For the first time, a CRISPR drug treats a child’s unique mutation
Scientists hope more children will benefit

WITHIN DAYS after KJ was born in Philadelphia in August 2024 it was clear that something was wrong. He was not eating and slept too much. Blood tests revealed sky-high levels of ammonia, a toxic substance the body usually expels. Genome sequencing confirmed that he had a rare genetic disease called carbamoyl-phosphate synthetase 1 (CPS1) deficiency, which often kills in infancy, and for which no good neonatal treatment exists. Then one of his doctors suggested something radical: a gene-editing drug designed specifically for him.
Explore more
This article appeared in the Science & technology section of the print edition under the headline “One of a kind”

From the May 17th 2025 edition
Discover stories from this section and more in the list of contents
Explore the edition
An interstellar object is cruising through the solar system
Its appearance puts a new branch of astronomy to the test

RFK junior wants to ban an ingredient in vaccines. Is he right?
Studies show that thimerosal does more good than harm

AI is helping to design proteins from scratch
They could treat diseases, test drugs and boost crop yields
A new project aims to synthesise a human chromosome
The tools developed along the way could revolutionise medicine
How sea slugs give themselves superpowers
Their slimy shenanigans might have applications for humans, too
Is being bilingual good for your brain?
Perhaps. Learning languages offers other, more concrete benefits