The patient is now in the room
For months, the researchers trying to save KJ Muldoon knew him only as ‘Patient Eta’.
He was born in August 2024 with CPS1 deficiency, an ultra‐ rare urea‐cycle disorder that can send ammonia levels soaring and devastate the brain. A liver transplant is often the only route forward — if the baby survives long enough.
Nobel laureate Jennifer Doudna, who co-developed CRISPR–Cas9 technology and co-founded the Innovative Genomics Institute, recalls the turning point for baby KJ: “He was diagnosed in late 2024. They identified the cause, and it was something that could, in principle, be corrected by a CRISPR modality.”
