Spinal Muscular Atrophy (SMA)

Spinal muscular atrophy (SMA) in children is a genetically based (inherited) neuromuscular disease that disrupts the ability of nerves to communicate with muscles. A child with SMA gradually loses control of most core muscle groups, which grow weak from lack of use. Nemours neuromuscular specialists offer many treatments and therapies to slow its progression and maximize function. Additionally, in 2016, there was a breakthrough in the treatment of SMA in children, allowing some children to live longer and reach developmental milestones. Nemours was on the forefront of the research leading to this discovery.

Learn More About Spinal Muscular Atrophy (SMA) in Children
Four Types of Spinal Muscular Atrophy (SMA) in Children

There are four types of SMA, based on how severe the symptoms are and when they begin. Generally, the longer it takes for symptoms to start appearing, the less severe the disease will be.

  • SMA type 1 (also called Werdnig-Hoffmann disease) is the most severe, with symptoms starting between birth and 6 months of age. These babies fail to sit or walk.
  • SMA type 2 (or chronic infantile SMA), has more moderate symptoms, which start when a child is six to 18 months old. These infants can sit but not walk.
  • SMA type 3 (Kugelberg-Welander disease or juvenile spinal muscular atrophy) has the mildest symptoms, which can start between 18 months and the teen years. These children do walk but have limitation and may lose skills over time.
  • SMA type 4 develops more slowly, with symptoms usually starting after age 35, with slowly progressive limitation in walking.
How Spinal Muscular Atrophy (SMA) in Children Develops

Healthy muscles depend on nerve cells called motor neurons to tell them what to do. The motor neurons are located in the brain and spinal cord and carry these instructions from the brain, down the spine, to the muscle. The motor neurons depend on a special protein called SMN (“Survival of Motor Neurons”) to function properly.

Children with spinal muscular atrophy (SMA) lack the ability to make this essential SMN protein, because the gene for SMA that makes it possible to produce SMN is either defective or missing. Without sufficient SMN protein the motor neurons lose the ability to carry the brain’s instructions to the muscles. The muscles grow weak from lack of use and waste away (muscular atrophy). Thus the term “spinal muscular atrophy.”

Diagnosing Spinal Muscular Atrophy (SMA) in Children

Doctors who think a child might have SMA usually rely on various tests and imaging procedures to narrow down the diagnosis. These may include an electromyogram (EMG) and nerve conduction study.

In most cases, when SMA in children is suspected, the physician goes right to a genetic test (blood test) that checks to see if the gene responsible for producing the SMN protein is defective or missing.

Nemours Children's Specialty Care, Jacksonville

807 Children’s Way
Jacksonville, FL 32207
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For Appointments: (904) 697-3600

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What to Bring
  • your photo ID
  • insurance and/or Medicaid cards
  • referral from your referring physician (if required by your insurance)
  • co-payment, if applicable
  • legal guardianship or custody papers if you are not the patient’s parent
If available, please provide:
  • preferred pharmacy contact information
  • names and dosages of all medications your child is taking (including over-the-counter medications)
  • name and number of your primary care physician
  • parent (and child’s) social security numbers
  • parent work information (address, telephone numbers)
  • immigration information (if your child was not born in the United States)
  • list of prior immunizations
New Patients
  • Patient Registration (PDF)
Returning Patients
  • Release of Information (PDF)
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  • Patient Presents Without Legal Guardian (PDF)
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    Note: A parent or legal guardian must be with a child for a first visit.
Forms & Resources
New Patient Forms
  • Patient Registration (PDF)
Returning Patient Forms
  • Release of Information (PDF)
    English | Spanish
  • Patient Presents Without Legal Guardian (PDF)
    English | Spanish
    Note: A parent or legal guardian must be with a child for a first visit.
Resources for Patients & Families
Support Services

Ronald McDonald House of Jacksonville: A safe, free, family-centered home away from home when your child is sick and needs to be hospitalized

CaringBridge: Visit this free website offering support and communication to help your family through your child's medical journey.

Children with SMA need an extra helping of love and care. Working with your child’s primary care physician, the pediatric specialists at Nemours Children’s Specialty Care, Jacksonville and Wolfson Children’s Hospital take a coordinated approach to caring for children with all forms of this inherited disease. Our SMA care is part of a comprehensive Neuromuscular Disease program that is approved and supported by the Muscular Dystrophy Association (MDA).

We partner seamlessly with specialists from Wolfson Children’s Hospital to deliver quality care for kids with SMA and other neuromuscular disorders. This unique relationship allows our Nemours specialists to provide pediatric consultation whether it’s in the Emergency Department, the hospital or on an outpatient basis.

It takes a team of pediatric professionals working together to care for a child with SMA. At Nemours Children’s Specialty Care, Jacksonville you’ll find doctors, nurses and staff who are uniquely qualified to provide this care, and who share a strong commitment to the long-term health and well-being of your child. Whatever form of this inherited disease your child has, our goal is simple: to treat each child as we would our own.

Our Coordinated Spinal Muscular Atrophy (SMA) Care Team

When you come to Nemours Children’s Specialty Care, Jacksonville you get a whole team of professionals devoted to your child’s care. Our experts treating SMA in children include:

  • Physicians like the neurologists who establish the diagnosis, consider treatment options and help manage symptoms as SMA progresses. Also neuromuscular disease specialists in rehabilitation, orthopedics, pulmonology and gastroenterology.
  • Dietitians who can provide nutritional support and advice.
  • Geneticists to help families understand the genetic basis of SMA and offer counseling to make informed decisions about expanding their family.
Improving the Quality of Life for Children With Spinal Muscular Atrophy

At Nemours Children’s Specialty Care, Jacksonville, our coordinated care team will work with your child to ease discomfort, build strength and preserve independent functioning for as long as possible. We treat SMA in children in a number of ways, including:

  • When appropriate, fit your child for orthotics (braces), mobility devices (such as a wheelchair and other assistive devices).
  • Work with your family and caregivers to show you how to prepare nutritious meals that are easier to swallow and digest. If needed, we can also provide mechanical feeding systems to ensure that your child receives ongoing nutrition.
  • Provide medication to help your child’s muscles function optimally.
  • Support your child’s bone structure if orthopedic problems develop.
  • Help your child avoid lung infections and related problems. If needed, we can offer breathing support devices.
Sharing Our Pediatric Neurology Expertise With Mayo Clinic

Nemours’ expert pediatric neurologists do more than treat children. We share our knowledge and expertise with other medical professionals in the area. In a program dating back to 2005, our neurology specialists collaborate with Mayo Clinic Jacksonville to give Mayo residents practical training about the special challenges of treating kids with neurological issues.

We are proud to work with Mayo Clinic Jacksonville on this successful program — and happy to share our unique knowledge with other physicians. Because from our perspective, it’s all about the kids.

We Value Your Involvement in Your Child's Care

We may know how to treat your child’s SMA, but no one knows your child better than you. That’s why we want you to be an active participant in the decision-making process for your child’s treatment. We’ll explain every step in easily understandable terms, present all options including alternative methods, and invite your input.