Baby gets world's first personalised gene therapy treatment

A baby born with a rare genetic disease is "growing and thriving" after getting bespoke gene therapy.

It's the first time anyone in the world has been given an experimental gene-editing treatment designed specifically for their disease and took scientists just seven months to develop. Nine-and-a-half-month-old KJ Muldoon, from Clifton Heights, Pennsylvania, has a rare metabolic condition - known as severe carbamoyl phosphate synthetase 1 (CPS1) deficiency - that meant he has spent the first months of his life in a US hospital on a very restrictive diet.

In February, however, the boy received the first dose of his bespoke treatment and then follow-up doses in March and April. "We prayed, we talked to people, we gathered information, and we eventually decided that this was the way we were going to go," said KJ's father Kyle Muldoon.

KJ has been able to eat more normally and has recovered well from illnesses like colds, which can strain the body and exacerbate his symptoms. He also now takes fewer medications.

Some experts estimate severe CPS1 deficiency affects one in a million babies. Those infants lack an enzyme needed to help remove ammonia from the body, so it can build up in their blood and become toxic.

"We're still very much in the early stages of understanding what this medication may have done for KJ," said study author Dr Rebecca Ahrens-Nicklas, a gene therapy expert at the Children's Hospital of Philadelphia (CHOP). "But every day, he's showing us signs that he's growing and thriving." Read more from climate, science and technology:Why do the moon's two sides look so different?AIs can make collective decisions and influence each otherWarning of heat impact on pregnant women and newborns Considering how poorly KJ had been, "any time we see even the smallest milestone that he's meeting - like a little wave or rolling over - that's a big moment for us.