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Ma K, Zhang K, Chen D, Wang C, Abdalla M, Zhang H, Tian R, Liu Y, Song L, Zhang X, Liu F, Liu G, Wang D. Real-world evidence: Risdiplam in a patient with spinal muscular atrophy type I with a novel splicing mutation and one SMN2 copy. Hum Mol Genet 2024:ddae052. [PMID: 38520738 DOI: 10.1093/hmg/ddae052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 03/08/2024] [Accepted: 03/08/2024] [Indexed: 03/25/2024] Open
Abstract
Spinal muscular atrophy (SMA), which results from the deletion or/and mutation in the SMN1 gene, is an autosomal recessive neuromuscular disorder that leads to weakness and muscle atrophy. SMN2 is a paralogous gene of SMN1. SMN2 copy number affects the severity of SMA, but its role in patients treated with disease modifying therapies is unclear. The most appropriate individualized treatment for SMA has not yet been determined. Here, we reported a case of SMA type I with normal breathing and swallowing function. We genetically confirmed that this patient had a compound heterozygous variant: one deleted SMN1 allele and a novel splice mutation c.628-3T>G in the retained allele, with one SMN2 copy. Patient-derived sequencing of 4 SMN1 cDNA clones showed that this intronic single transversion mutation results in an alternative exon (e)5 3' splice site, which leads to an additional 2 nucleotides (AG) at the 5' end of e5, thereby explaining why the patient with only one copy of SMN2 had a mild clinical phenotype. Additionally, a minigene assay of wild type and mutant SMN1 in HEK293T cells also demonstrated that this transversion mutation induced e5 skipping. Considering treatment cost and goals of avoiding pain caused by injections and starting treatment as early as possible, risdiplam was prescribed for this patient. However, the patient showed remarkable clinical improvements after treatment with risdiplam for 7 months despite carrying only one copy of SMN2. This study is the first report on the treatment of risdiplam in a patient with one SMN2 copy in a real-world setting. These findings expand the mutation spectrum of SMA and provide accurate genetic counseling information, as well as clarify the molecular mechanism of careful genotype-phenotype correlation of the patient.
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Affiliation(s)
- Kai Ma
- Pediatric Research Institute, Children's Hospital Affiliated to Shandong University, Jingshi road NO. 23976, Jinan, SD 250022, PR China
- Department of neurology, Children's Hospital Affiliated to Shandong University, Jingshi road NO. 23976, Jinan, SD 250022, PR China
| | - Kaihui Zhang
- Pediatric Research Institute, Children's Hospital Affiliated to Shandong University, Jingshi road NO. 23976, Jinan, SD 250022, PR China
| | - Defang Chen
- The Office of operation management committee, Central Hospital Affiliated to Shandong First Medical University, Jiefang road NO. 105, Jinan, SD 250022, PR China
| | - Chuan Wang
- Science, Education and Foreign Affairs Section, Children's Hospital Affiliated to Shandong University, Jingshi road NO. 23976, Jinan, SD 250022, PR China
| | - Mohnad Abdalla
- Pediatric Research Institute, Children's Hospital Affiliated to Shandong University, Jingshi road NO. 23976, Jinan, SD 250022, PR China
| | - Haozheng Zhang
- Pediatric Research Institute, Children's Hospital Affiliated to Shandong University, Jingshi road NO. 23976, Jinan, SD 250022, PR China
| | - Rujin Tian
- Pediatric Research Institute, Children's Hospital Affiliated to Shandong University, Jingshi road NO. 23976, Jinan, SD 250022, PR China
| | - Yang Liu
- Pediatric Research Institute, Children's Hospital Affiliated to Shandong University, Jingshi road NO. 23976, Jinan, SD 250022, PR China
- Ophthalmology department, Children's Hospital Affiliated to Shandong University, Jingshi road NO. 23976, Jinan, SD 250022, PR China
| | - Li Song
- Pediatric Hematology and Oncology, Children's Hospital Affiliated to Shandong University, Jingshi road NO. 23976, Jinan, SD 250022, PR China
| | - Xinyi Zhang
- Intensive Care Unit, The Second People's Hospital of Shandong Province, Duanxing west road NO. 4, Jinan, SD 250022, PR China
| | - Fangfang Liu
- Department of Ultrasound, Central Hospital Affiliated to Shandong First Medical University, Jiefang road NO. 105, Jinan, SD 250022, PR China
| | - Guohua Liu
- Ophthalmology department, Children's Hospital Affiliated to Shandong University, Jingshi road NO. 23976, Jinan, SD 250022, PR China
| | - Dong Wang
- Pediatric Research Institute, Children's Hospital Affiliated to Shandong University, Jingshi road NO. 23976, Jinan, SD 250022, PR China
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Audic F, Dubois SM, Durigneux J, Barnerias C, Isapof A, Nougues MC, Davion JB, Richelme C, Vuillerot C, Legoff L, Sabouraud P, Cances C, Laugel V, Ropars J, Espil-Taris C, Trommsdorff V, Pervillé A, Garcia-de-la-Banda MG, Testard H, Chouchane M, Walther-Louvier U, Schweizer C, Halbert C, Badri M, Quijano-Roy S, Chabrol B, Desguerre I. Effect of nusinersen after 3 years of treatment in 57 young children with SMA in terms of SMN2 copy number or type. Arch Pediatr 2024; 31:117-123. [PMID: 38135619 DOI: 10.1016/j.arcped.2023.10.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 10/20/2023] [Accepted: 10/21/2023] [Indexed: 12/24/2023]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is a rare genetic neuromuscular disorder due to an autosomal recessive mutation in the survival motor neuron 1 gene (SMN1), causing degeneration of the anterior horn cells of the spinal cord and resulting in muscle atrophy. This study aimed to report on the 36-month follow-up of children with SMA treated with nusinersen before the age of 3 years. Changes in motor function, nutritional and ventilatory support, and orthopedic outcomes were evaluated at baseline and 36 months after intrathecal administration of nusinersen and correlated with SMA type and SMN2 copy number. RESULTS We found that 93% of the patients gained new motor skills during the 3 years-standing without help for 12 of 37 and walking with help for 11 of 37 patients harboring three SMN2 copies. No patients with two copies of SMN2 can stand alone or walk. Patients bearing three copies of SMN2 are more likely to be spared from respiratory, nutritional, and orthopedic complications than patients with two SMN2 copies. CONCLUSION Children with SMA treated with nusinersen continue to make motor acquisitions at 3 years after initiation of treatment. Children with two SMN2 copies had worse motor, respiratory, and orthopedic outcomes after 3 years of treatment than children with three copies.
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Affiliation(s)
- Frédérique Audic
- Centre de Référence des Maladies Neuromusculaires de l'enfant PACARARE, Service de Neuropédiatrie, Hôpital Timone Enfants, 264 rue Saint Pierre, 13385, Marseille Cedex 5, France.
| | - Sonia M Dubois
- Centre de Référence des Maladies Neuromusculaires de l'enfant PACARARE, Service de Neuropédiatrie, Hôpital Timone Enfants, 264 rue Saint Pierre, 13385, Marseille Cedex 5, France
| | - Julien Durigneux
- Centre de Référence des Maladies Neuromusculaires AOC, CHU d'Angers, Angers, France
| | - Christine Barnerias
- Centre de Référence des Maladies Neuromusculaires Nord/Ile de France/Est, Service de Neurologie pédiatrique, Hôpital Necker-Enfants Malades, APHP, Paris, France
| | - Arnaud Isapof
- Centre de Référence des Maladies Neuromusculaires Nord/Ile de France/Est, Service de Neuropédiatrie, Hôpital Trousseau, APHP, Paris, France
| | - Marie-Christine Nougues
- Centre de Référence des Maladies Neuromusculaires Nord/Ile de France/Est, Service de Neuropédiatrie, Hôpital Trousseau, APHP, Paris, France
| | - Jean-Baptiste Davion
- Centre de Référence des Maladies Neuromusculaires Nord/Ile de France/Est, Service de Neuropédiatrie, Hôpital Salengro CHU Lille, Lille, France
| | - Christian Richelme
- Centre de Référence des Maladies Neuromusculaires PACARARE, Hôpitaux Pédiatriques de Nice CHU - Lenval, Nice, France
| | - Carole Vuillerot
- Centre de Référence des Maladies Neuromusculaires de l'enfant PACARARE, Service de MPR pédiatrique L'Escale Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Bron, France
| | - Laure Legoff
- Centre de Référence des Maladies Neuromusculaires de l'enfant PACARARE, Service de MPR pédiatrique L'Escale Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Bron, France
| | - Pascal Sabouraud
- Centre de Référence des Maladies Neuromusculaires Nord/Ile de France/Est, Site Reims enfant AMH, CHU Reims, Reims, France
| | - Claude Cances
- Centre de Référence des Maladies Neuromusculaires AOC, Unité de Neurologie Pédiatrique, Hôpital des Enfants CHU Toulouse, Toulouse, France
| | - Vincent Laugel
- Centre de Référence des Maladies Neuromusculaires Nord/Ile de France/Est, Pédiatrie médico-chirurgicale, CHU de Strasbourg - Hôpital de Hautepierre, Strasbourg, France
| | - Juliette Ropars
- Centre de Référence des Maladies Neuromusculaires AOC, Service de Pédiatrie, CHRU de Brest, Brest, France
| | - Caroline Espil-Taris
- Centre de Référence des Maladies Neuromusculaires AOC, Unité de Neurologie pédiatrique, CHU Pellegrin, Bordeaux, France
| | - Valérie Trommsdorff
- Centre de Référence des Maladies Neuromusculaires PACARARE, Service de Pédiatrie, CHU La Réunion, Saint-Pierre, France
| | - Anne Pervillé
- Centre de Compétence des Maladies Neuromusculaires PACARARE, Service de Pédiatrie, CHU La Réunion, Saint-Denis, France
| | - Marta Gomez Garcia-de-la-Banda
- Centre de Référence des Maladies Neuromusculaires Nord/Ile de France/Est, Hôpital Raymond Poincaré, APHP, Garches, France
| | - Hervé Testard
- Centre de Compétence des Maladies Neuromusculaires PACARARE, Neuropédiatrie, Clinique Universitaire Pédiatrique, Hôpital Couple Enfant - CHU Grenoble, Grenoble, France
| | - Mondher Chouchane
- Centre de Compétence des Maladies Neuromusculaires Nord/Ile de France/Est, Service de pédiatrie 1, Hôpital d'Enfants, CHU Dijon Bourgogne, Dijon, France
| | - Ulrike Walther-Louvier
- Centre de Référence des Maladies Neuromusculaires AOC, Service de Neuropédiatrie CHU Montpellier, Montpellier, France
| | - Cyril Schweizer
- Centre de Référence des Maladies Neuromusculaires Nord/Ile de France/Est, CHRU de Nancy, Hôpital d'Enfants, Vandoeuvre-Lès, Nancy, France
| | - Cécile Halbert
- Centre de Référence des Maladies Neuromusculaires de l'enfant PACARARE, Service de Neuropédiatrie, Hôpital Timone Enfants, 264 rue Saint Pierre, 13385, Marseille Cedex 5, France
| | - Myriam Badri
- Centre de Référence des Maladies Neuromusculaires de l'enfant PACARARE, Service de Neuropédiatrie, Hôpital Timone Enfants, 264 rue Saint Pierre, 13385, Marseille Cedex 5, France
| | - Susana Quijano-Roy
- Centre de Référence des Maladies Neuromusculaires Nord/Ile de France/Est, Hôpital Raymond Poincaré, APHP, Garches, France
| | - Brigitte Chabrol
- Centre de Référence des Maladies Neuromusculaires de l'enfant PACARARE, Service de Neuropédiatrie, Hôpital Timone Enfants, 264 rue Saint Pierre, 13385, Marseille Cedex 5, France
| | - Isabelle Desguerre
- Centre de Référence des Maladies Neuromusculaires Nord/Ile de France/Est, Service de Neurologie pédiatrique, Hôpital Necker-Enfants Malades, APHP, Paris, France
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Kiselev A, Maretina M, Shtykalova S, Al-Hilal H, Maslyanyuk N, Plokhih M, Serebryakova E, Frolova M, Shved N, Krylova N, Il’ina A, Freund S, Osinovskaya N, Sultanov I, Egorova A, Lobenskaya A, Koroteev A, Sosnina I, Gorelik Y, Bespalova O, Baranov V, Kogan I, Glotov A. Establishment of a Pilot Newborn Screening Program for Spinal Muscular Atrophy in Saint Petersburg. Int J Neonatal Screen 2024; 10:9. [PMID: 38390973 PMCID: PMC10885106 DOI: 10.3390/ijns10010009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 01/16/2024] [Accepted: 01/22/2024] [Indexed: 02/24/2024] Open
Abstract
Spinal muscular atrophy 5q (SMA) is one of the most common neuromuscular inherited diseases and is the most common genetic cause of infant mortality. SMA is associated with homozygous deletion of exon 7 in the SMN1 gene. Recently developed drugs can improve the motor functions of infants with SMA when they are treated in the pre-symptomatic stage. With aim of providing an early diagnosis, newborn screening (NBS) for SMA using a real-time PCR assay with dried blood spots (DBS) was performed from January 2022 through November 2022 in Saint Petersburg, which is a representative Russian megapolis. Here, 36,140 newborns were screened by the GenomeX real-time PCR-based screening test, and three genotypes were identified: homozygous deletion carriers (4 newborns), heterozygous carriers (772 newborns), and wild-type individuals (35,364 newborns). The disease status of all four newborns that screened positive for the homozygous SMN1 deletion was confirmed by alternate methods. Two of the newborns had two copies of SMN2, and two of the newborns had three copies. We determined the incidence of spinal muscular atrophy in Saint Petersburg to be 1 in 9035 and the SMA carrier frequency to be 1 in 47. In conclusion, providing timely information regarding SMN1, confirmation of disease status, and SMN2 copy number as part of the SMA newborn-screening algorithm can significantly improve clinical follow-up, testing of family members, and treatment of patients with SMA.
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Affiliation(s)
- Anton Kiselev
- Department of Genomic Medicine Named after V.S. Baranov, D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya Line 3, 199034 Saint Petersburg, Russia; (M.M.); (S.S.); (H.A.-H.); (N.M.); (M.P.); (E.S.); (N.S.); (N.K.); (A.I.); (S.F.); (I.S.); (A.E.); (O.B.); (I.K.); (A.G.)
| | - Marianna Maretina
- Department of Genomic Medicine Named after V.S. Baranov, D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya Line 3, 199034 Saint Petersburg, Russia; (M.M.); (S.S.); (H.A.-H.); (N.M.); (M.P.); (E.S.); (N.S.); (N.K.); (A.I.); (S.F.); (I.S.); (A.E.); (O.B.); (I.K.); (A.G.)
| | - Sofia Shtykalova
- Department of Genomic Medicine Named after V.S. Baranov, D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya Line 3, 199034 Saint Petersburg, Russia; (M.M.); (S.S.); (H.A.-H.); (N.M.); (M.P.); (E.S.); (N.S.); (N.K.); (A.I.); (S.F.); (I.S.); (A.E.); (O.B.); (I.K.); (A.G.)
| | - Haya Al-Hilal
- Department of Genomic Medicine Named after V.S. Baranov, D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya Line 3, 199034 Saint Petersburg, Russia; (M.M.); (S.S.); (H.A.-H.); (N.M.); (M.P.); (E.S.); (N.S.); (N.K.); (A.I.); (S.F.); (I.S.); (A.E.); (O.B.); (I.K.); (A.G.)
| | - Natalia Maslyanyuk
- Department of Genomic Medicine Named after V.S. Baranov, D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya Line 3, 199034 Saint Petersburg, Russia; (M.M.); (S.S.); (H.A.-H.); (N.M.); (M.P.); (E.S.); (N.S.); (N.K.); (A.I.); (S.F.); (I.S.); (A.E.); (O.B.); (I.K.); (A.G.)
| | - Mariya Plokhih
- Department of Genomic Medicine Named after V.S. Baranov, D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya Line 3, 199034 Saint Petersburg, Russia; (M.M.); (S.S.); (H.A.-H.); (N.M.); (M.P.); (E.S.); (N.S.); (N.K.); (A.I.); (S.F.); (I.S.); (A.E.); (O.B.); (I.K.); (A.G.)
| | - Elena Serebryakova
- Department of Genomic Medicine Named after V.S. Baranov, D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya Line 3, 199034 Saint Petersburg, Russia; (M.M.); (S.S.); (H.A.-H.); (N.M.); (M.P.); (E.S.); (N.S.); (N.K.); (A.I.); (S.F.); (I.S.); (A.E.); (O.B.); (I.K.); (A.G.)
- Saint Petersburg State Medical Diagnostic Center (Genetic Medical Center), Tobolskaya Street 5, 353912 Saint Petersburg, Russia; (M.F.); (A.L.); (A.K.)
| | - Marina Frolova
- Saint Petersburg State Medical Diagnostic Center (Genetic Medical Center), Tobolskaya Street 5, 353912 Saint Petersburg, Russia; (M.F.); (A.L.); (A.K.)
| | - Natalia Shved
- Department of Genomic Medicine Named after V.S. Baranov, D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya Line 3, 199034 Saint Petersburg, Russia; (M.M.); (S.S.); (H.A.-H.); (N.M.); (M.P.); (E.S.); (N.S.); (N.K.); (A.I.); (S.F.); (I.S.); (A.E.); (O.B.); (I.K.); (A.G.)
| | - Nadezhda Krylova
- Department of Genomic Medicine Named after V.S. Baranov, D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya Line 3, 199034 Saint Petersburg, Russia; (M.M.); (S.S.); (H.A.-H.); (N.M.); (M.P.); (E.S.); (N.S.); (N.K.); (A.I.); (S.F.); (I.S.); (A.E.); (O.B.); (I.K.); (A.G.)
| | - Arina Il’ina
- Department of Genomic Medicine Named after V.S. Baranov, D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya Line 3, 199034 Saint Petersburg, Russia; (M.M.); (S.S.); (H.A.-H.); (N.M.); (M.P.); (E.S.); (N.S.); (N.K.); (A.I.); (S.F.); (I.S.); (A.E.); (O.B.); (I.K.); (A.G.)
| | - Svetlana Freund
- Department of Genomic Medicine Named after V.S. Baranov, D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya Line 3, 199034 Saint Petersburg, Russia; (M.M.); (S.S.); (H.A.-H.); (N.M.); (M.P.); (E.S.); (N.S.); (N.K.); (A.I.); (S.F.); (I.S.); (A.E.); (O.B.); (I.K.); (A.G.)
| | - Natalia Osinovskaya
- Department of Genomic Medicine Named after V.S. Baranov, D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya Line 3, 199034 Saint Petersburg, Russia; (M.M.); (S.S.); (H.A.-H.); (N.M.); (M.P.); (E.S.); (N.S.); (N.K.); (A.I.); (S.F.); (I.S.); (A.E.); (O.B.); (I.K.); (A.G.)
| | - Iskender Sultanov
- Department of Genomic Medicine Named after V.S. Baranov, D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya Line 3, 199034 Saint Petersburg, Russia; (M.M.); (S.S.); (H.A.-H.); (N.M.); (M.P.); (E.S.); (N.S.); (N.K.); (A.I.); (S.F.); (I.S.); (A.E.); (O.B.); (I.K.); (A.G.)
| | - Anna Egorova
- Department of Genomic Medicine Named after V.S. Baranov, D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya Line 3, 199034 Saint Petersburg, Russia; (M.M.); (S.S.); (H.A.-H.); (N.M.); (M.P.); (E.S.); (N.S.); (N.K.); (A.I.); (S.F.); (I.S.); (A.E.); (O.B.); (I.K.); (A.G.)
| | - Anastasia Lobenskaya
- Saint Petersburg State Medical Diagnostic Center (Genetic Medical Center), Tobolskaya Street 5, 353912 Saint Petersburg, Russia; (M.F.); (A.L.); (A.K.)
| | - Alexander Koroteev
- Saint Petersburg State Medical Diagnostic Center (Genetic Medical Center), Tobolskaya Street 5, 353912 Saint Petersburg, Russia; (M.F.); (A.L.); (A.K.)
| | - Irina Sosnina
- Saint Petersburg State Budgetary Healthcare Institution “Consulting and Diagnostic Center for Children”, Aleksa Dundić Street 36/2, 192289 Saint Petersburg, Russia;
| | - Yulia Gorelik
- Children’s City Multidisciplinary Clinical Specialized Center of High Medical Technologies, Avangardnaya Street 14, 198205 Saint Petersburg, Russia;
| | - Olesya Bespalova
- Department of Genomic Medicine Named after V.S. Baranov, D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya Line 3, 199034 Saint Petersburg, Russia; (M.M.); (S.S.); (H.A.-H.); (N.M.); (M.P.); (E.S.); (N.S.); (N.K.); (A.I.); (S.F.); (I.S.); (A.E.); (O.B.); (I.K.); (A.G.)
| | - Vladislav Baranov
- Department of Genomic Medicine Named after V.S. Baranov, D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya Line 3, 199034 Saint Petersburg, Russia; (M.M.); (S.S.); (H.A.-H.); (N.M.); (M.P.); (E.S.); (N.S.); (N.K.); (A.I.); (S.F.); (I.S.); (A.E.); (O.B.); (I.K.); (A.G.)
| | - Igor Kogan
- Department of Genomic Medicine Named after V.S. Baranov, D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya Line 3, 199034 Saint Petersburg, Russia; (M.M.); (S.S.); (H.A.-H.); (N.M.); (M.P.); (E.S.); (N.S.); (N.K.); (A.I.); (S.F.); (I.S.); (A.E.); (O.B.); (I.K.); (A.G.)
| | - Andrey Glotov
- Department of Genomic Medicine Named after V.S. Baranov, D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya Line 3, 199034 Saint Petersburg, Russia; (M.M.); (S.S.); (H.A.-H.); (N.M.); (M.P.); (E.S.); (N.S.); (N.K.); (A.I.); (S.F.); (I.S.); (A.E.); (O.B.); (I.K.); (A.G.)
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4
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Nagy ZF, Pál M, Engelhardt JI, Molnár MJ, Klivényi P, Széll M. Beyond C9orf72: repeat expansions and copy number variations as risk factors of amyotrophic lateral sclerosis across various populations. BMC Med Genomics 2024; 17:30. [PMID: 38254109 PMCID: PMC10804878 DOI: 10.1186/s12920-024-01807-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 01/11/2024] [Indexed: 01/24/2024] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder which is characterized by the loss of both upper and lower motor neurons in the central nervous system. In a significant fraction of ALS cases - irrespective of family history- a genetic background may be identified. The genetic background of ALS shows a high variability from one ethnicity to another. The most frequent genetic cause of ALS is the repeat expansion of the C9orf72 gene. With the emergence of next-generation sequencing techniques and copy number alteration calling tools the focus in ALS genetics has shifted from disease causing genes and mutations towards genetic susceptibility and risk factors.In this review we aimed to summarize the most widely recognized and studied ALS linked repeat expansions and copy number variations other than the hexanucleotide repeat expansion in the C9orf72 gene. We compare and contrast their involvement and phenotype modifying roles in ALS among different populations.
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Affiliation(s)
- Zsófia Flóra Nagy
- Department of Medical Genetics, University of Szeged, Szeged, Hungary.
- Institute of Genomic Medicine and Rare Disorders, Semmelweis University, Budapest, Hungary.
| | - Margit Pál
- Department of Medical Genetics, University of Szeged, Szeged, Hungary
- HUN-REN - SZTE Functional Clinical Genetics Research Group, Szeged, Hungary
| | | | - Mária Judit Molnár
- Institute of Genomic Medicine and Rare Disorders, Semmelweis University, Budapest, Hungary
- HUN-REN-SE Multiomics Neurodegeneration Research Group, Budapest, Hungary
| | - Péter Klivényi
- Department of Neurology, University of Szeged, Szeged, Hungary
| | - Márta Széll
- Department of Medical Genetics, University of Szeged, Szeged, Hungary
- HUN-REN - SZTE Functional Clinical Genetics Research Group, Szeged, Hungary
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5
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Bouike Y, Sakima M, Taninishi Y, Matsutani T, Noguchi Y, Bo R, Awano H, Nishio H. Real-Time PCR-Based Screening for Homozygous SMN2 Deletion Using Residual Dried Blood Spots. Genes (Basel) 2023; 14:2159. [PMID: 38136980 PMCID: PMC10742981 DOI: 10.3390/genes14122159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 11/23/2023] [Accepted: 11/27/2023] [Indexed: 12/24/2023] Open
Abstract
The survival motor neuron 2 (SMN2) gene is a recognized modifier gene of spinal muscular atrophy (SMA). However, our knowledge about the role of SMN2-other than its modification of SMA phenotypes-is very limited. Discussions regarding the relationship between homozygous SMN2 deletion and motor neuron diseases, including amyotrophic lateral sclerosis, have been mainly based on retrospective epidemiological studies of the diseases, and the precise relationship remains inconclusive. In the present study, we first estimated that the frequency of homozygous SMN2 deletion was ~1 in 20 in Japan. We then established a real-time polymerase chain reaction (PCR)-based screening method using residual dried blood spots to identify infants with homozygous SMN2 deletion. This method can be applied to a future prospective cohort study to clarify the relationship between homozygous SMN2 deletion and motor neuron diseases. In our real-time PCR experiment, both PCR (low annealing temperatures) and blood (high hematocrit values and low white blood cell counts) conditions were associated with incorrect results (i.e., false negatives and positives). Together, our findings not only help to elucidate the role of SMN2, but also aid in our understanding of the pitfalls of current SMA newborn screening programs for detecting homozygous SMN1 deletions.
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Affiliation(s)
- Yoshihiro Bouike
- Faculty of Nutrition, Kobe Gakuin University, 518 Arise, Ikawadani-cho, Nishi-ku, Kobe 651-2180, Japan; (Y.B.); (M.S.); (Y.T.)
| | - Makoto Sakima
- Faculty of Nutrition, Kobe Gakuin University, 518 Arise, Ikawadani-cho, Nishi-ku, Kobe 651-2180, Japan; (Y.B.); (M.S.); (Y.T.)
| | - Yuya Taninishi
- Faculty of Nutrition, Kobe Gakuin University, 518 Arise, Ikawadani-cho, Nishi-ku, Kobe 651-2180, Japan; (Y.B.); (M.S.); (Y.T.)
| | - Takanori Matsutani
- Division of Physiology, Shinko Hospital, 1-4-47 Wakinohama-cho, Chuo-ku, Kobe 651-0072, Japan;
| | - Yoriko Noguchi
- Department of Clinical Laboratory, Kobe University Hospital, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan;
| | - Ryosuke Bo
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan;
| | - Hiroyuki Awano
- Organization for Research Initiative and Promotion, Research Initiative Center, Tottori University, 86 Nishi-cho, Yonago 683-8503, Japan;
| | - Hisahide Nishio
- Department of Occupational Therapy, Faculty of Rehabilitation, Kobe Gakuin University, 518 Arise, Ikawadani-cho, Nishi-ku, Kobe 651-2180, Japan
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Fonseca H, Ribeiro D, Guimarães F, Pinto C, Marcão A, Sousa C, Carvalho I, Lopes L, Rodrigues D, Rocha H, Vilarinho L. Pilot Study on Newborn Screening for Spinal Muscular Atrophy. Endocr Metab Immune Disord Drug Targets 2023; 23:EMIDDT-EPUB-134556. [PMID: 37711122 DOI: 10.2174/1871530323666230914122955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 08/17/2023] [Indexed: 09/16/2023]
Abstract
INTRODUCTION Newborn screening (NBS) in Portugal is a significant public health measure to provide early detection for specific disorders so that early treatment is possible. Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder that causes degeneration of anterior horn cells in the human spinal cord and subsequent loss of motor neurons. Its incidence is estimated in 1.6000-11.800 live births. A pilot study on 100.000 newborns is being carried out at the neonatal screening laboratory with the aim of determining the specificity, sensitivity, and feasibility of the SMA screening at the NBS laboratory in Portugal. METHODS The study presented here was based on data obtained from neonatal screening, involving the analysis of 25.000 newborns. SMA screening is performed by a qualitative detection of exon 7 of the SMN1 gene. The assay was performed using a commercially available real-time PCR, the Eonis SMN1, TREC, and KREC kit. RESULTS/CASE REPORT The dried blood spots of a total of 25.000 newborns were tested; among these newborns, two were diagnosed as having SMA with survival motor neuron 1 (SMN1) deletion. These two SMA-positive samples were sent to a specialized clinical centre and a peripheral blood sample was sent to the reference laboratory for confirmation of the exon 7 deletion and determination of the SMN2 copy number. CONCLUSION Early diagnosis and intervention are important for SMA treatment to be effective; the treatment should be started at the pre-symptomatic stage of SMA. Thus, newborn screening for SMA is strongly recommended. Currently, targeted therapies for SMA are available, and attempts are being made worldwide to include SMA screening in newborns.
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Affiliation(s)
- Helena Fonseca
- Unidade de Rastreio Neonatal Metabolismo e Genética, INSA, Porto, Portugal
| | - Diogo Ribeiro
- Unidade de Rastreio Neonatal Metabolismo e Genética, INSA, Porto, Portugal
| | - Fabio Guimarães
- Unidade de Rastreio Neonatal Metabolismo e Genética, INSA, Porto, Portugal
| | - Conceição Pinto
- Unidade de Rastreio Neonatal Metabolismo e Genética, INSA, Porto, Portugal
| | - Ana Marcão
- Unidade de Rastreio Neonatal Metabolismo e Genética, INSA, Porto, Portugal
| | - Carmen Sousa
- Unidade de Rastreio Neonatal Metabolismo e Genética, INSA, Porto, Portugal
| | - Ivone Carvalho
- Unidade de Rastreio Neonatal Metabolismo e Genética, INSA, Porto, Portugal
| | - Lurdes Lopes
- Unidade de Rastreio Neonatal Metabolismo e Genética, INSA, Porto, Portugal
| | - Diogo Rodrigues
- Unidade de Rastreio Neonatal Metabolismo e Genética, INSA, Porto, Portugal
| | - Hugo Rocha
- Unidade de Rastreio Neonatal Metabolismo e Genética, INSA, Porto, Portugal
| | - Laura Vilarinho
- Unidade de Rastreio Neonatal Metabolismo e Genética, INSA, Porto, Portugal
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Recinos Y, Ustianenko D, Yeh YT, Wang X, Jacko M, Yesantharao LV, Wu Q, Zhang C. Deep screening of proximal and distal splicing-regulatory elements in a native sequence context. bioRxiv 2023:2023.08.21.554109. [PMID: 37662340 PMCID: PMC10473672 DOI: 10.1101/2023.08.21.554109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Pre-mRNA splicing, a key process in gene expression, can be therapeutically modulated using various drug modalities, including antisense oligonucleotides (ASOs). However, determining promising targets is impeded by the challenge of systematically mapping splicing-regulatory elements (SREs) in their native sequence context. Here, we use the catalytically dead CRISPR-RfxCas13d RNA-targeting system (dCas13d/gRNA) as a programmable platform to bind SREs and modulate splicing by competing against endogenous splicing factors. SpliceRUSH, a high-throughput screening method, was developed to map SREs in any gene of interest using a lentivirus gRNA library that tiles the genetic region, including distal intronic sequences. When applied to SMN2, a therapeutic target for spinal muscular atrophy, SpliceRUSH robustly identified not only known SREs, but also a novel distal intronic splicing enhancer, which can be targeted to alter exon 7 splicing using either dCas13d/gRNA or ASOs. This technology enables a deeper understanding of splicing regulation with applications for RNA-based drug discovery.
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Affiliation(s)
- Yocelyn Recinos
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
| | - Dmytro Ustianenko
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
- Present address: Flagship Pioneering, Cambridge, MA 02142, USA
| | - Yow-Tyng Yeh
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
| | - Xiaojian Wang
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
| | - Martin Jacko
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
- Present address: Aperture Therapeutics, Inc., San Carlos, CA 94070, USA
| | - Lekha V. Yesantharao
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
- Present address: Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Qiyang Wu
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
| | - Chaolin Zhang
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
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Nishio H, Niba ETE, Saito T, Okamoto K, Takeshima Y, Awano H. Spinal Muscular Atrophy: The Past, Present, and Future of Diagnosis and Treatment. Int J Mol Sci 2023; 24:11939. [PMID: 37569314 PMCID: PMC10418635 DOI: 10.3390/ijms241511939] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/17/2023] [Accepted: 07/21/2023] [Indexed: 08/13/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a lower motor neuron disease with autosomal recessive inheritance. The first cases of SMA were reported by Werdnig in 1891. Although the phenotypic variation of SMA led to controversy regarding the clinical entity of the disease, the genetic homogeneity of SMA was proved in 1990. Five years later, in 1995, the gene responsible for SMA, SMN1, was identified. Genetic testing of SMN1 has enabled precise epidemiological studies, revealing that SMA occurs in 1 of 10,000 to 20,000 live births and that more than 95% of affected patients are homozygous for SMN1 deletion. In 2016, nusinersen was the first drug approved for treatment of SMA in the United States. Two other drugs were subsequently approved: onasemnogene abeparvovec and risdiplam. Clinical trials with these drugs targeting patients with pre-symptomatic SMA (those who were diagnosed by genetic testing but showed no symptoms) revealed that such patients could achieve the milestones of independent sitting and/or walking. Following the great success of these trials, population-based newborn screening programs for SMA (more precisely, SMN1-deleted SMA) have been increasingly implemented worldwide. Early detection by newborn screening and early treatment with new drugs are expected to soon become the standards in the field of SMA.
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Affiliation(s)
- Hisahide Nishio
- Faculty of Rehabilitation, Kobe Gakuin University, 518 Arise, Ikawadani-cho, Nishi-ku, Kobe 651-2180, Japan
| | - Emma Tabe Eko Niba
- Laboratory of Molecular and Biochemical Research, Biomedical Research Core Facilities, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan;
| | - Toshio Saito
- Department of Neurology, National Hospital Organization Osaka Toneyama Medical Center, 5-1-1 Toneyama, Toyonaka 560-8552, Japan;
| | - Kentaro Okamoto
- Department of Pediatrics, Ehime Prefectural Imabari Hospital, 4-5-5 Ishi-cho, Imabari 794-0006, Japan;
| | - Yasuhiro Takeshima
- Department of Pediatrics, Hyogo Medical University, 1-1 Mukogawacho, Nishinomiya 663-8501, Japan;
| | - Hiroyuki Awano
- Organization for Research Initiative and Promotion, Research Initiative Center, Tottori University, 86 Nishi-cho, Yonago 683-8503, Japan;
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De Siqueira Carvalho AA, Tychon C, Servais L. Newborn screening for spinal muscular atrophy - what have we learned? Expert Rev Neurother 2023; 23:1005-1012. [PMID: 37635694 DOI: 10.1080/14737175.2023.2252179] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/20/2023] [Accepted: 08/22/2023] [Indexed: 08/29/2023]
Abstract
INTRODUCTION Over the last decade, the treatment of spinal muscular atrophy (SMA) has become a paradigm of the importance of early and accurate diagnosis and prompt treatment. Three different therapeutic approaches that aims to increase SMN protein are approved now by Food and Drug Administration (FDA) and European Medicines Agency (EMA) for treatment of SMA; their efficacies have been demonstrated in pivotal trials. AREAS COVERED The authors report on the two controlled studies and real-world evidence that have demonstrated that the treatment of patients pre-symptomatically ensures normal or only slightly sub-normal motor development in children who would otherwise develop a severe form of the disease. Furthermore, the authors highlight the several newborn screening (NBS) methods that are now available, all of which are based on real-time PCR, that reliably and robustly diagnose SMA except in subjects with disease caused by a point mutation. EXPERT OPINION Pre-symptomatic treatment of SMA has been clearly demonstrated to prevent the most severe forms of the disease. NBS constitutes more than a simple test and should be considered as a global process to accelerate treatment access and provide global management of patients and parents. Even though the cost of NBS is low and health economics studies have clearly demonstrated its value, the fear of identifying more patients than the system can treat is often reported in large middle-income countries.
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Affiliation(s)
| | - Cyril Tychon
- Neuromuscular Reference Center, Department of Paediatrics, University and University Hospital of Liege, Liege, Belgium
| | - Laurent Servais
- Neuromuscular Reference Center, Department of Paediatrics, University and University Hospital of Liege, Liege, Belgium
- MDUK Oxford Neuromuscular Centre & NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, UK
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Yalcintepe S, Karal Y, Demir S, Atli EI, Atli E, Eker D, Mail C, Zhuri D, Guler HS, Gurkan H. The Frequency of SMN1, SMN2 Copy Numbers in 246 Turkish Cases Analyzed with MLPA Method. Glob Med Genet 2023; 10:117-122. [PMID: 37332684 PMCID: PMC10275673 DOI: 10.1055/s-0043-1770055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2023] Open
Abstract
This study aimed to define the copy numbers of SMN1 and SMN2 genes and the diagnosis rate and carrier frequency of spinal muscular atrophy (SMA) in the Thrace region of Turkey. In this study, the frequency of deletions in exons 7 and 8 in the SMN1 gene and SMN2 copy numbers were investigated. A total of 133 cases with the preliminary diagnosis of SMA and 113 cases with the suspicion of being an SMA carrier from independent families were analyzed by multiplex ligation-dependent probe amplification method for SMN1 and SMN2 gene copy numbers. SMN1 homozygous deletions were detected in 34 patients (25.5%) of 133 cases with the suspicion of SMA. Cases diagnosed with SMA type I was 41.17% (14/34), 29.4% (10/34) with type II, 26.4% (9/34) with type III, and 2.94% (1/34) with type IV. The SMA carrier rate was 46.01% in 113 cases. In 34 SMA cases, SMN2 copy numbers were: two copies - 28 cases (82.3%), three copies - 6 cases (17.6%). SMN2 homozygous deletions were detected in 15% (17/113) of carrier analysis cases. The consanguinity rate of the parents was 23.5% in SMA diagnosed cases. In this study, we had a 25.5% of SMA diagnosis rate and 46% SMA carrier frequency. The current study also showed the relatively low consanguinity rate of the Thrace region, with 23.5% according to the east of Turkey.
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Affiliation(s)
- Sinem Yalcintepe
- Department of Medical Genetics, Faculty of Medicine, Trakya University, Edirne, Turkey
| | - Yasemin Karal
- Department of Pediatric Neurology, Faculty of Medicine, Trakya University, Edirne, Turkey
| | - Selma Demir
- Department of Medical Genetics, Faculty of Medicine, Trakya University, Edirne, Turkey
| | - Emine Ikbal Atli
- Department of Medical Genetics, Faculty of Medicine, Trakya University, Edirne, Turkey
| | - Engin Atli
- Department of Medical Genetics, Faculty of Medicine, Trakya University, Edirne, Turkey
| | - Damla Eker
- Department of Medical Genetics, Faculty of Medicine, Trakya University, Edirne, Turkey
| | - Cisem Mail
- Department of Medical Genetics, Faculty of Medicine, Trakya University, Edirne, Turkey
| | - Drenushe Zhuri
- Department of Medical Genetics, Faculty of Medicine, Trakya University, Edirne, Turkey
| | - Hazal Sezginer Guler
- Department of Medical Genetics, Faculty of Medicine, Trakya University, Edirne, Turkey
| | - Hakan Gurkan
- Department of Medical Genetics, Faculty of Medicine, Trakya University, Edirne, Turkey
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Strathmann EA, Hölker I, Tschernoster N, Hosseinibarkooie S, Come J, Martinat C, Altmüller J, Wirth B. Epigenetic regulation of plastin 3 expression by the macrosatellite DXZ4 and the transcriptional regulator CHD4. Am J Hum Genet 2023; 110:442-459. [PMID: 36812914 PMCID: PMC10027515 DOI: 10.1016/j.ajhg.2023.02.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 02/03/2023] [Indexed: 02/23/2023] Open
Abstract
Dysregulated Plastin 3 (PLS3) levels associate with a wide range of skeletal and neuromuscular disorders and the most common types of solid and hematopoietic cancer. Most importantly, PLS3 overexpression protects against spinal muscular atrophy. Despite its crucial role in F-actin dynamics in healthy cells and its involvement in many diseases, the mechanisms that regulate PLS3 expression are unknown. Interestingly, PLS3 is an X-linked gene and all asymptomatic SMN1-deleted individuals in SMA-discordant families who exhibit PLS3 upregulation are female, suggesting that PLS3 may escape X chromosome inactivation. To elucidate mechanisms contributing to PLS3 regulation, we performed a multi-omics analysis in two SMA-discordant families using lymphoblastoid cell lines and iPSC-derived spinal motor neurons originated from fibroblasts. We show that PLS3 tissue-specifically escapes X-inactivation. PLS3 is located ∼500 kb proximal to the DXZ4 macrosatellite, which is essential for X chromosome inactivation. By applying molecular combing in a total of 25 lymphoblastoid cell lines (asymptomatic individuals, individuals with SMA, control subjects) with variable PLS3 expression, we found a significant correlation between the copy number of DXZ4 monomers and PLS3 levels. Additionally, we identified chromodomain helicase DNA binding protein 4 (CHD4) as an epigenetic transcriptional regulator of PLS3 and validated co-regulation of the two genes by siRNA-mediated knock-down and overexpression of CHD4. We show that CHD4 binds the PLS3 promoter by performing chromatin immunoprecipitation and that CHD4/NuRD activates the transcription of PLS3 by dual-luciferase promoter assays. Thus, we provide evidence for a multilevel epigenetic regulation of PLS3 that may help to understand the protective or disease-associated PLS3 dysregulation.
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Affiliation(s)
- Eike A Strathmann
- Institute of Human Genetics, University Hospital of Cologne, University Cologne, Kerpener Str. 34, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany
| | - Irmgard Hölker
- Institute of Human Genetics, University Hospital of Cologne, University Cologne, Kerpener Str. 34, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany
| | - Nikolai Tschernoster
- Institute of Human Genetics, University Hospital of Cologne, University Cologne, Kerpener Str. 34, 50931 Cologne, Germany; Cologne Center for Genomics and West German Genome Center, University of Cologne, 50931 Cologne, Germany
| | - Seyyedmohsen Hosseinibarkooie
- Institute of Human Genetics, University Hospital of Cologne, University Cologne, Kerpener Str. 34, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany
| | - Julien Come
- INSERM/ UEVE UMR 861, Université Paris Saclay, I-STEM, 91100 Corbeil-Essonnes, France
| | - Cecile Martinat
- INSERM/ UEVE UMR 861, Université Paris Saclay, I-STEM, 91100 Corbeil-Essonnes, France
| | - Janine Altmüller
- Cologne Center for Genomics and West German Genome Center, University of Cologne, 50931 Cologne, Germany
| | - Brunhilde Wirth
- Institute of Human Genetics, University Hospital of Cologne, University Cologne, Kerpener Str. 34, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany; Center for Rare Diseases, University Hospital of Cologne, 50931 Cologne, Germany.
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Muiños-Bühl A, Rombo R, Ling KK, Zilio E, Rigo F, Bennett CF, Wirth B. Long-Term SMN- and Ncald-ASO Combinatorial Therapy in SMA Mice and NCALD-ASO Treatment in hiPSC-Derived Motor Neurons Show Protective Effects. Int J Mol Sci 2023; 24:ijms24044198. [PMID: 36835624 PMCID: PMC9961752 DOI: 10.3390/ijms24044198] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/17/2023] [Accepted: 02/19/2023] [Indexed: 02/22/2023] Open
Abstract
For SMA patients with only two SMN2 copies, available therapies might be insufficient to counteract lifelong motor neuron (MN) dysfunction. Therefore, additional SMN-independent compounds, supporting SMN-dependent therapies, might be beneficial. Neurocalcin delta (NCALD) reduction, an SMA protective genetic modifier, ameliorates SMA across species. In a low-dose SMN-ASO-treated severe SMA mouse model, presymptomatic intracerebroventricular (i.c.v.) injection of Ncald-ASO at postnatal day 2 (PND2) significantly ameliorates histological and electrophysiological SMA hallmarks at PND21. However, contrary to SMN-ASOs, Ncald-ASOs show a shorter duration of action limiting a long-term benefit. Here, we investigated the longer-term effect of Ncald-ASOs by additional i.c.v. bolus injection at PND28. Two weeks after injection of 500 µg Ncald-ASO in wild-type mice, NCALD was significantly reduced in the brain and spinal cord and well tolerated. Next, we performed a double-blinded preclinical study combining low-dose SMN-ASO (PND1) with 2× i.c.v. Ncald-ASO or CTRL-ASO (100 µg at PND2, 500 µg at PND28). Ncald-ASO re-injection significantly ameliorated electrophysiological defects and NMJ denervation at 2 months. Moreover, we developed and identified a non-toxic and highly efficient human NCALD-ASO that significantly reduced NCALD in hiPSC-derived MNs. This improved both neuronal activity and growth cone maturation of SMA MNs, emphasizing the additional protective effect of NCALD-ASO treatment.
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Affiliation(s)
- Anixa Muiños-Bühl
- Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany
| | - Roman Rombo
- Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany
| | | | - Eleonora Zilio
- Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany
| | - Frank Rigo
- IONIS Pharmaceuticals, Carlsbad, CA 92010, USA
| | | | - Brunhilde Wirth
- Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany
- Center for Rare Diseases Cologne, University Hospital of Cologne, 50931 Cologne, Germany
- Correspondence:
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Torroba B, Macabuag N, Haisma EM, O'Neill A, Herva ME, Redis RS, Templin MV, Black LE, Fischer DF. RNA-based drug discovery for spinal muscular atrophy: a story of small molecules and antisense oligonucleotides. Expert Opin Drug Discov 2023; 18:181-192. [PMID: 36408582 DOI: 10.1080/17460441.2022.2149733] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
INTRODUCTION Spinal Muscular Atrophy (SMA), the second most prevalent autosomal genetic disease affecting infants, is caused by the lack of SMN1, which encodes a neuron functioning vital protein, SMN. Improving exon 7 splicing in the paralogous gene SMN2, also coding for SMN protein, increases protein production efficiency from SMN2 to overcome the genetic deficit in SMN1. Several molecular mechanisms have been investigated to improve SMN2 functional splicing. AREAS COVERED This manuscript will cover two of the three mechanistically distinct available treatment options for SMA, both targeting the SMN2 splicing mechanism. The first therapeutic, nusinersen (Spinraza®, 2017), is an antisense oligonucleotide (ASO) targeting the splicing inhibitory sequence in the intron downstream of exon 7 from SMN2, thus increasing exon 7 inclusion. The second drug is a small molecule, risdiplam (Evrysdi®, 2021), that enhances the binding of splice factors and also promotes exon 7 inclusion. Both therapies, albeit through different mechanisms, increase full-length SMN protein expression. EXPERT OPINION Nusinersen and risdiplam have directly helped SMA patients and families, but they also herald a sea change in drug development for genetic diseases. This piece aims to draw parallels between both development histories; this may help chart the course for future targeted agents.
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Affiliation(s)
| | | | | | - Amy O'Neill
- Charles River Laboratories, Saffron Walden, UK
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Sypniewski M, Kresa D, Dobosz P, Topolski P, Kotuła L, Sztromwasser P, Mroczek M. Population WGS-based spinal muscular atrophy carrier screening in a cohort of 1076 healthy Polish individuals. J Appl Genet 2023; 64:135-139. [PMID: 36417168 DOI: 10.1007/s13353-022-00737-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 11/11/2022] [Accepted: 11/16/2022] [Indexed: 11/24/2022]
Abstract
Spinal muscular atrophy is a severe neuromuscular disorder with an autosomal recessive inheritance pattern. The disease-causing gene is SMN1, and its paralogue, SMN2, is a disease course modifier. Both genes SMN1 and SMN2 show over 99.9% sequence identity and a high rate of crossing over in the genomic region. Due to this reason, SMN1/SMN2 is usually excluded from the whole-genome sequencing (WGS) analysis and investigated with traditional methods, such as MLPA and qPCR. Recently, novel bioinformatic algorithms dedicated to analyzing this particular genomic region have been developed. Here, we analyze the SMN1/SMN2 genomic region with a dedicated program, SMNCopyNumberCaller. We report a similar prevalence of SMN1 gene deletion carrier status (1 per 41 people) to published data from the Polish population (1 per 35 people). Additionally, SMNCopyNumberCaller can identify SMN2 CNVs and SMN2Δ7-8 present in 153 healthy Polish individuals. Two other programs for the CNV analysis in standard genomic regions were not able to provide reliable results. Using WGS-based tools for SMN1/2 genomic region analysis is not only an efficient method in terms of time but will also enable more complex analysis such screening for markers related with a silent carrier status and identification of further genetic modifiers. Although still an experimental method, soon WGS-based SMN1/SMN2 carrier identification may become a standard method for patients screened with WGS for other purposes.
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Affiliation(s)
- Mateusz Sypniewski
- Central Clinical Hospital of Ministry of the Interior and Administration in Warsaw, 02-507, Warsaw, Poland
| | - Dominika Kresa
- Faculty of Bioscience Engineering, KU Leuven, Louvain, Belgium
| | - Paula Dobosz
- Central Clinical Hospital of Ministry of the Interior and Administration in Warsaw, 02-507, Warsaw, Poland
| | - Piotr Topolski
- Central Clinical Hospital of Ministry of the Interior and Administration in Warsaw, 02-507, Warsaw, Poland
| | - Lidia Kotuła
- Zakład Genetyki Klinicznej, Uniwersytet Medyczny w Lublinie, Lublin, Poland
| | | | - Magdalena Mroczek
- Center for Cardiovascular Genetics & Gene Diagnostics, Foundation for People With Rare Diseases, 8952, Schlieren-Zurich, Switzerland.
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15
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Abstract
Spinal muscular atrophy (SMA) is a devastating neuromuscular disorder caused by recessive mutations in the SMN1 gene, globally affecting ~8-14 newborns per 100,000. The severity of the disease depends on the residual levels of functional survival of motor neuron protein, SMN. SMN is a ubiquitously expressed RNA binding protein involved in a plethora of cellular processes. In this review, we discuss the effects of SMN loss on mitochondrial functions in the neuronal and muscular systems that are the most affected in patients with spinal muscular atrophy. Our aim is to highlight how mitochondrial defects may contribute to disease progression and how restoring mitochondrial functionality may be a promising approach to develop new therapies. We also collected from previous studies a list of transcripts encoding mitochondrial proteins affected in various SMA models. Moreover, we speculate that in adulthood, when motor neurons require only very low SMN levels, the natural deterioration of mitochondria associated with aging may be a crucial triggering factor for adult spinal muscular atrophy, and this requires particular attention for therapeutic strategies.
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Affiliation(s)
- Eleonora Zilio
- Institute of Human Genetics, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
| | - Valentina Piano
- Institute of Human Genetics, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany
- Center for Rare Diseases, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
- Correspondence: (V.P.); (B.W.)
| | - Brunhilde Wirth
- Institute of Human Genetics, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany
- Center for Rare Diseases, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
- Correspondence: (V.P.); (B.W.)
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16
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Milligan JN, Blasco-Pérez L, Costa-Roger M, Codina-Solà M, Tizzano EF. Recommendations for Interpreting and Reporting Silent Carrier and Disease-Modifying Variants in SMA Testing Workflows. Genes (Basel) 2022; 13:1657. [PMID: 36140824 PMCID: PMC9498682 DOI: 10.3390/genes13091657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 09/09/2022] [Accepted: 09/13/2022] [Indexed: 11/16/2022] Open
Abstract
Genetic testing for SMA diagnosis, newborn screening, and carrier screening has become a significant public health interest worldwide, driven largely by the development of novel and effective molecular therapies for the treatment of spinal muscular atrophy (SMA) and the corresponding updates to testing guidelines. Concurrently, understanding of the underlying genetics of SMA and their correlation with a broad range of phenotypes and risk factors has also advanced, particularly with respect to variants that modulate disease severity or impact residual carrier risks. While testing guidelines are beginning to emphasize the importance of these variants, there are no clear guidelines on how to utilize them in a real-world setting. Given the need for clarity in practice, this review summarizes several clinically relevant variants in the SMN1 and SMN2 genes, including how they inform outcomes for spinal muscular atrophy carrier risk and disease prognosis.
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Affiliation(s)
| | - Laura Blasco-Pérez
- Department of Clinical and Molecular Genetics, University Hospital Vall d’Hebron, 08035 Barcelona, Spain
| | - Mar Costa-Roger
- Department of Clinical and Molecular Genetics, University Hospital Vall d’Hebron, 08035 Barcelona, Spain
| | - Marta Codina-Solà
- Department of Clinical and Molecular Genetics, University Hospital Vall d’Hebron, 08035 Barcelona, Spain
| | - Eduardo F. Tizzano
- Department of Clinical and Molecular Genetics, University Hospital Vall d’Hebron, 08035 Barcelona, Spain
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17
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Hatch ST, Smargon AA, Yeo GW. Engineered U1 snRNAs to modulate alternatively spliced exons. Methods 2022; 205:140-148. [PMID: 35764245 DOI: 10.1016/j.ymeth.2022.06.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 05/30/2022] [Accepted: 06/23/2022] [Indexed: 10/17/2022] Open
Abstract
Alternative splicing accounts for a considerable portion of transcriptomic diversity, as most protein-coding genes are spliced into multiple mRNA isoforms. However, errors in splicing patterns can give rise to mis-splicing with pathological consequences, such as the congenital diseases familial dysautonomia, Duchenne muscular dystrophy, and spinal muscular atrophy. Small nuclear RNA (snRNA) components of the U snRNP family have been proposed as a therapeutic modality for the treatment of mis-splicing. U1 snRNAs offer great promise, with prior studies demonstrating in vivo efficacy, suggesting additional preclinical development is merited. Improvements in enabling technologies, including screening methodologies, gene delivery vectors, and relevant considerations from gene editing approaches justify further advancement of U1 snRNA as a therapeutic and research tool. With the goal of providing a user-friendly protocol, we compile and demonstrate a methodological toolkit for sequence-specific targeted perturbation of alternatively spliced pre-mRNA with engineered U1 snRNAs. We observe robust modulation of endogenous pre-mRNA transcripts targeted in two contrasting splicing contexts, SMN2 exon 7 and FAS exon 6, exhibiting the utility and applicability of engineered U1 snRNA to both inclusion and exclusion of targeted exons. We anticipate that these demonstrations will contribute to the usability of U1 snRNA in investigating splicing modulation in eukaryotic cells, increasing accessibility to the broader research community.
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Affiliation(s)
- Samuel T Hatch
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA; Stem Cell Program, University of California San Diego, Sanford Consortium for Regenerative Medicine, La Jolla, USA; Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA; Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, CA, USA
| | - Aaron A Smargon
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA; Stem Cell Program, University of California San Diego, Sanford Consortium for Regenerative Medicine, La Jolla, USA; Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA; Stem Cell Program, University of California San Diego, Sanford Consortium for Regenerative Medicine, La Jolla, USA; Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA; Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, CA, USA.
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18
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Muinos-Bühl A, Rombo R, Janzen E, Ling KK, Hupperich K, Rigo F, Bennett CF, Wirth B. Combinatorial ASO-mediated therapy with low dose SMN and the protective modifier Chp1 is not sufficient to ameliorate SMA pathology hallmarks. Neurobiol Dis 2022; 171:105795. [PMID: 35724821 DOI: 10.1016/j.nbd.2022.105795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 05/17/2022] [Accepted: 06/14/2022] [Indexed: 10/18/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a devastating genetically inherited neuromuscular disorder characterized by the progressive loss of motor neurons in the spinal cord, leading to muscle atrophy and weakness. Although SMA is caused by homozygous mutations in SMN1, the disease severity is mainly determined by the copy number of SMN2, an almost identical gene that produces ~10% correctly spliced SMN transcripts. Recently, three FDA- and EMA-approved therapies that either increase correctly spliced SMN2 transcripts (nusinersen and risdiplam) or replace SMN1 (onasemnogen abeparvovec-xioi) have revolutionized the clinical outcome in SMA patients. However, for severely affected SMA individuals carrying only two SMN2 copies even a presymptomatic therapy might be insufficient to fully counteract disease development. Therefore, SMN-independent compounds supporting SMN-dependent therapies represent a promising therapeutic approach. Recently, we have shown a significant amelioration of SMA disease hallmarks in a severely affected SMA mouse carrying a mutant Chp1 allele when combined with low-dose of SMN antisense oligonucleotide (ASO) treatment. CHP1 is a direct interacting partner of PLS3, a strong protective modifier of SMA. Both proteins ameliorate impaired endocytosis in SMA and significantly restore pathological hallmarks in mice. Here, we aimed to pharmacologically reduce CHP1 levels in an ASO-based combinatorial therapy targeting SMN and Chp1. Chp1 modulation is a major challenge since its genetic reduction to ~50% has shown to ameliorate SMA pathology, while the downregulation below that level causes cerebellar ataxia. Efficacy and tolerability studies determined that a single injection of 30 μg Chp1-ASO4 in the CNS is a safe dosage that significantly reduced CHP1 levels to ~50% at postnatal day (PND)14. Unfortunately, neither electrophysiological predictors such as compound muscle action potential (CMAP) or motor unit number estimation (MUNE) nor histological hallmarks of SMA in neuromuscular junction (NMJ), spinal cord or muscle were ameliorated in SMA mice treated with Chp1-ASO4 compared to CTRL-ASO at PND21. Surprisingly, CHP1 levels were almost at control level 4-weeks post injection, indicating a rather short-term effect of the ASO. Therefore, we re-administrated Chp1-ASO4 by i.c.v. bolus injection at PND28. However, no significant improvement of SMA hallmarks were seen at 2 month-of-age either. In conclusion, in contrast to the protective effect of genetically-induced Chp1 reduction on SMA, combinatorial therapy with Chp1- and SMN-ASOs failed to significantly ameliorate the SMA pathology. Chp1-ASOs compared to SMN-ASO proved to have rather short-term effect and even reinjection had no significant impact on SMA progression, suggesting that further optimization of the ASO may be required to fully explore the combination.
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Affiliation(s)
- A Muinos-Bühl
- Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany.
| | - R Rombo
- Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany.
| | - E Janzen
- Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany
| | - K K Ling
- Ionis Pharmaceuticals, Carlsbad, CA 92008, USA.
| | - K Hupperich
- Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany
| | - F Rigo
- Ionis Pharmaceuticals, Carlsbad, CA 92008, USA.
| | - C F Bennett
- Ionis Pharmaceuticals, Carlsbad, CA 92008, USA.
| | - B Wirth
- Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany; Center for Rare Diseases, University Hospital of Cologne, 50931 Cologne, Germany.
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19
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Pinto A, Cunha C, Chaves R, Butchbach MER, Adega F. Comprehensive In Silico Analysis of Retrotransposon Insertions within the Survival Motor Neuron Genes Involved in Spinal Muscular Atrophy. Biology (Basel) 2022; 11:824. [PMID: 35741345 PMCID: PMC9219815 DOI: 10.3390/biology11060824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 05/19/2022] [Accepted: 05/25/2022] [Indexed: 11/16/2022]
Abstract
Transposable elements (TEs) are interspersed repetitive and mobile DNA sequences within the genome. Better tools for evaluating TE-derived sequences have provided insights into the contribution of TEs to human development and disease. Spinal muscular atrophy (SMA) is an autosomal recessive motor neuron disease that is caused by deletions or mutations in the Survival Motor Neuron 1 (SMN1) gene but retention of its nearly perfect orthologue SMN2. Both genes are highly enriched in TEs. To establish a link between TEs and SMA, we conducted a comprehensive, in silico analysis of TE insertions within the SMN1/2 loci of SMA, carrier and healthy genomes. We found an Alu insertion in the promoter region and one L1 element in the 3'UTR that may play an important role in alternative promoter as well as in alternative transcriptional termination. Additionally, several intronic Alu repeats may influence alternative splicing via RNA circularization and causes the presence of new alternative exons. These Alu repeats present throughout the genes are also prone to recombination events that could lead to SMN1 exons deletions and, ultimately, SMA. TE characterization of the SMA genomic region could provide for a better understanding of the implications of TEs on human disease and genomic evolution.
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Affiliation(s)
- Albano Pinto
- Laboratory of Cytogenomics and Animal Genomics (CAG), Department of Genetics and Biotechnology (DGB), University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal; (A.P.); (C.C.); (R.C.)
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, 1749-016 Lisbon, Portugal
| | - Catarina Cunha
- Laboratory of Cytogenomics and Animal Genomics (CAG), Department of Genetics and Biotechnology (DGB), University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal; (A.P.); (C.C.); (R.C.)
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, 1749-016 Lisbon, Portugal
| | - Raquel Chaves
- Laboratory of Cytogenomics and Animal Genomics (CAG), Department of Genetics and Biotechnology (DGB), University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal; (A.P.); (C.C.); (R.C.)
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, 1749-016 Lisbon, Portugal
| | - Matthew E. R. Butchbach
- Division of Neurology, Nemours Children’s Hospital Delaware, Wilmington, DE 19803, USA;
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
- Department of Pediatrics, Sidney Kimmel College of Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Filomena Adega
- Laboratory of Cytogenomics and Animal Genomics (CAG), Department of Genetics and Biotechnology (DGB), University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal; (A.P.); (C.C.); (R.C.)
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, 1749-016 Lisbon, Portugal
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20
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Tang Z, Hegde S, Zhao J, Zhu S, Johnson KA, Lorson CL, Wang J. CRISPR-mediated Enzyme Fragment Complementation Assay for Quantification of the Stability of Splice Isoforms. Chembiochem 2022; 23:e202200012. [PMID: 35235240 DOI: 10.1002/cbic.202200012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 02/22/2022] [Indexed: 11/06/2022]
Abstract
Small-molecule splicing modulators exemplified by an FDA-approved drug, risdiplam, are a new pharmacological modality for regulating the expression and stability of splice isoforms. We report a CRISPR-mediated enzyme fragment complementation (EFC) assay to quantify the splice isoform stability. The EFC assay harnessed a 42 amino acid split of a β-galactosidase (designate α-tag), which could be fused at the termini of the target genes using CRISPR/cas9. The α-tagged splice isoform would be quantified by measuring the enzymatic activity upon complementation with the rest of β-galactosidase. This EFC assay retained all the sequences of introns and exons of the target gene in the native genomic environment that recapitulates the cell biology of the diseases of interest. For a proof-of-concept, we developed a CRISPR-mediated EFC assay targeting the exon 7 of the survival of motor neuron 2 (SMN2) gene. The EFC assay compatible with 384-well plates robustly quantified the splicing modulation activity of small molecules. In this study, we also discovered that a coumarin derivative, compound 4, potently modulate SMN2 splicing at as low as 1.1 nM.
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Affiliation(s)
- Zhichao Tang
- University of Kansas School of Pharmacy, Medicinal Chemistry, UNITED STATES
| | - Shalakha Hegde
- University of Kansas School of Pharmacy, Medicinal Chemistry, UNITED STATES
| | - Junxing Zhao
- University of Kansas School of Pharmacy, Medicinal Chemistry, UNITED STATES
| | - Shoutian Zhu
- PhenoTarget BioSciences, Inc., Biology, UNITED STATES
| | | | | | - Jingxin Wang
- University of Kansas, Medicinal Chemistry, 2034 Becker Dr, 1050, 66047, Lawrence, UNITED STATES
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21
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Aslesh T, Yokota T. Restoring SMN Expression: An Overview of the Therapeutic Developments for the Treatment of Spinal Muscular Atrophy. Cells 2022; 11:417. [PMID: 35159227 DOI: 10.3390/cells11030417] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/14/2022] [Accepted: 01/24/2022] [Indexed: 02/06/2023] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disorder and one of the most common genetic causes of infant death. It is characterized by progressive weakness of the muscles, loss of ambulation, and death from respiratory complications. SMA is caused by the homozygous deletion or mutations in the survival of the motor neuron 1 (SMN1) gene. Humans, however, have a nearly identical copy of SMN1 known as the SMN2 gene. The severity of the disease correlates inversely with the number of SMN2 copies present. SMN2 cannot completely compensate for the loss of SMN1 in SMA patients because it can produce only a fraction of functional SMN protein. SMN protein is ubiquitously expressed in the body and has a variety of roles ranging from assembling the spliceosomal machinery, autophagy, RNA metabolism, signal transduction, cellular homeostasis, DNA repair, and recombination. Motor neurons in the anterior horn of the spinal cord are extremely susceptible to the loss of SMN protein, with the reason still being unclear. Due to the ability of the SMN2 gene to produce small amounts of functional SMN, two FDA-approved treatment strategies, including an antisense oligonucleotide (AON) nusinersen and small-molecule risdiplam, target SMN2 to produce more functional SMN. On the other hand, Onasemnogene abeparvovec (brand name Zolgensma) is an FDA-approved adeno-associated vector 9-mediated gene replacement therapy that can deliver a copy of the human SMN1. In this review, we summarize the SMA etiology, the role of SMN, and discuss the challenges of the therapies that are approved for SMA treatment.
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22
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Wijaya YOS, Ar Rohmah M, Niba ETE, Morisada N, Noguchi Y, Hidaka Y, Ozasa S, Inoue T, Shimazu T, Takahashi Y, Tozawa T, Chiyonobu T, Inoue T, Shiroshita T, Yokoyama A, Okamoto K, Awano H, Takeshima Y, Saito T, Saito K, Nishio H, Shinohara M. Phenotypes of SMA patients retaining SMN1 with intragenic mutation. Brain Dev 2021; 43:745-758. [PMID: 33892995 DOI: 10.1016/j.braindev.2021.03.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 03/17/2021] [Accepted: 03/21/2021] [Indexed: 01/09/2023]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder caused by homozygous deletion or intragenic mutation of the SMN1 gene. It is well-known that high copy number of its homologous gene, SMN2, modifies the phenotype of SMN1-deleted patients. However, in the patients with intragenic SMN1 mutation, the relationship between phenotype and SMN2 copy number remains unclear. METHODS We have analyzed a total of 515 Japanese patients with SMA-like symptoms (delayed developmental milestones, respiratory failures, muscle weakness etc.) from 1996 to 2019. SMN1 and SMN2 copy numbers were determined by quantitative polymerase chain reaction (PCR) method and/or multiplex ligation-dependent probe amplification (MLPA) method. Intragenic SMN1 mutations were identified through DNA and RNA analysis of the fresh blood samples. RESULTS A total of 241 patients were diagnosed as having SMA. The majority of SMA patients showed complete loss of SMN1 (n = 228, 95%), but some patients retained SMN1 and carried an intragenic mutation in the retaining SMN1 (n = 13, 5%). Ten different mutations were identified in these 13 patients, consisting of missense, nonsense, frameshift and splicing defect-causing mutations. The ten mutations were c.275G > C (p.Trp92Ser), c.819_820insT (p.Thr274Tyrfs*32), c.830A > G (p.Tyr277Cys), c.5C > T (p.Ala2Val), c.826 T > C (p.Tyr276His), c.79C > T (p.Gln27*), c.188C > A (p.Ser63*), c.422 T > C (p.Leu141Pro), c.835-2A > G (exon 7 skipping) and c.835-3C > A (exon 7 skipping). It should be noted here that some patients with milder phenotype carried only a single SMN2 copy (n = 3), while other patients with severe phenotype carried 3 SMN2 copies (n = 4). CONCLUSION Intragenic mutations in SMN1 may contribute more significantly to clinical severity than SMN2 copy numbers.
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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.
| | - Mawaddah Ar Rohmah
- Department of Neurology, Faculty of Medicine, Public Health, and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia.
| | - Emma Tabe Eko Niba
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan.
| | - Naoya Morisada
- Department of Clinical Genetics, Hyogo Prefectural Kobe Children's Hospital, Kobe, Japan.
| | - Yoriko Noguchi
- Department of Clinical Laboratory, Kobe University Hospital, Kobe, Japan.
| | - Yasufumi Hidaka
- Department of Pediatrics, Kitakyushu Municipal Medical Center, Kitakyushu, Japan.
| | - Shiro Ozasa
- Department of Pediatrics, Kumamoto University, Kumamoto, Japan.
| | - Takeshi Inoue
- Department of Neonatology, Kumamoto City Hospital, Kumamoto, Japan.
| | - Tomoyuki Shimazu
- Department of Pediatrics, National Hospital Organization Kumamoto Saishunso Hospital, Kumamoto, Japan.
| | - Yuya Takahashi
- Department of Pediatrics, Nagaoka Red Cross Hospital, Nagaoka, Japan.
| | - Takenori Tozawa
- Department of Pediatrics, Kyoto Prefectural University of Medicine, Kyoto, Japan.
| | - Tomohiro Chiyonobu
- Department of Pediatrics, Kyoto Prefectural University of Medicine, Kyoto, Japan.
| | - Takushi Inoue
- Department of Pediatrics, National Hospital Organization Okayama Medical Center, Okayama, Japan.
| | | | - Atsushi Yokoyama
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan.
| | - Kentaro Okamoto
- Department of Pediatrics, Ehime Prefectural Imabari Hospital, Imabari, Japan.
| | - Hiroyuki Awano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan.
| | - Yasuhiro Takeshima
- Department of Pediatrics, Hyogo College of Medicine, Nishinomiya, Japan.
| | - Toshio Saito
- Division of Child Neurology, Department of Neurology, National Hospital Organization Osaka Toneyama Medical Center, Toyonaka, Japan.
| | - Kayoko Saito
- Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, Japan.
| | - Hisahide Nishio
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan; Faculty of Medical Rehabilitation, Kobe Gakuin University, Kobe, Japan.
| | - Masakazu Shinohara
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan.
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23
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Butchbach MER. Genomic Variability in the Survival Motor Neuron Genes ( SMN1 and SMN2): Implications for Spinal Muscular Atrophy Phenotype and Therapeutics Development. Int J Mol Sci 2021; 22:ijms22157896. [PMID: 34360669 PMCID: PMC8348669 DOI: 10.3390/ijms22157896] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 07/14/2021] [Accepted: 07/21/2021] [Indexed: 02/07/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a leading genetic cause of infant death worldwide that is characterized by loss of spinal motor neurons leading to muscle weakness and atrophy. SMA results from the loss of survival motor neuron 1 (SMN1) gene but retention of its paralog SMN2. The copy numbers of SMN1 and SMN2 are variable within the human population with SMN2 copy number inversely correlating with SMA severity. Current therapeutic options for SMA focus on increasing SMN2 expression and alternative splicing so as to increase the amount of SMN protein. Recent work has demonstrated that not all SMN2, or SMN1, genes are equivalent and there is a high degree of genomic heterogeneity with respect to the SMN genes. Because SMA is now an actionable disease with SMN2 being the primary target, it is imperative to have a comprehensive understanding of this genomic heterogeneity with respect to hybrid SMN1–SMN2 genes generated by gene conversion events as well as partial deletions of the SMN genes. This review will describe this genetic heterogeneity in SMA and its impact on disease phenotype as well as therapeutic efficacy.
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Affiliation(s)
- Matthew E. R. Butchbach
- Center for Applied Clinical Genomics, Nemours Children’s Health Delaware, Wilmington, DE 19803, USA;
- Center for Pediatric Research, Nemours Children’s Health Delaware, Wilmington, DE 19803, USA
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
- Department of Pediatrics, Thomas Jefferson University, Philadelphia, PA 19107, USA
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24
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Kumar B, Barton S, Kordowska J, Eaton RB, Counihan AM, Hale JE, Comeau AM. Novel Modification of a Confirmatory SMA Sequencing Assay that Can Be Used to Determine SMN2 Copy Number. Int J Neonatal Screen 2021; 7:ijns7030047. [PMID: 34449530 PMCID: PMC8395917 DOI: 10.3390/ijns7030047] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/11/2021] [Accepted: 07/16/2021] [Indexed: 01/04/2023] Open
Abstract
Promising treatments for spinal muscular atrophy (SMA), the leading genetic cause of infant mortality, prompted calls for inclusion in newborn screening (NBS). In January 2018, the New England Newborn Screening Program (NENSP) began statewide screening for SMA using a tiered algorithm looking for the absence of SMN1 Exon 7. When results from the first and second tier needed reconciliation, we developed and validated a third tier DNA sequencing assay to ensure the presence or absence of SMN1 Exon 7. All nine infants referred to specialty centers through NBS showed single base substitution of c.840C>T, and were confirmed to have SMA. Further, a minor sequencing protocol modification allowed the estimation of SMN2 copy number in SMA affected patients; we developed and validated a copy-number assay yielding 100% match with seven previously characterized specimens of SMA patients. All nine SMA-affected infants found through NBS were also assayed for SMN2 copy number. Results were comparable but not 100% matched with those that were reported by independent diagnostic laboratories. In conclusion, a sequencing protocol confirms NBS findings from real-time qPCR, and its modified application allows NBS programs that have sequencing capabilities to provide SMN2 copy numbers without the need for additional instrumentation.
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Affiliation(s)
- Binod Kumar
- New England Newborn Screening Program, University of Massachusetts Medical School, Worcester, MA 01605, USA; (S.B.); (J.K.); (R.B.E.); (A.M.C.); (J.E.H.); (A.M.C.)
- Division of Genetics, Department of Pediatrics, University of Massachusetts Medical School, Worcester, MA 01605, USA
- Correspondence: ; Tel.: +1-774-455-4657
| | - Samantha Barton
- New England Newborn Screening Program, University of Massachusetts Medical School, Worcester, MA 01605, USA; (S.B.); (J.K.); (R.B.E.); (A.M.C.); (J.E.H.); (A.M.C.)
| | - Jolanta Kordowska
- New England Newborn Screening Program, University of Massachusetts Medical School, Worcester, MA 01605, USA; (S.B.); (J.K.); (R.B.E.); (A.M.C.); (J.E.H.); (A.M.C.)
| | - Roger B. Eaton
- New England Newborn Screening Program, University of Massachusetts Medical School, Worcester, MA 01605, USA; (S.B.); (J.K.); (R.B.E.); (A.M.C.); (J.E.H.); (A.M.C.)
- Division of Genetics, Department of Pediatrics, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Anne M. Counihan
- New England Newborn Screening Program, University of Massachusetts Medical School, Worcester, MA 01605, USA; (S.B.); (J.K.); (R.B.E.); (A.M.C.); (J.E.H.); (A.M.C.)
| | - Jaime E. Hale
- New England Newborn Screening Program, University of Massachusetts Medical School, Worcester, MA 01605, USA; (S.B.); (J.K.); (R.B.E.); (A.M.C.); (J.E.H.); (A.M.C.)
| | - Anne Marie Comeau
- New England Newborn Screening Program, University of Massachusetts Medical School, Worcester, MA 01605, USA; (S.B.); (J.K.); (R.B.E.); (A.M.C.); (J.E.H.); (A.M.C.)
- Division of Genetics, Department of Pediatrics, University of Massachusetts Medical School, Worcester, MA 01605, USA
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Winkelsas AM, Grunseich C, Harmison GG, Chwalenia K, Rinaldi C, Hammond SM, Johnson K, Bowerman M, Arya S, Talbot K, Wood MJ, Fischbeck KH. Targeting the 5' untranslated region of SMN2 as a therapeutic strategy for spinal muscular atrophy. Mol Ther Nucleic Acids 2021; 23:731-42. [PMID: 33575118 DOI: 10.1016/j.omtn.2020.12.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 12/30/2020] [Indexed: 11/21/2022]
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disorder caused by mutations in the survival motor neuron 1 (SMN1) gene. All patients have at least one copy of a paralog, SMN2, but a C-to-T transition in this gene results in exon 7 skipping in a majority of transcripts. Approved treatment for SMA involves promoting exon 7 inclusion in the SMN2 transcript or increasing the amount of full-length SMN by gene replacement with a viral vector. Increasing the pool of SMN2 transcripts and increasing their translational efficiency can be used to enhance splice correction. We sought to determine whether the 5' untranslated region (5' UTR) of SMN2 contains a repressive feature that can be targeted to increase SMN levels. We found that antisense oligonucleotides (ASOs) complementary to the 5' end of SMN2 increase SMN mRNA and protein levels and that this effect is due to inhibition of SMN2 mRNA decay. Moreover, use of the 5' UTR ASO in combination with a splice-switching oligonucleotide (SSO) increases SMN levels above those attained with the SSO alone. Our results add to the current understanding of SMN regulation and point toward a new therapeutic target for SMA.
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26
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Niba ETE, Nishio H, Wijaya YOS, Lai PS, Tozawa T, Chiyonobu T, Yamadera M, Okamoto K, Awano H, Takeshima Y, Saito T, Shinohara M. Clinical phenotypes of spinal muscular atrophy patients with hybrid SMN gene. Brain Dev 2021; 43:294-302. [PMID: 33036822 DOI: 10.1016/j.braindev.2020.09.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 08/26/2020] [Accepted: 09/08/2020] [Indexed: 01/09/2023]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is a neuromuscular disease caused by homozygous deletion of SMN1 exons 7 and 8. However, exon 8 is retained in some cases, where SMN2 exon 7 recombines with SMN1 exon 8, forming a hybrid SMN gene. It remains unknown how the hybrid SMN gene contribute to the SMA phenotype. METHOD We analyzed 515 patients with clinical suspicion for SMA. SMN1 exons 7 and 8 deletion was detected by PCR followed by enzyme digestion. Hybrid SMN genes were further analyzed by nucleotide sequencing. SMN2 copy number was determined by real-time PCR. RESULTS SMN1 exon 7 was deleted in 228 out of 515 patients, and SMN1 exon 8 was also deleted in 204 out of the 228 patients. The remaining 24 patients were judged to carry a hybrid SMN gene. In the patients with SMN1 exon 7 deletion, the frequency of the severe phenotype was significantly lower in the patients with hybrid SMN gene than in the patients without hybrid SMN gene. However, as for the distribution of SMN2 exon 7 copy number among the clinical phenotypes, there was no significant difference between both groups of SMA patients with or without hybrid SMN gene. CONCLUSION Hybrid SMN genes are not rare in Japanese SMA patients, and it appears to be associated with a less severe phenotype. The phenotype of patients with hybrid SMN gene was determined by the copy number of SMN2 exon 7, as similarly for the patients without hybrid SMN gene.
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Affiliation(s)
- Emma Tabe Eko Niba
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan.
| | - Hisahide Nishio
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan; Faculty of Medical Rehabilitation, Kobe Gakuin University, Kobe, Japan.
| | - Yogik Onky Silvana Wijaya
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan.
| | - Poh San Lai
- Department of Pediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
| | - Takenori Tozawa
- Department of Pediatrics, Kyoto Prefectural University of Medicine, Kyoto, Japan.
| | - Tomohiro Chiyonobu
- Department of Pediatrics, Kyoto Prefectural University of Medicine, Kyoto, Japan.
| | - Misaki Yamadera
- Department of Neurology, National Hospital Organization Osaka Toneyama Medical Center, Toyonaka, Japan.
| | - Kentaro Okamoto
- Department of Pediatrics, Ehime Prefectural Imabari Hospital, Ehime, Japan.
| | - Hiroyuki Awano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan.
| | - Yasuhiro Takeshima
- Department of Pediatrics, Hyogo College of Medicine, Nishinomiya, Japan.
| | - Toshio Saito
- Department of Neurology, National Hospital Organization Osaka Toneyama Medical Center, Toyonaka, Japan.
| | - Masakazu Shinohara
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan.
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27
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Abstract
The path from gene discovery to therapy in spinal muscular atrophy (SMA) has been a highly challenging endeavor, but also led to one of the most successful stories in neurogenetics. In SMA, a neuromuscular disorder with an often fatal outcome until recently, with those affected never able to sit, stand, or walk, children now achieve these motoric abilities and almost age-based development when treated presymptomatically. This review summarizes the challenges along this 30-year journey. It is also meant to inspire early-career scientists not to give up when things become difficult but to try to uncover the biological underpinnings and transform the challenge into the next big discovery. Without doubt, the improvements seen with the three therapeutic strategies in SMA are impressive; many open questions remain and are discussed in this review.
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Affiliation(s)
- Brunhilde Wirth
- Institute of Human Genetics, Center for Molecular Medicine, Center for Rare Disorders, University of Cologne, Kerpener Str. 34, 50931 Cologne, Germany.
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28
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Stabley DL, Holbrook J, Scavina M, Crawford TO, Swoboda KJ, Robbins KM, Butchbach MER. Detection of SMN1 to SMN2 gene conversion events and partial SMN1 gene deletions using array digital PCR. Neurogenetics 2021; 22:53-64. [PMID: 33415588 DOI: 10.1007/s10048-020-00630-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 11/26/2020] [Indexed: 12/15/2022]
Abstract
Proximal spinal muscular atrophy (SMA), a leading genetic cause of infant death worldwide, 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 mutations of survival motor neuron 1 (SMN1) but retention of one or more copies of the paralog SMN2. Within the SMA population, there is substantial variation in SMN2 copy number (CN); in general, those individuals with SMA who have a high SMN2 CN have a milder disease. Because SMN2 functions as a disease modifier, its accurate CN determination may have clinical relevance. In this study, we describe the development of array digital PCR (dPCR) to quantify SMN1 and SMN2 CNs in DNA samples using probes that can distinguish the single nucleotide difference between SMN1 and SMN2 in exon 8. This set of dPCR assays 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 CN and disease severity. We can detect SMN1-SMN2 gene conversion events in DNA samples by comparing CNs at exon 7 and exon 8. Partial deletions of SMN1 can also be detected with dPCR by comparing CNs at exon 7 or exon 8 with those at intron 1. Array dPCR is a practical technique to determine, accurately and reliably, SMN1 and SMN2 CNs from SMA samples as well as identify gene conversion events and partial deletions of SMN1.
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29
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Abstract
Spinal muscular atrophy (SMA) is a common autosomal recessive disorder which has been considered as the second common cause of infant death, with an estimated prevalence of 1 in 10,000 live births. The disorder is caused by survival motor neuron 1 gene (SMN1) deficiency leading to limb weakness, difficult swallowing and abnormal breathing. Here, a fast and accurate method for SMA detection has been developed. Genomic DNA sample collected from whole blood, amniotic fluid, or dried blood spots can be analysed by using the Clarity™ Digital PCR (dPCR) System for determining the copy numbers of SMN1 and SMN2 genes. Two hundred and fourteen clinical samples determined by qPCR-based method were enrolled and used to establish the cut-off ranges for unaffected individual, SMA carrier and SMA patient categories. After setting the cut-off range for each group, 12 samples were analyzed by both dPCR-based method and MLPA (multiplex ligation-dependent probe amplification), the current testing golden standard for SMA, and 100% concordant results between the two testing methods were performed. CSB SMA Detection Kit combined with dPCR platform provides a robust and precise approach to distinguish unaffected individuals, SMA carrier and SMA patients. This rapid molecular diagnostic method can be adapted to pre-pregnancy eugenics inspection, prenatal testing as well as newborns screening and help physicians or genetic counselors to improve population SMA incidence.
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Affiliation(s)
- Kai-Chen Wang
- Cheng-Hsin General Hospital, Taipei, Taiwan.,School of Medicine, National Yang Ming University, Taipei, Taiwan
| | | | | | | | - Yi-Wen Chen
- Cold Spring Biotech Corp, New Taipei City, Taiwan
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30
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Frederiksen SB, Holm LL, Larsen MR, Doktor TK, Andersen HS, Hastings ML, Hua Y, Krainer AR, Andresen BS. Identification of SRSF10 as a regulator of SMN2 ISS-N1. Hum Mutat 2020; 42:246-260. [PMID: 33300159 DOI: 10.1002/humu.24149] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 10/22/2020] [Accepted: 12/06/2020] [Indexed: 01/02/2023]
Abstract
Understanding the splicing code can be challenging as several splicing factors bind to many splicing-regulatory elements. The SMN1 and SMN2 silencer element ISS-N1 is the target of the antisense oligonucleotide drug, Spinraza, which is the treatment against spinal muscular atrophy. However, limited knowledge about the nature of the splicing factors that bind to ISS-N1 and inhibit splicing exists. It is likely that the effect of Spinraza comes from blocking binding of these factors, but so far, an unbiased characterization has not been performed and only members of the hnRNP A1/A2 family have been identified by Western blot analysis and nuclear magnetic resonance to bind to this silencer. Employing an MS/MS-based approach and surface plasmon resonance imaging, we show for the first time that splicing factor SRSF10 binds to ISS-N1. Furthermore, using splice-switching oligonucleotides we modulated the splicing of the SRSF10 isoforms generating either the long or the short protein isoform of SRSF10 to regulate endogenous SMN2 exon 7 inclusion. We demonstrate that the isoforms of SRSF10 regulate SMN1 and SMN2 splicing with different strength correlating with the length of their RS domain. Our results suggest that the ratio between the SRSF10 isoforms is important for splicing regulation.
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Affiliation(s)
- Sabrina B Frederiksen
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense M, Denmark
| | - Lise L Holm
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense M, Denmark
| | - Martin R Larsen
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense M, Denmark
| | - Thomas K Doktor
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense M, Denmark
| | - Henriette S Andersen
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense M, Denmark
| | - Michelle L Hastings
- Department of Cell Biology and Anatomy, Center for Genetic Diseases, Chicago Medical School and School of Graduate and Postdoctoral Studies, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, USA
| | - Yimin Hua
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, USA
| | - Adrian R Krainer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, USA
| | - Brage S Andresen
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense M, Denmark
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31
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Jędrzejowska M. Advances in Newborn Screening and Presymptomatic Diagnosis of Spinal Muscular Atrophy. Degener Neurol Neuromuscul Dis 2020; 10:39-47. [PMID: 33364872 PMCID: PMC7751307 DOI: 10.2147/dnnd.s246907] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 11/30/2020] [Indexed: 01/08/2023] Open
Abstract
Spinal muscular atrophy 5q (SMA5q) is one of the most severe and common genetic diseases. In the natural course, the disease leads to premature death (in acute forms) or severe motor disability (in chronic forms). As the genetic basis of SMA is very homogenous, the diagnostics are based entirely on simple and sensitive genetic testing. In the last few years, innovative methods of therapy have been developed based on SMN2 gene modification, such as splicing, or replacement of the damaged SMN1 gene (gene therapy). Although these approaches have shown high efficacy, results depend on the age/disease stage at which therapy is initiated. The best results have been obtained in presymptomatic patients. Indeed, introduction of therapy in the pre- or early symptomatic stage of the disease seems to be crucial for maximizing effects. Thus, all the criteria for the implementation of neonatal screening for SMA have been met, and many countries, ie, the USA, Germany, Belgium, and Australia, have started NBS national/pilot programs for SMA. The initial results of these programs indicate a high frequency of the disease, reaching 1 per 7 thousand live births in Europe, as well as early symptomatology (first weeks of life in severe cases) and a high frequency of patients with 4 SMN2 copies. Overall, the time for therapy inclusion in patients with 4 SMN2 copies remain under discussion. More precise predictors/biomarkers of the clinical course are needed. At the same time, it seems advisable to offer other solutions, such as population carrier screening. As the long-term effects of different treatments on the natural history of SMA are unknown, the natural history of the disease needs to be re-evaluated.
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Affiliation(s)
- Maria Jędrzejowska
- Rare Diseases Research Platform, Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
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32
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Müller-Felber W, Vill K, Schwartz O, Gläser D, Nennstiel U, Wirth B, Burggraf S, Röschinger W, Becker M, Durner J, Eggermann K, Müller C, Hannibal I, Olgemöller B, Schara U, Blaschek A, Kölbel H. Infants Diagnosed with Spinal Muscular Atrophy and 4 SMN2 Copies through Newborn Screening - Opportunity or Burden? J Neuromuscul Dis 2020; 7:109-117. [PMID: 32144995 PMCID: PMC7175938 DOI: 10.3233/jnd-200475] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Although the value of newborn screening (NBS) for early detection and treatment opportunity in SMA patients is generally accepted, there is still an ongoing discussion about the best strategy in children with 4 and more copies of the SMN2 gene. This gene is known to be the most important but not the only disease modifier. In our SMA-NBS pilot project in Germany comprising 278,970 infants screened between January 2018 and November 2019 were 38 positive cases with a homozygous SMN1 deletion. 40% of them had 4 or more SMN2 copies. The incidence for homozygous SMN1 deletion was 1 : 7350, which is within the known range of SMA incidence in Germany. Of the 15 SMA children with 4 SMN2 copies, one child developed physical signs of SMA by the age of 8 months. Reanalysis of the SMN2 copy number by a different test method revealed 3 copies. Two children had affected siblings with SMA Type III, who were diagnosed only after detection of the index patient in the NBS. One had a positive family history with an affected aunt (onset of disease at the age of 3 years). Three families were lost to medical follow up; two because of socioeconomic reasons and one to avoid the psychological stress associated with the appointments. Decisions on how to handle patients with 4 SMN2 copies are discussed in the light of the experience gathered from our NBS pilot SMA program.
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Affiliation(s)
- Wolfgang Müller-Felber
- Dr. v. Hauner Children's Hospital, Department of Pediatric Neurology and Developmental Medicine, LMU - University of Munich, Munich, Germany
| | - Katharina Vill
- Dr. v. Hauner Children's Hospital, Department of Pediatric Neurology and Developmental Medicine, LMU - University of Munich, Munich, Germany
| | - Oliver Schwartz
- Department of Pediatric Neurology, Muenster University Hospital, Münster, Germany
| | - Dieter Gläser
- Genetikum ®, Center for Human Genetics, Neu-Ulm, Germany
| | - Uta Nennstiel
- Screening Center of the Bavarian Health and Food Safety Authority, Oberschleissheim, Germany
| | - Brunhilde Wirth
- Institute of Human Genetics, Center for Molecular Genetics Cologne and Center for Rare Diseases Cologne, University of Cologne, Cologne, Germany
| | | | | | | | - Jürgen Durner
- Labor Becker und Kollegen, Munich, Germany.,Department of Operative/Restorative Dentistry, Periodontology and Pedodontics, Ludwig-Maximilians-Universität München, Goethestr. 70, 80336 Munich, Germany
| | - Katja Eggermann
- Institute of Human Genetics, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Christine Müller
- Dr. v. Hauner Children's Hospital, Department of Pediatric Neurology and Developmental Medicine, LMU - University of Munich, Munich, Germany
| | - Iris Hannibal
- Dr. v. Hauner Children's Hospital, Department of Pediatric Neurology and Developmental Medicine, LMU - University of Munich, Munich, Germany
| | | | - Ulrike Schara
- Department of Pediatric Neurology, Developmental Neurology and Social Pediatrics, University of Essen, Germany
| | - Astrid Blaschek
- Dr. v. Hauner Children's Hospital, Department of Pediatric Neurology and Developmental Medicine, LMU - University of Munich, Munich, Germany
| | - Heike Kölbel
- Department of Pediatric Neurology, Developmental Neurology and Social Pediatrics, University of Essen, Germany
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33
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Kirschner J, Butoianu N, Goemans N, Haberlova J, Kostera-Pruszczyk A, Mercuri E, van der Pol WL, Quijano-Roy S, Sejersen T, Tizzano EF, Ziegler A, Servais L, Muntoni F. European ad-hoc consensus statement on gene replacement therapy for spinal muscular atrophy. Eur J Paediatr Neurol 2020; 28:38-43. [PMID: 32763124 PMCID: PMC7347351 DOI: 10.1016/j.ejpn.2020.07.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/03/2020] [Accepted: 07/03/2020] [Indexed: 11/28/2022]
Abstract
Spinal muscular atrophy (SMA) used to be one of the most common genetic causes of infant mortality. New disease modifying treatments have changed the disease trajectories and most impressive results are seen if treatment is initiated in the presymptomatic phase of the disease. Very recently, the European Medicine Agency approved Onasemnogene abeparvovec (Zolgensma®) for the treatment of patients with SMA with up to three copies of the SMN2 gene or the clinical presentation of SMA type 1. While this broad indication provides new opportunities, it also triggers discussions on the appropriate selection of patients in the context of limited available evidence. To aid the rational use of Onasemnogene abeparvovec for the treatment of SMA, a group of European neuromuscular experts presents in this paper eleven consensus statements covering qualification, patient selection, safety considerations and long-term monitoring.
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Affiliation(s)
| | - Nina Butoianu
- Pediatric Neurology Clinic, "Prof. Dr. Al. Obregia" Hospital, Bucharest, Faculty of Medicine and Pharmacy "Carol Davila", Bucharest, Romania.
| | - Nathalie Goemans
- Dept of Pediatric Neurology, University Hospitals Leuven, Belgium.
| | - Jana Haberlova
- Dept of Pediatric Neurology, Motol University Hospital, Prague, Czech Republic.
| | | | - Eugenio Mercuri
- Pediatric Neurology, Università Cattolica del Sacro Cuore, Rome, Italy; Centro Clinico Nemo, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy.
| | - W Ludo van der Pol
- Department of Neurology, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, the Netherlands.
| | - Susana Quijano-Roy
- Neuromuscular Unit, Child Neurology and ICU Department, Raymond Poincaré University Hospital (UVSQ), APHP Paris Saclay, Garches, France.
| | - Thomas Sejersen
- Department of Womeńs and Childreńs Health, Karolinska Institutet, Stockholm, Sweden.
| | - Eduardo F Tizzano
- Department of Clinical and Molecular Genetics, Medicine Genetics Group, University Hospital Vall d'Hebron, Barcelona, Spain.
| | - Andreas Ziegler
- Department of Neuropediatrics and Metabolic Medicine, Centre for Childhood and Adolescent Medicine, University Hospital Heidelberg, Germany.
| | - Laurent Servais
- University of Liège, Neuromuscular Reference Center Disease, Department of Pediatrics, Liege, Belgium; MDUK Neuromuscular Center, Department of Pediatrics, University of Oxford, UK.
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health, and NIHR Biomedical Research Centre, Great Ormond Street Hospital for Children, London, UK.
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34
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Tan CA, Westbrook MJ, Truty R, Kvitek DJ, Kennemer M, Winder TL, Shieh PB. Incorporating Spinal Muscular Atrophy Analysis by Next-Generation Sequencing into a Comprehensive Multigene Panel for Neuromuscular Disorders. Genet Test Mol Biomarkers 2020; 24:616-624. [PMID: 32721234 DOI: 10.1089/gtmb.2019.0282] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Background: Spinal muscular atrophy (SMA) is traditionally molecularly diagnosed by multiplex ligation-dependent probe amplification or quantitative polymerase chain reaction (qPCR). SMA analyses are not routinely incorporated into gene panel analyses for individuals with suspected SMA or broader neuromuscular indications. Aim: We sought to determine whether a next-generation sequencing (NGS) approach that integrates SMA analyses into a multigene neuromuscular disorders panel could detect undiagnosed SMA. Materials and Methods: Sequence and copy number variants of the SMN1/SMN2 genes were simultaneously analyzed in samples from 5304 unselected individuals referred for testing using an NGS-based 122-gene neuromuscular panel. This diagnostic approach was validated using DNA from 68 individuals who had been previously diagnosed with SMA via quantitative PCR for SMN1/SMN2. Results: Homozygous loss of SMN1 was detected in 47 unselected individuals. Heterozygous loss of SMN1 was detected in 118 individuals; 8 had an indeterminate variant in "SMN1 or SMN2" that supported an SMA diagnosis but required additional disambiguation. Of the remaining SMA carriers, 44 had pathogenic variants in other genes. Concordance rates between NGS and qPCR were 100% and 93% for SMN1 and SMN2 copy numbers, respectively. Where there was disagreement, phenotypes were more consistent with the SMN2 results from NGS. Conclusion: Integrating NGS-based SMA testing into a multigene neuromuscular panel allows a single assay to diagnose SMA while comprehensively assessing the spectrum of variants that can occur in individuals with broad differential diagnoses or nonspecific/overlapping neuromuscular features.
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Affiliation(s)
| | | | | | | | | | | | - Perry B Shieh
- Department of Neurology, University of California, Los Angeles, Los Angeles, California, USA
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35
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Abstract
Diagnostic genetic testing for spinal muscular atrophy is key in establishing early diagnosis for affected individuals. Prenatal carrier testing of parents with subsequent testing of the fetus for homozygous SMN1 gene deletion in those at risk of this autosomal recessive disorder as well as newborn screening can identify the vast majority of affected individuals before the onset of symptoms. Patients presenting symptomatically must be genetically confirmed as soon as possible because targeted treatments are now available that profoundly impact symptoms and improve quality of life.
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Affiliation(s)
- John F Brandsema
- Division of Neurology, Colket Translational Research Building, 10th Floor, 3501 Civic Center Boulevard, Philadelphia, PA 19104, USA; Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | - Brianna N Gross
- Division of Neurology, Colket Translational Research Building, 10th Floor, 3501 Civic Center Boulevard, Philadelphia, PA 19104, USA
| | - Susan E Matesanz
- Division of Neurology, Colket Translational Research Building, 10th Floor, 3501 Civic Center Boulevard, Philadelphia, PA 19104, USA
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36
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Wadman RI, Jansen MD, Stam M, Wijngaarde CA, Curial CAD, Medic J, Sodaar P, Schouten J, Vijzelaar R, Lemmink HH, van den Berg LH, Groen EJN, van der Pol WL. Intragenic and structural variation in the SMN locus and clinical variability in spinal muscular atrophy. Brain Commun 2020; 2:fcaa075. [PMID: 32954327 PMCID: PMC7425299 DOI: 10.1093/braincomms/fcaa075] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 04/17/2020] [Accepted: 04/22/2020] [Indexed: 11/15/2022] Open
Abstract
Clinical severity and treatment response vary significantly between patients with spinal muscular atrophy. The approval of therapies and the emergence of neonatal screening programmes urgently require a more detailed understanding of the genetic variants that underlie this clinical heterogeneity. We systematically investigated genetic variation other than SMN2 copy number in the SMN locus. Data were collected through our single-centre, population-based study on spinal muscular atrophy in the Netherlands, including 286 children and adults with spinal muscular atrophy Types 1–4, including 56 patients from 25 families with multiple siblings with spinal muscular atrophy. We combined multiplex ligation-dependent probe amplification, Sanger sequencing, multiplexed targeted resequencing and digital droplet polymerase chain reaction to determine sequence and expression variation in the SMN locus. SMN1, SMN2 and NAIP gene copy number were determined by multiplex ligation-dependent probe amplification. SMN2 gene variant analysis was performed using Sanger sequencing and RNA expression analysis of SMN by droplet digital polymerase chain reaction. We identified SMN1–SMN2 hybrid genes in 10% of spinal muscular atrophy patients, including partial gene deletions, duplications or conversions within SMN1 and SMN2 genes. This indicates that SMN2 copies can vary structurally between patients, implicating an important novel level of genetic variability in spinal muscular atrophy. Sequence analysis revealed six exonic and four intronic SMN2 variants, which were associated with disease severity in individual cases. There are no indications that NAIP1 gene copy number or sequence variants add value in addition to SMN2 copies in predicting the clinical phenotype in individual patients with spinal muscular atrophy. Importantly, 95% of spinal muscular atrophy siblings in our study had equal SMN2 copy numbers and structural changes (e.g. hybrid genes), but 60% presented with a different spinal muscular atrophy type, indicating the likely presence of further inter- and intragenic variabilities inside as well as outside the SMN locus. SMN2 gene copies can be structurally different, resulting in inter- and intra-individual differences in the composition of SMN1 and SMN2 gene copies. This adds another layer of complexity to the genetics that underlie spinal muscular atrophy and should be considered in current genetic diagnosis and counselling practices.
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Affiliation(s)
- Renske I Wadman
- UMC Utrecht Brain Center, Department of Neurology and Neurosurgery, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Marc D Jansen
- UMC Utrecht Brain Center, Department of Neurology and Neurosurgery, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Marloes Stam
- UMC Utrecht Brain Center, Department of Neurology and Neurosurgery, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Camiel A Wijngaarde
- UMC Utrecht Brain Center, Department of Neurology and Neurosurgery, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Chantall A D Curial
- UMC Utrecht Brain Center, Department of Neurology and Neurosurgery, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Jelena Medic
- UMC Utrecht Brain Center, Department of Neurology and Neurosurgery, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Peter Sodaar
- UMC Utrecht Brain Center, Department of Neurology and Neurosurgery, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Jan Schouten
- MRC Holland BV, 1057 DL Amsterdam, the Netherlands
| | | | - Henny H Lemmink
- Department of Genetics, University Medical Center Groningen, 9713 GZ Groningen, the Netherlands
| | - Leonard H van den Berg
- UMC Utrecht Brain Center, Department of Neurology and Neurosurgery, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Ewout J N Groen
- UMC Utrecht Brain Center, Department of Neurology and Neurosurgery, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - W Ludo van der Pol
- UMC Utrecht Brain Center, Department of Neurology and Neurosurgery, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
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37
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Morizumi T, Ueno A, Takasone K, Ozawa K, Yoshinaga T, Nakamura K, Sekijima Y. Elderly patient with 5q spinal muscular atrophy type 4 markedly improved by Nusinersen. J Neurol Sci 2020; 415:116901. [PMID: 32464350 DOI: 10.1016/j.jns.2020.116901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 05/08/2020] [Accepted: 05/11/2020] [Indexed: 10/24/2022]
Affiliation(s)
- Teruya Morizumi
- Department of Medicine (Neurology and Rheumatology), Shinshu University School of Medicine, Matsumoto 390-8621, Japan
| | - Akihiro Ueno
- Department of Medicine (Neurology and Rheumatology), Shinshu University School of Medicine, Matsumoto 390-8621, Japan; Department of Neurology, Japanese Red Cross Society Suwa Hospital, Suwa 392-8510, Japan
| | - Ken Takasone
- Department of Medicine (Neurology and Rheumatology), Shinshu University School of Medicine, Matsumoto 390-8621, Japan
| | - Kazuki Ozawa
- Department of Medicine (Neurology and Rheumatology), Shinshu University School of Medicine, Matsumoto 390-8621, Japan
| | - Tsuneaki Yoshinaga
- Department of Medicine (Neurology and Rheumatology), Shinshu University School of Medicine, Matsumoto 390-8621, Japan
| | - Katsuya Nakamura
- Department of Medicine (Neurology and Rheumatology), Shinshu University School of Medicine, Matsumoto 390-8621, Japan; Center for Medical Genetics, Shinshu University Hospital, Matsumoto 390-8621, Japan.
| | - Yoshiki Sekijima
- Department of Medicine (Neurology and Rheumatology), Shinshu University School of Medicine, Matsumoto 390-8621, Japan
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38
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Jedličková I, Přistoupilová A, Nosková L, Majer F, Stránecký V, Hartmannová H, Hodaňová K, Trešlová H, Hýblová M, Solár P, Minárik G, Giertlová M, Kmoch S. Spinal muscular atrophy caused by a novel Alu-mediated deletion of exons 2a-5 in SMN1 undetectable with routine genetic testing. Mol Genet Genomic Med 2020; 8:e1238. [PMID: 32337852 PMCID: PMC7336725 DOI: 10.1002/mgg3.1238] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 03/10/2020] [Accepted: 03/12/2020] [Indexed: 12/26/2022] Open
Abstract
Background Spinal muscular atrophy (SMA) is an inherited neuromuscular disease affecting 1 in 8,000 newborns. The majority of patients carry bi‐allelic variants in the survival of motor neuron 1 gene (SMN1). SMN1 is located in a duplicated region on chromosome 5q13 that contains Alu elements and is predisposed to genomic rearrangements. Due to the genomic complexity of the SMN region and genetic heterogeneity, approximately 50% of SMA patients remain without genetic diagnosis that is a prerequisite for genetic treatments. In this work we describe the diagnostic odyssey of one SMA patient in whom routine diagnostics identified only a maternal heterozygous SMN1Δ(7–8) deletion. Methods We characterized SMN transcripts, assessed SMN protein content in peripheral blood mononuclear cells (PBMC), estimated SMN genes dosage, and mapped genomic rearrangement in the SMN region. Results We identified an Alu‐mediated deletion encompassing exons 2a‐5 of SMN1 on the paternal allele and a complete deletion of SMN1 on the maternal allele as the cause of SMA in this patient. Conclusion Alu‐mediated rearrangements in SMN1 can escape routine diagnostic testing. Parallel analysis of SMN gene dosage, SMN transcripts, and total SMN protein levels in PBMC can identify genomic rearrangements and should be considered in genetically undefined SMA cases.
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Affiliation(s)
- Ivana Jedličková
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Anna Přistoupilová
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Lenka Nosková
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Filip Majer
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Viktor Stránecký
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Hana Hartmannová
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Kateřina Hodaňová
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Helena Trešlová
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | | | - Peter Solár
- Department of Medical Biology, Faculty of Medicine, P.J. Safarik University, Kosice, Slovakia
| | - Gabriel Minárik
- Department of Clinical Genetics, Medirex A.S., Kosice, Slovakia
| | - Mária Giertlová
- Department of Clinical Genetics, Medirex A.S., Kosice, Slovakia
| | - Stanislav Kmoch
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
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Vitello GA, Calì F, Vinci M, Scuderi C, L’Episcopo F, Musumeci A, Musumeci SA, Nicotera AG. Possible implication of undescribed SMN1- SMN2 genotype in chronic EMG-pattern of SMA with transitory acute denervation. J Musculoskelet Neuronal Interact 2020; 20:610-613. [PMID: 33265090 PMCID: PMC7716687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Spinal muscular atrophy (SMA) refers to a group of genetic neuromuscular disorders affecting lower motor neurons causative of numerous phenotypes. To date, according to the age of onset, maximum muscular activity achieved, and life expectation four types of SMA are recognized, all caused by mutations in the SMN1 gene with SMN2 copy number influencing disease severity. Herein, we describe the case of a 31-year-old young male with normal psychomotor development who has experienced fatigue, cramps, and muscle fasciculations in the lower limbs for a period of 2 months. Based on electrophysiological and clinical findings we performed SMA genetic, clinical exome and RNA expression of candidate genes which led us to suggest SMN1-SMN2 genes [(2+0) and (0+0)] combination as possibly being implicated in the phenotype.
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Affiliation(s)
| | | | | | | | - Francesca L’Episcopo
- Oasi Research Institute – IRCCS, Troina, Italy,Corresponding author: Dr. Francesco Calì, Oasi Research Institute – IRCCS, Via Conte Ruggero 73, 94018Troina, Italy E-mail:
| | | | | | - Antonio G. Nicotera
- Oasi Research Institute – IRCCS, Troina, Italy,Child Neuropsychiatry Unit, Department of Human Pathology of the Adult and Developmental Age University Hospital “G. Martino” Messina, Italy
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40
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Konieczny P, Artero R. Drosophila SMN2 minigene reporter model identifies moxifloxacin as a candidate therapy for SMA. FASEB J 2019; 34:3021-3036. [PMID: 31909520 DOI: 10.1096/fj.201802554rrr] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 12/12/2019] [Accepted: 12/16/2019] [Indexed: 12/24/2022]
Abstract
Spinal muscular atrophy is a rare and fatal neuromuscular disorder caused by the loss of alpha motor neurons. The affected individuals have mutated the ubiquitously expressed SMN1 gene resulting in the loss or reduction in the survival motor neuron (SMN) protein levels. However, an almost identical paralog exists in humans: SMN2. Pharmacological activation of SMN2 exon 7 inclusion by small molecules or modified antisense oligonucleotides is a valid approach to treat SMA. Here we describe an in vivo SMN2 minigene reporter system in Drosophila motor neurons that serves as a cost-effective, feasible, and stringent primary screening model for identifying chemicals capable of crossing the conserved Drosophila blood-brain barrier and modulating exon 7 inclusion. The model was used for the screening of 1100 drugs from the Prestwick Chemical Library, resulting in 2.45% hit rate. The most promising candidate drugs were validated in patient-derived fibroblasts where they proved to increase SMN protein levels. Among them, moxifloxacin modulated SMN2 splicing by promoting exon 7 inclusion. The recovery of SMN protein levels was confirmed by increased colocalization of nuclear gems with Cajal Bodies. Thus, a Drosophila-based drug screen allowed the discovery of an FDA-approved small molecule with the potential to become a novel therapy for SMA.
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Affiliation(s)
- Piotr Konieczny
- Interdisciplinary Research Structure for Biotechnology and Biomedicine (ERI BIOTECMED), University of Valencia, Valencia, Spain.,Translational Genomics Group, Incliva Health Research Institute, Valencia, Spain.,Incliva-CIPF Joint Unit, Valencia, Spain
| | - Rubén Artero
- Interdisciplinary Research Structure for Biotechnology and Biomedicine (ERI BIOTECMED), University of Valencia, Valencia, Spain.,Translational Genomics Group, Incliva Health Research Institute, Valencia, Spain.,Incliva-CIPF Joint Unit, Valencia, Spain
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41
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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: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 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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42
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Shinohara M, Niba ETE, Wijaya YOS, Takayama I, Mitsuishi C, Kumasaka S, Kondo Y, Takatera A, Hokuto I, Morioka I, Ogiwara K, Tobita K, Takeuchi A, Nishio H. A Novel System for Spinal Muscular Atrophy Screening in Newborns: Japanese Pilot Study. Int J Neonatal Screen 2019; 5:41. [PMID: 33072999 PMCID: PMC7510215 DOI: 10.3390/ijns5040041] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 11/06/2019] [Indexed: 01/23/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disorder caused by SMN1 gene deletion/mutation. The drug nusinersen modifies SMN2 mRNA splicing, increasing the production of the full-length SMN protein. Recent studies have demonstrated the beneficial effects of nusinersen in patients with SMA, particularly when treated in early infancy. Because nusinersen treatment can alter disease trajectory, there is a strong rationale for newborn screening. In the current study, we validated the accuracy of a new system for detecting SMN1 deletion (Japanese patent application No. 2017-196967, PCT/JP2018/37732) using dried blood spots (DBS) from 50 patients with genetically confirmed SMA and 50 controls. Our system consists of two steps: (1) targeted pre-amplification of SMN genes by direct polymerase chain reaction (PCR) and (2) detection of SMN1 deletion by real-time modified competitive oligonucleotide priming-PCR (mCOP-PCR) using the pre-amplified products. Compared with PCR analysis results of freshly collected blood samples, our system exhibited a sensitivity of 1.00 (95% confidence interval [CI] 0.96-1.00) and a specificity of 1.00 (95% CI 0.96-1.00). We also conducted a prospective SMA screening study using DBS from 4157 Japanese newborns. All DBS tested negative, and there were no screening failures. Our results indicate that the new system can be reliably used in SMA newborn screening.
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Affiliation(s)
- Masakazu Shinohara
- Department of Community Medicine and Social Healthcare Science, Division of Epidemiology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan; (M.S.); (E.T.E.N.); (Y.O.S.W.); (I.T.)
| | - Emma Tabe Eko Niba
- Department of Community Medicine and Social Healthcare Science, Division of Epidemiology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan; (M.S.); (E.T.E.N.); (Y.O.S.W.); (I.T.)
| | - Yogik Onky Silvana Wijaya
- Department of Community Medicine and Social Healthcare Science, Division of Epidemiology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan; (M.S.); (E.T.E.N.); (Y.O.S.W.); (I.T.)
| | - Izumi Takayama
- Department of Community Medicine and Social Healthcare Science, Division of Epidemiology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan; (M.S.); (E.T.E.N.); (Y.O.S.W.); (I.T.)
| | - Chisako Mitsuishi
- Japanese Red Cross Katsushika Maternity Hospital, 5-11-12 Tateishi, Katsushika-ku, Tokyo 124-0012, Japan; (C.M.); (S.K.)
| | - Sakae Kumasaka
- Japanese Red Cross Katsushika Maternity Hospital, 5-11-12 Tateishi, Katsushika-ku, Tokyo 124-0012, Japan; (C.M.); (S.K.)
| | - Yoichi Kondo
- Matsuyama Red Cross Hospital, 1 Bunkyo-cho, Matsuyama 790-8524, Japan;
| | - Akihiro Takatera
- Chibune General Hospital, 3-2-39 Fukumachi, Nishiyodogawa-ku, Osaka 555-0034, Japan;
| | - Isamu Hokuto
- Department of Pediatrics, St. Marianna University School of Medicine, 2-16-1 Sugao, Kawasaki 216-8511, Japan;
| | - Ichiro Morioka
- Department of Pediatrics and Child Health, Nihon University School of Medicine, 30-1 Oyaguchi kamicho, Itabashi-ku, Tokyo 173-8610, Japan;
| | - Kazutaka Ogiwara
- Biogen Japan Ltd., 1-4-1 Nihonbashi, Chuo-ku, Tokyo 103-0027, Japan; (K.O.); (K.T.)
| | - Kimimasa Tobita
- Biogen Japan Ltd., 1-4-1 Nihonbashi, Chuo-ku, Tokyo 103-0027, Japan; (K.O.); (K.T.)
| | - Atsuko Takeuchi
- Kobe Pharmaceutical University, 4-19-1, Motoyamakitamachi, Higashinada-ku, Kobe 658-8558, Japan;
| | - Hisahide Nishio
- Department of Community Medicine and Social Healthcare Science, Division of Epidemiology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan; (M.S.); (E.T.E.N.); (Y.O.S.W.); (I.T.)
- Department of Occupational Therapy, Faculty of Rehabilitation, Kobe Gakuin University, 518 Arise, Ikawadani-cho, Nishi-ku, Kobe 651-2180, Japan
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43
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Li JJ, Lin X, Tang C, Lu YQ, Hu X, Zuo E, Li H, Ying W, Sun Y, Lai LL, Chen HZ, Guo XX, Zhang QJ, Wu S, Zhou C, Shen X, Wang Q, Lin MT, Ma LX, Wang N, Krainer AR, Shi L, Yang H, Chen WJ. Disruption of splicing-regulatory elements using CRISPR/Cas9 to rescue spinal muscular atrophy in human iPSCs and mice. Natl Sci Rev 2019; 7:92-101. [PMID: 34691481 PMCID: PMC8446915 DOI: 10.1093/nsr/nwz131] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/27/2019] [Accepted: 08/28/2019] [Indexed: 12/22/2022] Open
Abstract
We here report a genome-editing strategy to correct spinal muscular atrophy (SMA). Rather
than directly targeting the pathogenic exonic mutations, our strategy employed Cas9 and
guide-sgRNA for the targeted disruption of intronic splicing-regulatory elements. We
disrupted intronic splicing silencers (ISSs, including ISS-N1 and ISS + 100) of survival
motor neuron (SMN) 2, a key modifier gene of SMA, to enhance exon 7 inclusion and
full-length SMN expression in SMA iPSCs. Survival of splicing-corrected iPSC-derived motor
neurons was rescued with SMN restoration. Furthermore, co-injection of Cas9 mRNA from
Streptococcus pyogenes (SpCas9) or Cas9 from Staphylococcus
aureus (SaCas9) alongside their corresponding sgRNAs targeting ISS-N1 into
zygotes rescued 56% and 100% of severe SMA transgenic mice
(Smn−/−, SMN2tg/−). The median
survival of the resulting mice was extended to >400 days. Collectively, our study
provides proof-of-principle for a new strategy to therapeutically intervene in SMA and
other RNA-splicing-related diseases.
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Affiliation(s)
- Jin-Jing Li
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China.,Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou 350005, China
| | - Xiang Lin
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China.,Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou 350005, China
| | - Cheng Tang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Ying-Qian Lu
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - Xinde Hu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Erwei Zuo
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - He Li
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Wenqin Ying
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yidi Sun
- Key Lab of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Lu-Lu Lai
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - Hai-Zhu Chen
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - Xin-Xin Guo
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - Qi-Jie Zhang
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China.,Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou 350005, China
| | - Shuang Wu
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - Changyang Zhou
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xiaowen Shen
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Qifang Wang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Min-Ting Lin
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China.,Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou 350005, China
| | - Li-Xiang Ma
- Department of Anatomy, Histology & Embryology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Ning Wang
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China.,Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou 350005, China
| | - Adrian R Krainer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Linyu Shi
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Hui Yang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Wan-Jin Chen
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China.,Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou 350005, China
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Kariyawasam DST, D'Silva A, Lin C, Ryan MM, Farrar MA. Biomarkers and the Development of a Personalized Medicine Approach in Spinal Muscular Atrophy. Front Neurol 2019; 10:898. [PMID: 31481927 PMCID: PMC6709682 DOI: 10.3389/fneur.2019.00898] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 08/02/2019] [Indexed: 12/11/2022] Open
Abstract
Recent unprecedented advances in treatment for spinal muscular atrophy (SMA) enabled patients to access the first approved disease modifying therapy for the condition. There are however many uncertainties, regarding timing of treatment initiation, response to intervention, treatment effects and long-term outcomes, which are complicated by the evolving phenotypes seen in the post-treatment era for patients with SMA. Biomarkers of disease, with diagnostic, prognostic, predictive, and pharmacodynamic value are thus urgently required, to facilitate a wider understanding in this dynamic landscape. A spectrum of these candidate biomarkers, will be evaluated in this review, including genetic, epigenetic, proteomic, electrophysiological, and imaging measures. Of these, SMN2 appears to be the most significant modifier of phenotype to date, and its use in prognostication shows considerable clinical utility. Longitudinal studies in patients with SMA highlight an emerging role of circulatory markers such as neurofilament, in tracking disease progression and response to treatment. Furthermore, neurophysiological biomarkers such as CMAP and MUNE values show considerable promise in the real word setting, in following the dynamic response and output of the motor unit to therapeutic intervention. The specific value for these possible biomarkers across diagnosis, prognosis, prediction of treatment response, efficacy, and safety will be central to guide future patient-targeted treatments, the design of clinical trials, and understanding of the pathophysiological mechanisms of disease and intervention.
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Affiliation(s)
- Didu S T Kariyawasam
- Department of Neurology, Sydney Children's Hospital, Sydney, NSW, Australia.,School of Women's and Children's Health, University of New South Wales Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Arlene D'Silva
- School of Women's and Children's Health, University of New South Wales Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Cindy Lin
- Department of Neurophysiology, Brain and Mind Center, University of Sydney, Sydney, NSW, Australia
| | - Monique M Ryan
- Department of Neurology, Murdoch Children's Research Institute, Royal Children's Hospital, University of Melbourne, Melbourne, VIC, Australia
| | - Michelle A Farrar
- Department of Neurology, Sydney Children's Hospital, Sydney, NSW, Australia.,School of Women's and Children's Health, University of New South Wales Medicine, University of New South Wales, Sydney, NSW, Australia
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NIBA EMMATABEEKO, ROCHMAH MAWADDAHAR, HARAHAP NURIMMAFATIMAH, AWANO HIROYUKI, MORIOKA ICHIRO, IIJIMA KAZUMOTO, TAKESHIMA YASUHIRO, SAITO TOSHIO, SAITO KAYOKO, TAKEUCHI ATSUKO, LAI POHSAN, BOUIKE YOSHIHIRO, MATSUO MASAFUMI, NISHIO HISAHIDE, SHINOHARA MASAKAZU. Spinal Muscular Atrophy: Advanced Version of Screening System with Real-Time mCOP-PCR and PCR-RFLP for SMN1 Deletion. Kobe J Med Sci 2019; 65:E49-E53. [PMID: 31956256 PMCID: PMC7012194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 05/27/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND Spinal Muscular Atrophy (SMA) is a common autosomal recessive neuromuscular disease characterized by defects of lower motor neurons. More than 95% of SMA patients show homozygous deletion for the survival motor neuron 1 (SMN1) gene. For the screening of SMN1 deletion using dried blood spot (DBS), we developed a new combined system with real-time "modified competitive oligonucleotide priming"-polymerase chain reaction (mCOP-PCR) and PCR restriction fragment length polymorphism (PCR-RFLP). Although our real-time mCOP-PCR method is secured enough to be gene-specific, its amplification efficiency is not as good because the reverse primers carry a nucleotide mismatched with the sequence of the pre-amplified product. The mismatch has consequently been generated in the process of introducing a restriction enzyme site in the pre-amplified products for PCR-RFLP. METHOD DBS samples of the subjects were stored at room temperature for a period of less than one year. Each subject had already been genotyped by the first PCR-RFLP using fresh blood DNA. SMN1/SMN2 exon 7 was collectively amplified using conventional PCR (targeted pre-amplification). Pre-amplified products were used as template in the real-time mCOP-PCR, and, on the other hand, were digested with DraI enzyme (PCR-RFLP). To improve the amplification efficiency of mCOP-PCR, one nucleotide change was introduced in the original reverse primers (SMN1-COP and SMN2-COP) to eliminate the mismatched nucleotide. RESULTS The real-time mCOP-PCR with a new primer (SMN1-COP-DRA or SMN2-COP-DRA) more rapidly and specifically amplified SMN1 and SMN2, and clearly demonstrated SMN1 deletion in an SMA patient. With the new primers, the amplification efficiencies of real-time mCOP-PCR were improved and the Cq values of SMN1 (+) and SMN2 (+) samples were significantly lowered. CONCLUSION In the advanced version of our screening system for homozygous SMN1 deletion using DBS, the real-time mCOP-PCR with newly-designed reverse primers demonstrated the presence or absence of SMN1 and SMN2 within a shorter time, and the results were easily tested by PCR-RFLP. This rapid and accurate screening system will be useful for detection of newborn infants with SMA.
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Affiliation(s)
- EMMA TABE EKO NIBA
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan
| | - MAWADDAH AR ROCHMAH
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan
| | - NUR IMMA FATIMAH HARAHAP
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan
| | - HIROYUKI AWANO
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - ICHIRO MORIOKA
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - KAZUMOTO IIJIMA
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | | | - TOSHIO SAITO
- Division of Child Neurology, Department of Neurology, National Hospital Organization Toneyama National Hospital, Toneyama, Japan
| | - KAYOKO SAITO
- Institute of Medical Genetics, Tokyo Women’s Medical University, Tokyo, Japan
| | | | - POH SAN LAI
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | | | - MASAFUMI MATSUO
- Faculty of Rehabilitation, Kobe Gakuin University, Kobe, Japan
| | - HISAHIDE NISHIO
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan
- Faculty of Rehabilitation, Kobe Gakuin University, Kobe, Japan
| | - MASAKAZU SHINOHARA
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan
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NIBA EMMATABEEKO, ROCHMAH MAWADDAHAR, HARAHAP NURIMMAFATIMAH, AWANO HIROYUKI, MORIOKA ICHIRO, IIJIMA KAZUMOTO, TAKESHIMA YASUHIRO, SAITO TOSHIO, SAITO KAYOKO, TAKEUCHI ATSUKO, LAI POHSAN, BOUIKE YOSHIHIRO, MATSUO MASAFUMI, NISHIO HISAHIDE, SHINOHARA MASAKAZU. Spinal Muscular Atrophy: New Screening System with Real-Time mCOP-PCR and PCR-RFLP for SMN1 Deletion. Kobe J Med Sci 2019; 65:E44-E48. [PMID: 31956255 PMCID: PMC7012196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 05/27/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND Spinal Muscular Atrophy (SMA) is a common autosomal recessive neuromuscular disorder characterized by degeneration or loss of lower motor neurons. More than 95% of SMA patients show homozygous deletion for the survival motor neuron 1 (SMN1) gene. For the screening of SMN1 deletion, it is necessary to differentiate SMN1 from its highly homologous gene, SMN2. We developed a modified competitive oligonucleotide priming-PCR (mCOP-PCR) method using dried blood spot (DBS)-DNA, in which SMN1 and SMN2-specific PCR products are detected with gel-electrophoresis. Next, we added a targeted pre-amplification step prior to the mCOP-PCR step, to avoid unexpected, non-specific amplification. The pre-amplification step enabled us to combine mCOP-PCR and real-time PCR. In this study, we combined real-time mCOP-PCR and PCR-restriction fragment length polymorphism (PCR-RFLP) to develop a new screening system for detection of SMN1 deletion. METHODS DBS samples of the subjects were stored at room temperature for a period of less than one year. Each subject had already been genotyped by the first PCR-RFLP using fresh blood DNA. SMN1/SMN2 exon 7 was collectively amplified using conventional PCR (targeted pre-amplification), the products of which were then used as a template in the real-time PCR with mCOP-primer sets. To confirm the results, the pre-amplified products were subject to the second PCR-RFLP. RESULTS The real-time mCOP-PCR separately amplified SMN1 and SMN2 exon7, and clearly demonstrated SMN1 deletion in an SMA patient. The results of the real-time mCOP-PCR using DBS-DNA were completely consistent with those of the first and second PCR-RFLP analysis. CONCLUSION In our new system for detection of SMN1 deletion, real-time mCOP-PCR rapidly proved the presence or absence of SMN1 and SMN2, and the results were easily tested by PCR-RFLP. This solid genotyping system will be useful for SMA screening.
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Affiliation(s)
- EMMA TABE EKO NIBA
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan
| | - MAWADDAH AR ROCHMAH
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan
| | - NUR IMMA FATIMAH HARAHAP
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan
| | - HIROYUKI AWANO
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - ICHIRO MORIOKA
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - KAZUMOTO IIJIMA
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | | | - TOSHIO SAITO
- Division of Child Neurology, Department of Neurology, National Hospital Organization Toneyama National Hospital, Toneyama, Japan
| | - KAYOKO SAITO
- Institute of Medical Genetics, Tokyo Women’s Medical University, Tokyo, Japan
| | | | - POH SAN LAI
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | | | - MASAFUMI MATSUO
- Faculty of Rehabilitation, Kobe Gakuin University, Kobe, Japan
| | - HISAHIDE NISHIO
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan
- Faculty of Rehabilitation, Kobe Gakuin University, Kobe, Japan
| | - MASAKAZU SHINOHARA
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan
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WIJAYA YOGIKONKYSILVANA, NIBA EMMATABEEKO, ROCHMAH MAWADDAHAR, HARAHAP NURIMMAFATIMAH, AWANO HIROYUKI, TAKESHIMA YASUHIRO, SAITO TOSHIO, SAITO KAYOKO, TAKEUCHI ATSUKO, LAI POHSAN, BOUIKE YOSHIHIRO, NISHIO HISAHIDE, SHINOHARA MASAKAZU. Nested PCR Amplification Secures DNA Template Quality and Quantity in Real-time mCOP-PCR Screening for SMA. Kobe J Med Sci 2019; 65:E54-E58. [PMID: 31956257 PMCID: PMC7012193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 05/27/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND Spinal Muscular Atrophy (SMA) is a common autosomal recessive disorder caused by SMN1 gene deletion. SMA has been considered an incurable disease. However, a newly-developed antisense oligonucleotide drug, nusinersen, brings about a good outcome to SMA patients in the clinical trials. Now, a screening for SMA is required for early diagnosis and early treatment so as to give a better clinical outcome to the patients. We have invented a new technology, mCOP-PCR, for SMA screening using dried blood spot (DBS) on the filter paper. One of the problems encountered in SMA screening is poor quality and quantity of DNA extracted from DBS. METHODS DNA was extracted from DBS of six individuals. Fresh blood DNA of each individual had already been genotyped using PCR/RFLP. The fragments including the sequence of SMN1/SMN2 exon 7 were pre-amplified with conventional PCR. To determine which pre-amplified product is a better template for the real-time mCOP-PCR, we did pre-amplification with a single PCR or pre-amplification with a nested PCR. RESULTS The real-time mCOP-PCR using pre-amplified products with a single PCR brought about ambiguous results in some SMN1-carrying individuals. However, the results of real-time mCOP-PCR following pre-amplification with a nested PCR were completely matched with those of PCR-RFLP. CONCLUSION In our study on the real-time mCOP-PCR screening system for SMA, a nested PCR secured the DNA template quality and quantity, leading to unambiguous results of SMA screening.
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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
| | - EMMA TABE EKO NIBA
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan
| | - MAWADDAH AR ROCHMAH
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan
| | - NUR IMMA FATIMAH HARAHAP
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan
| | - HIROYUKI AWANO
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | | | - TOSHIO SAITO
- Division of Child Neurology, Department of Neurology, National Hospital Organization Toneyama National Hospital, Toneyama, Japan
| | - KAYOKO SAITO
- Institute of Medical Genetics, Tokyo Women’s Medical University, Tokyo, Japan
| | | | - POH SAN LAI
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | | | - HISAHIDE NISHIO
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan
- Faculty of Rehabilitation, Kobe Gakuin University, Kobe, Japan
| | - MASAKAZU SHINOHARA
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan
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Torres-Benito L, Schneider S, Rombo R, Ling KK, Grysko V, Upadhyay A, Kononenko NL, Rigo F, Bennett CF, Wirth B. NCALD Antisense Oligonucleotide Therapy in Addition to Nusinersen further Ameliorates Spinal Muscular Atrophy in Mice. Am J Hum Genet 2019; 105:221-30. [PMID: 31230718 DOI: 10.1016/j.ajhg.2019.05.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 05/10/2019] [Indexed: 12/11/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disease causing the most frequent genetic childhood lethality. Recently, nusinersen, an antisense oligonucleotide (ASO) that corrects SMN2 splicing and thereby increases full-length SMN protein, has been approved by the FDA and EMA for SMA therapy. However, the administration of nusinersen in severe and/or post-symptomatic SMA-affected individuals is insufficient to counteract the disease. Therefore, additional SMN-independent therapies are needed to support the function of motoneurons and neuromuscular junctions. We recently identified asymptomatic SMN1-deleted individuals who were protected against SMA by reduced expression of neurocalcin delta (NCALD). NCALD reduction is proven to be a protective modifier of SMA across species, including worm, zebrafish, and mice. Here, we identified Ncald-ASO3-out of 450 developed Ncald ASOs-as the most efficient and non-toxic ASO for the CNS, by applying a stepwise screening strategy in cortical neurons and adult and neonatal mice. In a randomized-blinded preclinical study, a single subcutaneous low-dose SMN-ASO and a single intracerebroventricular Ncald-ASO3 or control-ASO injection were presymptomatically administered in a severe SMA mouse model. NCALD reduction of >70% persisted for about 1 month. While low-dose SMN-ASO rescues multiorgan impairment, additional NCALD reduction significantly ameliorated SMA pathology including electrophysiological and histological properties of neuromuscular junctions and muscle at P21 and motoric deficits at 3 months. The present study shows the additional benefit of a combinatorial SMN-dependent and SMN-independent ASO-based therapy for SMA. This work illustrates how a modifying gene, identified in some asymptomatic individuals, helps to develop a therapy for all SMA-affected individuals.
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Bozorg Qomi S, Asghari A, Salmaninejad A, Mojarrad M. Spinal Muscular Atrophy and Common Therapeutic Advances. Fetal Pediatr Pathol 2019; 38:226-238. [PMID: 31060440 DOI: 10.1080/15513815.2018.1520374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is an autosomal recessive destructive motor neuron disease which is characterized primarily by the degeneration of α-motor neurons in the ventral gray horn of the spinal cord. It mainly affects children and represents the most common reason of inherited infant mortality. MATERIAL AND METHODS We provide an overview of the recent therapeutic strategies for the treatment of SMA together with available and developing therapeutic strategies. For this purpose, Google Scholar and PubMed databases were searched for literature on SMA, therapy and treatment. Titles were reviewed and 96 were selected and assessed in this paper. RESULT Over the last two decades, different therapeutic strategies have been proposed for SMA. Some methods are in the pre-clinical, others the clinical phase. CONCLUSION By emergence of the new approaches, especially in gene therapy, effective treatment in the close future is probable.
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Affiliation(s)
- Saeed Bozorg Qomi
- a Department of Medical Genetics, School of Medicine, Mashhad University of Medical Sciences , Mashhad , Iran.,b Medical Genetics Research Center, School of Medicine, Mashhad University of Medical Sciences , Mashhad , Iran
| | - Amir Asghari
- c Department of Medical Physiology, School of Medicine, Mashhad University of Medical Sciences , Mashhad , Iran
| | - Arash Salmaninejad
- d Drug Applied Research Center, Student Research Committee, Tabriz University of Medical Sciences , Tabriz , Iran
| | - Majid Mojarrad
- a Department of Medical Genetics, School of Medicine, Mashhad University of Medical Sciences , Mashhad , Iran.,b Medical Genetics Research Center, School of Medicine, Mashhad University of Medical Sciences , Mashhad , Iran
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Spring AM, Raimer AC, Hamilton CD, Schillinger MJ, Matera AG. Comprehensive Modeling of Spinal Muscular Atrophy in Drosophila melanogaster. Front Mol Neurosci 2019; 12:113. [PMID: 31156382 PMCID: PMC6532329 DOI: 10.3389/fnmol.2019.00113] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 04/18/2019] [Indexed: 01/02/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disorder that affects motor neurons, primarily in young children. SMA is caused by mutations in the Survival Motor Neuron 1 (SMN1) gene. SMN functions in the assembly of spliceosomal RNPs and is well conserved in many model systems including mouse, zebrafish, fruit fly, nematode, and fission yeast. Work in Drosophila has focused on the loss of SMN function during larval stages, primarily using null alleles or strong hypomorphs. A systematic analysis of SMA-related phenotypes in the context of moderate alleles that more closely mimic the genetics of SMA has not been performed in the fly, leading to debate over the validity and translational value of this model. We, therefore, examined 14 Drosophila lines expressing SMA patient-derived missense mutations in Smn, with a focus on neuromuscular phenotypes in the adult stage. Animals were evaluated on the basis of organismal viability and longevity, locomotor function, neuromuscular junction structure, and muscle health. In all cases, we observed phenotypes similar to those of SMA patients, including progressive loss of adult motor function. The severity of these defects is variable and forms a broad spectrum across the 14 lines examined, recapitulating the full range of phenotypic severity observed in human SMA. This includes late-onset models of SMA, which have been difficult to produce in other model systems. The results provide direct evidence that SMA-related locomotor decline can be reproduced in the fly and support the use of patient-derived SMN missense mutations as a comprehensive system for modeling SMA.
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Affiliation(s)
- Ashlyn M. Spring
- Integrative Program in Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, United States
| | - Amanda C. Raimer
- Integrative Program in Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, United States
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC, United States
| | - Christine D. Hamilton
- Integrative Program in Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, United States
| | | | - A. Gregory Matera
- Integrative Program in Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, United States
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC, United States
- Department of Biology, University of North Carolina, Chapel Hill, NC, United States
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, United States
- Department of Genetics, University of North Carolina, Chapel Hill, NC, United States
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