Receiving an SMA Diagnosis Through Newborn Screening

Spinal muscular atrophy, or SMA, is a rare disease that few people know about until they face a diagnosis.

Once your child has been diagnosed with SMA, it's important to quickly gain some understanding of the condition so that you can act quickly to seek treatment. With SMA, the earlier the treatment, the better.

This page is intended to give you a quick overview of some of the most important things you need to know about SMA. Many resources are also available to view and download on our website

What is spinal muscular atrophy?

Spinal muscular atrophy, or SMA, affects the cells in the nervous system that send signals to the muscles to work. When these special cells, called motor neurons, don’t function properly, muscles become very weak. People with SMA may have difficulty walking, eating, and even breathing because of muscle weakness. You may hear people refer to SMA “types.” Before newborn screening for SMA, patients were often diagnosed only after symptoms appeared and were then categorized into four main types depending on their age and development. You can find out more about SMA types here

What causes SMA?

SMA is an inherited disease, one that is passed from parents to children. It is caused by a missing or faulty gene—the survival motor neuron 1 gene, or SMN1. In healthy people, the SMN1 gene produces a protein called survival motor neuron (SMN) protein, which is important to motor neurons (special nerve cells that communicate with muscles). There’s also a second gene that plays a role in producing the SMN protein. It’s called the survival motor neuron gene 2 (SMN2), often referred to as a “back-up gene.” Because most of the SMN protein produced by SMN2 lacks a key building block normally produced by SMN1 it cannot fully make up for the missing or faulty SMN1 gene. However, the number of SMN2 genes varies from person to person, and people with more SMN2 copies may have a less severe form of SMA than those with fewer copies.

Without the protein, motor neurons don’t work right and eventually die, leading the muscles to weaken and die too.

Early is better

Early treatment offers the best chance for a child to stay as healthy as possible.

Without enough protein from the missing or faulty SMN1 gene or the backup SMN2 gene, motor neurons die quickly. Without any treatment, babies with the most severe cases of SMA lose 90% of their motor neurons by the time they are six months old.

Once lost, motor neurons cannot be replaced. The body does not generate new motor neurons, and none of the treatments available or being researched will do so either. That means that the best treatment may be before a baby shows signs of being sick. The goal is to save the greatest possible number of motor neurons so a baby’s muscles develop and function properly.

Liliana Grace was born with SMA. She began treatment with SPINRAZA through a drug study when she was 12 days old. Now age 2, she has reached or exceeded every developmental milestone expected for a child her age with SMA. 

"Do not wait to seek treatment. I don't know how to stress it enough."

—Denise, mother of Liliana Grace

Learn about early treatment 

How is SMA passed down?

A child with SMA received a missing or faulty SMN1 gene copy from both parents. Most children with SMA have two parents who do not have the disease but who carry it. These parents have one functioning SMN1 gene, but their second copy of the gene is missing or faulty. Learn more about the genetics of SMA here

How is SMA diagnosed?

Some states began testing newborns for SMA in 2018 by checking a small amount of blood at birth for the presence of SMN1 genes. Parents of babies who are missing two SMN1 genes receive notice that their babies likely have SMA. Doctors may then order a blood test to confirm the diagnosis.

Without a newborn screening test, doctors need to do multiple tests when SMA is suspected. This is because SMA is not the only condition that can cause weakness or a delay in meeting milestones, so further examination and testing is needed to find the cause of the symptoms.

Additional tests may be conducted to estimate how serious a case of SMA a child has and to determine the best course of treatment.

What treatments are available?

The first FDA-approved treatment for SMA, SPINRAZA, was approved in 2016. SPINRAZA, made by Biogen, cannot repair the damage done by SMA before treatment started. It may, however, be able to prevent symptoms from showing up or stop the progression of the disease so that a patient’s muscles stay as strong as they were when they started receiving the medication. Learn more about SPINRAZA here

Other treatments for SMA are being studied. You can check out clinical trials that your child may be eligible to participate in here

Will my child need help living with SMA?

With early treatment, many children with SMA may be able to live healthier lives. Nonetheless, they may occasionally require help with physical needs and daily activities. You can get more information on breathing and coughing devices, food and nutrition, adaptive equipment, and other needs here

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