Spinal muscular atrophy (SMA) is an inherited condition that causes progressive muscle weakness by affecting the motor neurons that control movement. It was historically a leading genetic cause of infant death, but newer treatments work best when started before symptoms appear, which is why newborn screening for SMA has been transformative.
What causes SMA
SMA is most often caused by loss of the SMN1 gene, which is needed to keep motor neurons healthy. It is inherited in an autosomal recessive pattern, so a child inherits a non-working copy from each parent.
How newborn screening detects SMA
SMA was added to the federal Recommended Uniform Screening Panel in 2018 and is now screened for in most states using a DNA test for the SMN1 gene on a dried blood spot. An abnormal result is referred for confirmatory testing and rapid specialist evaluation.
How SMA is treated
SMA is now treatable with disease-modifying therapies, including gene therapy and medications that increase SMN protein. Outcomes are dramatically better when treatment begins before motor neurons are lost, which is the entire rationale for screening newborns.
Related conditions beyond the standard panel
Standard newborn screening targets SMA specifically, but it does not cover most other inherited neuromuscular conditions. Disorders such as Duchenne muscular dystrophy (only recently added to federal recommendations and not yet screened in most states) and congenital myasthenic syndromes generally fall outside state panels. Genomic screening can assess the genes linked to a broader range of neuromuscular conditions.
How genomic screening fits in
State screening catches SMA well. Fore Genomics’ at-home cheek-swab screen looks at the genes tied to more than 1,000 clinically actionable childhood conditions, including neuromuscular disorders beyond SMA, sequenced in CLIA-certified and CAP-accredited labs with genetic counselor support. See what we screen for or start screening.
Frequently asked questions
Is SMA on every state’s newborn screening panel?
SMA is on the federal RUSP and screened in most states. Coverage is expanding; confirm with your state program.
Why does early SMA treatment matter so much?
Treatments work best before motor neurons are lost, so identifying SMA at birth, before symptoms, gives the best chance to preserve movement.
Medically reviewed by Fore’s Clinical Team. This article is for general educational purposes and is not medical advice. Sources: HRSA Newborn Screening; Cure SMA.