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Shum BOV, Henner I, Cairns A, Pretorius C, Wilgen U, Barahona P, Ungerer JPJ, Bennett G. Technical feasibility of newborn screening for spinal muscular atrophy by next-generation DNA sequencing. Front Genet 2023; 14:1095600. [PMID: 36713073 PMCID: PMC9878289 DOI: 10.3389/fgene.2023.1095600] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 01/02/2023] [Indexed: 01/14/2023] Open
Abstract
Newborn screening (NBS) assays for spinal muscular atrophy (SMA) typically use a polymerase chain reaction (PCR) based assay to identify individuals with homozygous deletion in exon 7 of the SMN1 gene. Due to high DNA sequence homology between SMN1 and SMN2, it has previously been difficult to accurately bioinformatically map short reads from next-generation DNA sequencing (NGS) to SMN1, resulting in low analytical performance and preventing NGS being used for SMA screening. Advances in bioinformatics have allowed NGS to be used in diagnostic settings, but to date these assays have not reached the scale required for high volume population newborn screening and have not been performed on the dried blood spot samples that NBS programs currently use. Here we integrate an NGS assay using hybridisation-based capture with a customised bioinformatics algorithm and purpose designed high throughput reporting software into an existing NBS program to achieve a laboratory workflow for population SMA screening. We tested the NGS assay on over 2500 newborns born over 2 weeks in a NBS program in a technical feasibility study and show high sensitivity and specificity. Our results suggest NGS may be an alternate method for SMA screening by NBS programs, providing a multiplex testing platform on which potentially hundreds of inherited conditions could be simultaneously tested.
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Affiliation(s)
- Bennett O. V. Shum
- Preventive Health Division, Genepath, Sydney, NSW, Australia,EMBL Australia Node in Single Molecule Science, School of Biomedical Sciences, University of NSW, Sydney, NSW, Australia
| | - Ilya Henner
- Preventive Health Division, Genepath, Sydney, NSW, Australia
| | - Anita Cairns
- Neurosciences Department, Queensland Children’s Hospital, Brisbane, QLD, Australia
| | - Carel Pretorius
- Department of Chemical Pathology, Pathology Queensland, Queensland Health, Brisbane, QLD, Australia
| | - Urs Wilgen
- Department of Chemical Pathology, Pathology Queensland, Queensland Health, Brisbane, QLD, Australia
| | | | - Jacobus P. J. Ungerer
- Department of Chemical Pathology, Pathology Queensland, Queensland Health, Brisbane, QLD, Australia,Faculty of Health and Behavioural Sciences, University of QLD, Brisbane, QLD, Australia,*Correspondence: Jacobus P. J. Ungerer, ; Glenn Bennett,
| | - Glenn Bennett
- Preventive Health Division, Genepath, Sydney, NSW, Australia,*Correspondence: Jacobus P. J. Ungerer, ; Glenn Bennett,
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2
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Onasemnogene abeparvovec for presymptomatic infants with two copies of SMN2 at risk for spinal muscular atrophy type 1: the Phase III SPR1NT trial. Nat Med 2022; 28:1381-1389. [PMID: 35715566 PMCID: PMC9205281 DOI: 10.1038/s41591-022-01866-4] [Citation(s) in RCA: 113] [Impact Index Per Article: 56.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 05/10/2022] [Indexed: 12/19/2022]
Abstract
SPR1NT ( NCT03505099 ) was a Phase III, multicenter, single-arm study to investigate the efficacy and safety of onasemnogene abeparvovec for presymptomatic children with biallelic SMN1 mutations treated at ≤6 weeks of life. Here, we report final results for 14 children with two copies of SMN2, expected to develop spinal muscular atrophy (SMA) type 1. Efficacy was compared with a matched Pediatric Neuromuscular Clinical Research natural-history cohort (n = 23). All 14 enrolled infants sat independently for ≥30 seconds at any visit ≤18 months (Bayley-III item #26; P < 0.001; 11 within the normal developmental window). All survived without permanent ventilation at 14 months as per protocol; 13 maintained body weight (≥3rd WHO percentile) through 18 months. No child used nutritional or respiratory support. No serious adverse events were considered related to treatment by the investigator. Onasemnogene abeparvovec was effective and well-tolerated for children expected to develop SMA type 1, highlighting the urgency for universal newborn screening.
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3
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Wijaya YOS, Nishio H, Niba ETE, Shiroshita T, Kato M, Bouike Y, Tode C, Ar Rochmah M, Harahap NIF, Nurputra DK, Okamoto K, Saito T, Takeuchi A, Lai PS, Yamaguchi S, Shinohara M. Dried Blood Spot Screening System for Spinal Muscular Atrophy with Allele-Specific Polymerase Chain Reaction and Melting Peak Analysis. Genet Test Mol Biomarkers 2021; 25:293-301. [PMID: 33877896 DOI: 10.1089/gtmb.2020.0312] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background and Aim: Spinal muscular atrophy (SMA) is a lower motor neuron disease with autosomal recessive inheritance caused by homozygous SMN1 deletions. Although SMA has been considered as incurable, newly developed drugs improve life prognoses and motor functions of patients. To maximize the efficacy of the drugs, SMA patients should be treated before symptoms become apparent. Thus, newborn screening for SMA is strongly recommended. In this study, we aim to establish a new simple screening system based on DNA melting peak analysis. Materials and Methods: A total of 124 dried blood spot (DBS) on FTA® ELUTE cards (51 SMN1-deleted patients with SMA, 20 carriers, and 53 controls) were punched and subjected to direct amplification of SMN1 and CFTR (reference gene). Melting peak analyses were performed to detect SMN1 deletions from DBS samples. Results: A combination of allele-specific polymerase chain reaction (PCR) and melting peak analyses clearly distinguished the DBS samples with and without SMN1. Compared with the results of fresh blood samples, our new system yielded 100% sensitivity and specificity. The advantages of our system include (1) biosafe collection, transfer, and storage for DBS samples, (2) obviating the need for DNA extraction from DBS preventing contamination, (3) preclusion of fluorescent probes leading to low PCR cost, and (4) fast and high-throughput screening for SMN1 deletions. Conclusion: We demonstrate that our system would be applicable to a real-world newborn screening program for SMA, because our new technology is efficient for use in routine clinical laboratories that do not have highly advanced PCR instruments.
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Affiliation(s)
- Yogik Onky Silvana Wijaya
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hisahide Nishio
- Faculty of Medical Rehabilitation, Kobe Gakuin University, Kobe, Japan
| | - Emma Tabe Eko Niba
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tomoyoshi Shiroshita
- Faculty of Medical Rehabilitation, Kobe Gakuin University, Kobe, Japan.,Sekisui Medical CO., LTD. 1-3, Tokyo, Japan
| | - Masako Kato
- Faculty of Medical Rehabilitation, Kobe Gakuin University, Kobe, Japan
| | | | - Chisato Tode
- Instrumental Analysis Center, Kobe Pharmaceutical University, Kobe, Japan
| | - Mawaddah Ar Rochmah
- Department of Neurology, Faculty of Medicine, Public Health, and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Nur Imma Fatimah Harahap
- Department of Clinical Pathology and Laboratory Medicine, Faculty of Medicine, Public Health, and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Dian Kesumapramudya Nurputra
- Department of Pediatrics, Faculty of Medicine, Public Health, and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Kentaro Okamoto
- Department of Pediatrics, Ehime Prefectural Imabari Hospital, Imabari, Japan
| | - Toshio Saito
- Department of Neurology, National Hospital Organization Osaka Toneyama Medical Center, Toyonaka, Japan
| | - Atsuko Takeuchi
- Instrumental Analysis Center, Kobe Pharmaceutical University, Kobe, Japan
| | - Poh San Lai
- Department of Pediatrics, National University of Singapore, Singapore, Singapore
| | - Seiji Yamaguchi
- Department of Pediatrics, Shimane University School of Medicine, Izumo, Japan
| | - Masakazu Shinohara
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan
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4
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Butchbach MER. Genomic Variability in the Survival Motor Neuron Genes ( SMN1 and SMN2): Implications for Spinal Muscular Atrophy Phenotype and Therapeutics Development. Int J Mol Sci 2021; 22:ijms22157896. [PMID: 34360669 PMCID: PMC8348669 DOI: 10.3390/ijms22157896] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 07/14/2021] [Accepted: 07/21/2021] [Indexed: 02/07/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a leading genetic cause of infant death worldwide that is characterized by loss of spinal motor neurons leading to muscle weakness and atrophy. SMA results from the loss of survival motor neuron 1 (SMN1) gene but retention of its paralog SMN2. The copy numbers of SMN1 and SMN2 are variable within the human population with SMN2 copy number inversely correlating with SMA severity. Current therapeutic options for SMA focus on increasing SMN2 expression and alternative splicing so as to increase the amount of SMN protein. Recent work has demonstrated that not all SMN2, or SMN1, genes are equivalent and there is a high degree of genomic heterogeneity with respect to the SMN genes. Because SMA is now an actionable disease with SMN2 being the primary target, it is imperative to have a comprehensive understanding of this genomic heterogeneity with respect to hybrid SMN1–SMN2 genes generated by gene conversion events as well as partial deletions of the SMN genes. This review will describe this genetic heterogeneity in SMA and its impact on disease phenotype as well as therapeutic efficacy.
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Affiliation(s)
- Matthew E. R. Butchbach
- Center for Applied Clinical Genomics, Nemours Children’s Health Delaware, Wilmington, DE 19803, USA;
- Center for Pediatric Research, Nemours Children’s Health Delaware, Wilmington, DE 19803, USA
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
- Department of Pediatrics, Thomas Jefferson University, Philadelphia, PA 19107, USA
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Zhang C, Li Z, Chen M, Hu Z, Wu L, Zhou M, Liang D. Cas12a and Lateral Flow Strip-Based Test for Rapid and Ultrasensitive Detection of Spinal Muscular Atrophy. BIOSENSORS-BASEL 2021; 11:bios11050154. [PMID: 34068874 PMCID: PMC8153588 DOI: 10.3390/bios11050154] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/09/2021] [Accepted: 05/12/2021] [Indexed: 12/12/2022]
Abstract
Spinal muscular atrophy (SMA) is characterized by severe lethality and irreversible progression. Early diagnosis of SMA is of more practical significance with the emergence of effective therapy. However, existing techniques to identify SMA patients rely on cumbersome instruments, hindering their accessibility and application. An SMA-Cas12a-strip assay was developed with the integration of Cas12a-based nucleic acid detection, isothermal amplification, and lateral flow strip. The analytical performance of the assay was assessed with clinical samples. To explore its extensible utility, various specimens were tested. Validated with 168 clinical samples, the sensitivity and specificity of the SMA-Cas12a-strip assay were both 100%. The minimum detectable concentration of genomic DNA containing the target gene achieved 526 aM. The assay was compatible with specimens from several sources, and the turnaround time could be within 1.5 h. We developed a simple, cost-effective, and highly sensitive and specific assay to detect SMA patients. With little and field-portable equipment, the assay holds great promise in the detection of SMA patients, particularly in low-resource regions.
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Affiliation(s)
| | | | | | | | | | - Miaojin Zhou
- Correspondence: (M.Z.); (D.L.); Tel.: +86-731-84805252 (M.Z. & D.L.); Fax: +86-731-84478152 (M.Z. & D.L.)
| | - Desheng Liang
- Correspondence: (M.Z.); (D.L.); Tel.: +86-731-84805252 (M.Z. & D.L.); Fax: +86-731-84478152 (M.Z. & D.L.)
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6
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Moreda-Piñeiro J, Cocho JA, Couce ML, Moreda-Piñeiro A, Bermejo-Barrera P. Trace elements in dried blood spots as potential discriminating features for metabolic disorder diagnosis in newborns. Metallomics 2021; 13:6261194. [PMID: 33930140 PMCID: PMC8755940 DOI: 10.1093/mtomcs/mfab018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 03/26/2021] [Accepted: 04/08/2021] [Indexed: 11/13/2022]
Abstract
Trace elements in dried blood spots (DBSs) from newborns were determined by laser ablation coupled with inductively coupled plasma mass spectrometry, and data were subjected to chemometric evaluation in an attempt to classify healthy newborns and newborns suffering from metabolic disorders. Unsupervised [principal component analysis (PCA) and cluster analysis (CA)] and supervised [linear discriminant analysis (LDA) and soft independent modeling by class analogy (SIMCA)] pattern recognition techniques were used as classification techniques. PCA and CA have shown a clear tendency to form two groups (healthy newborns and newborns suffering from metabolic disorders). LDA and SIMCA have predicted that 90.5% and 83.9% of originally grouped healthy newborn cases were correctly classified by LDA and SIMCA, respectively. In addition, these percentages were 97.6% (LDA) and 80.6% (SIMCA) for DBSs from newborns suffering from metabolic disorders. However, SIMCA has only detected one misclassified DBS from the healthy group, and the lower percentage is attributed to four DBSs from the healthy newborn group and five DBSs from newborns with disorders that were found as belonging to both categories (healthy newborns and newborns with disorders) in the training set. LDA also gave a percentage of grouped maple syrup urine disease (MSUD) cases correctly classified of 100%, although the percentage fells to 66.7% when classifying phenylketonuria (PKU) cases. Finally, essential elements such as Fe, K, Rb, and Zn were found to be matched (correlated) with the concentration of amino acids such as phenylalanine, valine, and leucine, biomarkers linked with MSUD and PKU diseases.
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Affiliation(s)
- Jorge Moreda-Piñeiro
- Department of Chemistry, Faculty of Sciences, Universidade da Coruña, Grupo Química Analítica Aplicada (QANAP), University Institute of Research in Environmental Studies (IUMA), Centro de Investigaciones Científicas Avanzadas (CICA), Campus de A Coruña, s/n, 15071 A Coruña, Spain
| | - José A Cocho
- Unit of Diagnosis and Treatment of Congenital Metabolic Diseases, Department of Pediatrics, University Hospital of Santiago de Compostela, IDIS, CIBERER, A Choupana, s/n, 15706 Santiago de Compostela, Spain
| | - María Luz Couce
- Unit of Diagnosis and Treatment of Congenital Metabolic Diseases, Department of Pediatrics, University Hospital of Santiago de Compostela, IDIS, CIBERER, A Choupana, s/n, 15706 Santiago de Compostela, Spain
| | - Antonio Moreda-Piñeiro
- Group of Trace Elements, Speciation and Spectroscopy (GETEE), Strategic Grouping in Materials (AEMAT), Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, Universidade de Santiago de Compostela, Avenida das Ciencias, s/n, 15782 Santiago de Compostela, Spain
| | - Pilar Bermejo-Barrera
- Group of Trace Elements, Speciation and Spectroscopy (GETEE), Strategic Grouping in Materials (AEMAT), Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, Universidade de Santiago de Compostela, Avenida das Ciencias, s/n, 15782 Santiago de Compostela, Spain
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7
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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.
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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.)
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8
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Viall S, Calhoun A, Mew NA, Tarini BA. How a baby with classic galactosemia was nearly missed: When the test succeeds but system fails. Am J Med Genet A 2020; 182:1750-1753. [PMID: 32275121 DOI: 10.1002/ajmg.a.61587] [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: 01/09/2020] [Revised: 03/06/2020] [Accepted: 03/25/2020] [Indexed: 11/07/2022]
Abstract
Newborn screening (NBS) is a well-established state-run public health program which has targeted the early identification of treatable diseases like classic galactosemia (CG) for over a decade. We describe the case of a symptomatic newborn with CG and an abnormal screen report, including positive DNA-based test, who still managed to fall through the cracks in a sub-optimally functioning NBS program, despite decades of screening experience. While much attention is paid to testing technology, this case illustrates basic minimum requirements a newborn screening program must fulfill to reliably identify and treat all affected individuals including minimum reporting requirements, case surveillance and a dedicated short-term follow-up program. In newborn screening, success is systematic.
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Affiliation(s)
- Sarah Viall
- Rare Disease Institute, Children's National Hospital, Washington, District of Columbia, USA
| | - Amy Calhoun
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Nicholas Ah Mew
- Rare Disease Institute, Children's National Hospital, Washington, District of Columbia, USA
| | - Beth A Tarini
- Center for Translational Research, Children's National Research Institute, Children's National Medical Center, Washington, District of Columbia, USA
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9
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Lin Y, Lin CH, Yin X, Zhu L, Yang J, Shen Y, Yang C, Chen X, Hu H, Ma Q, Shi X, Shen Y, Hu Z, Huang C, Huang X. Newborn Screening for Spinal Muscular Atrophy in China Using DNA Mass Spectrometry. Front Genet 2019; 10:1255. [PMID: 31921298 PMCID: PMC6928056 DOI: 10.3389/fgene.2019.01255] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Accepted: 11/14/2019] [Indexed: 12/13/2022] Open
Abstract
Background: Spinal muscular atrophy (SMA) is the most common neurodegenerative disorder and the leading genetic cause of infant mortality. Early detection of SMA through newborn screening (NBS) is essential to selecting pre-symptomatic treatment and ensuring optimal outcome, as well as, prompting the urgent need for effective screening methods. This study aimed to determine the feasibility of applying an Agena iPLEX SMA assay in NBS for SMA in China. Methods: We developed an Agena iPLEX SMA assay based on the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and evaluated the performance of this assay through assessment of 167 previously-genotyped samples. Then we conducted a pilot study to apply this assay for SMA NBS. The SMN1 and SMN2 copy number of screen-positive patients were determined by multiplex ligation-dependent probe amplification analysis. Results: The sensitivity and specificity of the Agena iPLEX SMA assay were both 100%. Three patients with homozygous SMN1 deletion were successfully identified and conformed by multiplex ligation-dependent probe amplification analysis. Two patients had two SMN2 copies, which was correlated with severe SMA type I phenotype; both of them exhibited neurogenic lesion and with decreased muscle power. Another patient with four SMN2 copies, whose genotype correlated with milder SMA type III or IV phenotype, had normal growth and development without clinical symptoms. Conclusions: The Agena iPLEX SMA assay is an effective and reliable approach for population-based SMA NBS. The first large-scale pilot study using this assay in the Mainland of China showed that large-scale implementation of population-based NBS for SMA is feasible.
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Affiliation(s)
- Yiming Lin
- Department of Genetics and Metabolism, Children's Hospital of Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China.,Neonatal Disease Screening Center, Quanzhou Maternity and Children's Hospital, Quanzhou, China
| | - Chien-Hsing Lin
- Department of Research and Development, Feng Chi Biotech Corp, Taipei, Taiwan
| | - Xiaoshan Yin
- Department of Clinical Psychology, School of Health in Social Science, The University of Edinburg, Edinburg, United Kingdom
| | - Lin Zhu
- Department of Translational Medicine, Hangzhou Genuine Clinical Laboratory Co. Ltd, Hangzhou, China
| | - Jianbin Yang
- Department of Genetics and Metabolism, Children's Hospital of Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Yuyan Shen
- Neonatal Disease Screening Center, Huaihua Maternal and Child Health Hospital, Huaihua, China
| | - Chiju Yang
- Neonatal Disease Screening Center, Jining Maternal and Child Health Family Service Center, Jining, China
| | - Xigui Chen
- Neonatal Disease Screening Center, Jining Maternal and Child Health Family Service Center, Jining, China
| | - Haili Hu
- Neonatal Disease Screening Center, Hefei Women and Children's Health Care Hospital, Hefei, China
| | - Qingqing Ma
- Neonatal Disease Screening Center, Hefei Women and Children's Health Care Hospital, Hefei, China
| | - Xueqin Shi
- Department of Pediatrics, Yancheng Maternity and Child Health Care Hospital, Yancheng, China
| | - Yaping Shen
- Department of Genetics and Metabolism, Children's Hospital of Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Zhenzhen Hu
- Department of Genetics and Metabolism, Children's Hospital of Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Chenggang Huang
- Research and Development Center, Zhejiang Biosan Biochemical Technologies Co., Ltd, Hangzhou, China
| | - Xinwen Huang
- Department of Genetics and Metabolism, Children's Hospital of Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
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10
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Shorrock HK, Gillingwater TH, Groen EJN. Overview of Current Drugs and Molecules in Development for Spinal Muscular Atrophy Therapy. Drugs 2019; 78:293-305. [PMID: 29380287 PMCID: PMC5829132 DOI: 10.1007/s40265-018-0868-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disease primarily characterized by a loss of spinal motor neurons, leading to progressive paralysis and premature death in the most severe cases. SMA is caused by homozygous deletion of the survival motor neuron 1 (SMN1) gene, leading to low levels of SMN protein. However, a second SMN gene (SMN2) exists, which can be therapeutically targeted to increase SMN levels. This has recently led to the first disease-modifying therapy for SMA gaining formal approval from the US Food and Drug Administration (FDA) and European Medicines Agency (EMA). Spinraza (nusinersen) is a modified antisense oligonucleotide that targets the splicing of SMN2, leading to increased SMN protein levels, capable of improving clinical phenotypes in many patients. In addition to Spinraza, several other therapeutic approaches are currently in various stages of clinical development. These include SMN-dependent small molecule and gene therapy approaches along with SMN-independent strategies, such as general neuroprotective factors and muscle strength-enhancing compounds. For each therapy, we provide detailed information on clinical trial design and pharmacological/safety data where available. Previous clinical studies are also discussed to provide context on SMA clinical trial development and the insights these provided for the design of current studies.
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Affiliation(s)
- Hannah K Shorrock
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Hugh Robson Building, 15 George Square, Edinburgh, EH8 9XD, UK.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Hugh Robson Building, 15 George Square, Edinburgh, EH8 9XD, UK
| | - Thomas H Gillingwater
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Hugh Robson Building, 15 George Square, Edinburgh, EH8 9XD, UK.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Hugh Robson Building, 15 George Square, Edinburgh, EH8 9XD, UK
| | - Ewout J N Groen
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Hugh Robson Building, 15 George Square, Edinburgh, EH8 9XD, UK. .,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Hugh Robson Building, 15 George Square, Edinburgh, EH8 9XD, UK.
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11
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Pechmann A, Langer T, Schorling D, Stein S, Vogt S, Schara U, Kölbel H, Schwartz O, Hahn A, Giese K, Johannsen J, Denecke J, Weiß C, Theophil M, Kirschner J. Evaluation of Children with SMA Type 1 Under Treatment with Nusinersen within the Expanded Access Program in Germany. J Neuromuscul Dis 2018; 5:135-143. [PMID: 29689734 PMCID: PMC6004898 DOI: 10.3233/jnd-180315] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Background: Spinal muscular atrophy (SMA) is a neuromuscular disorder characterized by muscle weakness and muscle atrophy. Nusinersen acts as a splicing modifier and has recently been approved for intrathecal treatment of SMA. Objective: Prior to approval, nusinersen was provided to patients with SMA type 1 in Germany within an Expanded Access Program (EAP). In contrast to previous clinical trials, children of different age groups and different stages of the disease were treated with nusinersen. Methods: We conducted a prospective, longitudinal data collection of patients treated with nusinersen within the EAP in seven neuromuscular centers in Germany. Standardized assessments including CHOP-INTEND and HINE-2 motor milestones were performed at baseline and 60 and 180 days after start of treatment. Results: Data from 61 SMA type 1 patients (mean age 21.08 months, range 1–93) were available for analysis. After six months of treatment, 47 children (77.0%) improved by ≥4 points in CHOP INTEND score. Mean change in CHOP INTEND score was 9.0±8.0 points. Nineteen patients (31.1%) improved by ≥2 points in HINE-2 motor milestones. Regression analysis revealed age at onset of treatment as major determinant of change in CHOP INTEND from baseline. Conclusion: When analyzing a broad spectrum of SMA type 1 patients, many children showed an improvement of motor function after six months of treatment with nusinersen, which is generally not expected within the natural course of the disease. Long-term observation and follow-up of patients with later onset types of SMA are crucial to understand the clinical impact of treatment with nusinersen.
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Affiliation(s)
- Astrid Pechmann
- Department of Neuropediatrics and Muscle Disorders, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Thorsten Langer
- Department of Neuropediatrics and Muscle Disorders, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - David Schorling
- Department of Neuropediatrics and Muscle Disorders, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Sabine Stein
- Department of Neuropediatrics and Muscle Disorders, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Sibylle Vogt
- Department of Neuropediatrics and Muscle Disorders, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Ulrike Schara
- Department of Neuropediatrics, Children's Hospital 1, University of Duisburg-Essen, Essen, Germany
| | - Heike Kölbel
- Department of Neuropediatrics, Children's Hospital 1, University of Duisburg-Essen, Essen, Germany
| | - Oliver Schwartz
- Department of Neuropediatrics, University Children's Hospital Muenster, Muenster, Germany
| | - Andreas Hahn
- Departement of Child Neurology, University Hospital Giessen, Justus-Liebig-University, Giessen, Germany
| | - Kerstin Giese
- Departement of Child Neurology, University Hospital Giessen, Justus-Liebig-University, Giessen, Germany
| | - Jessika Johannsen
- Department of Pediatrics, Neuropediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jonas Denecke
- Department of Pediatrics, Neuropediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Claudia Weiß
- Department of Neuropediatrics, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Manuela Theophil
- Department of Pediatrics and Neuropediatrics, DRK Klinikum Westend, Berlin, Germany
| | - Janbernd Kirschner
- Department of Neuropediatrics and Muscle Disorders, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
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12
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Vidal-Folch N, Gavrilov D, Raymond K, Rinaldo P, Tortorelli S, Matern D, Oglesbee D. Multiplex Droplet Digital PCR Method Applicable to Newborn Screening, Carrier Status, and Assessment of Spinal Muscular Atrophy. Clin Chem 2018; 64:1753-1761. [PMID: 30352867 DOI: 10.1373/clinchem.2018.293712] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 10/02/2018] [Indexed: 11/06/2022]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is a progressive neuromuscular disorder with neuronal degeneration leading to muscular atrophy and respiratory failure. SMA is frequently caused by homozygous deletions that include exon 7 of the survival motor neuron gene SMN1, and its clinical course is influenced by the copy number of a nearby 5q SMN1 paralog, SMN2. Multiple ligation probe amplification (MLPA) and real-time quantitative PCR (qPCR) can detect SMN1 deletions. Yet, qPCR needs normalization or standard curves, and MLPA demands DNA concentrations above those obtainable from dried blood spots (DBSs). We developed a multiplex, droplet digital PCR (ddPCR) method for the simultaneous detection of SMN1 deletions and SMN2 copy number variation in DBS and other tissues. An SMN1 Sanger sequencing process for DBS was also developed. METHODS SMN1, SMN2, and RPP30 concentrations were simultaneously measured with a Bio-Rad AutoDG and QX200 ddPCR system. A total of 1530 DBSs and 12 SMA patients were tested. RESULTS Population studies confirmed 1 to 5 SMN1 exon 7 copies detected in unaffected specimens, whereas patients with SMA revealed 0 SMN1 copies. Intraassay and interassay imprecisions were <7.1% CV for individuals with ≥1 SMN1 copies. Testing 12 SMA-positive samples resulted in 100% sensitivity and specificity. CONCLUSIONS This ddPCR method is sensitive, specific, and applicable to newborn screening and carrier status determination for SMA. It can also be incorporated with a parallel ddPCR T-cell excision circles assay for severe combined immunodeficiencies.
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Affiliation(s)
| | - Dimitar Gavrilov
- Departments of Laboratory Medicine and Pathology.,Medical Genetics
| | - Kimiyo Raymond
- Departments of Laboratory Medicine and Pathology.,Medical Genetics
| | - Piero Rinaldo
- Departments of Laboratory Medicine and Pathology.,Medical Genetics.,Pediatric and Adolescent Medicine, Mayo Clinic College of Medicine, Rochester, MN
| | | | - Dietrich Matern
- Departments of Laboratory Medicine and Pathology.,Medical Genetics.,Pediatric and Adolescent Medicine, Mayo Clinic College of Medicine, Rochester, MN
| | - Devin Oglesbee
- Departments of Laboratory Medicine and Pathology.,Medical Genetics
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13
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Groen EJN, Talbot K, Gillingwater TH. Advances in therapy for spinal muscular atrophy: promises and challenges. Nat Rev Neurol 2018; 14:214-224. [PMID: 29422644 DOI: 10.1038/nrneurol.2018.4] [Citation(s) in RCA: 150] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Spinal muscular atrophy (SMA) is a devastating motor neuron disease that predominantly affects children and represents the most common cause of hereditary infant mortality. The condition results from deleterious variants in SMN1, which lead to depletion of the survival motor neuron protein (SMN). Now, 20 years after the discovery of this genetic defect, a major milestone in SMA and motor neuron disease research has been reached with the approval of the first disease-modifying therapy for SMA by US and European authorities - the antisense oligonucleotide nusinersen. At the same time, promising data from early-stage clinical trials of SMN1 gene therapy have indicated that additional therapeutic options are likely to emerge for patients with SMA in the near future. However, the approval of nusinersen has generated a number of immediate and substantial medical, ethical and financial implications that have the potential to resonate beyond the specific treatment of SMA. Here, we provide an overview of the rapidly evolving therapeutic landscape for SMA, highlighting current achievements and future opportunities. We also discuss how these developments are providing important lessons for the emerging second generation of combinatorial ('SMN-plus') therapies that are likely to be required to generate robust treatments that are effective across a patient's lifespan.
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Affiliation(s)
- Ewout J N Groen
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK.,Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh, UK
| | - Kevin Talbot
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, UK
| | - Thomas H Gillingwater
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK.,Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh, UK
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14
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15
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Chien YH, Chiang SC, Weng WC, Lee NC, Lin CJ, Hsieh WS, Lee WT, Jong YJ, Ko TM, Hwu WL. Presymptomatic Diagnosis of Spinal Muscular Atrophy Through Newborn Screening. J Pediatr 2017; 190:124-129.e1. [PMID: 28711173 DOI: 10.1016/j.jpeds.2017.06.042] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 05/15/2017] [Accepted: 06/16/2017] [Indexed: 11/15/2022]
Abstract
OBJECTIVE To demonstrate the feasibility of presymptomatic diagnosis of spinal muscular atrophy (SMA) through newborn screening (NBS). STUDY DESIGN We performed a screening trial to assess all newborns who underwent routine newborn metabolic screening at the National Taiwan University Hospital newborn screening center between November 2014 and September 2016. A real-time polymerase chain reaction (RT-PCR) genotyping assay for the SMN1/SMN2 intron 7 c.888+100A/G polymorphism was performed to detect homozygous SMN1 deletion using dried blood spot (DBS) samples. Then the exon 7 c.840C>T mutation and SMN2 copy number were determined by both droplet digital PCR (ddPCR) using the original screening DBS and multiplex ligation-dependent probe amplification (MLPA) using a whole blood sample. RESULTS Of the 120 267 newborns, 15 tested positive according to the RT-PCR assay. The DBS ddPCR assay excluded 8 false-positives, and the other 7 patients were confirmed by the MLPA assay. Inclusion of the second-tier DBS ddPCR screening assay resulted in a positive prediction value of 100%. The incidence of SMA was 1 in 17 181 (95% CI, 1 in 8323 to 1 in 35 468). Two of the 3 patients with 2 copies of SMN2 and all 4 patients with 3 or 4 copies of SMN2 were asymptomatic at the time of diagnosis. Five of the 8 false-positives were caused by intragenic recombination between SMN1 and SMN2. CONCLUSION Newborn screening can detect patients affected by SMA before symptom onset and enable early therapeutic intervention. A combination of a RT-PCR and a second-tier ddPCR can accurately diagnose SMA from DBS samples with no false-positives. TRIAL REGISTRATION ClinicalTrials.gov NCT02123186.
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Affiliation(s)
- Yin-Hsiu Chien
- Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan; Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan
| | - Shu-Chuan Chiang
- Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan
| | - Wen-Chin Weng
- Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan
| | - Ni-Chung Lee
- Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan; Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan
| | - Ching-Jie Lin
- Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan
| | - Wu-Shiun Hsieh
- Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan
| | - Wang-Tso Lee
- Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan
| | - Yuh-Jyh Jong
- Department of Biological Science and Technology, College of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan; Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Pediatrics and Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Tsang-Ming Ko
- Genephile Bioscience Laboratory, Ko's Obstetrics and Gynecology, Taipei, Taiwan
| | - Wuh-Liang Hwu
- Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan; Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan.
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16
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Kichula EA. Inherited Neuromuscular Disorders: Presentation, Diagnosis, and Advances in Treatment. CURRENT PEDIATRICS REPORTS 2017. [DOI: 10.1007/s40124-017-0118-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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17
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Farrar MA, Park SB, Vucic S, Carey KA, Turner BJ, Gillingwater TH, Swoboda KJ, Kiernan MC. Emerging therapies and challenges in spinal muscular atrophy. Ann Neurol 2017; 81:355-368. [PMID: 28026041 PMCID: PMC5396275 DOI: 10.1002/ana.24864] [Citation(s) in RCA: 128] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 12/13/2016] [Accepted: 12/18/2016] [Indexed: 12/14/2022]
Abstract
Spinal muscular atrophy (SMA) is a hereditary neurodegenerative disease with severity ranging from progressive infantile paralysis and premature death (type I) to limited motor neuron loss and normal life expectancy (type IV). Without disease‐modifying therapies, the impact is profound for patients and their families. Improved understanding of the molecular basis of SMA, disease pathogenesis, natural history, and recognition of the impact of standardized care on outcomes has yielded progress toward the development of novel therapeutic strategies and are summarized. Therapeutic strategies in the pipeline are appraised, ranging from SMN1 gene replacement to modulation of SMN2 encoded transcripts, to neuroprotection, to an expanding repertoire of peripheral targets, including muscle. With the advent of preliminary trial data, it can be reasonably anticipated that the SMA treatment landscape will transform significantly. Advancement in presymptomatic diagnosis and screening programs will be critical, with pilot newborn screening studies underway to facilitate preclinical diagnosis. The development of disease‐modifying therapies will necessitate monitoring programs to determine the long‐term impact, careful evaluation of combined treatments, and further acceleration of improvements in supportive care. In advance of upcoming clinical trial results, we consider the challenges and controversies related to the implementation of novel therapies for all patients and set the scene as the field prepares to enter an era of novel therapies. Ann Neurol 2017;81:355–368
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Affiliation(s)
- Michelle A Farrar
- Discipline of Paediatrics, School of Women's and Children's Health, UNSW Medicine, The University of New South Wales, Sydney, Australia
| | - Susanna B Park
- Brain & Mind Centre and Sydney Medical School, University of Sydney, Sydney, Australia
| | - Steve Vucic
- Department of Neurology, Westmead Hospital and Western Clinical School, University of Sydney, Sydney, Australia
| | - Kate A Carey
- Discipline of Paediatrics, School of Women's and Children's Health, UNSW Medicine, The University of New South Wales, Sydney, Australia
| | - Bradley J Turner
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia
| | - Thomas H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburg, Edinburg, United Kingdom
| | - Kathryn J Swoboda
- Center for Human Genetics Research, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA
| | - Matthew C Kiernan
- Brain & Mind Centre and Sydney Medical School, University of Sydney, Sydney, Australia
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18
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Ghaloul-Gonzalez L, Goldstein A, Walsh Vockley C, Dobrowolski SF, Biery A, Irani A, Ibarra J, Morton DH, Mohsen AW, Vockley J. Mitochondrial respiratory chain disorders in the Old Order Amish population. Mol Genet Metab 2016; 118:296-303. [PMID: 27344355 DOI: 10.1016/j.ymgme.2016.06.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 06/06/2016] [Accepted: 06/06/2016] [Indexed: 12/20/2022]
Abstract
The Old Order Amish populations in the US are one of the Plain People groups and are descendants of the Swiss Anabaptist immigrants who came to North America in the early eighteenth century. They live in numerous small endogamous demes that have resulted in reduced genetic diversity along with a high prevalence of specific genetic disorders, many of them autosomal recessive. Mitochondrial respiratory chain deficiencies arising from mitochondrial or nuclear DNA mutations have not previously been reported in the Plain populations. Here we present four different Amish families with mitochondrial respiratory chain disorders. Mutations in two mitochondrial encoded genes leading to mitochondrial respiratory chain disorder were identified in two patients. In the first case, MELAS syndrome caused by a mitochondrial DNA (mtDNA) mutation (m.3243A>G) was identified in an extended Amish pedigree following a presentation of metabolic strokes in the proband. Characterization of the extended family of the proband by a high resolution melting assay identified the same mutation in many previously undiagnosed family members with a wide range of clinical symptoms. A MELAS/Leigh syndrome phenotype caused by a mtDNA mutation [m.13513G>A; p.Asp393Asn] in the ND5 gene encoding the ND5 subunit of respiratory chain complex I was identified in a patient in a second family. Mutations in two nuclear encoded genes leading to mitochondrial respiratory chain disorder were also identified in two patients. One patient presented with Leigh syndrome and had a homozygous deletion in the NDUFAF2 gene, while the second patient had a homozygous mutation in the POLG gene, [c.1399G>A; p.Ala467Thr]. Our findings identify mitochondrial respiratory chain deficiency as a cause of disease in the Old Order Amish that must be considered in the context of otherwise unexplained systemic disease, especially if neuromuscular symptoms are present.
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Affiliation(s)
- Lina Ghaloul-Gonzalez
- Department of Pediatrics, School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, USA.
| | - Amy Goldstein
- Department of Pediatrics, School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, USA
| | - Catherine Walsh Vockley
- Department of Pediatrics, School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, USA
| | - Steven F Dobrowolski
- Department of Pathology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Amy Biery
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Afifa Irani
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jordan Ibarra
- University of Pittsburgh, School of Medicine, Pittsburgh, PA, USA
| | - D Holmes Morton
- Central Pennsylvania Clinic, A Medical Home for Special Children and Adults, Belleville, PA, USA
| | - Al-Walid Mohsen
- Department of Pediatrics, School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, USA
| | - Jerry Vockley
- Department of Pediatrics, School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, USA; Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
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19
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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.
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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
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20
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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.
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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
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21
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Zhou L, Palais RA, Paxton CN, Geiersbach KB, Wittwer CT. Copy Number Assessment by Competitive PCR with Limiting Deoxynucleotide Triphosphates and High-Resolution Melting. Clin Chem 2015; 61:724-33. [DOI: 10.1373/clinchem.2014.236208] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2014] [Accepted: 02/02/2015] [Indexed: 11/06/2022]
Abstract
Abstract
BACKGROUND
DNA copy number variation is associated with genetic disorders and cancer. Available methods to discern variation in copy number are typically costly, slow, require specialized equipment, and/or lack precision.
METHODS
Multiplex PCR with different primer pairs and limiting deoxynucleotide triphosphates (dNTPs) (3–12 μmol/L) were used for relative quantification and copy number assessment. Small PCR products (50–121 bp) were designed with 1 melting domain, well-separated Tms, minimal internal sequence variation, and no common homologs. PCR products were displayed as melting curves on derivative plots and normalized to the reference peak. Different copy numbers of each target clustered together and were grouped by unbiased hierarchical clustering.
RESULTS
Duplex PCR of a reference gene and a target gene was used to detect copy number variation in chromosomes X, Y, 13, 18, 21, epidermal growth factor receptor (EGFR), survival of motor neuron 1, telomeric (SMN1), and survival of motor neuron 2, centromeric (SMN2). Triplex PCR was used for X and Y and CFTR exons 2 and 3. Blinded studies of 50 potential trisomic samples (13, 18, 21, or normal) and 50 samples with potential sex chromosome abnormalities were concordant to karyotyping, except for 2 samples that were originally mosaics that displayed a single karyotype after growth. Large cystic fibrosis transmembrane conductance regulator (ATP-binding cassette sub-family C, member 7) (CFTR) deletions, EGFR amplifications, and SMN1 and SMN2 copy number assessments were also demonstrated. Under ideal conditions, copy number changes of 1.11-fold or lower could be discerned with CVs of about 1%.
CONCLUSIONS
Relative quantification by restricting the dNTP concentration with melting curve display is a simple and precise way to assess targeted copy number variation.
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Affiliation(s)
- Luming Zhou
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT
| | | | - Christian N Paxton
- ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT
| | - Katherine B Geiersbach
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT
- ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT
| | - Carl T Wittwer
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT
- ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT
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22
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Contreras-Capetillo SN, Blanco HLG, Cerda-Flores RM, Lugo-Trampe J, Torres-Muñoz I, Bravo-Oro A, Esmer C, DE Villarreal LEM. Frequency of SMN1 deletion carriers in a Mestizo population of central and northeastern Mexico: A pilot study. Exp Ther Med 2015; 9:2053-2058. [PMID: 26136935 DOI: 10.3892/etm.2015.2436] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 03/16/2015] [Indexed: 11/05/2022] Open
Abstract
Individuals who suffer from spinal muscular atrophy (SMA) exhibit progressive muscle weakness that frequently results in mortality in the most severe forms of the disease. In 98% of cases, there is a homozygous deletion of the survival of motor neuron 1 (SMN1) gene, and both parents carry the same heterozygous genetic abnormality in the majority of cases. Various population studies have been conducted to estimate the frequency of carriers and thereby identify the communities or countries in which children are at a high risk of being affected by SMA. However, the prevalence of SMA in Mexican populations has not yet been established. In the present pilot study, the frequency of the heterozygous deletion of the SMN1 gene was determined in two groups from northeastern (n=287) and central (n=133) Mexican Mestizo populations and compared with other ethnic populations. Amplification refractory mutation system polymerase chain reaction analysis yielded a disease carrier frequency of 11/420 (2.62%) healthy individuals, comprising 9/287 (3.14%) northeastern and 2/133 (1.5%) central Mexican individuals. In summary, no significant differences were identified between the northeastern and central populations of Mexico and other ethnic populations, with the exception of the general worldwide Hispanic population, which exhibited the lowest carrier frequency of 8/1,030. The results of the present study may be used to improve the evaluation procedure, and appear to justify further studies involving larger sample populations.
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Affiliation(s)
- Silvina Noemi Contreras-Capetillo
- Department of Genetics, Dr. Hideyo Noguchi Regional Research Center, Autonomous University of Yucatan, Mérida, Yucatán CP 97225, Mexico
| | | | | | - José Lugo-Trampe
- Department of Genetics, School of Medicine, Monterrey, Nuevo León CP 64460, Mexico
| | - Iris Torres-Muñoz
- Department of Genetics, School of Medicine, Monterrey, Nuevo León CP 64460, Mexico
| | - Antonio Bravo-Oro
- Neuropediatrics, Central Hospital 'Dr. Ignacio Morones Prieto', San Luis Potosí CP 78240, Mexico
| | - Carmen Esmer
- Department of Genetics, Central Hospital 'Dr. Ignacio Morones Prieto', San Luis Potosí CP 78240, Mexico
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Phan HC, Taylor JL, Hannon H, Howell R. Newborn screening for spinal muscular atrophy: Anticipating an imminent need. Semin Perinatol 2015; 39:217-29. [PMID: 25979781 DOI: 10.1053/j.semperi.2015.03.006] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Spinal muscular atrophy (SMA) is the most common genetic cause of infant mortality. Children with type I SMA typically die by the age of 2 years. Recent progress in gene modification and other innovative therapies suggest that improved outcomes may soon be forthcoming. In animal models, therapeutic intervention initiated before the loss of motor neurons alters SMA phenotype and increases lifespan. Presently, supportive care including respiratory, nutritional, physiatry, and orthopedic management can ameliorate clinical symptoms and improve survival rates if SMA is diagnosed early in life. Newborn screening could help optimize these potential benefits. A recent report demonstrated that SMA detection can be multiplexed at minimal additional cost with the assay for severe combined immunodeficiency, already implemented by many newborn screening programs. The public health community should remain alert to the rapidly changing developments in early detection and treatment of SMA.
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Affiliation(s)
- Han C Phan
- Department of Pediatrics, Emory University, Atlanta, GA.
| | | | - Harry Hannon
- Newborn Screening Consensus Committee, Clinical and Laboratory Standards Institute (CLSI), Wayne, PA
| | - Rodney Howell
- Miller School of Medicine, University of Miami, Miami, FL
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Therrell BL, Padilla CD, Loeber JG, Kneisser I, Saadallah A, Borrajo GJC, Adams J. Current status of newborn screening worldwide: 2015. Semin Perinatol 2015; 39:171-87. [PMID: 25979780 DOI: 10.1053/j.semperi.2015.03.002] [Citation(s) in RCA: 353] [Impact Index Per Article: 39.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Newborn screening describes various tests that can occur during the first few hours or days of a newborn's life and have the potential for preventing severe health problems, including death. Newborn screening has evolved from a simple blood or urine screening test to a more comprehensive and complex screening system capable of detecting over 50 different conditions. While a number of papers have described various newborn screening activities around the world, including a series of papers in 2007, a comprehensive review of ongoing activities since that time has not been published. In this report, we divide the world into 5 regions (North America, Europe, Middle East and North Africa, Latin America, and Asia Pacific), assessing the current NBS situation in each region and reviewing activities that have taken place in recent years. We have also provided an extensive reference listing and summary of NBS and health data in tabular form.
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Affiliation(s)
- Bradford L Therrell
- National Newborn Screening and Genetics Resource Center (NNSGRC), Austin, TX; Department of Pediatrics, University of Texas Health Science Center at San Antonio, San Antonio, TX.
| | - Carmencita David Padilla
- College of Medicine, University of the Philippines Manila, Manila, Philippines; Newborn Screening Reference Center, National Institutes of Health (Philippines), Manila, Ermita, Philippines
| | - J Gerard Loeber
- International Society for Neonatal Screening, Bilthoven, Netherlands
| | - Issam Kneisser
- Newborn Screening Unit, Medical Genetic Unit, Faculty of Medicine, Saint Joseph University, Beirut, Lebanon
| | - Amal Saadallah
- Newborn Screening and Biochemical Genetics Laboratory, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Gustavo J C Borrajo
- Programa de Detección de Errores Congénitos, Fundación Bioquímica Argentina, La Plata, Argentina
| | - John Adams
- Canadian Organization for Rare Disorders, Toronto, Ontario, Canada
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Taylor JL, Lee FK, Yazdanpanah GK, Staropoli JF, Liu M, Carulli JP, Sun C, Dobrowolski SF, Hannon WH, Vogt RF. Newborn blood spot screening test using multiplexed real-time PCR to simultaneously screen for spinal muscular atrophy and severe combined immunodeficiency. Clin Chem 2015; 61:412-9. [PMID: 25502182 PMCID: PMC7906865 DOI: 10.1373/clinchem.2014.231019] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is a motor neuron disorder caused by the absence of a functional survival of motor neuron 1, telomeric (SMN1) gene. Type I SMA, a lethal disease of infancy, accounts for the majority of cases. Newborn blood spot screening (NBS) to detect severe combined immunodeficiency (SCID) has been implemented in public health laboratories in the last 5 years. SCID detection is based on real-time PCR assays to measure T-cell receptor excision circles (TREC), a byproduct of T-cell development. We modified a multiplexed real-time PCR TREC assay to simultaneously determine the presence or absence of the SMN1 gene from a dried blood spot (DBS) punch in a single reaction well. METHOD An SMN1 assay using a locked nucleic acid probe was initially developed with cell culture and umbilical cord blood (UCB) DNA extracts, and then integrated into the TREC assay. DBS punches were placed in 96-well arrays, washed, and amplified directly using reagents specific for TREC, a reference gene [ribonuclease P/MRP 30kDa subunit (RPP30)], and the SMN1 gene. The assay was tested on DBS made from UCB units and from peripheral blood samples of SMA-affected individuals and their family members. RESULTS DBS made from SMA-affected individuals showed no SMN1-specific amplification, whereas DBS made from all unaffected carriers and UCB showed SMN1 amplification above a well-defined threshold. TREC and RPP30 content in all DBS were within the age-adjusted expected range. CONCLUSIONS SMA caused by the absence of SMN1 can be detected from the same DBS punch used to screen newborns for SCID.
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Affiliation(s)
- Jennifer L Taylor
- Newborn Screening and Molecular Biology Branch, Division of Laboratory Sciences, Centers for Disease Control and Prevention, Atlanta, GA
| | - Francis K Lee
- Newborn Screening and Molecular Biology Branch, Division of Laboratory Sciences, Centers for Disease Control and Prevention, Atlanta, GA
| | | | | | - Mei Liu
- Genetics and Genomics, Biogen Idec, Cambridge, MA
| | | | - Chao Sun
- Genetics and Genomics, Biogen Idec, Cambridge, MA
| | - Steven F Dobrowolski
- Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - W Harry Hannon
- Newborn Screening Translation Research Initiative, CDC Foundation, Atlanta, GA
| | - Robert F Vogt
- Newborn Screening and Molecular Biology Branch, Division of Laboratory Sciences, Centers for Disease Control and Prevention, Atlanta, GA;
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Wood MF, Hughes SC, Hache LP, Naylor EW, Abdel-Hamid HZ, Barmada MM, Dobrowolski SF, Stickler DE, Clemens PR. Parental attitudes toward newborn screening for Duchenne/Becker muscular dystrophy and spinal muscular atrophy. Muscle Nerve 2014; 49:822-8. [PMID: 24307279 DOI: 10.1002/mus.24100] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 10/10/2013] [Accepted: 10/14/2013] [Indexed: 11/11/2022]
Abstract
INTRODUCTION Disease inclusion in the newborn screening (NBS) panel should consider the opinions of those most affected by the outcome of screening. We assessed the level and factors that affect parent attitudes regarding NBS panel inclusion of Duchenne muscular dystrophy (DMD), Becker muscular dystrophy (BMD), and spinal muscular atrophy (SMA). METHODS The attitudes toward NBS for DMD, BMD, and SMA were surveyed and compared for 2 categories of parents, those with children affected with DMD, BMD, or SMA and expectant parents unselected for known family medical history. RESULTS The level of support for NBS for DMD, BMD, and SMA was 95.9% among parents of children with DMD, BMD, or SMA and 92.6% among expectant parents. CONCLUSIONS There was strong support for NBS for DMD, BMD, and SMA in both groups of parents. Given advances in diagnostics and promising therapeutic approaches, discussion of inclusion in NBS should continue.
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Affiliation(s)
- Molly F Wood
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Nurputra DK, Lai PS, Harahap NIF, Morikawa S, Yamamoto T, Nishimura N, Kubo Y, Takeuchi A, Saito T, Takeshima Y, Tohyama Y, Tay SKH, Low PS, Saito K, Nishio H. Spinal muscular atrophy: from gene discovery to clinical trials. Ann Hum Genet 2013; 77:435-63. [PMID: 23879295 DOI: 10.1111/ahg.12031] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 04/26/2013] [Indexed: 12/25/2022]
Abstract
Spinal muscular atrophy (SMA) is a common neuromuscular disorder with autosomal recessive inheritance, resulting in the degeneration of motor neurons. The incidence of the disease has been estimated at 1 in 6000-10,000 newborns with a carrier frequency of 1 in 40-60. SMA is caused by mutations of the SMN1 gene, located on chromosome 5q13. The gene product, survival motor neuron (SMN) plays critical roles in a variety of cellular activities. SMN2, a homologue of SMN1, is retained in all SMA patients and generates low levels of SMN, but does not compensate for the mutated SMN1. Genetic analysis demonstrates the presence of homozygous deletion of SMN1 in most patients, and allows screening of heterozygous carriers in affected families. Considering high incidence of carrier frequency in SMA, population-wide newborn and carrier screening has been proposed. Although no effective treatment is currently available, some treatment strategies have already been developed based on the molecular pathophysiology of this disease. Current treatment strategies can be classified into three major groups: SMN2-targeting, SMN1-introduction, and non-SMN targeting. Here, we provide a comprehensive and up-to-date review integrating advances in molecular pathophysiology and diagnostic testing with therapeutic developments for this disease including promising candidates from recent clinical trials.
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Affiliation(s)
- Dian K Nurputra
- Department of Community Medicine and Social Health Care, Kobe University Graduate School of Medicine, Kobe, Japan
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Rothwell E, Anderson RA, Swoboda KJ, Stark L, Botkin JR. Public attitudes regarding a pilot study of newborn screening for spinal muscular atrophy. Am J Med Genet A 2013; 161A:679-86. [PMID: 23443997 DOI: 10.1002/ajmg.a.35756] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2012] [Accepted: 10/11/2012] [Indexed: 11/12/2022]
Abstract
A population-based pilot study of newborns screening for a rare genetic condition, spinal muscular atrophy (SMA), is being conducted with funding from the National Institutes of Health. The first component of the study is to assess the ethical, legal, and social implications of population-based pilot studies with a focus on public engagement and parental decision-making for the proposed opt-out approach in this research. We conducted focus groups with members of the general public to ascertain attitudes about the pilot study and acceptability of an opt-out approach in two states, Colorado and Utah, where the pilot screening is being proposed (N = 70). We developed an informational video for the project and showed it to the groups prior to the discussion in order to inform participants about population-based research, newborn screening (NBS), permission/consent models, and SMA. Results indicated support for the conduct of pilot studies that is consistent with the current standard of practice for similar population-based programs. There was support for an opt-out approach for parental decision-making; however there was limited parental knowledge about population-based research, NBS and SMA. In general, our participants considered this pilot study to be low risk and of potential benefit to infants and families. The majority of participants were supportive of an opt-out approach with information delivered through various avenues
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Affiliation(s)
- Erin Rothwell
- College of Nursing, University of Utah, Salt Lake City, UT 84112, USA.
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Electrophysiological and motor function scale association in a pre-symptomatic infant with spinal muscular atrophy type I. Neuromuscul Disord 2012; 23:112-5. [PMID: 23146148 DOI: 10.1016/j.nmd.2012.09.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 09/06/2012] [Accepted: 09/26/2012] [Indexed: 11/20/2022]
Abstract
A term infant, at familial risk for spinal muscular atrophy (SMA), had the diagnosis genetically confirmed on day 3 of life. Clinical evaluation, the CHOP INTEND motor scale and the CMAP amplitude were obtained on days 5 (pre-symptomatic), 20 (mildly weak), 34 (moderately weak) and 63 (severely weak). Palliative care was provided and he expired of an acute pulmonary infection on day 81. The CMAP amplitude and INTEND scores were initially in the normal range, then followed a corresponding decline to a nadir at day 34 and remained so at the 4th assessment. A log-transformed plot of CMAP amplitude from days 5-34 was linear. These data suggest that early motor neuron loss in SMA type I may be logarithmic and demonstrates that the INTEND motor scale closely follows the CMAP electrophysiological biomarker. This single case report supports the consideration that early intervention with a potential therapy is necessary, before the pool of functional motor neurons has plummeted. Further study of these parameters in pre-symptomatic infants with SMA type I will help guide the design of future intervention studies.
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Er TK, Chang JG. High-resolution melting: applications in genetic disorders. Clin Chim Acta 2012; 414:197-201. [PMID: 22995429 DOI: 10.1016/j.cca.2012.09.012] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 09/08/2012] [Accepted: 09/08/2012] [Indexed: 12/16/2022]
Abstract
High-resolution melting (HRM) analysis is a feasible and powerful method for mutation scanning of sequence variants. Denatured doubled-stranded DNA can be detected in fluorescence changes by increasing the melting temperature and wild-type and heterozygous samples can be easily differentiated in the melting plots. HRM analysis represents the next generation of mutation-scanning technology and offers considerable time and cost savings compared to other screening methods. HRM analysis is a closed-tube method, indicating that polymerase chain reaction amplification and subsequent analysis are sequentially performed in the well, making HRM analysis more convenient than other scanning methodologies. Taken together, HRM analysis can be used for high-throughput mutation screening for research, as well as for molecular diagnostic and clinical purposes. This review summarizes the effectiveness of HRM analysis in the diagnosis of autosomal recessive, dominant, and X-linked genetic disorders. Notably, we will also discuss the limitations of HRM analysis and how to overcome them.
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Affiliation(s)
- Tze-Kiong Er
- Division of Molecular Diagnostics, Department of Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
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