Doctors have successfully treated a baby born with a rare genetic disorder using a gene-editing therapy tailored to correct his unique mutation. The treatment involved infusions of gene-editors that targeted a liver mutation, potentially reversing the defect and reducing the risk of brain damage and death. The case, described in The New England Journal of Medicine, marks a significant advancement in personalized medicine for rare diseases. While more research is needed, the success of this treatment could pave the way for transformative gene-editing therapies in the future.