Baby who received personalized gene editing therapy at CHOP takes first steps

A baby born with a rare and life-threatening genetic disorder has taken his first steps after receiving a groundbreaking, personalized gene editing treatment at Children’s Hospital of Philadelphia.

KJ Muldoon was born with an ultra-rare and dangerous CPS1 deficiency syndrome that affects 1 in 1.3 million live births and has a 50% mortality rate. Just days after his birth, KJ’s parents, Nicole and Kyle, were faced with an overwhelming choice: pursue a liver transplant or try an experimental gene therapy that had never been used before.

Earlier this year, KJ became the first patient in the world to receive a personalized CRISPR gene editing therapy explicitly designed to treat his condition. he treatment was developed by a team led by Dr. Dr. Rebecca Ahrens-Nicklas, a physician-scientist in CHOP’s Metabolic Disease Program, and Dr. Kiran Musunuru, a cardiologist, geneticist, and professor at the University of Pennsylvania’s Perelman School of Medicine.

For the first 10 months of his life, KJ remained hospitalized as doctors closely monitored his progress. In June, after continuing to grow stronger, he was finally discharged.

Since going home, KJ has reached milestones his family once feared might never come. He celebrated his first birthday in August and, most recently, took his very first steps, offering new hope for the future of personalized gene therapy.

“He’s also getting ready to celebrate his first Christmas at home, something that had to happen in his hospital room a year ago,” a spokesperson for CHOP shared in a news release.

According to CHOP, researchers are continuing to explore the causes and potential treatments for other difficult-to-treat metabolic disorders. KJ’s case is also prompting discussions on how to move forward with new models for approving personalized therapies for rare diseases.