Shortly after being born during the summer of 2024, KJ Muldoon was diagnosed with severe Carbamoyl Phosphate Synthetase 1 deficiency, a rare genetic disorder.

While the only effective long-term treatment for the ailment had been a liver transplant, doctors at the Children’s Hospital of Philadelphia and Penn Medicine decided to take a different approach with KJ, writes Jon LaPook for CBS News Philadelphia.

Baby KJ is now the first known patient in the world to be treated using a personalized gene-editing therapy, known as CRISPR.

The therapy found the one unique mutated gene out of 20,000. From there, the infant received three infusions of the experimental therapy to his liver.

Up to now, there has been no serious side effects to the treatment.

“While KJ will need to be monitored carefully for the rest of his life, our initial findings are quite promising,” Dr. Rebecca Ahrens-Nicklas, director of the Gene Therapy for Inherited Metabolic Disorders Frontier Program at Children’s Hospital of Philadelphia, said in a statement.

The infant’s mother, Nicole Muldoon, is relieved to see her baby laughing and jumping around when there was a point when she wasn’t sure it would happen.

Researchers are hopeful that CRISPR treatment could someday help address other rare genetic disorders.

Read more about the doctor’s innovative new way to treat an infant’s rare disease at CBS News Philadelphia.

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