World-First Gene Therapy Halts 'Childhood Dementia' in 3-Year-Old
- 5 days ago
- 3 min read
Three-year-old Oliver (Ollie) Chu, a California resident, has become the world's first patient to receive a revolutionary one-off stem cell gene therapy to treat Hunter syndrome. This developmental treatment, developed over 10 years at the University of Manchester and tested at the Royal Manchester Children’s Hospital (RMCH), offers profound hope for children facing this life-threatening disorder.
Hunter syndrome, also known as mucopolysaccharidosis type II (MPS II), is an extremely rare, progressive, inherited disorder that overwhelmingly affects boys, occurring in about one in 100,000 male births globally. The condition is caused by a faulty gene that prevents the body from producing a vital enzyme. Without this essential enzyme, complex sugar molecules accumulate in organs and tissues, leading to progressive damage often likened to a form of childhood dementia. Symptoms include joint stiffness, hearing loss, heart/breathing issues, developmental delays, and cognitive decline, with a typical life expectancy between 10 and 20 years.
Until now, the licensed treatment has been a costly, lifelong, weekly Enzyme Replacement Therapy (ERT) called Elaprase, which costs approximately £375,000 per patient annually. While Elaprase can manage physical and organ problems, it is inefficient at crossing the blood-brain barrier, meaning it cannot treat or improve mental decline.
The new gene therapy is a one-off procedure involving the collection of the child’s stem cells. In a laboratory, the faulty gene is corrected by inserting a working copy of the missing enzyme gene (iduronate-2-sulfatase or IDS) into the cells. Crucially, the gene is modified to produce an enzyme that can cross the blood-brain barrier more efficiently. These modified cells are then re-injected into the patient.
"Gene therapy is not only safer and more effective, but it enables us to use the child’s own cells, which cuts out the need to find a donor," stated Professor Rob Wynn, Consultant Paediatric Haematologist and joint clinical lead.
Ollie received the infusion in February 2025. Months later, he has shown promising results. Professor Simon Jones, Consultant in Paediatric Inherited Metabolic Disease and joint leader of the trial, noted that Ollie is now making hundreds of times the normal amount of the missing enzyme.
Since receiving the therapy, Ollie is no longer having weekly Elaprase infusions. His father, Ricky Chu, reports dramatic improvements, noting that Ollie is "doing great" and continues to grow physically and cognitively. "His speech, agility and cognitive development have all got dramatically better," Ricky Chu said, adding that his progress has "shot up exponentially since the transplant". Ollie is now nine months post-treatment and appears to be developing normally.
The success of this blood cell gene therapy approach is significant and offers an exciting blueprint for treating many other genetic conditions. The same approach is already being applied to disorders such as Hurler syndrome and Sanfilippo syndrome.
Ollie is the first of five children participating in the trial, which also includes boys from Europe and Australia. While the results are extremely encouraging, doctors remain cautious, emphasizing the need to monitor the children for at least two years to ensure the benefit is long-lasting. The Chu family, who also have an older son, Skyler, with Hunter syndrome, are eternally grateful and hopeful that Ollie will live a normal life without infusions.
🔖 Sources
Keywords: Gene Therapy
Gene Therapy
Comments