Baby saved by rewriting a letter of his DNA

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In just six months, researchers from the University of Pennsylvania and the Children's Hospital of Philadelphia managed to save a nine-month-old baby's life by modifying one of his genes.

KJ Muldoon, a 9-month-old baby with a deadly mutation, has been saved thanks to treatment that corrects a mistake in his genetic material. © Lynne Cameron / PA Wire

For the first time ever, doctors have successfully modified a gene in an infant's body to correct a fatal mutation that would have doomed him to death in the very near future. The feat was achieved in just six months, with the University of Pennsylvania and the Children's Hospital of Philadelphia urgently developing a custom gene therapy protocol for 9-month-old KJ Muldoon.

"We managed to penetrate his genome to rewrite the only error in his genetic material, which prevented his liver from eliminating the ammonia naturally produced by the body," explains researcher Kiran Musunuru. Of the 3 billion letters in his DNA code , only one was the cause of the life-threatening disease.

It was specifically targeted with lipid nanoparticles to be rewritten. Researchers believe they have thus avoided the risk of unforeseen mutations, which would have altered its entire DNA code. This exclusively medical procedure potentially opens a new avenue for the treatment of rare diseases.

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