MDA 2026: Newborn screening helps infants with SMA start treatment sooner
Study finds earlier therapy linked to better motor development outcomes
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- Newborn screening for SMA enables significantly earlier initiation of disease-modifying treatments.
- Early treatment was associated with motor function and development in infants with SMA.
- Prenatal diagnosis allowed the earliest treatment and was linked to positive outcomes.
Genetic screening for spinal muscular atrophy (SMA) in newborns may allow treatment to begin earlier, which could help support motor development, a study suggests.
This “adds to the evidence that [newborn screening] for SMA is associated with significantly earlier time to first treatment and is subsequently associated with improved [motor function],” the researchers wrote in a study abstract.
Infants diagnosed with SMA through newborn screening began disease-modifying treatment significantly earlier than those diagnosed only after symptoms appeared. Infants diagnosed before birth through prenatal genetic testing began treatment even sooner.
These results were presented at the Muscular Dystrophy Association‘s 2026 MDA Clinical & Scientific Conference in Orlando, Florida, in a poster titled, “Impact of Newborn Screening and Early Disease Modifying Treatment on Motor Function in Spinal Muscular Atrophy (SMA).”
Early diagnosis and treatment can improve outcomes in SMA
In SMA, mutations in the SMN1 gene disrupt production of survival motor neuron (SMN) protein. SMN normally supports motor neurons, the specialized nerve cells that control movement. Without enough functional SMN, motor neurons become damaged, leading to gradual muscle weakness and wasting, along with other symptoms.
Available disease-modifying therapies (DMTs) for SMA aim to increase the amount of functional SMN protein. While this can slow disease progression, it usually cannot fully reverse muscle damage that has already occurred. Screening newborns for disease-causing genetic mutations may allow for faster diagnosis and earlier treatment with DMTs. Starting treatment sooner may help limit early declines in movement ability and lead to better outcomes.
“Disease modifying treatments (DMT) and implementation of newborn screening (NBS) have transformed management for those with SMA,” the researchers wrote.
The team at Ann and Robert H. Lurie Children’s Hospital of Chicago investigated the real-world impact of newborn screening and prenatal diagnosis. The study included 21 participants — three diagnosed prenatally, 13 diagnosed through newborn screening, and five diagnosed after clinical signs of SMA appeared.
The participants had at least two copies of SMN2, a so-called “backup gene” that produces a small amount of SMN protein. In general, having more SMN2 copies is associated with milder disease. Nine infants received a single DMT, while the remaining 12 received more than one therapy, either sequentially or in combination.
The time from birth to starting a DMT differed significantly depending on how the infants were diagnosed. Infants diagnosed prenatally began treatment after a mean of 11.3 days, compared with 24.8 days for those diagnosed through newborn screening and 49.4 days for those diagnosed after symptoms appeared. All infants began treatment with a DMT within the first three months of life.
Most infants showed improvements in motor function
Regardless of the diagnostic method, most children showed improvements in motor function while receiving a DMT. On one motor function scale, the Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND), many participants approached the maximum score by the age of 3 months.
Infants with more SMN2 copies showed significantly larger CHOP INTEND gains. Scores on another assessment, the Test of Infant Motor Performance Screening Items, also increased, particularly among infants with more SMN2 copies.
Likewise, scores on the Hammersmith Infant Neurological Examination, Part 2 (HINE-2), another measure of motor function in SMA, improved over time for most participants. These improvements occurred more quickly in infants with three or more SMN2 copies. Two infants diagnosed after clinical symptoms appeared had notably lower HINE-2 scores than those identified through genetic screening.
Across the group, most children achieved motor milestones within typical age ranges, including sitting, crawling, standing, and walking.
Findings highlight benefits of early diagnosis and treatment
The study showed positive outcomes across different diagnosis methods, but the results suggest that starting treatment earlier may be most beneficial, according to the researchers. “Prenatal diagnosis and/or short time intervals between a positive [newborn screening] result and subsequent referral to an urban therapy-ready specialized treatment center likely facilitated positive outcomes,” they wrote.
This study was small and involved participants from a single treatment center. “Longer-term studies with larger numbers [of participants] should be considered to further explore [motor function] outcomes as well as systemic barriers creating unnecessary delays in treatment in this population,” the team wrote.
Note: The SMA News Today team is providing live coverage of the 2026 MDA Clinical & Scientific Conference March 8-11 in Orlando, Florida. Go here to see the latest stories from the conference.
