Researchers reported meaningful clinical benefits from an mRNA-based CRISPR base editing therapy delivered directly to an infant with CPS1 deficiency, in a case study involving the University of Pennsylvania and Children’s Hospital of Philadelphia. The intervention aimed to correct the CPS1 gene in liver cells and avoid an immediate need for liver transplant at an age when the procedure was not feasible. In commentary around the case, lead investigator Kiran Musunuru emphasized that the intervention was not a clinical trial or “cure,” describing it instead as expanded access delivered as clinical care for a single patient. Still, the outcomes described—such as enabling a normal protein-filled diet—reinforce feasibility for in-human genome editing with direct delivery. The report adds to momentum in base editing programs in industry, where multiple companies are advancing similarly targeted approaches in clinical development.