SMA is a rare genetic condition caused by a lack of SMN protein in the central nervous system. This leads to damage and death of motor neurons (the nerves that control muscle movement), causing muscle weakness throughout the body.3 This muscle weakness occurs in all types of SMA. However, it can be hard to recognise in teens and adults at first.1,4
“Samuel started to lose strength over the years. At the age of 14, he started to walk differently, his pace was different, he was throwing his hip before his legs. Walking up the stairs, he was pulling on the rail all the time, couldn’t do it on his own.”
— Caregiver of a young adult living with SMA
The gradual loss of muscle function over time varies in different types of SMA. In SMA Type 2a, we see a steady loss of muscle strength. However, in SMA types 2b and 3, there is a phase where muscle strength seems relatively stable, which can start to worsen after the age of 30 or 40.1
“From the period of like 26 to probably age 31, I was just you know, swimming, I was doing the treadmill, …and I felt like SMA was stable at that point, and I was moving around a lot and I felt really good.
At age 31, I’m not sure really what prompted the decline, I understood that the disease is progressive, so I think it was just time for it to do that, and then around the age of 33 I hit another drop. I really noticed it when I was showering, it was hard to get my arms up in certain positions and things of that nature.”
— Ian, an adult living with SMA Type 3
A lot has changed in the management of spinal muscular atrophy (SMA). Ask your doctor for a special referral today.
In teens and adults living with SMA, the “Hammersmith Motor Function Scale – Expanded” (HFMSE) is widely used to monitor motor function. By measuring 33 activities related to daily life, the HFMSE score is proven to measure changes in motor function over time accurately.6,7
With the development of treatments, people living with SMA can improve their motor function and increase their HFMSE score.8,9 Improvement can mean going from needing help with an activity to being able to perform it on their own.6,7
Although SMA has no cure, treatment options have significantly improved over the past few years.
Not only can they help stabilise the disease, but they may even help improve motor function.8-10
A survey revealed that people living with SMA wish to carry out daily activities that enable them to maintain their independence.2
HFMSE=Hammersmith Functional Motor Scale Expanded; SMA=spinal muscular atrophy; SMN=survival motor neuron.
The characters shown are real patients and the required consent to use their stories has been obtained from the patients and families. Photographs are for illustrative purposes only.
1. Wadman RI, Wijngaarde CA, Stam M, et al. Muscle strength and motor function throughout life in a cross-sectional cohort of 180 patients with spinal muscular atrophy types 1c-4. Eur J Neurol. 2018;25(3):512-518.
2. Rouault F, Christie-Brown V, Broekgaarden R, et al. Disease impact on general well-being and therapeutic expectations of European type II and type III spinal muscular atrophy patients. Neuromuscul Disord. 2017;27(5):428-438.
3. Lunn MR, Wang CH. Spinal muscular atrophy. Lancet. 2008;371(9630):2120-2133.
4. Mercuri E, Sumner CJ, Muntoni F, et al. Spinal muscular atrophy. Nat Rev Dis Primers. 2022;8(1):52.
5. Kaufmann P, McDermott MP, Darras BT, et al. Prospective cohort study of spinal muscular atrophy types 2 and 3. Neurology. 2012;79(18):1889-1897.
6. Biogen. Hammersmith functional motor scale – expanded (HFMSE) [Accessed 10 March 2023]. Available from:
7. Pera MC, Coratti G, Forcina N, et al. Content validity and clinical meaningfulness of the HFMSE in spinal muscular atrophy. BMC Neurol. 2017;17(1):39.
8. Coratti G, Cutrona C, Pera MC, et al. Motor function in type 2 and 3 SMA patients treated with nusinersen: A critical review and meta-analysis. Orphanet J Rare Dis. 2021;16(1):430.
9. Hagenacker T, Wurster CD, Günther R, et al. Nusinersen in adults with 5q spinal muscular atrophy: A non-interventional, multicentre, observational cohort study. Lancet Neurol. 2020;19(4):317-325.
10. Bharucha-Goebel D, Kaufmann P. Treatment advances in spinal muscular atrophy. Curr Neurol Neurosci. 2017;17(11).
11. Harvard Health. Top 6 ways to get the most out of your doctor visit. Harvard Health Letter. 2015;40(4).