We are standing at the edge of a new era for urea cycle disorders.
Research is accelerating. Genetic breakthroughs are happening. Treatments that once seemed out of reach are becoming a reality.
One of the clearest signs of this progress comes from the story of baby KJ Muldoon. Earlier this year, at just seven months old, KJ received a first-in-human, individualized gene-editing treatment for CPS1 deficiency, a severe neonatal-onset UCD.
The therapy—designed specifically for him—was delivered directly into his liver cells using CRISPR technology. Doctors continue to follow him closely, but so far, the treatment has transformed his condition from a life-threatening neonatal disorder into a much milder form of the disease.
KJ’s mom recently shared an update that speaks to both the science and the heart behind this breakthrough: “Thanks to this team, he’s hitting milestones that we get to celebrate together. He can catch and throw a ball, loves to play with his siblings, and has just begun walking!”
It’s important to note: KJ’s early stability was possible because an astute neonatologist recognized symptoms of high ammonia and ordered a test when he was just 36 hours old—underscoring the lifesaving power of early diagnosis. Our Check Ammonia!™ campaign raises awareness of this life-saving test so that no patients are harmed by delayed diagnosis
While the customized treatment itself was created for one child through a massive global effort, the impact reaches far beyond one family. Leading researchers Dr. Rebecca Ahrens-Nicklas and Dr. Kiran Musunuru have already outlined a plan for a new clinical trial that could treat additional patients with editable variants in seven different UCD genes—including CPS1, OTC, ASS1, ASL/ASA, ARG1, NAGS, and HHH.
New federal research investments, evolving FDA approval pathways, and major national initiatives like NIH’s Somatic Cell Genome Editing program and ARPA-H’s THRIVE and GIVE programs are accelerating the next generation of treatments even further. Research teams across the country are now working to make individualized therapies more accessible, faster to produce, and possible for more families.
This moment—this momentum—is exactly why NUCDF exists.
Foundational research from the Urea Cycle Disorders Consortium, built over decades and supported by NUCDF, helped make KJ’s breakthrough possible by giving scientists the deep natural history data needed to develop and assess such treatments.
We share this story because it represents something profoundly important: hope grounded in science, and a glimpse of what may soon be possible for more families.
Every step forward—every improved testing protocol, every research collaboration, every new educational effort—brings us closer to a future where children and adults with UCDs have access to life-changing treatments.
Thank you for being part of this community at a time when progress is accelerating faster than ever before. I’m so grateful for each of our families, researchers, clinicians, donors, and community partners.
Thank you for all that you do today—and for the tomorrow we are building together.
With gratitude,
Tresa Warner
Executive Director, NUCDF
