An 18-month-old boy has successfully undergone pioneering gene therapy to correct a potentially fatal bone marrow condition that left his frail body incapable of fighting infection.
Rhys Evans, a toddler unaware of his place in British medical history, is the first recipient in this country of a treatment that scientists hope will pave the way for conquering a host of other diseases, from haemophilia to cancers and cystic fibrosis.
But he and his parents are, for now, more interested in catching up on the time they lost from four months into his life, when repeated chest infections then pneumonia turned him into skin and bone, a mere 12lb (5.44kg) in weight, little more than a healthy newborn baby. The problems seemed to have started as his mother stopped breast-feeding him, thus no longer passing on her own immunity.
By last April, Rhys was in intensive care, on a ventilator, in a hospital near their home outside Cardiff, south Wales. By May last year, he had been transferred to the world's most famous children's hospital, Great Ormond Street in London. Exhaustive tests eventually revealed he was the victim of a faulty gene, called gamma c, believed to be responsible for a failure of the immune system.
A generation ago, the prognosis for survival beyond a year or two from the condition known as X-linked SCID or severe combined immunodeficiency disorder would be dire. Children with the condition were kept in sterile "bubbles", unable to have normal human contact or take part in childhood activities. Then came bone marrow transplants, offering genuine hope of long-term survival, while not always totally successful. Donors are always in short supply, especially those that can provide a satisfactory match.
Worldwide search
Rhys had no brothers or sisters whose bone marrow could be used to renew his immune system. His parents, Marie and Mark, were told that doctors could not find a satisfactory match in Britain, so they started a worldwide search. Meanwhile, the sickly boy was confined to a sterile room.
Eventually a donor was tracked down in the US. But the timing of Rhys's arrival at Great Ormond Street meant he could potentially benefit from trials about to start there, in conjunction with the hospital's research partner the Institute of Child Health.
The London researchers had been preparing the ground for years and had closely monitored the first successful use of gene therapy at another children's hospital, the Necker, in the Montparnasse district of Paris. Since February 2000, doctors there had treated a handful of children by taking out some of their bone marrow cells, coaxing in a healthy gene and watching it invigorate their immune systems.
Marie and Mark Evans weighed up the alternatives of conventional transplant and a still infant technology. Mr Evans said, as they went public about their son's story yesterday, that in the end they had not been ready to see their child "going through chemotherapy, sickness, loss of hair, loss of taste in the mouth - and he might be sterile in future".
"We went for gene therapy. It has proved itself. We are over the moon, pleased and really proud we have our son back. He is bouncy and full of it. We can't do enough for him."
At the end of February, the family went on holiday to Tenerife for a fortnight. "He went in the pool for the first time. It is still early days though," said Mr Evans, 40, who gave up his job working for a gas company while the family desperately tried to save Rhys.
The operation took place in July. Rhys went home in October and just before Christmas the family sent doctors a thank-you video, with Rhys already bearing no resemblance to the weak infant he had been and taking some uncertain steps toward the camera.
About six weeks ago, Mr and Mrs Evans stopped treating him with injections of immunoglobulin to boost the antibodies in his body. By February, his blood results were almost normal. Rhys is still on antibiotics but will not be indefinitely.
Mrs Evans, 31, a teacher, said she and her husband had been devastated when they first learned of Rhys's condition. Before the treatment, he had been cut off from the normal world in a clinically clean room where he could only be visited under strict supervision. She remembered too the awful early months of his decline, his sickness, his diarrhoea. "He just fell off the side of a cliff," she said, as she recalled a day in April she had to take him to the Cardiff hospital.
"It was an incredible shock when we first found out Rhys had a genetic condition. Now we are living at home like a normal family. He's been to the park to play in the sand and get into mischief and we never thought that was going to happen. He can walk and run around like any toddler can. He is catching up so quickly. His progress seems nothing short of a miracle."
Adrian Thrasher, who led the gene therapy team, said there were no complications. "We are very relieved. We are ecstatic." He was not however as prepared as the hospital's public relations team to call it a cure. "We cannot say it is a cure until 50 years down the line or 70 years down the line and we know Rhys's immune system is restored for life." But he added that the team was confident the treatment was at least as good as a conventional bone-marrow transplant.
"We've been working in gene therapy for many years in the lab and it is great to take that work into the clinic and see some therapeutic success."
Another boy aged 10 months underwent the treatment at the hospital about 12 weeks ago. Soon three or four a year might be getting it.
Much of the work has been made possible by a charity initiative called Jeans for Genes, which has raised more than £12m for research into children's genetic diseases since it was launched in 1996. This year's target is £2.5m, much of it being raised from a special day on October 4 when thousands of people are expected to wear jeans to work or school and donate £1 each to the appeal.
