Without treatment, babies with severe SMA typically do not survive past their third birthday, highlighting the significance of this prenatal treatment.

SMA affects approximately 1 in every 11,000 births in the United States and is caused by a deficiency in survival motor neuron protein, leading to progressive muscle weakness.

This case suggests that early intervention in genetic conditions like SMA could lead to better outcomes, warranting further research on prenatal treatments.

Findings regarding this treatment were published on February 19, 2025, in the New England Journal of Medicine, supporting further investigation into prenatal interventions for SMA.

A groundbreaking case has emerged where a two-and-a-half-year-old girl has become the first person treated for spinal muscular atrophy (SMA) while still in the womb, showing no signs of the disorder.

Dr. Richard Finkel, the study's corresponding author, emphasized the importance of these results, suggesting continued research into prenatal treatments for SMA.

The treatment involved the gene-targeting drug Risdiplam, which the mother began taking at 32 weeks of pregnancy, and has continued post-birth.

At birth, the infant exhibited higher levels of SMN protein and less nerve damage compared to typical SMA type 1 infants, and she has shown no signs of muscle development issues since then.

The FDA has approved three drugs for treating SMA in newborns over the past decade, with Risdiplam enhancing the expression of the SMN2 gene to produce more SMN protein.

Historically, SMA treatments were administered post-birth, but about half of affected newborns show symptoms at birth, indicating a need for improved early intervention.

The infant was diagnosed with SMA type 1 after genetic testing indicated mutations in both copies of the SMN1 gene, following the loss of a previous sibling to the same condition.

The most severe form of the condition occurs when individuals lack both copies of the SMN1 gene, having only limited copies of the SMN2 gene which can partially compensate.