A Derby family whose son spent part of his early life in a "bubble" to protect him from infection are celebrating 10 years since he was given life-saving treatment.
Christopher Reid, from Allestree, was diagnosed with Severe Combined Immuno-Deficiency (SCID) at eight months, a genetic condition which meant he had no natural immune system.
His father Steve Reid said: "To see him now - playing with his friends, going to mainstream school, going camping with the cubs and scouts - it is just remarkable."
Christopher became the first child in England to receive pioneering gene replacement therapy at Great Ormond Street Hospital in 2001.
'Step into the unknown'
Prior to the treatment, doctors had given Christopher three months to live.
"We got the news on Halloween and we walked into hell, being told that our child had no chance of survival beyond his first birthday," his mother Rachel Reid said.
The family was rushed to London and he was put straight into isolation.
He had a protective bubble put around his head and was banned from playing with other children.
An operation in December 2001 introduced an artificially created gene which was mixed with his bone marrow and injected into Christopher's body to correct the problem.
"They had all the science there to say that the treatment would work but until they actually started these trials it was a step into the unknown for us and them," said Mrs Reid.
Gene therapy for SCID is now considered a cure, as reported in journal Science Translational Medicine in August 2011.
"We were faced with death. Unlike us, other parents now have hope and other children have this cure.
"They are now faced with life, that is what this treatment means."
The family plans to raise £5,000 for the hospital to mark the anniversary.