Code of life rewritten: In a first, doctors treat baby with gene-edited drug

Doctors and scientists in the US have done the impossible by healing a baby using customised gene-editing therapy, which involves rewriting faulty DNA. In a medical feat that has been hailed internationally, doctors from the Children’s Hospital of Philadelphia and researchers from the University of Pennsylvania have proved that rare genetic disorders can potentially be treated by editing the faulty genes.

What was the baby's diagnosis?

The baby, KJ, was born with severe CPS1 deficiency, a rare genetic condition that affects only one in 1.3 million people. A lack of Carbamoyl phosphate synthetase 1 (CPS1), a type of protein that produces enzymes, affects the liver due to ammonia buildup, which should ideally be excreted via urine after the enzyme converts it into urea. This can affect the liver and other organs, including the brain.

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Although some patients with CPS1 deficiency undergo liver transplants, infants with severe forms of the disease may already have sustained damage by the time they are old enough for surgery.

'Years and years of progress'

The one-of-a-kind treatment did not come easily. Dr Rebecca Ahrens-Nicklas, a senior physician on the team, said the breakthrough in gene rewriting was preceded by “years and years of progress” of the technique.

In the New England Journal of Medicine, the doctors detailed the meticulous process of pinpointing the exact mutations causing KJ’s disorder, developing a gene-editing therapy to fix them, and testing both the treatment and the fatty nanoparticles used to deliver it to the liver. The therapy employs a cutting-edge technique known as base editing, which allows scientists to alter the DNA code one letter at a time.

How is the baby doing?

While doctors asserted that KJ, who received the first dose of the treatment via an infusion in February and two more doses in March and April, is "thriving", he would require careful monitoring throughout his life.

KJ spent the early months of his life in the hospital on a strict diet, but following his treatment, doctors have been able to raise the protein content in his meals and reduce the use of medication needed to eliminate nitrogen from his body.

However, the medical team has added that longer follow-ups are needed to gauge the total success of the therapy. Prof Kiran Musunuru at the University of Pennsylvania said, "The promise of gene therapy that we’ve heard about for decades is coming to fruition, and it’s going to utterly transform the way we approach medicine."

Why does it matter?

Over 30 million people in the US live with rare genetic disorders caused by DNA errors, many of which lack treatments due to commercial unviability.

This case demonstrates the potential of precision gene editing to bypass traditional drug development hurdles, especially for ultra-rare diseases.