A rare diseased baby given the world’s first personal CRISPR gene therapy

A boy with a life-threatening genetic condition will become the first to receive custom-made CRISPR gene editing treatments, giving him a glimpse into what the future of medicine will look like.

This is the first time someone has been given a gene editing treatment designed to correct mutations that cause diseases that are only seen in that individual. Rebecca Ahrens-Nicklas He spoke to a press briefing at Children’s Hospital in Philadelphia, Pennsylvania. “He shows early signs of profit,” she says, but it’s too early to tell how well the treatment worked.

Researchers released details as soon as possible, hoping to inspire others, team members say Kiran Musnur At the University of Pennsylvania. “We are very hoping to show that it is possible to perform personalized gene editing therapy for one patient in a few months will encourage others to do the same,” he says.

“When I say this is the future of medicine, I don’t think I’m exaggerating,” he says. “This is the first step towards the use of gene editing therapies to treat a variety of rare genetic disorders that have few treatments actually under development.”

The boy KJ inherited mutations in each of two copies of the gene of the liver enzyme called CPS1. Without this enzyme, ammonia accumulates in the blood when the proteins that we eat, including those we eat, break down and damage our brain. More than half of children born with CPS1 deficiency have died, according to Ahrens-Nicklas.

She and Musnur are developing treatments for this type of condition targeting the liver, allowing them to quickly create basic editing therapy that will modify one of the two copies of KJ. CPS1 gene.

The team contacted US regulators early. “They realized this was an extraordinary situation,” Musnur says. “KJ was very sick and, as usual, had no time for business. When we officially submitted our application to the FDA [Food and Drug Administration] When KJ was six months old, the FDA approved it in just a week. ”

KJ received low-dose treatment at six months in February 2025, followed by high doses in March and April. He can now eat more protein than before, despite taking other medications to manage his condition.

Ideally, the child is treated even earlier to prevent long-term damage conditions such as CPS1 deficiency. As New Scientist Musnur, reported last year, aims to edit human genes one day before birth.

Other gene editing therapies are designed to work for many people regardless of the specific mutations that cause the condition. For example, the first approved gene editing treatment for sickle cell disease works by turning on the production of fetal hemoglobin, rather than modifying mutations in adult hemoglobin that cause the condition. Despite being a “one size fit” treatment, Each treatment course costs £1,651,000 In the UK.

Personalized treatments can be even more expensive. Musnur says he can’t put numbers into KJ’s treatment because the companies involved have done a lot of work for free. But he thinks prices will go down. “As we do this better, we can expect economies of scale to begin and costs will fall by orders of magnitude,” he says.

One reason personalized gene editing therapy has never been developed before is that regulators viewed treatments separately that target different mutations in the same gene. This means that companies had to restart the approval process for all the different mutations from scratch. However, there is a movement towards what is currently called a platform approach, with regulators giving broad approval for treatment of either condition to target either mutation.

“Platform-based approaches, such as genome editing using CRISPR, provide scalable ways to treat even the rarest diseases, as seen in the treatment of KJs.” Nick Mead Genetic Alliance UK is a charity that supports people with rare diseases. “This finally makes treatment a realistic outlook for thousands of families.”