In a remarkable turn of events that has captured the attention of the medical community, a three-year-old named Oliver Chu has made history as the first individual with a rare and debilitating condition to undergo a pioneering gene therapy treatment. Oliver, who hails from California, was diagnosed with Hunter syndrome, or MPSII—a genetic disorder that primarily affects boys and leads to progressive damage to the body’s organs and brain. In severe cases, the condition can be likened to childhood dementia, with life expectancy often not extending beyond the age of 20.

Because of a genetic mutation, Oliver was unable to produce a crucial enzyme necessary for maintaining cellular health. However, a groundbreaking trial in Manchester has opened new possibilities for him. NHS medical professionals are attempting to stop the progression of his condition by employing gene therapy to modify Oliver’s cells. The process involves extracting stem cells from the patient’s blood and then inserting a functional copy of the defective gene into a virus. This virus then transports the gene to the stem cells, which are subsequently reintroduced into the patient’s body. The genetically altered stem cells then repopulate the bone marrow, allowing the body to naturally produce the previously missing enzyme.

Since receiving this innovative treatment, Oliver has experienced an astonishing improvement in his health. He travels from the United States to the Royal Manchester Children’s Hospital every three months for several days of follow-up testing to monitor his progress.

Professor Simon Jones, who is co-leading this groundbreaking trial, expressed his excitement to the BBC, saying, “I’ve been waiting 20 years to see a boy like Ollie doing as well as he is, and it’s just so exciting.”

Professor Jones, affectionately nicknamed ‘Santa’ by Oliver due to his white beard, is overjoyed by the results: “Before the transplant, Ollie didn’t produce any enzyme at all, and now he’s generating hundreds of times the normal amount. More importantly, we can see tangible improvements—he’s learning, acquiring new words and skills, and moving around much more easily.”

“But more importantly, we can see he’s improving, he’s learning, he’s got new words and new skills and he’s moving around much more easily.” 

However, Prof Jones exercises a degree of caution: “We need to be careful and not get carried away in the excitement of all this, but things are as good as they could be at this point in time.” 

While Oliver’s dad Ricky said from the hospital after his son’s latest round of health checks:  “He’s like a completely different child. He’s running around everywhere, he won’t stop talking. 

“The future for Ollie seems very bright and hopefully this means more kids will get the treatment.” 

While relieved mum Jingru added: “Every time we talk about it I want to cry because it’s just so amazing.” 

Hunter syndrome almost always occurs in boys. It’s extremely rare, affecting one in 100,000 male births in the world. 

Until now, the only medicine available for Hunter syndrome was Elaprase, which costs around £300,000 per patient, per year and can slow the physical effects of the disease. The drug is unable to cross the blood-brain barrier and so does not help with cognitive symptoms. 

Children are born apparently healthy, but around the age of two they start to show symptoms of the disease. 

These vary and can include changes to physical features, stiffness of the limbs and short stature. It can cause damage throughout the body, including to the heart, liver, bones and joints and in the most serious cases can lead to severe mental impairment and progressive neurological decline. 

Oliver is the first of five boys – from the US, Europe and Australia – to get the treatment. None are from the UK as patients here were diagnosed too late to qualify. 

But the medical trial almost didn’t get off the ground due to lack of funds. 

Researchers at the University of Manchester led by Prof Brian Bigger had spent more than 15 years working on creating the gene therapy for Hunter syndrome. 

In 2020 the university announced a partnership with a small US biotech company Avrobio, to conduct a clinical trial. 

But three years later the company handed back the licence to the university, following poor results from another gene therapy study and a lack of funds. 

The first-in-human trial, which would soon help Oliver, was in jeopardy before it had even begun.

It was then that British medical research charity, LifeArc, stepped in, providing £2.5m of funding. 

LifeArc’s CEO Dr Sam Barrell said: “A huge challenge for the more than 3.5 million people in the UK living with rare conditions, is getting access to effective treatments – currently 95% of conditions have none. ” 

Since being diagnosed with Hunter syndrome in April, Oliver’s life – like that of his elder brother, Skyler, who also has the condition – has been dominated by hospital visits. 

Ricky explained: “When you find out about Hunter syndrome, the first thing the doctor tells you is ‘Don’t go on the internet and look it up because you’ll find the worst cases and you’ll be very, very disheartened’. 

“But, like anybody, you look it up and you’re like, ‘Oh my goodness, is this what’s going to happen to both my sons?’” 

Last December Oliver had some stem cells removed, carefully packaged and sent to a laboratory at Great Ormond Street Hospital (GOSH) in London. 

Hunter syndrome’s genetic error means cells are missing the instructions for making enzyme iduronate-2-sulfatase (IDS), essential for breaking down large sugar molecules which over time accumulate in tissues and organs. 

Scientists insert the missing IDS gene into a virus, which has its genetic material removed so that it can’t cause disease. 

A similar method has been used in other gene therapies, such as the treatment for another rare inherited condition, MLD. 

Dr Karen Buckland, from the Cell and Gene Therapy Service at GOSH, explains: “We use the machinery from the virus to insert a working copy of the faulty gene into each of the stem cells. 

“They repopulate his bone marrow and start to produce new white blood cells and each of these will hopefully start to produce the missing protein [enzyme] in his body.” 

Then in February 2025 Oliver returned to Royal Manchester Children’s Hospital and clear fluid containing around 125 million gene-modified stem cells were injected back into him. 

Last May crucial tests showed how Oliver was already more mobile, brighter and healthier with thrilled Ricky saying: “He’s doing really well. We have seen him progressing in his speech, and mobility. He has matured. 

“My wish upon the star is for Skyler, to be able to get the same treatment. It feels like Oliver has got a reset in his life, and I want the same thing for Skyler (deemed too old for the trial).” 

Ricky explained that Skyler has delayed development in speech and motor skills, but is undergoing infusion therapy, which gets the treatment to his body, but not his brain. 

By August checks confirmed Oliver’s gene therapy is working and Prof Jones says the same gene therapy approach is being applied to other gene disorders. 

There are similar treatments on trial in Manchester for MPS type 1 or Hurler syndrome and MPS type 3 or Sanfilippo syndrome. 

Ricky has added: “I don’t want to jinx it, but I feel like it’s gone very, very well. 

“His life is no longer dominated by needles and hospital visits. His speech, agility and cognitive development have all got dramatically better. 

“I would walk to the end of the earth, backwards, forwards, upside down, barefoot, to make sure my kids have a better future.”