Spinal muscular atrophy (SMA) is a genetic condition causing muscle weakness and atrophy. It usually starts in infancy or early childhood. New therapies and supportive measures can help improve the outlook.

SMA can lead to joint deformities, feeding difficulties, and potentially life threatening breathing problems. Children and adults with SMA may have difficulty sitting, standing, walking, or completing other activities without assistance.

Take a moment to learn more about treatment options for SMA.

There’s no cure for SMA, and it can affect your child’s body in different ways. To manage their varied support needs, it’s essential to get comprehensive care from a multidisciplinary team of healthcare professionals.

Regular checkups will allow your child’s health team to monitor their condition and assess the best treatment and how well it works.

They may recommend changes to your child’s treatment plan if your child develops new or worsened symptoms. They may also recommend changes if new treatments become available.

Doctors may determine the best treatment based on various factors such as:

  • the type of SMA your child has
  • which parts of the body does the disease affect, such as the muscles involved with breathing, leg muscles, or the digestive system (swallowing)
  • your child’s age
  • whether your child has any other health issues
  • how your child tolerates various treatments

To treat the underlying causes of SMA, the Food and Drug Administration (FDA) has recently approved three specific therapies:

  • Nusinersen (Spinraza): This is approved to treat SMA in children and adults. It’s designed to boost the production of the sensor motor neuron (SMN) protein, which is insufficient in people with most types of SMA. The protein helps motor nerves survive.
  • Onasemnogene abeparvovec-xioi (Zolgensma): This is approved to treat SMA in children under 2 years old.
  • Risdiplam (Evrysdi): This is approved to treat SMA in individuals ages 2 months and older.

These treatments are relatively new, so experts don’t yet know what the long-term effects of using these treatments may be. So far, studies suggest that they may significantly limit or slow the progression of SMA.

Spinraza

Spinraza treats SMA in children and adults. It’s designed to boost the production of the sensor motor neuron (SMN) protein, which is insufficient in people with most types of SMA. The protein helps motor nerves survive.

The FDA approved the treatment based on clinical studies that suggest infants and children who receive the treatment may be able to achieve improved motor milestones, such as crawling, sitting, rolling, standing, or walking.

If your child’s doctor prescribes Spinraza, they’ll inject the medication into the fluid surrounding your child’s spinal cord. They’ll start by giving four doses of the medication over the first couple months of treatment. After that, they’ll administer one dose every 4 months.

Potential side effects from this medication include:

  • increased risk of respiratory infection
  • increased risk of bleeding complications
  • kidney damage
  • constipation
  • vomiting
  • headache
  • back pain
  • fever

Although side effects are possible, keep in mind that your child’s healthcare professional will only recommend the medication if they believe the benefits outweigh the chance of developing side effects.

Zolgensma

Zolgensma is a type of gene therapy in which a modified virus is used to deliver a functionalSMN1 gene. People with SMA have a defect in this gene that normally codes for SMN protein.

The FDA approved the medication based on clinical trials involving only infants with SMA under 2 years old. Participants in the trials showed significant improvements in developmental milestones, such as head control and the ability to sit without support, compared to what would be expected for patients who didn’t receive treatment.

Zolgensma is a one-time treatment that’s administered through intravenous (IV) infusion.

Potential side effects include:

  • vomiting
  • abnormally elevated liver enzymes
  • serious liver damage
  • increased markers of heart muscle damage

If your child’s doctor prescribes Zolgensma, they’ll need to order tests to monitor your child’s liver enzyme health before, during, and after treatment. They can also provide more information about the benefits and risks of the treatment.

Evrysdi

Evrysdi is the first oral medication approved for the treatment of SMA. It’s composed of a small molecule that works by modifying the amount of SMN protein that’s made from the SMN2 gene.

Like SMN1, the SMN2 gene produces SMN protein. However, it typically does this at lower levels. In fact, the extent to which SMN2 produces functional SMN protein has an impact on the severity of SMA.

Taking Evrysdi promotes more effective production of SMN protein from the SMN2 gene. This, in turn, helps to increase levels of SMN protein available in the nervous system.

Clinical trials of Evrysdi were performed in both infants and older individuals. After 12 months of treatment, 41 percent of infants could sit without support for 5 seconds or longer. Trials in older individuals found that, when compared to a placebo, muscle function improved after 12 months of treatment.

The FDA approved Evrysdi for use in individuals ages 2 months and older. The medication is taken orally once per day after a meal and is given using an oral syringe. The most common side effects of Evrysdi are:

  • fever
  • diarrhea
  • rash
  • mouth ulcers
  • joint aches and pains
  • urinary tract infections

Additional side effects may also occur in infants with SMA who are taking this medication. These include:

  • vomiting
  • constipation
  • upper respiratory tract infections
  • pneumonia

Talk with your child’s doctor about using Evrysdi to treat SMA. They can discuss the potential benefits and risks associated with Evrysdi and how it compares to other treatments for SMA.

In addition to SMA treatment that affects the SMN protein, your child’s doctor might recommend other treatments to help manage symptoms or potential complications.

Respiratory health

Children with SMA tend to have weak respiratory muscles, which makes it harder to breathe and cough. Many also develop rib deformities, which can worsen breathing difficulties.

If your child has difficulty breathing or coughing, it puts them at increased risk of pneumonia. This is a potentially life threatening lung infection.

To help clear your child’s airways and support their breathing, their health team may prescribe:

  • Manual chest physiotherapy: A healthcare professional taps on your child’s chest and uses other techniques to loosen and clear mucus from their airways.
  • Oronasal suctioning: A special tube or syringe is inserted into your child’s nose or mouth and used to remove mucus from their airways.
  • Mechanical insufflation: Your child is hooked up to a special machine that simulates a cough to clear mucus from their airways.
  • Mechanical ventilation: A breathing mask or tracheostomy tube is used to connect your child to a special machine that helps them breathe.

It’s also important to follow your child’s recommended vaccination schedule to lower their risk of infections, including influenza and pneumonia.

Nutritional and digestive health

SMA can make it hard for children to suck and swallow, which can limit their ability to eat. This can lead to poor growth.

Children and adults with SMA may also experience digestive complications, such as chronic constipation, gastroesophageal reflux, or delayed gastric emptying.

To support your child’s nutritional and digestive health, their healthcare team may recommend:

  • changes to their diet
  • vitamin or mineral supplements
  • enteric feeding, in which a feeding tube is used to deliver fluid and food to the stomach
  • medications to treat constipation, gastroesophageal reflux, or other digestive issues

Babies and young children with SMA have a higher chance of being underweight. On the other hand, older children and adults with SMA are at risk of being overweight due to low physical activity levels.

If your child is overweight, their healthcare team may recommend changes to their diet or physical activity habits.

Bone and joint health

Children and adults with SMA have weak muscles. This can limit their movement and put them at risk of joint complications, such as:

  • a type of joint deformity known as contractures
  • unusual curvature of the spine, known as scoliosis
  • distortion of the rib cage
  • hip dislocation
  • bone fractures

To help support and stretch their muscles and joints, your child’s healthcare team may prescribe:

  • physical therapy exercises
  • splints, braces, or other orthoses
  • other postural support devices

If your child has severe joint deformities or fractures, they may need surgery.

As your child gets older, they may need a wheelchair or other assistive device to help them get around.

Experimental treatments

Scientists are studying several other potential treatments for SMA, including:

  • branaplam
  • reldesemtiv
  • SRK-015

The FDA has not yet approved these experimental treatments. However, it’s possible that one or more of these treatments could be available in the future.

If you’re interested in learning more about experimental options, talk with your child’s doctor about clinical trials. Your healthcare team may be able to give you more information about whether your child could participate in a clinical trial and the potential benefits and risks.

Living with a serious health condition can be stressful for children, as well as their parents and other caregivers.

If you or your child is experiencing anxiety, depression, or other mental health challenges, let your doctor know.

They may refer you to a mental health specialist for counseling or other treatment. They may also encourage you to connect with a support group for people living with SMA.

What is the life expectancy of a person with SMA?

Life expectancy for SMA varies by type, with type 0 having the poorest outlook and type 4 having the best. Treatments can improve outcomes in many cases.

Is SMA always inherited, and can you get SMA if only one parent is a carrier?

In most cases, SMA is passed down through autosomal recessive inheritance, which means that the affected person has two mutated genes — typically, one from each parent. Those who have only one mutated gene are carriers of the disease but do not show any symptoms themselves.

What is the cause of death with SMA?

The cause of death for SMA is often respiratory because your breathing is affected, and you’re also more prone to lung infections like pneumonia.

What gender is SMA most common in?

In the United States, roughly 1 in 11,000 births result in a child with SMA. About 1 in 50 Americans carry the genetic mutation for this condition, which affects both males and females and people of all races.

However, a 2023 study suggests that it may affect more males than females.

Can someone with SMA have kids?

While we know that it’s possible, in theory, to become pregnant if you have SMA, there isn’t much research on this. It’s believed, however, that pregnancy may increase the chance of various complications from the disease and the pregnancy itself.

Though there’s currently no cure for SMA, there are treatments available to help slow the development of the disease, relieve symptoms, and manage potential complications.

Your child’s recommended treatment plan will depend on their specific symptoms and support needs. To learn more about the treatments that are available, talk with their healthcare team.

Early treatment is important for promoting the best possible outcomes in people with SMA.