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Three Things You Should Know About Spinal Muscular Atrophy

Published on Aug. 22, 2022

August is Spinal Muscular Atrophy (SMA) Awareness Month. If you’ve never heard of SMA, you’re not alone; although one in 50 people is a genetic carrier of SMA, it affects just 1 in 10,000 babies. SMA is a rare and devastating disease, but thanks to advancements in early detection and treatment, there is hope.

In recognition of SMA Awareness Month and in honor of those in our communities living with SMA, here are three key things to know about spinal muscular atrophy.


1. SMA is a progressive disease that affects a person’s muscles.

SMA is a genetically inherited neuromuscular disease that is caused by a deletion or mutation of the survival motor neuron gene 1 (SMN-1), which produces a protein essential for nerve cells to function properly and control muscles. Without the SMN-1 protein, nerve cells weaken and eventually die, leading to muscle weakness and atrophy, which is often fatal. This loss of muscle function includes losing the ability to eat, swallow, breathe and move, but does not impact a person’s ability to think or understand.

2. There are different types of SMA.

SMA is classified into four main types, based on age of onset and severity:

  • In SMA type I, symptoms begin to show as early as birth to 6 months. At first, a baby might appear to be an awake, alert baby who is very floppy. However, they eventually have trouble breathing, swallowing and eating, and do not develop the ability to sit on their own.
  • In SMA type II, symptoms start between 6 months to 18 months. Children with this type of SMA are usually unable to walk or stand without support.
  • In type III SMA, symptoms usually begin after 18 months of age. Children with SMA type III are able to walk but eventually have progressive muscle weakness and may lose this ability over time.
  • SMA type IV is adult onset. Weakness starts between 20 to 30 years of age, and similar to type III SMA, they may lose the ability to walk in adulthood.

3. While there is no cure for SMA, there is hope.

Thanks to years of research and advocacy, there have been significant medical breakthroughs in the past six years in SMA management. Before December 2016, there were no treatments for SMA. Now there are three FDA-approved therapeutic options, all of which are offered at Valley Children’s. Beyond that, SMA was added to California’s newborn screening panel in June 2020. This means that today, babies born in California are screened for SMA at birth, allowing for earlier detection and treatment. This step has been lifesaving, as SMA is an irreversible disease – the sooner a child can be diagnosed and treated, the less their muscles are irreversibly weakened.

As one of only seven service centers designated by the California Public Health Newborn Screening Program and the only newborn screening program in the Central Valley, Valley Children's oversees newborn screening results for all babies born in our 32-county region of California. Since August 2021, Valley Children’s has helped confirm a SMA diagnosis for six newborns. Thanks to this early detection and intervention, all received treatment within weeks of their first breaths and most have met their developmental milestones.

Together with our communities and families, please join us in celebrating these truly life-changing accomplishments in honor of SMA Awareness Month.


Learn more about SMA

Read Rafael's story, "One Big Step for Rafael, One Giant Leap for Spinal Muscular Atrophy," to learn more about SMA and how early screening and intervention helped him take his first steps. Click here to read Rafael's story.