Doctors at the Children's Hospital of Philadelphia (CHOP) have announced a breakthrough that sounds like something from science fiction: they have successfully rewritten the DNA of 15-month-old KJ Muldoon, making him the first infant in the world to undergo CRISPR gene editing as a treatment for a life-threatening genetic condition.
For the Muldoon family, this announcement, shared on CHOP's YouTube channel on Friday, 16 May 2025, couldn't have come at a more critical moment. Their lives were turned upside down when KJ was diagnosed with CPS1 deficiency, a rare disorder that disrupts the liver's ability to process ammonia. Without intervention, toxic ammonia levels can quickly cause permanent brain damage—or worse.
