A 12-year-old girl who had her heart transplant reversed has been told she is barred from winning medals at a sports event for transplant patients.
Hannah Clark is no longer eligible to compete in the games
Hannah Clark, from Mountain Ash, south Wales, is thought to be the first in the UK to have her own heart restarted after a donor heart was rejected.
She can no longer compete officially at the British Transplant Games because she no longer has a transplant.
Organisers say they are trying to arrange a special event for Hannah.
Hannah underwent pioneering surgery at London's Great Ormond Street Hospital in February this year after a donor heart which had been working for 10 years was rejected by her body.
The donor heart was disconnected, and Hannah's own heart - which was never removed - was able to continue working on its own.
The original transplant operation took place because Hannah had cardiomyopathy, which made her heart double in size and risk giving out within a year.
The donor heart was able to take over most of the role of pumping blood around Hannah's body, effectively allowing her own heart, which continued beating, to rest.
But the operation in February to remove Hannah's donor heart has meant she is no longer classed as a transplant patient to compete for medals at the British Transplant Games which are being held in Bath in August.
The games allow patients with transplanted organs from across the UK to compete in athletics and other sports.
Hannah has previously taken part in the games several times in events including table tennis, long jump and the 50m sprint.
Christine Evans who chairs the Transplant Sports Association of Great Britain said she would be delighted to see Hannah at the games and she would be invited to present prizes.
Elizabeth Clarke said her daughter was disappointed
Ms Evans added if Hannah was well enough, she would be welcome to participate in events but said because she no longer has a transplant she would not qualify as an official competitor.
Carol Davidson, children's events organiser for the transplant games, added she was trying to arrange a special event for Hannah - either an obstacle race or throwing event - in which she would compete against siblings of transplantees.
But Hannah's mother, Elizabeth Clark, criticised the decision by organisers not to allow Hannah to compete officially.
She said: "It was a real boost for her. In fact when she had her heart removed the only way we could get her into the operating theatre was by promising her that she could still do the transplant games."
The news came as Hannah returned to school after more than six months away from lessons at Mountain Ash Comprehensive school.
"She is so excited, " said her mother, who said Hannah had been taking home tuition to keep up with her classmates.
"I know she will be fine. If she sets her mind to go back to school and spend the full day there then that is what she will do," she added.