Spinal muscular atrophy

Spinal muscular atrophy (SMA) affects the motor neurons – the nerve cells responsible for controlling movement of the skeletal muscles. Damage to or complete loss of motor neurons causes muscle wasting or atrophy and weakness. The weakness is usually more severe in the proximal muscles (close to the centre of the body) and usually worsens with age.

SMA is caused by defects in the SMN1 gene, which is responsible for making a protein called the survival motor neuron (SMN) protein. Various factors can affect the amount of SMN protein available and this in turn affects the severity of the disease, which has been classified into different types depending on the maximum functional ability the affected person reaches: individuals with type I never manage to sit independently; those with type II achieve the ability to sit up on their own but never manage to walk independently; type III patients achieve the ability to walk but may lose this ability later or require a wheelchair for longer distances.

Read more about SMA at the NIH Genetics Home Reference site here

Our research in SMA focuses on the epidemiology of the disease, as well as standards of care, data sharing and patient registries. SMA is at the forefront of therapy development in neuromuscular disease, and with new treatments being developed and approved, this background data is becoming essential for providing evidence to payers about the numbers of people benefiting from new therapies as well as determining long-term outcomes and access to therapies.



*Photo with the kind permission of Vitaliy Matyushenko, Children with Spinal Muscular Atrophy, Ukraine


Girl with SMA takes selfie with her brother

Relevant publications

Jacquier, A, Risson, V, Simonet, T, Roussange, F, Lacoste, N, Ribault, S et al.. Severe congenital myasthenic syndromes caused by agrin mutations affecting secretion by motoneurons. Acta Neuropathol. 2022.144 (4)707-731 PMID:35948834

Pechmann, A, Behrens, M, Dörnbrack, K, Tassoni, A, Stein, S, Vogt, S et al.. Effect of nusinersen on motor, respiratory and bulbar function in early-onset spinal muscular atrophy. Brain. 2022. PMID:35857854

Schorling, DC, Kölbel, H, Hentschel, A, Pechmann, A, Meyer, N, Wirth, B et al.. Cathepsin D as biomarker in cerebrospinal fluid of nusinersen-treated patients with spinal muscular atrophy. Eur J Neurol. 2022.29 (7)2084-2096 PMID:35318785

Regensburger, AP, Wagner, AL, Danko, V, Jüngert, J, Federle, A, Klett, D et al.. Multispectral optoacoustic tomography for non-invasive disease phenotyping in pediatric spinal muscular atrophy patients. Photoacoustics. 2022.25 100315 PMID:34849338

Töpf, A, Pyle, A, Griffin, H, Matalonga, L, Schon, K, Solve-RD SNV-indel working group et al.. Exome reanalysis and proteomic profiling identified TRIP4 as a novel cause of cerebellar hypoplasia and spinal muscular atrophy (PCH1). Eur J Hum Genet. 2021.29 (9)1348-1353 PMID:34075209

Slayter, J, Hodgkinson, V, Lounsberry, J, Brais, B, Chapman, K, Genge, A et al.. A Canadian Adult Spinal Muscular Atrophy Outcome Measures Toolkit: Results of a National Consensus using a Modified Delphi Method. J Neuromuscul Dis. 2021.8 (4)579-588 PMID:33867362

McMillan, HJ, Gerber, B, Cowling, T, Khuu, W, Mayer, M, Wu, JW et al.. Burden of Spinal Muscular Atrophy (SMA) on Patients and Caregivers in Canada. J Neuromuscul Dis. 2021.8 (4)553-568 PMID:33749617

Landfeldt, E, Pechmann, A, McMillan, HJ, Lochmüller, H, Sejersen, T. Costs of Illness of Spinal Muscular Atrophy: A Systematic Review. Appl Health Econ Health Policy. 2021.19 (4)501-520 PMID:33576939

Hodgkinson, V, Lounsberry, J, M'Dahoma, S, Russell, A, Jewett, G, Benstead, T et al.. The Canadian Neuromuscular Disease Registry 2010-2019: A Decade of Facilitating Clinical Research Througha Nationwide, Pan-NeuromuscularDisease Registry. J Neuromuscul Dis. 2021.8 (1)53-61 PMID:32925088

Hodgkinson, VL, Chapman, K, Izenberg, A, Lochmüller, H, O'Connell, C, O'Ferrall, EK et al.. Response to Provincial Governments' Decisions Regarding Monitoring for Adults with Spinal Muscular Atrophy. Can J Neurol Sci. 2021.48 (2)201-203 PMID:32713403

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