First Personalised CRISPR-based Successful gene-editing Therapy in an Infant First Personalised CRISPR-based Successful gene-editing Therapy in an Infant Content Editor: Dr. Harshita May 23, 2025 Nature Journal Gene-editing therapy, genetic disorder The first successful gene-editing therapy promises an optimistic future for children diagnosed with genetic disorders. CRISPR , short for C lustered R egularly I nterspaced S hort P alindromic R epeats, is a gene-editing technology that helps scientists to modify DNA selectively. KJ Muldoon, the name of the first infant to receive such a therapy, was diagnosed with CPS-1 deficiency after experiencing lethargy and difficulty in breathing. Carbamoyl phosphate synthetase - 1 (CPS-1) deficiency is a urea cycle disorder that leads to high ammonia levels in the body due to a lack of the CPS-1 enzyme that converts ammonia to urea. Complications include multiple organ damage due to accumulation of ammonia, such as liver damage requiring a transplant, irreversible brain injury, and death, with mortality as high as 50%. The children usually do not survive long enough to receive the transplant. CRISPR-based scissors can precisely scan through the genetic code and pinpoint the exact error and correct it. Animal testing was conducted prior to the human experiment, for which researchers took FDA approval. Baby Muldoon received 3 doses of infusion in February, March, and April, which led to a decrease in doses of medicine and ammonia levels, helping baby Muldoon gain weight. The infant suffered two viral infections, vomiting and diarrhea post-infusion, but without causing a shoot-up in his ammonia levels. There were no serious side effects reported. Parents were relieved as medicine doses were halved with an increase in proteins in his diet, leading to weight gain. These therapies hold great promise for future generations , offering hope to parents of affected children through the potential of gene therapy, but more research is needed to know if they can be widely applied. Click here to read more.