Gene-editing just took a giant leap forward, and it started with a baby named KJ Muldoon. Born in summer 2024, KJ was diagnosed with a rare and often deadly condition called severe CPS1 deficiency.
For years, the only shot at survival for babies with this disorder was a liver transplant. That all changed when doctors offered his family a bold new option.
Instead of going through surgery, KJ became the first person ever to receive a personalized gene-editing treatment using CRISPR. His doctors at the Children’s Hospital of Philadelphia, working with Penn Medicine, tailored the therapy to fix one single broken gene in his liver. Out of 20,000 genes in the human body, they found the one causing the damage and corrected it.
A Custom Fix for a Deadly Gene
Scientists have been chasing this kind of precision for decades. Gene-editing using CRISPR is not new, but what makes KJ’s case historic is the level of personalization. His treatment wasn’t off the shelf; it was designed just for him.
The News / Now, months after the treatment, the baby is doing well, gaining weight, and bouncing around like a healthy baby should.
The treatment involved three separate infusions of the gene-editing therapy into KJ’s liver earlier this year. So far, he hasn’t shown any serious side effects, which is a big deal. CPS1 deficiency is a metabolic disease that can quickly become life-threatening. But now, KJ is thriving.
The Future of Gene-Editing Medicine
Doctors say they will need to keep a close eye on him for the rest of his life. But the early signs are promising. His medical team says that seeing him smile, laugh, and grow is nothing short of remarkable. For his family, it is a chance they never thought they would get.
Gene-editing has long promised to change the way we treat inherited diseases, but it has always seemed just out of reach. KJ’s case is proof that the future may be here sooner than we think.
The CRISPR tool works by targeting the DNA inside our cells and correcting errors at the source. Instead of just treating symptoms, this tech goes in and fixes the root cause.
CRISPR Shows Its Power
The idea of editing genes to treat diseases is no longer a mere theory. What is different now is how fast and accurate these treatments are becoming. KJ’s gene-editing therapy didn’t just patch him up. It corrected a deadly error in his DNA before it could take his life.
E Online / Doctors involved in the case published their findings this week in the New England Journal of Medicine. That is a big sign that the medical community is taking this seriously.
It is something that could soon be used for many other rare conditions that don’t yet have a cure.
Sharp Targeting With Real Results
Penn Medicine explained how CRISPR allows researchers to zero in on broken genes and fix them without touching the rest of the DNA. It is like correcting a single typo in a massive book without disturbing the other pages. For KJ, that precision meant life.
Researchers say we are still early in the game. Personalized gene-editing is far from becoming routine. But the fact that it worked in a real child, with a real disease, is huge. It opens the door to treating other rare genetic disorders that have, until now, left families with few or no options.
Experts around the country are calling the news a game-changer. Some believe this moment marks the start of a whole new era in medicine. Instead of using one-size-fits-all treatments, doctors could one day design therapies built from scratch for each patient’s DNA.
