed. With ongoing development of vector technology, more specific tissue tropism, reduced "off-target" effects, and an enhanced safety profile will continue to evolve.
Collapse
Affiliation(s)
- Hugh J McMillan
- Departments of Pediatrics, Neurology & Neurosurgery, Montreal Children's Hospital, McGill University Health Centre, Montreal, Canada
| | - Crystal M Proud
- Children's Hospital of The King's Daughters, Norfolk, VA, United States
| | - Michelle A Farrar
- School of Women's and Children's Health, UNSW Medicine, UNSW Sydney.,Sydney Children's Hospital Network, Sydney, Australia
| | - Ian E Alexander
- Gene Therapy Research Unit, Children's Medical Research Institute, Faculty of Medicine and Health, The University of Sydney and Sydney Children's Hospitals Network, Westmead, NSW, Australia.,Discipline of Child and Adolescent Health, Sydney Medical School, Faculty of Medicine and Health, The University of Sydney, Westmead, NSW, Australia
| | - Francesco Muntoni
- The Dubowitz Neuromuscular Centre, University College London, Great Ormond Street Institute of Child Health London, UK.,NIHR Great Ormond Street Hospital Biomedical Research Centre, Great Ormond Street Institute of Child Health, University College London, & Great Ormond Street Hospital Trust, London, UK
| | - Laurent Servais
- Department of Pediatrics, Centre Hospitalier Universitaire de Liège & Université de Liège, Liège, Belgium.,MDUK Oxford Neuromuscular Centre, University of Oxford, Oxford, UK
| |
Collapse
|
6
|
UCHIO Y, KAJIMA K, SUZUKI H, NAKAMURA K, SAITO M, IKAI T. Pain in Spinal Muscular Atrophy: A Questionnaire Study. Phys Ther Res 2022; 25:150-155. [PMID: 36819911 PMCID: PMC9910355 DOI: 10.1298/ptr.e10201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 09/13/2022] [Indexed: 12/23/2022]
Abstract
OBJECTIVE This study aimed to reveal the chronic pain prevalence in spinal muscular atrophy (SMA) patients and identify the clinical characteristics of these patients with chronic pain. The pain status was also investigated in SMA patients with chronic pain. METHODS This cross-sectional study was conducted between July 2018 and December 2018. SMA type II and type III patients in Japan were mailed a survey questionnaire. The survey items were chronic pain prevalence, clinical characteristics, and motor function. Patients with chronic pain also answered questions on various pain status parameters: pain intensity, frequency, duration, location using body map, and factors that exacerbated and relieved pain. RESULTS The questionnaire recovery rate was 61.1%. Sixty-four type II (mean age 17.3 ± 11.7 years) and 22 type III (mean age 44.9 ± 21.6 years) patients were eligible for inclusion. The prevalence of chronic pain in type II and III patients was 40.6% and 40.9%, respectively. Type II patients with chronic pain were more likely to report the inability to sit without manual support than those without pain (p = 0.03). Pain intensity in SMA patients was mild, but pain usually occurred daily, for prolonged durations, most often in the neck, back, and lower extremities. Sitting and high physical activity exacerbated pain the most. CONCLUSION The percentage of patients with SMA with chronic pain was high, at above 40%. Moreover, the pain experienced by patients with SMA was low in intensity but frequent and most common in the lower extremities.
Collapse
Affiliation(s)
- Yuu UCHIO
- Department of Rehabilitation, Faculty of Health Sciences, University of Tokyo Health Sciences, Japan,Department of Rehabilitation, Tokyo Women’s Medical University, Japan
| | - Kota KAJIMA
- Department of Rehabilitation, Faculty of Health Sciences, University of Tokyo Health Sciences, Japan
| | - Hayato SUZUKI
- Department of Rehabilitation, Faculty of Health Sciences, University of Tokyo Health Sciences, Japan
| | - Kaho NAKAMURA
- Department of Rehabilitation, Faculty of Health Sciences, University of Tokyo Health Sciences, Japan
| | - Midori SAITO
- Department of Rehabilitation, Faculty of Health Sciences, University of Tokyo Health Sciences, Japan
| | - Tetsuo IKAI
- Department of Rehabilitation, Tokyo Women’s Medical University, Japan
| |
Collapse
|
7
|
Andrysiak K, Martyniak A, Potulska-Chromik A, Kostera-Pruszczyk A, Stępniewski J, Dulak J. Generation of DMBi002-A human induced pluripotent stem cell line from patient with Spinal muscular atrophy type 3. Stem Cell Res 2021; 57:102563. [PMID: 34678665 DOI: 10.1016/j.scr.2021.102563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 10/03/2021] [Indexed: 11/22/2022] Open
Abstract
Spinal Muscular Atrophy (SMA) is a genetic neuromuscular disease caused by mutations inSMN1 gene encoding survival motor neuron (SMN) protein. Lack of this protein leads to progressive loss of motor neurons and therefore to gradual loss of signal transmission between motor neurons and skeletal muscle cells. As a consequence, patients develop muscle atrophy and lose the ability to move independently, what is also related to problems with breathing and swallowing. Here, we describe the generation of human induced pluripotent stem cells (hiPSC) from peripheral blood mononuclear cells (PBMC) of adult SMA type 3 patient with a use of Sendai virus vectors.
Collapse
Affiliation(s)
- Kalina Andrysiak
- Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Alicja Martyniak
- Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | | | | | - Jacek Stępniewski
- Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Józef Dulak
- Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland.
| |
Collapse
|
8
|
Kotulska K, Fattal-Valevski A, Haberlova J. Recombinant Adeno-Associated Virus Serotype 9 Gene Therapy in Spinal Muscular Atrophy. Front Neurol 2021; 12:726468. [PMID: 34721262 PMCID: PMC8548432 DOI: 10.3389/fneur.2021.726468] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 09/17/2021] [Indexed: 11/14/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease caused by deletion or mutation of the SMN1 gene. It is characterized by a progressive loss of motor neurons resulting in muscle weakness. The disease affects 1 in 11,000 live births and before the era of treatment SMA was a leading genetic cause of mortality in infants. Recently, disease modifying therapies have been introduced in clinical practice. They include intrathecal and oral antisense oligonucleotides binding to pre-mRNA of SMN2 gene and increasing the translation of fully functional SMN protein as well as SMN1 gene replacement therapy. Onasemnogene abeparvovec uses the adeno-associated virus 9 (AAV9) vector to deliver the SMN1 gene. Phase 1 and phase 3 clinical trials showed that a single administration of onasemnogene abeparvovec resulted in improvement of motor functions in the majority of infants with SMA. Currently, phase 3 trials in SMA1 and SMA2 patients, as well as presymptomatic infants diagnosed with SMA, are ongoing. The drug was approved for medical use in the US in 2019, and in Japan and the European Union in 2020. Thus, first real-world data on efficacy and safety of onasemnogene abeparvovec in SMA patients are available.
Collapse
Affiliation(s)
- Katarzyna Kotulska
- Department of Neurology and Epileptology, The Children's Memorial Health Institute, Warsaw, Poland
| | - Aviva Fattal-Valevski
- Pediatric Neurology Institute, "Dana-Dwek" Children Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv University, Tel Aviv, Israel
| | - Jana Haberlova
- Neuromuscular Center, Department of Pediatric Neurology, Faculty Hospital Motol, 2nd School of Medicine Charles University, Prague, Czechia
| |
Collapse
|
9
|
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] [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.
Collapse
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
| |
Collapse
|
10
|
Boulay C, Delmont E, Audic F, Chabrol B, Attarian S. Motor unit number index: A potential electrophysiological biomarker for pediatric spinal muscular atrophy. Muscle Nerve 2021; 64:445-453. [PMID: 34255873 DOI: 10.1002/mus.27372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 07/05/2021] [Accepted: 07/09/2021] [Indexed: 11/08/2022]
Abstract
INTRODUCTION/AIMS In adult spinal muscular atrophy (SMA), the motor unit number index (MUNIX) has been shown to be an useful electrophysiological biomarker. This study evaluated the feasibility and the clinical relevance of using the MUNIX technique for patients with pediatric SMA (Ped-SMA) and correlated MUNIX results with clinical scores. METHODS Fourteen patients with type II Ped-SMA (11 females; median age 11 y [interquartile range (IQR), 4.8-17 y]) and 14 controls (nine females; median age 10.75 y [IQR, 6.5-13.4 y]) were enrolled and matched by sex, age, height, weight, and body mass index. Clinical examination included manual muscle testing, dynamometry (grasp and pinch), and motor function measure (MFM). The MUNIX technique was evaluated in the abductor digiti minimi (ADM) and abductor pollicis brevis (APB) on two sides when possible. RESULTS In the patients with Ped-SMA, the MUNIX and compound muscle action potential (CMAP) amplitudes were significantly decreased and the motor size unit index (MUSIX) was significantly increased in the ADM and APB when compared to controls. The intraclass correlation coefficient was good for the intrarater variability of the CMAP amplitude, MUNIX, and MUSIX in the ADM (0.95, 0.83, and 0.89, respectively) and the APB (0.98, 0.96, and 0.94, respectively). The total CMAP amplitude correlated with the grasp and pinch scores (P < .05), and the MUNIX measurements correlated with the MFM scores. DISCUSSION The MUNIX technique, which accurately estimated lower motor neuron loss and the number of remaining functional motor units, was shown to be a useful electrophysiological biomarker for disease progression and a potential biomarker for treatment response.
Collapse
Affiliation(s)
- Christophe Boulay
- Neuropediatric Department, Children Timone University Hospital, Aix-Marseille University, Marseille, France.,Reference Center for Neuromuscular Diseases and ALS Timone University Hospital, Aix-Marseille University, Marseille, France.,Aix-Marseille University, CNRS, ISM UMR 7287, Marseille, France
| | - Emilien Delmont
- Reference Center for Neuromuscular Diseases and ALS Timone University Hospital, Aix-Marseille University, Marseille, France.,Aix-Marseille University, UMR 7286, Medicine Faculty, Marseille, France
| | - Frédérique Audic
- Neuropediatric Department, Children Timone University Hospital, Aix-Marseille University, Marseille, France.,Reference Center for Neuromuscular Diseases and ALS Timone University Hospital, Aix-Marseille University, Marseille, France
| | - Brigitte Chabrol
- Neuropediatric Department, Children Timone University Hospital, Aix-Marseille University, Marseille, France.,Reference Center for Neuromuscular Diseases and ALS Timone University Hospital, Aix-Marseille University, Marseille, France.,Aix-Marseille University, Inserm UMR S 910, Medical Genetics and Functional Genomics, Marseille, France
| | - Shahram Attarian
- Reference Center for Neuromuscular Diseases and ALS Timone University Hospital, Aix-Marseille University, Marseille, France.,Aix-Marseille University, Inserm UMR S 910, Medical Genetics and Functional Genomics, Marseille, France
| |
Collapse
|
11
|
Pierzchlewicz K, Kępa I, Podogrodzki J, Kotulska K. Spinal Muscular Atrophy: The Use of Functional Motor Scales in the Era of Disease-Modifying Treatment. Child Neurol Open 2021; 8:2329048X211008725. [PMID: 33997096 PMCID: PMC8107939 DOI: 10.1177/2329048x211008725] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 03/09/2021] [Accepted: 03/12/2021] [Indexed: 12/11/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a genetic condition characterized by progressive motoneuron loss. Infants affected by SMA type 1 do not gain developmental milestones and acutely decline, requiring ventilatory support. Several scales are used to assess motor disability and its progression in SMA. Recently, 3 disease-modifying therapies have been approved for SMA patients: nusinersen, an intrathecal antisense oligonucleotide enhancing SMN protein production by the SMN2 gene, risdiplam, also influencing the SMN2 gene to stimulate SMN production but administered orally, and onasemnogene abeparvovec-xioi, an SMN1 gene replacement therapy. Thus, the functional scales should now be applicable for patients improving their motor function over time to assess treatment efficacy. In this paper, we compare different functional scales used in SMA patients. Their usefulness in different SMA types, age groups, and feasibility in daily clinical practice is described below. Some changes in motor function assessments in SMA are also suggested.
Collapse
Affiliation(s)
- Katarzyna Pierzchlewicz
- Department of Neurology and Epileptology, Children’s Memorial Health
Institute, Warsaw, Poland
| | - Izabela Kępa
- Department of Neurology and Epileptology, Children’s Memorial Health
Institute, Warsaw, Poland
| | - Jacek Podogrodzki
- Department of Neurology and Epileptology, Children’s Memorial Health
Institute, Warsaw, Poland
| | - Katarzyna Kotulska
- Department of Neurology and Epileptology, Children’s Memorial Health
Institute, Warsaw, Poland
| |
Collapse
|
12
|
Smeriglio P, Langard P, Querin G, Biferi MG. The Identification of Novel Biomarkers Is Required to Improve Adult SMA Patient Stratification, Diagnosis and Treatment. J Pers Med 2020; 10:jpm10030075. [PMID: 32751151 PMCID: PMC7564782 DOI: 10.3390/jpm10030075] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/22/2020] [Accepted: 07/24/2020] [Indexed: 12/12/2022] Open
Abstract
Spinal muscular atrophy (SMA) is currently classified into five different subtypes, from the most severe (type 0) to the mildest (type 4) depending on age at onset, best motor function achieved, and copy number of the SMN2 gene. The two recent approved treatments for SMA patients revolutionized their life quality and perspectives. However, upon treatment with Nusinersen, the most widely administered therapy up to date, a high degree of variability in therapeutic response was observed in adult SMA patients. These data, together with the lack of natural history information and the wide spectrum of disease phenotypes, suggest that further efforts are needed to develop precision medicine approaches for all SMA patients. Here, we compile the current methods for functional evaluation of adult SMA patients treated with Nusinersen. We also present an overview of the known molecular changes underpinning disease heterogeneity. We finally highlight the need for novel techniques, i.e., -omics approaches, to capture phenotypic differences and to understand the biological signature in order to revise the disease classification and device personalized treatments.
Collapse
Affiliation(s)
- Piera Smeriglio
- Centre of Research in Myology, Institute of Myology, Sorbonne Université, INSERM, 75013 Paris, France; (P.L.); (G.Q.)
- Correspondence: (P.S.); (M.G.B.)
| | - Paul Langard
- Centre of Research in Myology, Institute of Myology, Sorbonne Université, INSERM, 75013 Paris, France; (P.L.); (G.Q.)
| | - Giorgia Querin
- Centre of Research in Myology, Institute of Myology, Sorbonne Université, INSERM, 75013 Paris, France; (P.L.); (G.Q.)
- Association Institut de Myologie, Plateforme Essais Cliniques Adultes, 75013 Paris, France
- APHP, Service de Neuromyologie, Hôpital Pitié-Salpêtrière, 75013 Paris, France
| | - Maria Grazia Biferi
- Centre of Research in Myology, Institute of Myology, Sorbonne Université, INSERM, 75013 Paris, France; (P.L.); (G.Q.)
- Correspondence: (P.S.); (M.G.B.)
| |
Collapse
|
13
|
Ramdas S, Servais L. New treatments in spinal muscular atrophy: an overview of currently available data. Expert Opin Pharmacother 2020; 21:307-315. [PMID: 31973611 DOI: 10.1080/14656566.2019.1704732] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Introduction: Spinal muscular atrophy (SMA) is one of the most common inherited neuromuscular disorders. It causes progressive muscle weakness and results in significant disability. Until recently, there were no drugs available for the treatment of SMA. Several phase 1-3 studies, including three double-blind randomized placebo-controlled studies have demonstrated the efficacy of disease-modifying approaches including gene replacement therapy, antisense oligonucleotides, and splicing modifiers.Areas covered: This article covers the publically available data on therapeutic strategies that address the underlying cause of SMA and clinical data available on approved treatments and drugs in the pipeline.Expert opinion: The newer therapeutic options in SMA have a good safety profile and deliver a therapeutic benefit in most patients. It is essential that the recommended standards of care are delivered along with the drugs for the best outcomes. No biomarkers to distinguish responders from non-responders are available; it is important that biomarkers be identified. Early treatment is essential for the maximum efficacy of the newly available treatments.
Collapse
Affiliation(s)
- Sithara Ramdas
- MDUK Neuromuscular Center, Department of Paediatrics, University of Oxford, Oxford, UK
| | - Laurent Servais
- MDUK Neuromuscular Center, Department of Paediatrics, University of Oxford, Oxford, UK.,Division of Child Neurology, Centre de Références des Maladies Neuromusculaires, Department of Pediatrics, University Hospital Liège & University of Liège, Belgium
| |
Collapse
|
14
|
Mercuri E, Lucibello S, Pera MC, Carnicella S, Coratti G, de Sanctis R, Messina S, Mazzone E, Forcina N, Fanelli L, Norcia G, Antonaci L, Frongia AL, Pane M. Long-term progression in type II spinal muscular atrophy: A retrospective observational study. Neurology 2019; 93:e1241-e1247. [PMID: 31451515 DOI: 10.1212/wnl.0000000000008166] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 04/30/2019] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To report the long-term progression in a cohort of patients with type II spinal muscular atrophy (SMA) assessed with the Hammersmith Functional Motor Scale-Expanded. METHODS Seventy-three patients (age 2.6-25 years) were included in the study. Twenty-eight of the 73 were first assessed before the age of 5 years and had been followed up for ≈5 years or longer. We observed an overall progression that was not linear. A piecewise regression analysis showed an improvement of scores in the younger patients with a point of slope change at ≈5 years of age, a decline between 5 and 13 years of age, and stability/slower decline after that. RESULTS Patients with the lowest scores at baseline had the earliest onset of scoliosis and a higher need for noninvasive ventilation compared to those with higher scores. Our results confirm that on the long-term follow-up all patients with type II SMA show a clear and progressive decline. CONCLUSION The severity of functional impairment at baseline can help to predict the magnitude of changes over time and the overall progression, including onset of scoliosis and need for noninvasive ventilation.
Collapse
Affiliation(s)
- Eugenio Mercuri
- From Pediatric Neurology (E.M., S.L., M.C.P., G.C., L.A., A.L.F.), Department of Woman and Child Health and Public Health, Child Health Area, Università Cattolica del Sacro Cuore; Centro Clinico Nemo (E.M., S.L., M.C.P., S.C., G.C., R.d.S., E.M., N.F., L.F., G.N., L.A., A.L.F., M.P.), Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome; and Department of Neurosciences, Psychiatry and Anaesthesiology (S.M.), University of Messina, Italy.
| | - Simona Lucibello
- From Pediatric Neurology (E.M., S.L., M.C.P., G.C., L.A., A.L.F.), Department of Woman and Child Health and Public Health, Child Health Area, Università Cattolica del Sacro Cuore; Centro Clinico Nemo (E.M., S.L., M.C.P., S.C., G.C., R.d.S., E.M., N.F., L.F., G.N., L.A., A.L.F., M.P.), Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome; and Department of Neurosciences, Psychiatry and Anaesthesiology (S.M.), University of Messina, Italy
| | - Maria Carmela Pera
- From Pediatric Neurology (E.M., S.L., M.C.P., G.C., L.A., A.L.F.), Department of Woman and Child Health and Public Health, Child Health Area, Università Cattolica del Sacro Cuore; Centro Clinico Nemo (E.M., S.L., M.C.P., S.C., G.C., R.d.S., E.M., N.F., L.F., G.N., L.A., A.L.F., M.P.), Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome; and Department of Neurosciences, Psychiatry and Anaesthesiology (S.M.), University of Messina, Italy
| | - Sara Carnicella
- From Pediatric Neurology (E.M., S.L., M.C.P., G.C., L.A., A.L.F.), Department of Woman and Child Health and Public Health, Child Health Area, Università Cattolica del Sacro Cuore; Centro Clinico Nemo (E.M., S.L., M.C.P., S.C., G.C., R.d.S., E.M., N.F., L.F., G.N., L.A., A.L.F., M.P.), Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome; and Department of Neurosciences, Psychiatry and Anaesthesiology (S.M.), University of Messina, Italy
| | - Giorgia Coratti
- From Pediatric Neurology (E.M., S.L., M.C.P., G.C., L.A., A.L.F.), Department of Woman and Child Health and Public Health, Child Health Area, Università Cattolica del Sacro Cuore; Centro Clinico Nemo (E.M., S.L., M.C.P., S.C., G.C., R.d.S., E.M., N.F., L.F., G.N., L.A., A.L.F., M.P.), Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome; and Department of Neurosciences, Psychiatry and Anaesthesiology (S.M.), University of Messina, Italy
| | - Roberto de Sanctis
- From Pediatric Neurology (E.M., S.L., M.C.P., G.C., L.A., A.L.F.), Department of Woman and Child Health and Public Health, Child Health Area, Università Cattolica del Sacro Cuore; Centro Clinico Nemo (E.M., S.L., M.C.P., S.C., G.C., R.d.S., E.M., N.F., L.F., G.N., L.A., A.L.F., M.P.), Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome; and Department of Neurosciences, Psychiatry and Anaesthesiology (S.M.), University of Messina, Italy
| | - Sonia Messina
- From Pediatric Neurology (E.M., S.L., M.C.P., G.C., L.A., A.L.F.), Department of Woman and Child Health and Public Health, Child Health Area, Università Cattolica del Sacro Cuore; Centro Clinico Nemo (E.M., S.L., M.C.P., S.C., G.C., R.d.S., E.M., N.F., L.F., G.N., L.A., A.L.F., M.P.), Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome; and Department of Neurosciences, Psychiatry and Anaesthesiology (S.M.), University of Messina, Italy
| | - Elena Mazzone
- From Pediatric Neurology (E.M., S.L., M.C.P., G.C., L.A., A.L.F.), Department of Woman and Child Health and Public Health, Child Health Area, Università Cattolica del Sacro Cuore; Centro Clinico Nemo (E.M., S.L., M.C.P., S.C., G.C., R.d.S., E.M., N.F., L.F., G.N., L.A., A.L.F., M.P.), Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome; and Department of Neurosciences, Psychiatry and Anaesthesiology (S.M.), University of Messina, Italy
| | - Nicola Forcina
- From Pediatric Neurology (E.M., S.L., M.C.P., G.C., L.A., A.L.F.), Department of Woman and Child Health and Public Health, Child Health Area, Università Cattolica del Sacro Cuore; Centro Clinico Nemo (E.M., S.L., M.C.P., S.C., G.C., R.d.S., E.M., N.F., L.F., G.N., L.A., A.L.F., M.P.), Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome; and Department of Neurosciences, Psychiatry and Anaesthesiology (S.M.), University of Messina, Italy
| | - Lavinia Fanelli
- From Pediatric Neurology (E.M., S.L., M.C.P., G.C., L.A., A.L.F.), Department of Woman and Child Health and Public Health, Child Health Area, Università Cattolica del Sacro Cuore; Centro Clinico Nemo (E.M., S.L., M.C.P., S.C., G.C., R.d.S., E.M., N.F., L.F., G.N., L.A., A.L.F., M.P.), Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome; and Department of Neurosciences, Psychiatry and Anaesthesiology (S.M.), University of Messina, Italy
| | - Giulia Norcia
- From Pediatric Neurology (E.M., S.L., M.C.P., G.C., L.A., A.L.F.), Department of Woman and Child Health and Public Health, Child Health Area, Università Cattolica del Sacro Cuore; Centro Clinico Nemo (E.M., S.L., M.C.P., S.C., G.C., R.d.S., E.M., N.F., L.F., G.N., L.A., A.L.F., M.P.), Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome; and Department of Neurosciences, Psychiatry and Anaesthesiology (S.M.), University of Messina, Italy
| | - Laura Antonaci
- From Pediatric Neurology (E.M., S.L., M.C.P., G.C., L.A., A.L.F.), Department of Woman and Child Health and Public Health, Child Health Area, Università Cattolica del Sacro Cuore; Centro Clinico Nemo (E.M., S.L., M.C.P., S.C., G.C., R.d.S., E.M., N.F., L.F., G.N., L.A., A.L.F., M.P.), Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome; and Department of Neurosciences, Psychiatry and Anaesthesiology (S.M.), University of Messina, Italy
| | - Anna Lia Frongia
- From Pediatric Neurology (E.M., S.L., M.C.P., G.C., L.A., A.L.F.), Department of Woman and Child Health and Public Health, Child Health Area, Università Cattolica del Sacro Cuore; Centro Clinico Nemo (E.M., S.L., M.C.P., S.C., G.C., R.d.S., E.M., N.F., L.F., G.N., L.A., A.L.F., M.P.), Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome; and Department of Neurosciences, Psychiatry and Anaesthesiology (S.M.), University of Messina, Italy
| | - Marika Pane
- From Pediatric Neurology (E.M., S.L., M.C.P., G.C., L.A., A.L.F.), Department of Woman and Child Health and Public Health, Child Health Area, Università Cattolica del Sacro Cuore; Centro Clinico Nemo (E.M., S.L., M.C.P., S.C., G.C., R.d.S., E.M., N.F., L.F., G.N., L.A., A.L.F., M.P.), Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome; and Department of Neurosciences, Psychiatry and Anaesthesiology (S.M.), University of Messina, Italy
| |
Collapse
|
15
|
Tiziano FD, Lomastro R, Abiusi E, Pasanisi MB, Di Pietro L, Fiori S, Baranello G, Angelini C, Sorarù G, Gaiani A, Mongini T, Vercelli L, Mercuri E, Vasco G, Pane M, Vita G, Vita G, Messina S, Petillo R, Passamano L, Politano L, Campanella A, Mantegazza R, Morandi L. Longitudinal evaluation of SMN levels as biomarker for spinal muscular atrophy: results of a phase IIb double-blind study of salbutamol. J Med Genet 2018; 56:293-300. [DOI: 10.1136/jmedgenet-2018-105482] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 11/10/2018] [Accepted: 11/30/2018] [Indexed: 11/04/2022]
Abstract
BackgroundSpinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder, due to the loss of function of the survival motor neuron (SMN1) gene. The first treatment for the condition, recently approved, is based on the reduction of exon 7 skipping in mRNAs produced by a highly homologous gene (SMN2). The primary objective of the present study was to evaluate the applicability of the dosage of SMN gene produts in blood, as biomarker for SMA, and the safety of oral salbutamol, a beta2-adrenergic agonist modulating SMN2 levels.MethodsWe have performed a 1-year multicentre, double-blind, placebo-controlled study with salbutamol in 45 adult patients with SMA. Patients assumed 4 mg of salbutamol or placebo/three times a day. Molecular tests were SMN2 copy number, SMN transcript and protein levels. We have also explored the clinical effect, by the outcome measures available at the time of study design.ResultsThirty-six patients completed the study. Salbutamol was safe and well tolerated. We observed a significant and progressive increase in SMN2 full-length levels in peripheral blood of the salbutamol-treated patients (p<0.00001). The exploratory analysis of motor function showed an improvement in most patients.ConclusionsOur data demonstrate safety and molecular efficacy of salbutamol. We provide the first longitudinal evaluation of SMN levels (both transcripts and protein) in placebo and in response to a compound modulating the gene expression: SMN transcript dosage in peripheral blood is reliable and may be used as pharmacodynamic marker in clinical trials with systemic compounds modifying SMN2levels.Trial registration numberEudraCT no. 2007-001088-32.
Collapse
|
16
|
Saffari A, Kölker S, Hoffmann GF, Weiler M, Ziegler A. Novel challenges in spinal muscular atrophy - How to screen and whom to treat? Ann Clin Transl Neurol 2018; 6:197-205. [PMID: 30656198 PMCID: PMC6331314 DOI: 10.1002/acn3.689] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 10/17/2018] [Accepted: 10/18/2018] [Indexed: 12/27/2022] Open
Abstract
In recent years, disease‐modifying and life‐prolonging therapies for spinal muscular atrophy (SMA) have been developed. However, patients are currently diagnosed with significant delay and therapies are often administered in advanced stages of motor neuron degeneration, showing limited effects. Methods to identify children in presymptomatic stages are currently evaluated in newborn screening programs. Yet, not all children develop symptoms shortly after birth raising the question whom to treat and when to initiate therapy. Finally, monitoring disease progression becomes essential to individualize management. Here, we review the literature on screening approaches, strategies to predict disease severity, and biomarkers to monitor therapy.
Collapse
Affiliation(s)
- Afshin Saffari
- Division of Child Neurology and Metabolic Medicine Center for Child and Adolescent Medicine University Hospital Heidelberg Heidelberg Germany
| | - Stefan Kölker
- Division of Child Neurology and Metabolic Medicine Center for Child and Adolescent Medicine University Hospital Heidelberg Heidelberg Germany
| | - Georg F Hoffmann
- Division of Child Neurology and Metabolic Medicine Center for Child and Adolescent Medicine University Hospital Heidelberg Heidelberg Germany
| | - Markus Weiler
- Department of Neurology University Hospital Heidelberg Heidelberg Germany
| | - Andreas Ziegler
- Division of Child Neurology and Metabolic Medicine Center for Child and Adolescent Medicine University Hospital Heidelberg Heidelberg Germany
| |
Collapse
|
17
|
Ziemka-Nalecz M, Jaworska J, Sypecka J, Zalewska T. Histone Deacetylase Inhibitors: A Therapeutic Key in Neurological Disorders? J Neuropathol Exp Neurol 2018; 77:855-870. [DOI: 10.1093/jnen/nly073] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Malgorzata Ziemka-Nalecz
- NeuroRepair Department, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Joanna Jaworska
- NeuroRepair Department, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Joanna Sypecka
- NeuroRepair Department, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Teresa Zalewska
- NeuroRepair Department, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| |
Collapse
|
18
|
Butchbach MER, Lumpkin CJ, Harris AW, Saieva L, Edwards JD, Workman E, Simard LR, Pellizzoni L, Burghes AHM. Protective effects of butyrate-based compounds on a mouse model for spinal muscular atrophy. Exp Neurol 2016; 279:13-26. [PMID: 26892876 PMCID: PMC4834225 DOI: 10.1016/j.expneurol.2016.02.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 02/11/2016] [Accepted: 02/13/2016] [Indexed: 11/17/2022]
Abstract
Proximal spinal muscular atrophy (SMA) is a childhood-onset degenerative disease resulting from the selective loss of motor neurons in the spinal cord. SMA is caused by the loss of SMN1 (survival motor neuron 1) but retention of SMN2. The number of copies of SMN2 modifies disease severity in SMA patients as well as in mouse models, making SMN2 a target for therapeutics development. Sodium butyrate (BA) and its analog (4PBA) have been shown to increase SMN2 expression in SMA cultured cells. In this study, we examined the effects of BA, 4PBA as well as two BA prodrugs-glyceryl tributyrate (BA3G) and VX563-on the phenotype of SMNΔ7 SMA mice. Treatment with 4PBA, BA3G and VX563 but not BA beginning at PND04 significantly improved the lifespan and delayed disease end stage, with administration of VX563 also improving the growth rate of these mice. 4PBA and VX563 improved the motor phenotype of SMNΔ7 SMA mice and prevented spinal motor neuron loss. Interestingly, neither 4PBA nor VX563 had an effect on SMN expression in the spinal cords of treated SMNΔ7 SMA mice; however, they inhibited histone deacetylase (HDAC) activity and restored the normal phosphorylation states of Akt and glycogen synthase kinase 3β, both of which are altered by SMN deficiency in vivo. These observations show that BA-based compounds with favorable pharmacokinetics ameliorate SMA pathology possibly by modulating HDAC and Akt signaling.
Collapse
Affiliation(s)
- Matthew E R Butchbach
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, DE, USA; Center for Pediatric Research, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, DE, USA; Department of Pediatrics, Thomas Jefferson University, Philadelphia, PA, USA; Department of Biological Sciences, University of Delaware, Newark, DE, USA.
| | - Casey J Lumpkin
- Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, DE, USA; Department of Biological Sciences, University of Delaware, Newark, DE, USA
| | - Ashlee W Harris
- Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, DE, USA
| | - Luciano Saieva
- Center for Motor Neuron Biology and Disease, Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Jonathan D Edwards
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Eileen Workman
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Louise R Simard
- Department of Biochemistry and Medical Genetics, University of Manitoba Faculty of Health Sciences, Winnipeg, Manitoba, Canada
| | - Livio Pellizzoni
- Center for Motor Neuron Biology and Disease, Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Arthur H M Burghes
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
| |
Collapse
|
19
|
Butchbach MER. Copy Number Variations in the Survival Motor Neuron Genes: Implications for Spinal Muscular Atrophy and Other Neurodegenerative Diseases. Front Mol Biosci 2016; 3:7. [PMID: 27014701 PMCID: PMC4785180 DOI: 10.3389/fmolb.2016.00007] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 02/25/2016] [Indexed: 12/11/2022] Open
Abstract
Proximal spinal muscular atrophy (SMA), a leading genetic cause of infant death worldwide, is an early-onset, autosomal recessive neurodegenerative disease characterized by the loss of spinal α-motor neurons. This loss of α-motor neurons is associated with muscle weakness and atrophy. SMA can be classified into five clinical grades based on age of onset and severity of the disease. Regardless of clinical grade, proximal SMA results from the loss or mutation of SMN1 (survival motor neuron 1) on chromosome 5q13. In humans a large tandem chromosomal duplication has lead to a second copy of the SMN gene locus known as SMN2. SMN2 is distinguishable from SMN1 by a single nucleotide difference that disrupts an exonic splice enhancer in exon 7. As a result, most of SMN2 mRNAs lack exon 7 (SMNΔ7) and produce a protein that is both unstable and less than fully functional. Although only 10–20% of the SMN2 gene product is fully functional, increased genomic copies of SMN2 inversely correlates with disease severity among individuals with SMA. Because SMN2 copy number influences disease severity in SMA, there is prognostic value in accurate measurement of SMN2 copy number from patients being evaluated for SMA. This prognostic value is especially important given that SMN2 copy number is now being used as an inclusion criterion for SMA clinical trials. In addition to SMA, copy number variations (CNVs) in the SMN genes can affect the clinical severity of other neurological disorders including amyotrophic lateral sclerosis (ALS) and progressive muscular atrophy (PMA). This review will discuss how SMN1 and SMN2 CNVs are detected and why accurate measurement of SMN1 and SMN2 copy numbers is relevant for SMA and other neurodegenerative diseases.
Collapse
Affiliation(s)
- Matthew E R Butchbach
- Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for ChildrenWilmington, DE, USA; Center for Pediatric Research, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for ChildrenWilmington, DE, USA; Department of Biological Sciences, University of DelawareNewark, DE, USA; Department of Pediatrics, Thomas Jefferson UniversityPhiladelphia, PA, USA
| |
Collapse
|
20
|
Mechanistic principles of antisense targets for the treatment of spinal muscular atrophy. Future Med Chem 2015; 7:1793-808. [PMID: 26381381 DOI: 10.4155/fmc.15.101] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a major neurodegenerative disorder of children and infants. SMA is primarily caused by low levels of SMN protein owing to deletions or mutations of the SMN1 gene. SMN2, a nearly identical copy of SMN1, fails to compensate for the loss of the production of the functional SMN protein due to predominant skipping of exon 7. Several compounds, including antisense oligonucleotides (ASOs) that elevate SMN protein from SMN2 hold the promise for treatment. An ASO-based drug currently under Phase III clinical trial employs intronic splicing silencer N1 (ISS-N1) as its target. Cumulative studies on ISS-N1 reveal a wealth of information with significance to the overall therapeutic development for SMA. Here, the authors summarize the mechanistic principles behind various antisense targets currently available for SMA therapy.
Collapse
|
21
|
Stabley DL, Harris AW, Holbrook J, Chubbs NJ, Lozo KW, Crawford TO, Swoboda KJ, Funanage VL, Wang W, Mackenzie W, Scavina M, Sol-Church K, Butchbach MER. SMN1 and SMN2 copy numbers in cell lines derived from patients with spinal muscular atrophy as measured by array digital PCR. Mol Genet Genomic Med 2015; 3:248-57. [PMID: 26247043 PMCID: PMC4521962 DOI: 10.1002/mgg3.141] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 02/22/2015] [Accepted: 02/26/2015] [Indexed: 11/22/2022] Open
Abstract
Proximal spinal muscular atrophy (SMA) is an early-onset motor neuron disease characterized by loss of α-motor neurons and associated muscle atrophy. SMA is caused by deletion or other disabling mutation of survival motor neuron 1 (SMN1). In the human genome, a large duplication of the SMN-containing region gives rise to a second copy of this gene (SMN2) that is distinguishable by a single nucleotide change in exon 7. Within the SMA population, there is substantial variation in SMN2 copy number; in general, those individuals with SMA who have a high SMN2 copy number have a milder disease. Because SMN2 functions as a disease modifier, its accurate copy number determination may have clinical relevance. In this study, we describe the development of an assay to assess SMN1 and SMN2 copy numbers in DNA samples using an array-based digital PCR (dPCR) system. This dPCR assay can accurately and reliably measure the number of SMN1 and SMN2 copies in DNA samples. In a cohort of SMA patient-derived cell lines, the assay confirmed a strong inverse correlation between SMN2 copy number and disease severity. Array dPCR is a practical technique to determine, accurately and reliably, SMN1 and SMN2 copy numbers from SMA samples.
Collapse
Affiliation(s)
- Deborah L Stabley
- Nemours Biomolecular Core Laboratory, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for ChildrenWilmington, Delaware
| | - Ashlee W Harris
- Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for ChildrenWilmington, Delaware
| | - Jennifer Holbrook
- Nemours Biomolecular Core Laboratory, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for ChildrenWilmington, Delaware
| | - Nicholas J Chubbs
- Department of Biological Sciences, University of DelawareNewark, Delaware
| | - Kevin W Lozo
- Department of Biological Sciences, University of DelawareNewark, Delaware
| | - Thomas O Crawford
- Department of Neurology, Johns Hopkins UniversityBaltimore, Maryland
- Department of Pediatrics, Johns Hopkins UniversityBaltimore, Maryland
| | - Kathryn J Swoboda
- Neurogenetics Research Program, Center for Human Genetics Research, Massachusetts General HospitalBoston, Massachusetts
| | - Vicky L Funanage
- Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for ChildrenWilmington, Delaware
- Center for Pediatric Research, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for ChildrenWilmington, Delaware
- Department of Pediatrics, Thomas Jefferson UniversityPhiladelphia, Pennsylvania
| | - Wenlan Wang
- Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for ChildrenWilmington, Delaware
- Center for Pediatric Research, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for ChildrenWilmington, Delaware
- Department of Pediatrics, Thomas Jefferson UniversityPhiladelphia, Pennsylvania
| | - William Mackenzie
- Division of Orthopedics, Nemours Alfred I. duPont Hospital for ChildrenWilmington, Delaware
| | - Mena Scavina
- Division of Neurology, Nemours Alfred I. duPont Hospital for ChildrenWilmington, Delaware
| | - Katia Sol-Church
- Nemours Biomolecular Core Laboratory, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for ChildrenWilmington, Delaware
| | - Matthew E R Butchbach
- Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for ChildrenWilmington, Delaware
- Department of Biological Sciences, University of DelawareNewark, Delaware
- Center for Pediatric Research, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for ChildrenWilmington, Delaware
- Department of Pediatrics, Thomas Jefferson UniversityPhiladelphia, Pennsylvania
| |
Collapse
|
22
|
Finkel R, Bertini E, Muntoni F, Mercuri E. 209th ENMC International Workshop: Outcome Measures and Clinical Trial Readiness in Spinal Muscular Atrophy 7-9 November 2014, Heemskerk, The Netherlands. Neuromuscul Disord 2015; 25:593-602. [PMID: 26045156 DOI: 10.1016/j.nmd.2015.04.009] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 04/22/2015] [Accepted: 04/23/2015] [Indexed: 10/23/2022]
Affiliation(s)
| | - Enrico Bertini
- UCL Institute of Child Health, Dubowitz Neuromuscular Centre, London, UK
| | | | | | | |
Collapse
|
23
|
Mack SG, Cook DJ, Dhurjati P, Butchbach MER. Systems biology investigation of cAMP modulation to increase SMN levels for the treatment of spinal muscular atrophy. PLoS One 2014; 9:e115473. [PMID: 25514431 PMCID: PMC4267815 DOI: 10.1371/journal.pone.0115473] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Accepted: 11/24/2014] [Indexed: 12/31/2022] Open
Abstract
Spinal muscular atrophy (SMA), a leading genetic cause of infant death worldwide, is an autosomal recessive disorder caused by the loss of SMN1 (survival motor neuron 1), which encodes the protein SMN. The loss of SMN1 causes a deficiency in SMN protein levels leading to motor neuron cell death in the anterior horn of the spinal cord. SMN2, however, can also produce some functional SMN to partially compensate for loss of SMN1 in SMA suggesting increasing transcription of SMN2 as a potential therapy to treat patients with SMA. A cAMP response element was identified on the SMN2 promoter, implicating cAMP activation as a step in the transcription of SMN2. Therefore, we investigated the effects of modulating the cAMP signaling cascade on SMN production in vitro and in silico. SMA patient fibroblasts were treated with the cAMP signaling modulators rolipram, salbutamol, dbcAMP, epinephrine and forskolin. All of the modulators tested were able to increase gem formation, a marker for SMN protein in the nucleus, in a dose-dependent manner. We then derived two possible mathematical models simulating the regulation of SMN2 expression by cAMP signaling. Both models fit well with our experimental data. In silico treatment of SMA fibroblasts simultaneously with two different cAMP modulators resulted in an additive increase in gem formation. This study shows how a systems biology approach can be used to develop potential therapeutic targets for treating SMA.
Collapse
Affiliation(s)
- Sean G. Mack
- Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, Delaware, United States of America
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, United States of America
| | - Daniel J. Cook
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, United States of America
| | - Prasad Dhurjati
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, United States of America
| | - Matthew E. R. Butchbach
- Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, Delaware, United States of America
- Center for Pediatric Research, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, Delaware, United States of America
- Department of Biological Sciences, University of Delaware, Newark, Delaware, United States of America
- Department of Pediatrics, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
- * E-mail:
| |
Collapse
|
24
|
Maeda M, Harris AW, Kingham BF, Lumpkin CJ, Opdenaker LM, McCahan SM, Wang W, Butchbach MER. Transcriptome profiling of spinal muscular atrophy motor neurons derived from mouse embryonic stem cells. PLoS One 2014; 9:e106818. [PMID: 25191843 PMCID: PMC4156416 DOI: 10.1371/journal.pone.0106818] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 08/01/2014] [Indexed: 01/20/2023] Open
Abstract
Proximal spinal muscular atrophy (SMA) is an early onset, autosomal recessive motor neuron disease caused by loss of or mutation in SMN1 (survival motor neuron 1). Despite understanding the genetic basis underlying this disease, it is still not known why motor neurons (MNs) are selectively affected by the loss of the ubiquitously expressed SMN protein. Using a mouse embryonic stem cell (mESC) model for severe SMA, the RNA transcript profiles (transcriptomes) between control and severe SMA (SMN2+/+;mSmn−/−) mESC-derived MNs were compared in this study using massively parallel RNA sequencing (RNA-Seq). The MN differentiation efficiencies between control and severe SMA mESCs were similar. RNA-Seq analysis identified 3,094 upregulated and 6,964 downregulated transcripts in SMA mESC-derived MNs when compared against control cells. Pathway and network analysis of the differentially expressed RNA transcripts showed that pluripotency and cell proliferation transcripts were significantly increased in SMA MNs while transcripts related to neuronal development and activity were reduced. The differential expression of selected transcripts such as Crabp1, Crabp2 and Nkx2.2 was validated in a second mESC model for SMA as well as in the spinal cords of low copy SMN2 severe SMA mice. Furthermore, the levels of these selected transcripts were restored in high copy SMN2 rescue mouse spinal cords when compared against low copy SMN2 severe SMA mice. These findings suggest that SMN deficiency affects processes critical for normal development and maintenance of MNs.
Collapse
Affiliation(s)
- Miho Maeda
- Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, Delaware, United States of America
- Department of Biological Sciences, University of Delaware, Newark, Delaware, United States of America
| | - Ashlee W. Harris
- Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, Delaware, United States of America
| | - Brewster F. Kingham
- Sequencing and Genotyping Center, University of Delaware, Newark, Delaware, United States of America
| | - Casey J. Lumpkin
- Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, Delaware, United States of America
- Department of Biological Sciences, University of Delaware, Newark, Delaware, United States of America
| | - Lynn M. Opdenaker
- Center for Translational Cancer Research, University of Delaware, Newark, Delaware, United States of America
| | - Suzanne M. McCahan
- Center for Pediatric Research, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, Delaware, United States of America
- Bioinformatics Core Facility, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, Delaware, United States of America
- Department of Pediatrics, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Wenlan Wang
- Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, Delaware, United States of America
- Center for Pediatric Research, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, Delaware, United States of America
- Department of Biological Sciences, University of Delaware, Newark, Delaware, United States of America
| | - Matthew E. R. Butchbach
- Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, Delaware, United States of America
- Center for Pediatric Research, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, Delaware, United States of America
- Department of Biological Sciences, University of Delaware, Newark, Delaware, United States of America
- Department of Pediatrics, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
- * E-mail:
| |
Collapse
|
25
|
Zanetta C, Nizzardo M, Simone C, Monguzzi E, Bresolin N, Comi GP, Corti S. Molecular therapeutic strategies for spinal muscular atrophies: current and future clinical trials. Clin Ther 2013; 36:128-40. [PMID: 24360800 DOI: 10.1016/j.clinthera.2013.11.006] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 10/28/2013] [Accepted: 11/22/2013] [Indexed: 11/17/2022]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is an autosomal recessive motor neuron disease caused by mutations in the survival motor neuron gene (SMN1) and the leading genetic cause of infant mortality. Currently, there is no effective treatment other than supportive care. OBJECTIVE This article provides a general overview of the main aspects that need to be taken into account to design a more efficient clinical trial and to summarize the most promising molecular trials that are currently in development or are being planned for the treatment of SMA. METHODS A systematic review of the literature was performed, identifying key clinical trials involving novel molecular therapies in SMA. In addition, abstracts presented at the meetings of the Families of Spinal Muscular Atrophy were searched and the Families of Spinal Muscular Atrophy Web site was carefully analyzed. Finally, a selection of SMA clinical trials registered at clinical-trials.gov has been included in the article. RESULTS The past decade has seen a marked advancement in the understanding of both SMA genetics and molecular mechanisms. New molecules targeting SMN have shown promise in preclinical studies, and various clinical trials have started to test the drugs that were discovered through basic research. CONCLUSIONS Both preclinical and early clinical trial results involving novel molecular therapies suggest that the clinical care paradigm in SMA will soon change.
Collapse
Affiliation(s)
- Chiara Zanetta
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Monica Nizzardo
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Chiara Simone
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Erika Monguzzi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Nereo Bresolin
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Giacomo P Comi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Stefania Corti
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
| |
Collapse
|
26
|
Tiziano FD, Melki J, Simard LR. Solving the puzzle of spinal muscular atrophy: what are the missing pieces? Am J Med Genet A 2013; 161A:2836-45. [PMID: 24124019 DOI: 10.1002/ajmg.a.36251] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Accepted: 08/30/2013] [Indexed: 12/13/2022]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive, lower motor neuron disease. Clinical heterogeneity is pervasive: three infantile (type I-III) and one adult-onset (type IV) forms are recognized. Type I SMA is the most common genetic cause of death in infancy and accounts for about 50% of all patients with SMA. Most forms of SMA are caused by mutations of the survival motor neuron (SMN1) gene. A second gene that is 99% identical to SMN1 (SMN2) is located in the same region. The only functionally relevant difference between the two genes identified to date is a C → T transition in exon 7 of SMN2, which determines an alternative spliced isoform that predominantly excludes exon 7. Thus, SMN2 genes do not produce sufficient full length SMN protein to prevent the onset of the disease. Since the identification of the causative mutation, biomedical research of SMA has progressed by leaps and bounds: from clues on the function of SMN protein, to the development of different models of the disease, to the identification of potential treatments, some of which are currently in human trials. The aim of this review is to elucidate the current state of knowledge, emphasizing how close we are to the solution of the puzzle that is SMA, and, more importantly, to highlight the missing pieces of this puzzle. Filling in these gaps in our knowledge will likely accelerate the development and delivery of efficient treatments for SMA patients and be a prerequisite towards achieving our final goal, the cure of SMA.
Collapse
|
27
|
Clinical and molecular cross-sectional study of a cohort of adult type III spinal muscular atrophy patients: clues from a biomarker study. Eur J Hum Genet 2012; 21:630-6. [PMID: 23073312 DOI: 10.1038/ejhg.2012.233] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Proximal spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder caused by mutations of the SMN1 gene. Based on severity, three forms of SMA are recognized (types I-III). All patients usually have 2-4 copies of a highly homologous gene (SMN2), which produces insufficient levels of functional survival motor neuron (SMN) protein due to the alternative splicing of exon 7. The availability of potential candidates to the treatment of SMA has raised a number of issues, including the availability of biomarkers. This study was aimed at evaluating whether the quantification of SMN2 products in peripheral blood is a suitable biomarker for SMA. Forty-five adult type III patients were evaluated by Manual Muscle Testing, North Star Ambulatory Assessment scale, 6-min walk test, myometry, forced vital capacity, and dual X-ray absorptiometry. Molecular assessments included SMN2 copy number, levels of full-length SMN2 (SMN2-fl) transcripts and those lacking exon 7 and SMN protein. Clinical outcome measures strongly correlated to each other. Lean body mass correlated inversely with years from diagnosis and with several aspects of motor performance. SMN2 copy number and SMN protein levels were not associated with motor performance or transcript levels. SMN2-fl levels correlated with motor performance in ambulant patients. Our results indicate that SMN2-fl levels correlate with motor performance only in patients preserving higher levels of motor function, whereas motor performance was strongly influenced by disease duration and lean body mass. If not taken into account, the confounding effect of disease duration may impair the identification of potential SMA biomarkers.
Collapse
|
28
|
Abstract
Spinal muscular atrophy is an autosomal recessive disorder characterised by degeneration of motor neurons in the spinal cord and is caused by mutations of the survival of motor neuron 1 gene SMN1. The severity of spinal muscular atrophy is highly variable and no cure is available at present. Consensus has been reached on several aspects of care, the availability of which can have a substantial effect on prognosis, but controversies remain. The development of standards of care for children with the disorder and the identification of promising treatment strategies have changed the natural history of spinal muscular atrophy, and the prospects are good for further improvements in function, quality of life, and survival. A long-term benefit for patients will be the development of effective interventions (such as antisense oligonucleotides), some of which are in clinical trials. The need to be prepared for clinical trials has been the impetus for a remarkable and unprecedented cooperation between clinicians, scientists, industry, government, and volunteer organisations on an international scale.
Collapse
|
29
|
Glanzman AM, O'Hagen JM, McDermott MP, Martens WB, Flickinger J, Riley S, Quigley J, Montes J, Dunaway S, Deng L, Chung WK, Tawil R, Darras BT, De Vivo DC, Kaufmann P, Finkel RS. Validation of the Expanded Hammersmith Functional Motor Scale in spinal muscular atrophy type II and III. J Child Neurol 2011; 26:1499-507. [PMID: 21940700 DOI: 10.1177/0883073811420294] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The relationships between the Expanded Hammersmith Functional Motor Scale (HFMSE) and genotype and motor and respiratory outcomes were examined in patients with spinal muscular atrophy types II and III (n = 70). The correlation between the HFMSE and Gross Motor Function Measure was r = 0.98. Correlations between HFMSE and forced vital capacity (percentage of predicted normal) (n = 56) and a functional rating (n = 57) were r = 0.87 and r = 0.92, respectively. Correlations with strength were as follows: knee extension, r = 0.74 (n = 60); elbow flexion, r = 0.77 (n = 61); and knee flexion, r = 0.74 (n = 58). The HFMSE differentiated patients by SMN2 copy number (P = .0007); bi-level positive airway pressure use, <8 versus ≥8 hours/day (P < .0001); ambulatory status (P < .0001); and spinal muscular atrophy type (P < .0001). The HFMSE demonstrates significant associations with established measures of function, strength, and genotype, and discriminates patients based on function, diagnostic category, and bi-level positive airway pressure need. Time of administration averaged 12 minutes. The HFMSE is a valid, time-efficient outcome measure for clinical trials in spinal muscular atrophy types II and III.
Collapse
Affiliation(s)
- Allan M Glanzman
- Department of Physical Therapy, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Alías L, Bernal S, Barceló MJ, Also-Rallo E, Martínez-Hernández R, Rodríguez-Alvarez FJ, Hernández-Chico C, Baiget M, Tizzano EF. Accuracy of marker analysis, quantitative real-time polymerase chain reaction, and multiple ligation-dependent probe amplification to determine SMN2 copy number in patients with spinal muscular atrophy. Genet Test Mol Biomarkers 2011; 15:587-94. [PMID: 21548796 DOI: 10.1089/gtmb.2010.0253] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder caused by absence of or mutations in the survival motor neuron1 gene (SMN1). All SMA patients have a highly homologous copy of SMN1, the SMN2 gene. Severe (type I) SMA patients present one or two SMN2 copies, whereas milder chronic forms (type II-III) usually have three or four SMN2 copies. SMN2 dosage is important to stratify patients for motor function tests and clinical trials. Our aim was to compare three methods, marker analysis, real-time quantitative polymerase chain reaction using the LightCycler instrument, and multiple ligation-dependent probe amplification (MLPA), to characterize their accuracy in quantifying SMN2 genes. We studied a group of 62 genetically confirmed SMA patients, 54 with homozygous absence of exons 7 and 8 of SMN1 and 8 with SMN2-SMN1 hybrid genes. A complete correlation using the three methods was observed in 32 patients (51.6%). In the remaining 30 patients, discordances between the three methods were found, including under or overestimation of SMN2 copies by marker analysis with respect to the quantitative methods (LightCycler and MLPA) because of lack of informativeness of markers, 3' deletions of SMN genes, and breakpoints in SMN2-SMN1 hybrid genes. The technical limitations and advantages and disadvantages of these methods are discussed. We conclude that the three methods complement each other in estimating the SMN2 copy number in most cases. However, MLPA offers additional information to characterize SMA cases with particular rearrangements such as partial deletions and hybrid genes.
Collapse
Affiliation(s)
- Laura Alías
- Servicio de Genética, Hospital de la Santa Creu i Sant Pau, CIBERER (U705), Barcelona, Spain
| | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Sproule DM, Punyanitya M, Shen W, Dashnaw S, Martens B, Montgomery M, Montes J, Battista V, Finkel R, Darras B, De Vivo DC, Kaufmann P. Muscle volume estimation by magnetic resonance imaging in spinal muscular atrophy. J Child Neurol 2011; 26:309-17. [PMID: 20929908 DOI: 10.1177/0883073810380457] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Thigh muscle volume was assessed using magnetic resonance imaging in 16 subjects with spinal muscular atrophy. Scans were successful for 14 of 16 subjects (1 type 1, 6 type 2, and 7 type 3) as young as 5.7 years. Muscle volume with normal and abnormal signal was measured using blinded, semiautomated analysis of reconstructed data. Results were compared with segmental lean mass estimated by dual-energy X-ray absorptiometry and correlated with clinical and electrophysiological measures of disease severity. Muscle volume was reduced with abnormal signal quality. Test-retest reliability (r = .99) and correlation with dual-energy X-ray absorptiometry (r = .91) were excellent. Type 2 subjects had lower volume (3.5 ± 1.6 vs 6.3 ± 2.8 mL/cm height; P = .06) and higher percentage of muscle with abnormal signal (68% ± 20% vs 47% ± 27%; P = .14) than type 3. Reproducibility, tolerability, and strong correlation with clinical measures make magnetic resonance imaging a candidate biomarker for clinical research.
Collapse
Affiliation(s)
- Douglas M Sproule
- Division of Pediatric Neurosciences, Department of Neurology, SMA Clinical Research Center, Columbia University Medical Center, New York, New York 10032-3791, USA.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Petit F, Cuisset JM, Rouaix-Emery N, Cancés C, Sablonnière B, Bieth E, Moerman A, Sukno S, Hardy N, Holder-Espinasse M, Manouvrier-Hanu S, Vallée L. Insights into genotype-phenotype correlations in spinal muscular atrophy: a retrospective study of 103 patients. Muscle Nerve 2011; 43:26-30. [PMID: 21171094 DOI: 10.1002/mus.21832] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive disorder associated with homozygous deletion of the survival motor neuron 1 gene (SMN1). Its centromeric copy gene, SMN2, is the major modifying factor. However, the genotype-phenotype correlation is incomplete and is therefore not useful in clinical practice. We studied a cohort of 103 patients in order to refine this correlation. In addition to standard disease severity data, we collected three additional criteria: age at death; brainstem involvement; and loss of ambulation. Gene dosage analysis was conducted by multiplex ligation-dependent probe amplification (MLPA). SMN2 copynumber was highly correlated with survival duration in SMA type I and ambulation conservation or loss in type III. Among SMA severity groups, it was not significantly different in cases with brainstem involvement. Although the SMN2 copynumber could provide prognostic indications, clinical discrepancies still exist among patients, suggesting the existence of unidentified modifying factors.
Collapse
Affiliation(s)
- Florence Petit
- Service de Génétique Clinique, CHU Hôpital Jeanne de Flandre, Lille, France
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Tiziano FD, Neri G, Brahe C. Biomarkers in rare disorders: the experience with spinal muscular atrophy. Int J Mol Sci 2010; 12:24-38. [PMID: 21339974 PMCID: PMC3039940 DOI: 10.3390/ijms12010024] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 12/06/2010] [Accepted: 12/16/2010] [Indexed: 12/20/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder caused by homozygous mutations of the SMN1 gene. Based on clinical severity, three forms of SMA are recognized (type I–III). All patients have at least one (usually 2–4) copies of a highly homologous gene (SMN2) which produces insufficient levels of functional SMN protein, due to alternative splicing of exon7. Recently, evidence has been provided that SMN2 expression can be enhanced by different strategies. The availability of potential candidates to treat SMA has raised a number of issues, including the availability of data on the natural history of the disease, the reliability and sensitivity of outcome measures, the duration of the studies, and the number and clinical homogeneity of participating patients. Equally critical is the availability of reliable biomarkers. So far, different tools have been proposed as biomarkers in SMA, classifiable into two groups: instrumental (the Compound Motor Action Potential, the Motor Unit Number Estimation, and the Dual-energy X-ray absorptiometry) and molecular (SMN gene products dosage, either transcripts or protein). However, none of the biomarkers available so far can be considered the gold standard. Preclinical studies on SMA animal models and double-blind, placebo-controlled studies are crucial to evaluate the appropriateness of biomarkers, on the basis of correlations with clinical outcome.
Collapse
Affiliation(s)
- Francesco D Tiziano
- Institute of Medical Genetics, Catholic University of Sacro Cuore, Roma, Italy; E-Mails: (G.N.); (C.B.)
| | | | | |
Collapse
|
34
|
Sproule DM, Montes J, Dunaway S, Montgomery M, Battista V, Koenigsberger D, Martens B, Shen W, Punyanitya M, Benton M, Butler H, Caracciolo J, Mercuri E, Finkel R, Darras B, De Vivo DC, Kaufmann P. Adiposity is increased among high-functioning, non-ambulatory patients with spinal muscular atrophy. Neuromuscul Disord 2010; 20:448-52. [PMID: 20610154 DOI: 10.1016/j.nmd.2010.05.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Revised: 05/07/2010] [Accepted: 05/24/2010] [Indexed: 12/24/2022]
Abstract
The relationship between body composition and function in spinal muscular atrophy (SMA) is poorly understood. 53 subjects with SMA were stratified by type and Hammersmith functional motor scale, expanded score into three cohorts: low-functioning non-ambulatory (type 2 with Hammersmith score < 12, n=19), high-functioning non-ambulatory (type 2 with Hammersmith score > or = 12 or non-ambulatory type 3, n=17), and Ambulatory (n=17). Lean and fat mass was estimated using dual-energy X-ray absorptiometry. Anthropometric data was incorporated to measure fat-free (lean mass in kg/stature in m(2)) and fat (fat mass in kg/stature in m(2)) mass indices, the latter compared to published age and sex norms. Feeding dysfunction among type 2 subjects was assessed by questionnaire. Fat mass index was increased in the high-functioning non-ambulatory cohort (10.4+/-4.5) compared with both the ambulatory (7.2+/-2.1, P=0.013) and low-functioning non-ambulatory (7.6+/-3.1, P=0.040) cohorts. 12 of 17 subjects (71%) in the high-functioning non-ambulatory cohort had fat mass index > 85th percentile for age and gender (connoting "at risk of overweight") versus 9 of 19 subjects (47%) in the low-functioning non-ambulatory cohort and 8 of 17 ambulatory subjects (47%). Despite differences in clinical function, a similar proportion of low functioning (7/18, 39%) and high functioning (2/7, 29%) type 2 subjects reported swallowing or feeding dysfunction. Non-ambulatory patients with relatively high clinical function may be at particular risk of excess adiposity, perhaps reflecting access to excess calories despite relative immobility, emphasizing the importance of individualized nutritional management in SMA.
Collapse
Affiliation(s)
- Douglas M Sproule
- Division of Pediatric Neurosciences, Department of Neurology, SMA Clinical Research Center, Columbia University Medical Center, New York, NY 10032-3791, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Tiziano FD, Pinto AM, Fiori S, Lomastro R, Messina S, Bruno C, Pini A, Pane M, D'Amico A, Ghezzo A, Bertini E, Mercuri E, Neri G, Brahe C. SMN transcript levels in leukocytes of SMA patients determined by absolute real-time PCR. Eur J Hum Genet 2010; 18:52-8. [PMID: 19603064 DOI: 10.1038/ejhg.2009.116] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder caused by homozygous mutations of the SMN1 gene. Three forms of SMA are recognized (type I-III) on the basis of clinical severity. All patients have at least one or more (usually 2-4) copies of a highly homologous gene (SMN2), which produces insufficient levels of functional SMN protein, because of alternative splicing of exon 7. Recently, evidence has been provided that SMN2 expression can be enhanced by pharmacological treatment. However, no reliable biomarkers are available to test the molecular efficacy of the treatments. At present, the only potential biomarker is the dosage of SMN products in peripheral blood. However, the demonstration that SMN full-length (SMN-fl) transcript levels are reduced in leukocytes of patients compared with controls remains elusive (except for type I). We have developed a novel assay based on absolute real-time PCR, which allows the quantification of SMN1-fl/SMN2-fl transcripts. For the first time, we have shown that SMN-fl levels are reduced in leukocytes of type II-III patients compared with controls. We also found that transcript levels are related to clinical severity as in type III patients SMN2-fl levels are significantly higher compared with type II and directly correlated with functional ability in type II patients and with age of onset in type III patients. Moreover, in haploidentical siblings with discordant phenotype, the less severely affected individuals showed significantly higher transcript levels. Our study shows that SMN2-fl dosage in leukocytes can be considered a reliable biomarker and can provide the rationale for SMN dosage in clinical trials.
Collapse
|
36
|
Werlauff U, Steffensen B, Bertelsen S, Fløytrup I, Kristensen B, Werge B. Physical characteristics and applicability of standard assessment methods in a total population of spinal muscular atrophy type II patients. Neuromuscul Disord 2010; 20:34-43. [DOI: 10.1016/j.nmd.2009.11.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2009] [Revised: 10/30/2009] [Accepted: 11/06/2009] [Indexed: 11/15/2022]
|
37
|
Elsheikh B, Prior T, Zhang X, Miller R, Kolb SJ, Moore D, Bradley W, Barohn R, Bryan W, Gelinas D, Iannaccone S, Leshner R, Mendell JR, Mendoza M, Russman B, Smith S, King W, Kissel JT. An analysis of disease severity based on SMN2 copy number in adults with spinal muscular atrophy. Muscle Nerve 2009; 40:652-6. [PMID: 19760790 DOI: 10.1002/mus.21350] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
To evaluate the effect of SMN2 copy number on disease severity in spinal muscular atrophy (SMA), we stratified 45 adult SMA patients based on SMN2 copy number (3 vs. 4 copies). Patients with 3 copies had an earlier age of onset and lower spinal muscular atrophy functional rating scale (SMAFRS) scores and were more likely to be non-ambulatory. There was, however, no difference between the groups in quantitative muscle strength or pulmonary function testing. Functional scale may be a more discriminating outcome measure for SMA clinical trials.
Collapse
Affiliation(s)
- Bakri Elsheikh
- Department of Neurology, Ohio State University, 421 Means Hall, 1654 Upham Drive, Columbus, Ohio 43210, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Montes J, Gordon AM, Pandya S, De Vivo DC, Kaufmann P. Clinical outcome measures in spinal muscular atrophy. J Child Neurol 2009; 24:968-78. [PMID: 19509409 DOI: 10.1177/0883073809332702] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Spinal muscular atrophy is one of the most devastating neurological diseases of childhood. Affected infants and children suffer from often severe muscle weakness caused by degeneration of lower motor neurons in the spinal cord and brainstem. Identification of the causative genetic mutation in most cases has resulted in development of potential treatment strategies. To test these new drugs, clinically feasible outcomes are needed. Several different assessments, validated in spinal muscular atrophy or similar disorders, are being used by national and international research groups; however, their sensitivity to detect change is unknown. Acceptance of a few standardized, easily administered, and functionally meaningful outcomes, applicable to the phenotypic spectrum of spinal muscular atrophy, is needed. Consensus is imperative to facilitate collaboration and explore the ability of these measures to identify the therapeutic effect of disease-modifying agents. Following is an evidence-based review of available clinical outcome measures in spinal muscular atrophy.
Collapse
Affiliation(s)
- Jacqueline Montes
- Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA.
| | | | | | | | | |
Collapse
|
39
|
Arkblad E, Tulinius M, Kroksmark AK, Henricsson M, Darin N. A population-based study of genotypic and phenotypic variability in children with spinal muscular atrophy. Acta Paediatr 2009; 98:865-72. [PMID: 19154529 DOI: 10.1111/j.1651-2227.2008.01201.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS To describe the occurrence of spinal muscular atrophy (SMA) in childhood; to evaluate if any of the genes in the SMA region on chromosome 5q13 correlates with disease severity; to make genotype-phenotype correlations; to evaluate the variability of different disease alleles in carriers and the sensitivity of multiplex ligation-dependent probe amplification (MLPA) for detecting carriers. METHODS In a population-based study from Western Sweden MLPA was used to determine the copy-numbers of several genes in the SMA region (SMN1, SMN2, BIRC1, GTF2H2 and SERF1A) in SMA-patients and their parents. RESULTS We estimated the incidence of SMN1-related SMA in childhood at 1 in 11 800 live births and confirmed the relationship between the number of SMN2 copies and the severity of disease. No other direct relationships were found. All but one of the analysed parents were confirmed as carriers by MLPA analysis. A total of at least 30 different disease alleles were identified and no specific disease allele represented more than 15% of the total. CONCLUSION The childhood incidence of SMA in the Swedish population is around 1 in 12,000 live births and it is unlikely that there is any founder effect involved in SMA in western Sweden.
Collapse
Affiliation(s)
- Eva Arkblad
- Department of Clinical Genetics, Sahlgrenska University Hospital, Göteborg, Sweden.
| | | | | | | | | |
Collapse
|
40
|
Messina S, Pane M, De Rose P, Vasta I, Sorleti D, Aloysius A, Sciarra F, Mangiola F, Kinali M, Bertini E, Mercuri E. Feeding problems and malnutrition in spinal muscular atrophy type II. Neuromuscul Disord 2008; 18:389-93. [DOI: 10.1016/j.nmd.2008.02.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2007] [Revised: 02/12/2008] [Accepted: 02/29/2008] [Indexed: 10/22/2022]
|