Gene-Editing Breakthrough

A personalized gene-editing treatment successfully treated an infant with a rare genetic disease known as CPS1 deficiency, doctors announced yesterday. It marks the first time a patient of any age has been successfully treated via customized CRISPR gene editing.

While CRISPR—which typically acts as molecular scissors, deleting faulty genetic code (see deep dive)—has been approved to treat diseases like sickle cell and beta-thalassemia, these are relatively common diseases. CPS1 deficiency, which blocks the liver's ability to process ammonia, affects around one in 1.3 million children and is linked to specific mutations in each patient. Doctors used an advanced form of CRISPR known as base editing, which acts more like a "spell check" for genes and is capable of replacing individual bases with the correct code (watch explainer video).

Researchers hope the demonstration can be extended to treat millions of patients with rare or otherwise unique diseases. Read more about the development of the treatment here.