If your child was recently diagnosed with spinal muscular atrophy (SMA) — or if you were recently diagnosed as an adult — you’re likely wondering how the condition will affect the future. A quick online search shows that neuromuscular diseases like SMA may affect your ability to walk. While this is a scary realization, new treatments and devices are helping people with SMA live healthier, more comfortable lives.

In this article, we’ll clarify if walking is possible for individuals with SMA and how your specific SMA type may affect your ability to walk. We’ll also go over how assistive equipment, standers, and even new treatments can improve walking ability.

What Is SMA and How Does It Affect Your Muscles?

SMA is a motor neuron disease that affects the nerve cells in the spinal cord responsible for controlling muscle movements. It’s caused by a mutation (change) in the survival motor neuron 1 (SMN1) gene that’s passed down through family members.

Motor neurons need SMN proteins to work normally — without them, they can’t send electrical signals from the brain to the spinal cord and muscles. As a result, people with SMA have:

• Weakened muscles
• Hypotonia (loss of muscle tone), which can make babies look “floppy”
• Scoliosis or curvature of the spine
• Trouble standing and walking on their own

SMA affects everyone differently, so it’s important to understand which factors have an impact on mobility with this disease. Here are four things to know about walking with SMA.

1. Walking Ability Changes Based on the Type of SMA

There are four types of SMA based on the age it begins and how severe the symptoms are:

• SMA type 1 (infantile-onset SMA or Werdnig-Hoffmann disease) — The most severe form of SMA that starts in infants
• SMA type 2 (Dubowitz disease) — An intermediate form of SMA that develops in children ages 6 to 18 months
• SMA type 3 (Kugelberg-Welander disease) — A mild form of SMA that starts in children ages 18 months and older
• SMA type 4 — Begins in adulthood in people in their 20s and 30s; symptoms are mild and progress slowly over time

Infants with SMA type 1 will develop extremely weak and shortened muscles. These infants won’t be able to walk. Unfortunately, many children die before they reach their second birthday.

Children with type 2 SMA can typically sit up on their own but need help walking. They need supportive devices and wheelchairs to help them stand up and get around. Most people with type 2 SMA live into their 20s or 30s.

Those with type 3 SMA can typically walk on their own but may need additional support when standing up, climbing stairs, or running. As their disease progresses, they’ll eventually lose their ability to walk and will need a wheelchair later in life.

Adults with SMA type 4 typically don’t have many mobility issues. They can still walk on their own but may experience tremors, muscle weakness, and some breathing problems.

It’s important to note that SMA is a progressive disease that changes and gets worse over time. Children who can walk on their own early on may eventually lose this ability and require extra help.

2. Assistive Devices May Help People With SMA Walk

SMA causes atrophy (muscle weakness and wasting), which can make walking difficult. Fortunately, there are several assistive devices available to meet your needs or your child’s. Every person is unique, so it’s important to work with your doctor or your child’s pediatrician to find the best device to suit your needs.

If it’s an option for you, a walker is a great way for you or your child to maintain their independence while still being able to move safely. They can help build upper body strength, improve muscle tone, and take stress off weakened leg muscles and joints.

Your child’s doctor can refer you to occupational therapy and/or physical therapy to learn more about available options. They may suggest a rolling walker for your child. If your child has weak feet or ankles, splints and braces can provide added support while they’re walking.

For those who can’t walk, standers help people with SMA stand upright, work their leg muscles, and maintain bone health.

3. New SMA Treatments May Help Children Hit Developmental Milestones

In recent years, the U.S. Food and Drug Administration (FDA) has approved three SMA treatments. One of these is nusinersen (Spinraza), a medication that increases SMN protein production. It creates more SMN2 protein to make up for the mutations in the SMN1 gene. Nusinersen is injected directly into the spinal cord canal to target motor neurons there.

Because this treatment is still relatively new, doctors and researchers continue to learn more about it in studies. Data from the NURTURE clinical trial published in 2022 showed that nusinersen is helping children with SMA hit important developmental milestones and walk on their own.

The researchers followed 25 children treated with nusinersen for nearly three years and found that all of them were able to sit up on their own without support. Even more importantly, 22 of the 25 children were able to walk by themselves.

Other studies have investigated gene replacement therapy with onasemnogene abeparvovec-xioi (Zolgensma) and its effects on hitting milestones. This treatment works by providing a working SMN1 gene to motor neurons. As a result, children with SMA can make SMN proteins needed for proper muscle function.

One study from the journal Nature Medicine followed 14 children treated with onasemnogene abeparvovec-xioi and found that many of them were able to walk independently. The study authors used two developmental criteria to define when the children walked and found that most could walk alone within the normal developmental window — generally from 1 to 1.5 years old.

These studies show that new SMA treatments are helping children achieve what wasn’t possible only a decade ago. It’s important to note that we don’t know the long-term effects of these therapies on mobility and the progressive nature of SMA. However, these results seem promising, and more information is constantly being discovered.

4. New Treatments May Improve Endurance in Children and Teens With SMA

Researchers have also looked into how new treatments affect children and teenagers with type 2 and type 3 SMA. One study cited in the journal Muscle & Nerve followed 14 participants aged 2 to 15 years who were treated with nusinersen.

The study authors followed the participants for three years and found that they were able to perform better on the six-minute walk test over time. This test measures how far you can walk in six minutes. The authors also found that the people in the study experienced less fatigue.

This study showed that nusinersen could help improve walking endurance in children and teenagers with later-onset SMA. Information like this helps doctors and researchers understand the longer-term effects of SMA treatment.

More research is needed to learn more about these therapies and their effects on walking ability. Your doctor can provide you with information tailored to you or your child’s specific disease progression and symptoms. If you have any questions about getting around and walking or need details on assistive devices, don’t hesitate to reach out to your neurology team — their job is to help you!

Talk With Others Who Understand

On mySMAteam, the social network for people with SMA and their loved ones, more than 2,300 members come together to ask questions, give advice, and share their stories with others who understand life with SMA.

Do you or your child use an assistive device for walking? What works best? Share your experience in the comments below, or start a conversation by posting on your Activities page.