living with sma and defying expectations
when mason stewart was diagnosed with a rare neuromuscular disorder as a toddler, his world seemed to be shrinking. now a teenager, his future is turning out to be brighter than anyone could have imagined.
published feb 23, 2026
4 minute read
4 minute read
despite being diagnosed with sma, 16-year-old mason stewart (second from left) leads an exceptionally active life. ashley fraser
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when he’s not in school, 16-year-old mason stewart doesn’t spend much time sitting still. he works on his family’s farm near perth, ont., holds a job on weekends at a local grocery store and enjoys hunting and fishing in his down time. “i like to be outside as much as i can,” he says.
but mason’s ability to lead such an active lifestyle wasn’t always a sure thing. when he was just two years old he was diagnosed with spinal muscular atrophy (sma), a serious and rare genetic disease that robs patients of muscle and leads to progressive loss of strength, mobility and independence.
in its severest forms, sma impacts a patient’s ability to eat and breathe and can cut life short while still in infancy. at the time of mason’s diagnosis in 2011, the future looked bleak. “they told us there was no treatment, and to just go home and love him,” recalls his mom, jenna.
things are looking very different for her son today due to advancements in sma research that occurred in the years that followed his diagnosis. “if someone had told me then that mason would be walking at 16,” says jenna, “i honestly wouldn’t have thought it could be possible.”
a degenerative disease
“sma results from an abnormality in each of two copies of a very critical gene called survival motor neuron one (smn1),” explains dr. hugh mcmillan, a pediatric neurologist and neuromuscular specialist at the children’s hospital of eastern ontario (cheo) in ottawa. the alteration prevents the production of the smn1 protein, which keeps the motor neurons in the spinal cord alive.
“in the natural course of the disease, the motor neurons degenerate without the smn1 protein, and the nerves that extend out to different parts of the body then die and the muscles they control will slowly waste,” dr. mcmillan says.
in mason’s case, subtle signs of muscle atrophy appeared early in his life. although he hit most normal developmental milestones, his ability to walk was delayed until he was more than a year and a half old. when he was on his feet as a toddler, jenna noticed that his gait was unusual and that he often had difficulty when supporting himself. the stewart family consulted doctors to seek possible explanations for what they saw, and anxiously awaited test results.
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when their medical team confirmed that mason had type 3 sma, it seemed as though their worst fears were being realized. the hopes and dreams they had about mason’s future were suddenly in doubt as he faced a lifetime of continuous muscle weakness and disability.
“i went home and researched sma obsessively, and there was a lot of negative information on social media,” recalls jenna. “at the time, there was nothing that could be done for kids with this condition. they said that mason would probably be in a wheelchair permanently by the time he was eight.”
as he grew, mason could feel how the disease was increasingly taking its toll, remembering that he was particularly aware of its effect on him by the time he turned nine. “i started to realize i was getting weaker,” he says. “my dad would have to carry me up the stairs or into the bush to go hunting. i really started to notice being held back by this and felt that i was ‘different.’”
mason and his mom, jenna. ashley fraser
the turning point that changed mason’s life
in the years that followed, the stewart family kept tabs on sma research and began to learn about promising new scientific developments, which eventually gave rise to the availability of new treatment approaches. although new hope was being offered to sma patients like mason, the stewarts couldn’t help but feel skeptical — how would he respond? they would soon find out, just months before their son’s 11th birthday in 2020 when mason began treatment.
mason can still picture a watershed moment that occurred soon afterward, when he had a sudden realization that he was able to able to do things he couldn’t do before. “i remember stepping up over this curb one day, and just being aware that i could do it without needing any help from my dad like usual,” he says. gains in strength and endurance followed, and everyday tasks grew less difficult. “i can go up a couple of stairs; fishing is easier; when i shoot a gun, i don’t have to lean on a rest,” he says.
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jenna struggles to find words that explain how watching this unfold made her feel. “i remember being in disbelief at the improvements we saw,” she says. “it’s been life changing. he lives an inclusive life now, without feeling left out or different from others.”
x-rays would later reveal that the degree of scoliosis in mason’s spine – a common symptom resulting from muscle weakness caused by sma — had also improved. it was a development that elated jenna. “i had them blown up into a poster,” she says.
had mason not received this intervention when he did, however, “there is a strong likelihood that he would not be able to walk or do a lot of the things that bring him joy today,” dr. mcmillan notes. “the landscape is changing very rapidly right now — there’s a significant amount of research going on to advance care for sma and many other neuromuscular conditions. it’s a time of hope.”
he adds that keeping the progression of muscle loss at bay requires ongoing care, and mason and his parents certainly don’t plan to change a thing about the path they’re on. “it’s like a miracle,” jenna says. “why fix it if it’s not broken?”
this story was created by healthing content works, healthing.ca’s commercial content division, on behalf of biogen canada.
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