Science & discoveries / Clinical case · 1 patient
A gene therapy designed for one child
What the CPS1 case teaches us about personalised medicine.
Key takeaway
An early result can open a research direction without yet proving long-term safety.
What was studied
In 2025, a team developed gene editing tailored to the variant of an infant with severe CPS1 enzyme deficiency. The treatment was delivered using lipid nanoparticles. The paper reported two infusions and seven weeks of follow-up after the first.
What was found
During that period, the child tolerated more dietary protein and received half the starting dose of a medicine that helps remove nitrogen. No serious adverse events were reported.
What it does not prove
This was one patient, without a comparison group and with short initial follow-up. It does not establish a permanent cure or applicability to other diseases. Funding came from the NIH and other sources.
Why it matters
The significance lies in adapting treatment to a specific genetic change. The next question is whether benefit and safety persist, and whether the approach can be repeated.
Sources
- Patient-Specific In Vivo Gene Editing to Treat a Rare Genetic Disease ↗NEJM · Musunuru and colleagues · Accessed 5 September 2026
An editorial explanation referring to the listed sources. General information; individual interpretation and treatment require clinical assessment.
Updated 5 September 2026. How we prepare our content