Newborn screening (NBS) is a genetic test performed just after birth to identify certain treatable diseases. Early diagnosis through NBS leads to timely treatment, which is essential to prevent severe disability and sometimes even death.1–3 SMA is a rare genetic disease that results in the rapid and irreversible loss of motor neurons, affecting muscle functions involved in sitting, crawling, swallowing and even breathing, therefore early diagnosis and hence treatment is critical.3,4 For patients with SMA, time is of the essence

Early intervention in SMA is vital to limit irreversible damage3,5–7

Research demonstrates the importance of early treatment and management of SMA, before irreversible damage can take place.3,6,8,9 Once motor neurons are lost, the body does not generate new ones. The aim with early intervention is to save the greatest possible number of motor neurons to prevent serious, life-threating manifestations of the disease and achieve optimal patient outcomes.3,10,11 If left untreated, in its most severe form, more than 90% of untreated patients with SMA Type 1 will not survive or will need permanent ventilatory support by 2 years of age.12 Ultimately, early treatment offers the best chance for patients and their families

Learn more about why early diagnosis of SMA is essential5,6

Diagnosing SMA with NBS

Because SMA is a rare disease, many clinicians may not initially recognize the early signs of SMA, which often leads to a delay in diagnosis and treatment. Sometimes, there is a lack of understanding about the signs to look out for which is another contributing factor3,13–16

The signs and symptoms for SMA vary between 0-6 months and 6-18 months, but often include hypotonia, areflexia, respiratory symptoms, difficulty swallowing and other delayed motor milestones17–20

For more information on how to identify the early warning signs of SMA, check out the ‘Signs of SMA’ page

NBS offers hope for the SMA community, with the ability to test for disease, using a heel prick test, with high specificity and sensitivity within 2–4 days after birth, regardless of whether a baby shows signs or symptoms of SMA.3,8,10,21 NBS for SMA enables intervention and management strategies to be implemented sooner, limiting disease progression and increasing the potential benefits of SMA therapies3,5,7

In the absence of SMA screening, as part of NBS programmes, the mean age for babies with SMA Type 1 to receive a diagnosis is 189 days.14 With a NBS test, SMA can be diagnosed in 9–23 days, meaning babies could receive therapeutic intervention 166 days earlier than without22

“There is convincing evidence that early initiation of treatment — ideally in the presymptomatic stage of the disease — is associated with markedly better outcomes as compared to later start of treatment. Spinal muscular atrophy is therefore a good candidate for inclusion in newborn screening programmes. In newly diagnosed patients any delay of treatment should be avoided.”8
- 2020 consensus statement from 13 experts in paediatric neurology

Current situation:

Experts have expressed a strong need and urgency for the implementation of NBS as means to improve care for patients with SMA. Several SMA newborn screening pilots and national programs have been implemented worldwide, including Australia, Belgium, Canada, Germany, Italy, Japan, Taiwan and United States of America. The global landscape is continuously changing and the annual proportion of newborns to be screened in the coming years is expected to increase steadily23

A number of health authorities are considering the inclusion of SMA in their NBS programmes.11,24,25 This can be a lengthy process prior to implementation24,26

In the USA, 48 of 50 states screen for SMA as of June 2023, which means 99% of newborns are screened for the disease27

There is also a drive from organizations such as the European Alliance for Newborn Screening in SMA, who demand that newborn screening programs in all European countries should test for SMA by 202510

The future of NBS testing worldwide

Expert opinion on the need for NBS screening for SMA has been recognized by associations across the world, of which some have set up initiatives to support the development of NBS programs.10,28–30 The SMA NBS World Study Group expect the annual proportion of newborns to be screened in the coming years to increase steadily with coverage in some countries reaching up to 24% of newborns by 2025.*23

“We needed this”34
- Kariyawasam DST, et al., 2021

While challenges of NBS were identified by both caregivers and healthcare professionals caring for infants diagnosed with SMA through NBS, these were felt to be outweighed by the magnitude of benefits and optimization of lifelong outcomes made possible by NBS.34

The current implementation of national NBS panels may help to urge global health authorities move towards change. Enabling the ~14,000 babies born with SMA every year worldwide,15,31–33 to receive earlier intervention and care, giving them and their families the best chance of positive outcomes3,5–7