The eldest of four brothers saved from a rare terminal illness is joining a charity walk for transplant patients.
Joshua Hartley (third from left) had his life-saving operation last year
Josh Hartley, 13, from Romsey, Hampshire, was diagnosed with XLP, which attacks the immune system.
The Anthony Nolan Trust found donors for his brothers, Nathan, 11, Daniel, nine, and Luke, five, while Josh had a transplant from his mother Allison.
The Hartley family is organising the four-mile Walk 4 Life at Broadlands estate in Romsey, Hampshire, on 22 May.
Josh said: "It's now 10 months since my transplant and I would like to raise funds for the Anthony Nolan Trust to help other people find bone marrow donors."
It cost the charity £70 to register each potential donor who volunteered during last year's campaign.
David Hartley, the boys' father, said: "The Anthony Nolan Trust has helped us so much over the past year and we just wanted to do whatever we could to help them in return.
"We have raised around £13,000 already and we hope this walk will be a big push to raise even more.
"It is fantastic that Josh is doing the walk and that he wants to do it. It will be a real challenge for him because, with the steroids he is on, it won't be easy.
"Josh is 13 now and understands what he has been going through and this is his way of saying thank you to all those people who have helped him and his brothers."
When the brothers were diagnosed in November 2003, they were not expected to live into their teens.
But this January Josh celebrated his 13th birthday, a few days after returning to school after recovering from his transplant, which took place in June 2004.
His brother Daniel had surgery last November, while Nathan and Luke are waiting to undergo their transplants at Great Ormond Street Hospital in London later this year.
XLP, also known as Duncan's Syndrome, is one of the world's rarest disorders, affecting about 100 families world-wide.