Early Treatment Linked to Better Outcomes in SMA

Beginning treatment for spinal muscular atrophy (SMA) within 21 days of birth was associated with fewer comorbidities and better odds of meeting motor milestones than initiating therapy later, new research showed.Patients treated earlier with disease-modifying therapies (DMTs) reported lower rates of scoliosis, dysphagia, and cognitive delay and were more likely to meet certain major milestones, such as walking independently, than those whose treatment began later.Lisa Belter, MPHThe results underline the importance of “moving quickly and getting that baby treated early” following a diagnosis of SMA, study author Lisa Belter, MPH, vice president, Research Data Analytics, Cure SMA, told Medscape Medical News.“Do not wait even three weeks. Three weeks is not a lot of time to educate the family about what SMA is and to get them connected with a multidisciplinary team.”The findings were presented on September 30, 2026, at the American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM) 2026.Uncertainties PersistSMA, a condition leading to worsening muscle weakness, is caused by a deletion or mutation of the SMN1 gene. However, a nearly identical gene, SMN2, can produce some functional protein. The number of copies of SMN2 is inversely related to the severity of the disease, said Belter.The condition is rare, occurring in about 1 in 15,000 babies born in the US.The FDA has approved four DMTs for SMA. These, along with newborn screening programs initiated in recent years across the country, have led to earlier diagnosis, increased life expectancy, and improved motor function in patients with SMA.However, uncertainties persist around the risk of emerging comorbidities.Belter and her colleagues used caregiver-reported data from the 2025 and 2026 Cure SMA Community Update Surveys. The surveys have collected data on patients with SMA annually since 2017.The new analysis included data for 139 children aged 2-9 years. Researchers categorized them into two groups: an early-treated group (who received their first DMT within 21 days of birth) and a later-treated group (who initiated DMT treatment after that point).The mean age at first treatment was 14.3 days in the early group vs 341 days in the late group. Receipt of two DMTs was reported in about 57% of the early group and 45% of the late group.The early group was about 2 years younger than the late group at the time of the survey (mean age, 3.7 years vs 5.6 years). Most of those in the early group had one or two SMN2 copies, whereas those in the late group were more likely to have two or three copies. SMA type 1 was the most common subtype in both groups.Less ScoliosisAbout 25% in the early-treated group were diagnosed with scoliosis compared to 48% in the later-treated group. Of those diagnosed with scoliosis, 80% in both groups received the diagnosis by age 3, and most had SMA type 1.Dysphagia was diagnosed in 14.3% of children in the early group vs 26.8% of those in the late group. Of these children, all in the early group and 94.1% in the late group were diagnosed by the age of 1. Overall, most children with dysphasia had SMA type 1.None of the children in the early group and 5.4% of children in the late group were diagnosed with a neurocognitive delay or deficit.These new results suggest that early treatment could delay the onset or progression of these comorbidities, Belter said. But she cautions that only time will tell, as it’s possible that some conditions may develop later.Meeting the Highest MilestoneResearchers also looked at how many kids met certain milestones, such as being able to grasp objects, roll over, stand, and walk alone. Walking independently is the highest possible motor milestone, said Belter.In this survey, 83% of the early group were able to walk alone at the time of the survey, despite the majority having two SMA2 copies. Independent walking was reported in just 35% of children treated later.“Historically, without early treatment, a baby with two copies of SMA 2 would never go on to sit independently, let alone go on to walk independently,” saidBelter.A more streamlined process of therapy initiation after diagnosis, with fewer delays and barriers — such as insurance coverage — could better position patients to meet these milestones, she said.Newborn screening for SMA — now available in every state — has changed what’s possible for families, said Mary Curry, ND, study co-author and senior vice president of research at Cure SMA.“The real-world data in this research builds on that progress, giving us the evidence we need to advocate for faster treatment and stronger outcomes for the SMA community,” she told Medscape Medical News.The study received funding from the Cure SMA Industry Collaboration. There were no reported conflicts of interest.