Newborn Screening for SMA

SMA affects the nerves in the spinal cord that send signals to the muscles to tell them how to work. When these nerves don’t work, muscles can’t do their job and become very weak. People with SMA may have difficulty walking, eating, and breathing because of muscle weakness. The condition is serious and can lead to early death, but research shows that early diagnosis and early treatment can help.

When a baby is born, blood is taken to test for conditions that could affect the child’s health. If someone receives a positive result for SMA, the baby likely has SMA. The good news is that there are ways to treat SMA. A baby is tested at birth because it’s important to start treatment early. Though the baby may be healthy now, infants with SMA have a missing or faulty gene that can cause serious health problems later if not treated. A healthcare provider’s early determination about treatment offers the best chance that a baby will stay as healthy as possible.

The results of a newborn screening test show that a baby most likely has SMA. A doctor will order more tests to confirm the diagnosis. Additional tests may also provide information that helps predict how serious a case of SMA each child has.

Signs that a child has SMA (before receiving a treatment) will depend on the type of SMA the baby has. Historically, most cases of SMA are Type 1, which is the most serious. These symptoms appear within the first six months after birth. In some cases, like Types 2 and 3, symptoms may not appear until later. Depending on how serious a child’s condition is, the best chance to prevent dangerous muscle weakness in the child is to get treatment early. A child with SMA who is identified by newborn screening is often identified before signs and symptoms of SMA are present and are referred to as pre-symptomatic SMA. 

SMA is caused by a missing or faulty gene, known as the SMN1 gene. Babies usually receive two copies of this gene—one from the mother and one from the father. A person with only one functioning SMN1 gene is deemed to be healthy, so parents may pass down a missing or faulty SMN1 copy without knowing it. A baby born with SMA has received a missing or faulty SMN1 gene copy from both parents.

A small number, approximately 5%, of children with SMA have a point mutation in the SMN1 gene that is not picked up by newborn screening or usual genetic testing for SMA. The 5% not identified by newborn screening will develop signs of SMA, and the diagnosis of SMA will require additional testing with SMN1 gene sequence analysis.

Currently, there are multiple FDA-approved treatments for SMA. Evrysdi^® is a treatment developed by Genentech, a member of the Roche Group, and approved for the treatment of SMA in all ages and all types. Spinraza^®, a treatment developed by Biogen and Ionis, is approved to treat all ages and types. Zolgensma^® is a treatment developed by Novartis Gene Therapies to also treat all types of SMA in patients who are under two years of age. In addition to these approved treatments, several other treatments are being tested in clinical trials. If you are managing a new SMA diagnosis, make an appointment with your healthcare provider to discuss the best approach to treatment.

Take the following actions right away after receiving notice that your child has a positive newborn screen for SMA:

• Contact the baby’s doctor or other healthcare provider and share these test results, if they have not been shared already

• Ask the healthcare provider for a referral to a specialist, who will order more tests to confirm whether the baby has SMA. Often, though not always, the referral will be to a pediatric neurologist, a doctor who specializes in nerve diseases in children

• Get more information to share with the baby’s healthcare provider and other caregivers. The more you know, the quicker decisions can be made

• Contact Cure SMA by emailing your mailing address to [email protected] so we can overnight you an information packet and provide you with support and resources