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

Schwartz, O, Vill, K, Pfaffenlehner, M, Behrens, M, Weiß, C, Johannsen, J et al.. Clinical Effectiveness of Newborn Screening for Spinal Muscular Atrophy: A Nonrandomized Controlled Trial. JAMA Pediatr. 2024. PMID:38587854

Vill, K, Tacke, M, König, A, Baumann, M, Baumgartner, M, Steinbach, M et al.. 5qSMA: standardised retrospective natural history assessment in 268 patients with four copies of SMN2. J Neurol. 2024.271 (5)2787-2797 PMID:38409538

Günther, R, Wurster, CD, Brakemeier, S, Osmanovic, A, Schreiber-Katz, O, Petri, S et al.. Long-term efficacy and safety of nusinersen in adults with 5q spinal muscular atrophy: a prospective European multinational observational study. Lancet Reg Health Eur. 2024.39 100862 PMID:38361750

Baranello, G, Neurodevelopment in SMA Working Group. The emerging spectrum of neurodevelopmental comorbidities in early-onset Spinal Muscular Atrophy. Eur J Paediatr Neurol. 2024.48 67-68 PMID:38043384

Walter, MC, Laforêt, P, van der Pol, WL, Pegoraro, E, 254th ENMC Workshop Study Group. 254th ENMC international workshop. Formation of a European network to initiate a European data collection, along with development and sharing of treatment guidelines for adult SMA patients. Virtual meeting 28 - 30 January 2022. Neuromuscul Disord. 2023.33 (6)511-522 PMID:37245491

Danko, V, Jüngert, J, Schuessler, S, Buehler, A, Klett, D, Federle, A et al.. Hybrid reflected-ultrasound computed tomography versus B-mode-ultrasound for muscle scoring in spinal muscular atrophy. J Neuroimaging. 2023.33 (3)393-403 PMID:36627228

Pechmann, A, Behrens, M, Dörnbrack, K, Tassoni, A, Wenzel, F, Stein, S et al.. Improvements in Walking Distance during Nusinersen Treatment - A Prospective 3-year SMArtCARE Registry Study. J Neuromuscul Dis. 2023.10 (1)29-40 PMID:36565133

Landfeldt, E, Abner, S, Pechmann, A, Sejersen, T, McMillan, HJ, Lochmüller, H et al.. Caregiver Burden of Spinal Muscular Atrophy: A Systematic Review. Pharmacoeconomics. 2023.41 (3)275-293 PMID:36515815

Karimzadeh, P, Najmabadi, H, Lochmuller, H, Babaee, M, Dehdahsi, S, Miryounesi, M et al.. Five patients with spinal muscular atrophy-progressive myoclonic epilepsy (SMA-PME): a novel pathogenic variant, treatment and review of the literature. Neuromuscul Disord. 2022.32 (10)806-810 PMID:36309462

Pechmann, A, Behrens, M, Dörnbrack, K, Tassoni, A, Wenzel, F, Stein, S et al.. Improved upper limb function in non-ambulant children with SMA type 2 and 3 during nusinersen treatment: a prospective 3-years SMArtCARE registry study. Orphanet J Rare Dis. 2022.17 (1)384 PMID:36274155

See more on PubMed