Doctors in the United States have treated a baby named KJ using a personalized gene-editing therapy based on CRISPR technology. KJ was diagnosed shortly after birth with CPS1 deficiency, a rare condition affecting about one in a million infants. This disorder causes toxic ammonia buildup in the body, leading to symptoms such as vomiting, seizures, brain swelling, and often early death.
Standard treatment for CPS1 deficiency includes a low-protein diet and possibly a liver transplant, both of which carry significant health risks. At six months old, KJ received his first gene-editing treatment, which helped reduce his dependence on ammonia-lowering medication. The procedure was performed at the Children’s Hospital of Philadelphia and was later documented in a leading medical journal. Doctors will continue to monitor KJ’s health throughout his life to ensure the treatment’s long-term effectiveness.
CRISPR technology allows doctors to identify and cut faulty gene sequences in a patient’s DNA with precision. In KJ’s case, the medical team edited his liver cells to repair a broken gene responsible for producing a vital enzyme needed to regulate ammonia levels. This correction helped his body manage toxic ammonia more effectively and reduced dangerous symptoms.
The success of this treatment suggests that similar therapies could benefit other patients with rare diseases caused by single-gene mutations. This gene-editing technique uses the body’s natural repair system to replace defective genetic material with healthy code. Researchers believe that CRISPR’s flexibility could allow future adaptations to treat a variety of rare conditions involving single faulty genes.
Despite the promising results, there are still challenges to overcome. Editing genes in organs other than the liver remains difficult due to delivery and safety issues. The treatment cost for KJ was over €700,000, close to the price of a liver transplant, making widespread use expensive. Long-term side effects are still unknown because of safety restrictions in early-stage procedures like this one.
Most genetic diseases involve multiple mutations, which makes CRISPR less effective in those cases. Broader gene repair strategies may be needed to address more complex disorders. Nevertheless, the medical community remains optimistic that precision gene editing will reshape the treatment of rare genetic diseases in the future.