A two-and-a-half-year-old girl has defied expectations by not showing signs of a rare genetic disorder, after becoming the first person to be treated for spinal muscular atrophy while in the womb. The child’s mother received a gene-targeting drug called Risdiplam during late pregnancy, and the child continues to take it.
According to Michelle Farrar, a paediatric neurologist at UNSW Sydney in Australia, “the baby has been effectively treated with no manifestations of the condition.” This breakthrough was published in the New England Journal of Medicine yesterday.
Spinal muscular atrophy is a genetic condition affecting motor neurons that control movement, leading to progressive muscle weakening. It’s a leading genetic cause of death in infants and children, with only one in every 10,000 births being affected. The child in question lacks both copies of the SMN1 gene, but received treatment that partially compensates for this deficiency.
Risdiplam is an oral drug manufactured by Roche that works by modifying the expression of the SMN2 gene to produce more SMN protein. This is a significant improvement over previous treatments, which were given after birth. The study’s lead author, Richard Finkel, says that the idea of in-utero treatment came from the parents themselves, who wanted to explore alternative options before birth.
The mother took Risdiplam daily for six weeks during pregnancy and the child started taking it at one week old. The results show promise for this new approach to treating spinal muscular atrophy, offering hope for families affected by this devastating disease.
Source: https://www.nature.com/articles/d41586-025-00534-0