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World-First Gene Therapy Halts Rare Disease in Three-Year-Old Boy
A three-year-old boy with a devastating genetic disorder has become the first patient in the world to receive a groundbreaking gene therapy that appears to have halted his condition, offering hope to families affected by Hunter syndrome. Oliver Chu, diagnosed with the rare inherited disease MPSII (Hunter syndrome), has shown remarkable progress since undergoing the experimental treatment at Royal Manchester Children's Hospital, doctors report.
The Disease and Its Toll
Hunter syndrome, which predominantly affects boys, occurs in roughly one in 100,000 male births. Caused by a faulty gene, the condition prevents the body from producing an enzyme critical for breaking down sugar molecules, leading to progressive damage in the brain, heart, liver, bones, and joints. In severe cases, children experience cognitive decline akin to childhood dementia, with most patients dying before age 20.
Until now, the only available treatment-Elaprase, costing around £300,000 per patient annually-could only slow physical symptoms but failed to address neurological decline, as it cannot cross the blood-brain barrier.
A Revolutionary Approach
The experimental therapy, developed over 15 years by researchers at the University of Manchester, modifies a patient's stem cells to produce the missing enzyme, iduronate-2-sulfatase (IDS). Scientists used a disabled virus to insert a functional copy of the faulty gene into Oliver's cells, which were then reinfused into his body. The gene was further engineered to help the enzyme penetrate the blood-brain barrier-a critical hurdle in treating neurological symptoms.
"We use the machinery from the virus to insert a working copy of the faulty gene into each of the stem cells. When those go back to Oliver, they should repopulate his bone marrow and start producing the missing protein in his body."
Dr. Karen Buckland, Cell and Gene Therapy Service, Great Ormond Street Hospital
The Treatment Journey
Oliver's journey began in December 2024, when his stem cells were extracted at Royal Manchester Children's Hospital and sent to a lab in London for genetic modification. Months later, the edited cells-around 125 million of them-were reinfused in a procedure lasting just 20 minutes. Within months, tests confirmed Oliver's body was producing the enzyme independently, eliminating the need for weekly infusions of Elaprase.
"Every time we talk about it, I want to cry because it's just so amazing," said Jingru Chu, Oliver's mother. "He's so different now-talking constantly, engaging with other children, and thriving in ways we never thought possible."
Remarkable Progress and Cautious Optimism
Nine months post-treatment, Oliver's development has exceeded expectations. His speech, mobility, and cognitive abilities have improved dramatically, with his parents describing him as "a completely different child." Prof. Simon Jones, co-leader of the trial, noted that Oliver is now producing "hundreds of times the normal amount" of the enzyme, with visible gains in learning and physical agility.
"Before the transplant, Ollie didn't make any enzyme at all. Now, he's improving, learning new words, and moving around much more easily."
Prof. Simon Jones, Royal Manchester Children's Hospital
While cautious about long-term outcomes, Jones called the results "as good as they could be at this stage." The trial includes five boys from the U.S., Europe, and Australia, all of whom will be monitored for at least two years. If successful, the team aims to partner with a biotech firm to license the therapy.
A Race Against Time
The trial nearly collapsed in 2023 when its original sponsor, U.S. biotech firm Avrobio, withdrew due to funding shortages and disappointing results from another study. British medical charity LifeArc intervened with £2.5 million in emergency funding, saving the project. "A huge challenge for rare-disease patients is access to treatments-95% of conditions currently have none," said LifeArc CEO Dr. Sam Barrell.
For the Chu family, the stakes are deeply personal. Oliver's older brother, Skyler, also has Hunter syndrome but was diagnosed too late to qualify for the trial. "My wish is for Skyler to get the same treatment," said Ricky Chu, Oliver's father. "It feels like Oliver's been given a reset in life. I'd do anything for Skyler to have that chance too."
The Future of Gene Therapy
The success of Oliver's treatment could pave the way for similar therapies for other lysosomal storage disorders, including MPS types 1 and 3 (Hurler and Sanfilippo syndromes). Researchers emphasize that while the results are promising, longer-term data is needed to confirm durability. For now, Oliver's case stands as a beacon of hope-proof that gene therapy can transform lives where no other options exist.
"His life is no longer dominated by needles and hospital visits. His speech, agility, and cognitive development have improved exponentially."
Ricky Chu, Oliver's father
