A World First at Children’s Hospital Of Philadelphia: How In Vivo CRISPR Therapy on a Newborn in Philadelphia Signals Hope for Families Affected by Birth Injuries and Genetic Disorders
CRISPR In Vivo vs. In Vitro – What’s the Difference?
In vivo CRISPR treatment occurs inside the patient’s body, while in vitro means the editing happens outside the body, typically in a lab. In a groundbreaking, world-first in vivo CRISPR therapy, a newborn named KJ at Children’s Hospital of Philadelphia (CHOP) received a personalized gene-editing treatment for a rare and deadly genetic disorder known as CPS1 deficiency. The disease affects the urea cycle, causing dangerous ammonia buildup in the blood. Without treatment, KJ had slim chances of survival or living a normal life. Doctors at CHOP and Penn Medicine administered the treatment between 6 and 7 months of age, using lipid nanoparticles to deliver mRNA and guide RNA directly into KJ’s body—a technique never before attempted in a human, let alone an infant. KJ’s parents did not know about the condition during pregnancy—it was discovered shortly after birth. This complex and historic intervention is a massive leap for genetic medicine, previously used in in vitro contexts or for adult cases. This method has treated cancers and blood disorders, but this marks the first time a living newborn was treated internally using CRISPR, potentially opening the door for thousands of future Philadelphia birth defect treatments.