[An image of a baby. Photo Credit to Pexels]

KJ, a six-to-seven-month-old infant, has become the first patient in medical history to undergo genetic modification to treat a rare disorder known as CPS1 deficiency.

Born in August 2024 at the Children’s Hospital of Philadelphia (CHOP), KJ was diagnosed almost immediately with the life-threatening condition.

Working together with Penn Medicine, researchers developed a personalized gene-editing therapy using a form of CRISPR technique called base editing.

CPS1 deficiency occurs when the body lacks enzymes needed to convert ammonia into urea.

Without this function, byproducts of protein metabolism accumulate in the liver, causing dangerous levels of ammonia in the bloodstream.

When left untreated, excess ammonia severely damages both the brain and liver.

Historically, infants diagnosed with CPS1 deficiency rarely survive longer than a week. 

Those who do often live with profound developmental disabilities.

Standard treatment has relied on strict protein restriction and, ultimately, a liver transplant.

Yet many infants die before receiving a donor organ due to organ failure during the waiting period.

With the support of NIH (National Institutes of Health), doctors and scientists obtained unprecedented approval from the U.S. Food and Drug Administration (FDA) to attempt gene therapy for KJ. 

After receiving approval, scientists worked and completed on record time; they were able to complete KJ’s treatment in less than six months.

In comparison, a typical approval and treatment creation takes years, meaning the scientists were racing against KJ’s limited lifespan.

Using advanced gene-editing technology, the scientists created an infusion designed to correct the defective DNA.

To be specific, base editing, a refined method of CRISPR, uses a guide RNA to target the precise location of the mutation.  

Instead of cutting out entire DNA segments, it replaces the faulty section with the correct code.

This approach reduces the risk of errors such as missing or duplicated sequences.

Although base editing is more complete and gentle, there are chances of errors during the CRISPR process.

After weeks of infusion therapy, KJ’s condition began to improve.

He was able to tolerate higher protein levels in his diet and required less medication to control ammonia levels.

Scientists observed no severe side effects, though monitoring continues for potential long-term complications.

The early results suggest that the customized therapy was both safe and effective.

Researchers emphasize, however, the cost of such highly personalized treatments continues to pose a major challenge.

Questions now loom over who will have access and how healthcare systems might bear the expense.Even with these challenges, the achievement offers a new sense of hope.

Families facing rare and devastating genetic conditions may now see a path to survival.

KJ’s case is expected to be the beginning of a new era in which personalized gene therapies could transform outcomes for patients once considered untreatable.