Three-year-old Ava Stark has a rare blood condition and needs a stem cell transplant or she will die.
Her desperate mum Marie, 33, made a public plea, urging people from around the world to get tested as they desperately try to find a life-saving match.
After a search of the register worldwide - which has about 25 million people on it - only one suitable candidate was found.
Ava was due to have a bone marrow transplant next month after the donor agreed to proceed, but 10 days ago the family learned the donor had pulled out.
Now blood cancer charity The Anthony Nolan Trust have praised ‘The Ava Effect’ for a massive 500 per cent increase in the number of donor sign ups compared to the same day last week.
Ann O’Leary, Head of Register Development at Anthony Nolan, said: “It’s amazing to see what a difference Ava’s story is making, she has clearly inspired so many selfless Scottish people to sign up to our register and we can’t thank them enough.
“Despite going through so much themselves it is heartening to see Ava’s family tirelessly campaigning to raise awareness of stem cell donation.
“We still urgently need more people to come forward, especially young men as they are the most likely to be chosen to donate but are under-represented on the register.
“What many people don’t realise is how easy it is to join the bone marrow register – it simply involves filling in a form and providing a saliva sample.”
Ava has a condition called inherited bone marrow failure and needs weekly platelet transfusions and two blood transfusions a month - both from donors - while she awaits a transplant.
Earlier this week, her mum, from Lochgelly in Fife, said: “Because of her low platelet count, something as simple as brushing her teeth turns into a bloodbath.
“She loves animals and wanted to go to Blair Drummond Safari Park but, because she basically has no immune system, she couldn’t in case she caught something from the animals.
“We even had to get rid of the family dog. Ava loves her toys, though.
“If you ask the nurses, they will tell you she is constantly the happy one.”