Late last year, a group of researchers from different parts of the world came together in a race against time to save the life of a baby boy. This collaborative effort resulted in a groundbreaking achievement – the development of a cutting-edge, gene-editing therapy tailored specifically for the baby boy, known as KJ Muldoon. What made this accomplishment even more remarkable was the fact that the therapy was produced in a record-breaking six months.
Now, the doctors who treated baby KJ Muldoon are gearing up to replicate their success on a larger scale. They plan to conduct the same gene-editing therapy on at least five more children, and do it even faster this time around.
The innovative clinical trial, detailed in the American Journal of Human Genetics, will utilize a form of the CRISPR-Cas9 gene-editing technique called base editing. This technique allows scientists to make precise, single-letter changes to DNA sequences, offering a more targeted approach to genetic therapies. The trial is set to begin next year, following extensive negotiations with US regulators to streamline the regulatory process for gene-editing therapies.
Dr. Kiran Musunuru, a cardiologist at the Perelman School of Medicine at the University of Pennsylvania and one of the doctors involved in KJ’s treatment, expressed confidence in their ability to expedite the process. He believes that they can significantly shorten the timeline for developing personalized gene-editing therapies.
The success of KJ’s treatment has sparked hope among families of children with rare genetic disorders. The prospect of personalized gene-editing therapies becoming more accessible is becoming a reality. The Center for Pediatric CRISPR Cures at the University of California, Berkeley and the University of California, San Francisco, as well as the US government’s Advanced Research Projects Agency for Health, are actively supporting research in precision genetic medicine.
The journey to develop KJ’s treatment was a challenging and intense six months, but the results have been incredibly rewarding. KJ, who was born with a rare genetic mutation that affects his liver enzyme production, responded positively to the base-editing therapy. His progress has been remarkable, with improved ammonia levels and significant developmental milestones achieved.
As the team prepares to expand access to this innovative therapy, they are sharing their experience and correspondence with regulators to guide other researchers in the field. By streamlining the regulatory process and sharing their knowledge, they hope to pave the way for more personalized gene-editing therapies to be developed and approved.
The impact of personalized gene-editing therapies could be revolutionary, offering new hope for children with rare genetic disorders. The potential for this technology to transform healthcare is immense, and the progress made in KJ’s case serves as a beacon of hope for many families facing similar challenges.
This article was originally published on October 31, 2025, and has been reproduced with permission.
