World-First Gene Therapy Successfully Treats Rare Genetic Disorder

The first child in history has successfully been treated with a groundbreaking gene therapy for Hunter syndrome, an ultra-rare genetic disorder. Oliver Chu, a three-year-old from California, became the first recipient of this innovative treatment in February 2023.

He received autologous hematopoietic stem cell gene therapy at Royal Manchester Children's Hospital, where five patients were part of a clinical trial. Hunter syndrome affects primarily boys, with an incidence of one in 100,000 live births, and is characterized by the body's inability to properly break down complex sugar molecules, leading to severe symptoms such as cognitive decline, heart and lung dysfunction, and skeletal abnormalities.

The underlying cause is a defect in the gene responsible for producing the enzyme iduronate-2-sulfatase, or IDS. Professor Brian Pigger from the University of Manchester developed the method to replace the faulty gene.

In December 2022, Oliver underwent a procedure to extract his hematopoietic stem cells, which were sent to a laboratory at Great Ormond Street Hospital in London. There, a functioning copy of the IDS gene was inserted into a virus and then introduced into Oliver's stem cells.

On February 15, 2023, Oliver received an injection of 125 million modified cells, marking a historic moment for gene therapy. After a few days, he returned home to California, where he reunited with his family, including his older brother Skyler, who also has Hunter syndrome.

As of May 2023, reports indicate that Oliver's development has normalized significantly; he has stopped enzyme infusions, is speaking fluently, and exhibits curiosity typical for his age. His mother, Jingru, expressed her amazement at his progress, stating, 'Every time we talk about it, I want to cry because it's just so amazing.' Professor Simon Jones, who led the trial, emphasized the importance of cautious optimism regarding Oliver's improvement.

However, Oliver's older brother Skyler, aged five, is unfortunately too old to receive this treatment as the trial had a specified age limit of three months to one year. Skyler continues to receive enzyme infusions, which do not cross the blood-brain barrier, limiting their effectiveness.

The success of Oliver's treatment has raised hopes for further innovations in gene therapy, particularly for older children affected by Hunter syndrome. This monumental achievement in gene therapy exemplifies the potential of personalized medicine and genetic interventions to address conditions where traditional treatments have failed.