In a groundbreaking medical breakthrough, a two-and-a-half-year-old girl has shown no signs of a typically fatal genetic disorder after receiving treatment while still in the womb. The case, reported by The Nature and published in the New England Journal of Medicine, marks the first time a motor neuron condition has been successfully treated before birth, offering new hope for families affected by rare genetic diseases.
The child was diagnosed with spinal muscular atrophy (SMA), a devastating genetic disorder that affects approximately 1 in 10,000 births. The condition impairs motor neurons responsible for muscle control, leading to progressive muscle weakening. In its most severe form, infants typically lack both copies of the SMN1 gene, leaving them without the essential protein required for maintaining motor neuron health. Without treatment, many affected babies do not survive past their third birthday.
Led by Dr. Richard Finkel from St. Jude Children’s Research Hospital in Memphis, Tennessee, and Dr. Michelle Farrar, a pediatric neurologist at UNSW Sydney, the pioneering treatment involved administering the gene-targeting drug Risdiplam to the child’s mother during late pregnancy. Developed by the Swiss biotech company Roche, Risdiplam works by modifying the expression of the SMN2 gene to increase the production of the critical SMN protein.
The treatment plan was initiated after the child’s parents, who had previously experienced a devastating loss due to the same disease, proposed trying the therapy in utero. With the U.S. Food and Drug Administration (FDA) granting approval for this unprecedented approach, the mother began taking the drug at 32 weeks of pregnancy for six weeks. The infant began her own regimen of Risdiplam shortly after birth and is expected to continue treatment for life.
Tests conducted on amniotic fluid and cord blood confirmed that the drug was reaching the fetus. Remarkably, at birth, the child showed higher levels of SMN protein and reduced nerve damage compared to other infants with the same genetic profile. Now, nearly three years later, she exhibits normal muscle development and no signs of muscle weakness—an outcome that Dr. Farrar describes as “very reassuring.”
Experts believe this breakthrough could revolutionize the treatment of genetic disorders. Speaking with The Nature, Dr. Finkel emphasized the significance of early intervention: “The therapeutic window that we’re targeting is very narrow, and this case shows how impactful treatment can be when started even before birth.”
While this study involves just one patient, it sets a crucial precedent for future research. Scientists are hopeful that larger trials could confirm the potential of in-utero treatments, opening the door to treating other genetic conditions where post-birth interventions may be insufficient.
