Gene-editing therapy used to save baby in world first

Doctors in the US have become the first to treat a baby with a customized gene-editing therapy after diagnosing the child with a severe genetic disorder that kills about half of those affected in early infancy.

- Ian Sample

International researchers have hailed the feat as a medical milestone, saying it demonstrated the potential for treating an array of devastating genetic diseases by rewriting faulty DNA soon after affected children are born.

Specialists at the Children's Hospital of Philadelphia and the University of Pennsylvania started work as soon as the boy was diagnosed and completed the complex design, manufacture and safety testing of the personalized therapy within six months.

The baby, known as KJ, had the first dose of the bespoke treatment via an infusion in February and two more doses in March and April.

Doctors said he was thriving, but would need monitoring for life.

Dr Rebecca Ahrens-Nicklas, a senior physician on the team, said the breakthrough had been made possible by "years and years of progress" in gene editing.