Evie Hodgson was just a few weeks away from the stem cell transplant surgery that doctors hoped would cure her when the donor pulled out last Friday.
It came as a cruel blow but the courageous eight-year-old and her family are determined to overcome the disease.
Her mum Tina said Evie's love of singing is helping her - you can see the video here of her singing Somewhere Over The Rainbow.
“It was a kick in the teeth but we’re a positive family and this isn’t going to beat Evie,” said Tina.
Evie, who goes to Fyling Hall School in Robin Hood’s Bay, was diagnosed with aplastic anaemia in May.
Tina, who works at RAF Fylingdales, and her husband Andrew, Chief Executive of Whitby and District Fishing Industry Training School, had rung 111 after their little girl developed a rash that would not fade under a glass.
They were told to take her to Whitby Hospital where she was given antibiotics before being transferred to James Cook Hospital and then Great North Children’s Hospital in Newcastle.
It was a shock, said Tina, as until the rash Evie had shown no obvious signs of the illness.
“One minute we’re an ordinary, healthy family.
"The next, we’re on an oncology ward with Evie having a platelet transfusion,” she said.
After several tests, doctors broke the news that Evie has aplastic anaemia, also known as bone marrow failure.
Evie’s body struggles to fight off even the most minor infection and she needs blood transfusions twice a week.
The most successful treatment is a stem cell transplant. Tina, Andy and Evie’s five-year-old brother William have been tested but are not eligible.
Amazingly, a perfect match - the only one in the world - was found and the surgery was scheduled.
Evie had one of her ovaries removed to provide options as she grows older, as a course of chemotherapy she would have undergone to prepare her body for the transplant would have prevented her body starting puberty.
She also had a central line put in her chest and, because the chemotherapy would likely mean she would lose her hair, Evie had it cut and donated it to the Princess Trust.
Since the stem cell donor pulled out - with no explanation - doctors have recommended Evie start a course of medication aimed at re-energising her bone marrow.
It has a 60 per cent chance of success and will be tried for three months.
If it does not work, doctors will consider a transplant from a donor who is less of a match, but this is less likely to work.
Tina is keen to raise awareness of the stem cell donation register and hopes sharing Evie’s story will encourage more people to join.
She said Evie’s love of singing is helping the little girl, who wants to be a doctor when she is older.
“I’m grateful that singing has helped her through. It makes her happy,” she said.
“She’s so thoughtful and caring. She’s just a lovely little girl.
“Even with everything that she’s going through, she’s never once complained.”