US 3-Year-Old Is First to Be Treated for Rare, Fatal Disease

A California boy is defying bleak odds after becoming the first patient to receive a new gene therapy for Hunter syndrome, a rare genetic disorder that usually proves fatal before adulthood. Oliver Chu, 3, took part in a clinical trial at the UK's Royal Manchester Children's Hospital, where doctors used gene editing to reprogram his own stem cells to produce a missing enzyme, per the BBC. "I've been waiting 20 years to see a boy like Ollie doing as well as he is, and it's just so exciting," says Dr. Simon Jones, who's co-leading the trial.

Oliver was diagnosed last year with Hunter syndrome, a condition that causes progressive damage to the body and brain, and which almost always occurs in boys. Before the gene therapy, the only available treatment could slow physical decline but couldn't cross the blood-brain barrier to help stop cognitive symptoms. Children with the condition are born seemingly healthy but typically begin to deteriorate around age 2. The disease, sometimes referred to as a type of childhood dementia, affects roughly 1 in 100,000 male births and is often fatal by age 20.

The February treatment process began with doctors removing some of Oliver's stem cells, which were then sent to a lab and modified to include a healthy copy of the gene that produces the missing enzyme. The modified cells were then infused back into Oliver's body. Within months, he was off weekly enzyme infusions and, per his parents, showing significant progress in speech, mobility, and social interaction. "Every time we talk about it I want to cry because it's just so amazing," says mom Jingru.

Oliver and his family return to Manchester every three months for follow-ups. If the trial is successful, the hospital hopes to partner with another biotech firm to seek licensing for the treatment. "Things look really hopeful right now," Jones says, per the Guardian. Oliver's parents say they're "eternally grateful" he was able to take part, per the BBC. "His life is no longer dominated by needles and hospital visits," says dad Ricky. The couple hope their older son, who's 5 and also affected by Hunter syndrome, can one day benefit from the same therapy. Chu explains that Skyler, 5, wasn't able to take part in the UK study due to his age and is part of a US study instead, per a release.