A breakthrough in personalized gene editing—and what it means for ASXL-related disorders

The cover image for the May 15, 2025 New York Times story, "Baby Is Healed With World's First Personalized Gene-Editing Treatment" and a picture of newborn KJ who received this new CRISPR-based treatment

If you’ve read the recent New York Times article about baby KJ—the first person in the world to receive a custom gene-editing treatment—you might be wondering what this means for individuals with ASXL-related disorders, such as Bohring-Opitz Syndrome (ASXL1), Shashi-Pena Syndrome (ASXL2), and Bainbridge-Ropers Syndrome (ASXL3).

The story is a remarkable one. KJ was born with a rare metabolic disorder called CPS1 deficiency. Without treatment, his condition would likely have been fatal within weeks. But a team of scientists developed a bespoke gene-editing treatment just for him, using CRISPR-based technology to target his exact genetic mutation. KJ received three doses of this experimental therapy—and the results were extraordinary. He’s now meeting developmental milestones and is preparing to leave the hospital for the first time.

This is a powerful reminder of what’s possible when science, speed, and collaboration come together—and why research investment matters. KJ’s treatment was only possible because of decades of government-funded research into gene editing and rare disease biology.

But what does this mean for our ASXL community?

We’re hopeful—and also realistic. There are key differences between KJ’s condition and ASXL-related disorders:

• KJ’s condition affects the liver, where delivery of genetic treatments is relatively well-established. ASXL-related disorders primarily affect the brain, where delivery remains a major hurdle. Getting therapies across the blood-brain barrier is still an unsolved challenge—especially for large genes like ASXL1, ASXL2, and ASXL3.

• CPS1 deficiency is caused by a single base change that could be targeted with a gene editor. ASXL-related disorders are caused by a wider range of genetic changes (or “mutations”), many of which result in truncated or missing proteins. This means we may need a variety of treatment strategies—not just one fix.

• Gene therapy for neurological conditions is still in early stages. While there are exciting developments in brain-targeted gene therapy, they are not yet approved or accessible—and most are years away from clinical use.

Despite these challenges, the future is not out of reach. At the ASXL Rare Research Endowment (ARRE) Foundation, we’re deeply committed to this future. Our team, including Chief Scientific Officer Dr. Karen Ho, participates in major conferences like the American Society of Cell and Gene Therapy (ASCGT), where groundbreaking discoveries are shared.

At the recent Milken Global Conference, Karen heard firsthand from some of the leading voices shaping the future of rare disease therapeutics—including Dr. Fyodor Urnov of the University of California, Berkeley, who played a central role in KJ’s treatment. These innovators are working closely with the FDA to create new regulatory pathways that make personalized treatments more feasible and accessible for rare disease communities like ours.

Momentum is really building—and momentum is exactly what we need. This kind of progress is the result of years of research, public investment, and dedicated communities pushing for change.

Want to help? One of the most important things you can do right now is participate in the ASXL Census. Every person counted strengthens our case for research funding and future therapies.