Breakthrough Gene Therapy Successfully Treats Hunter Syndrome in Child

The first child in history has been successfully treated with a groundbreaking gene therapy for Hunter syndrome. Oliver Chu, a three-year-old from California, received the stem cell-based treatment at the Royal Manchester Children’s Hospital in February 2023.

This therapy, developed by Professor Brian Pigger from the University of Manchester, replaces the defective gene responsible for producing the enzyme iduronate-2-sulfatase, which is crucial for breaking down complex sugar molecules.

Children with severe Hunter syndrome, which affects approximately one in 100,000 live births and predominantly boys, experience a range of debilitating symptoms including cognitive decline, heart and lung dysfunction, and joint malformations.

Oliver underwent a procedure where his blood was cycled to extract hematopoietic stem cells, which were then sent to Great Ormond Street Hospital in London. There, a functional copy of the defective gene was inserted into a virus and introduced back into Oliver's stem cells.

On February 23rd, Oliver received an injection of 125 million modified cells. Remarkably, just three months later, Oliver has shown significant improvement, demonstrating normal development milestones, increased vocabulary, and the ability to play without supervision.

His mother Jingru expressed overwhelming joy, stating, "Every time we talk about it I want to cry because it's just so amazing." Professor Simon Jones, who oversaw the trial, noted that Oliver's progress has been exceptional, but cautioned against premature optimism.

Unfortunately, Oliver's older brother, Skyler, who is five and also suffers from Hunter syndrome, is too old to receive the same treatment, as the trial's eligibility was limited to children aged three months to one year.

Skyler currently receives enzyme infusions, which do not cross the blood-brain barrier, limiting their effectiveness. Ricky Chu, their father, remains hopeful that this pioneering treatment for Oliver will lead to further innovations in addressing Hunter syndrome in older children.

This breakthrough represents a significant advancement in gene therapy for rare genetic disorders, offering hope to families affected by similar conditions.