The Polish woman who believes she is Madeleine McCann has been dealt a devastating blow.

Julia Wendell, 21, has submitted DNA to be tested in the hope that she will be confirmed to be the British girl, who vanished aged three from a Portuguese holiday apartment in 2007.

But Wendell may be battling cancer, her spokeswoman has revealed, and she is awaiting test results back over fears she has leukaemia.

“We are still waiting on the result of DNA testing that will show us exactly what Julia’s ethnic background is and what country she and her true family are from. These kinds of tests are very accurate,” Wendell’s representative and private detective Dr Fia Johansson told The Sun.

“Of course depending on the result of that we will continue our investigation to see if Julia is could be Madeleine or another missing person.

“But now the focus is on Julia as a person - not Madeleine.

“She has had a neglected childhood and suffered much abuse.

“Her health is very poor she has bad asthma and she suffers lots of pain in her bones.

“She is booked in for a CT and MRI scan because of the pain in her bones.

“Her blood work is also abnormal so my doctor here in the US is investigating whether she could have leukaemia so we are awaiting the results of that. And if she needs any treatment we will make sure she gets that.”

Wendell has submitted samples for three different forensic examinations that will outline her DNA sequence, along with a 23andMe-style genetic test to establish her ancestry.

If Wendell’s ancestry comes from the same region as Madeleine’s parents, Gerry and Kate McCann, Dr Johansson said she will immediately send the DNA sequence to Portuguese investigators for comparison.

Wendell – who has said she does not “remember most of my childhood” – previously said that Madeleine’s parents have agreed to a DNA test.

She claims that details of her childhood don’t add up, leading her to believe that she was abducted as a toddler, and that she has a spot in her right eye and a beauty mark on her cheek similar to Madeleine.

Earlier this month, however, Pawel Noga from the Provincial Police Headquarters in Wroclaw told Polish news outlet Gazeta that authorities have “ruled out” Wendell’s version of events to be “true”, according to an English translation of the outlet’s report.

In a 15-minute video posted to her Instagram, Wendell and Dr Johansson refuted the officers’ statement.

Dr Johansson said that “no police officers in Poland said that she (Julia) or she is not Madeleine McCann” and it was “all lies”.

She said the pair also intended to “force” Wendell’s mother to submit to a DNA test.

Internet users have also speculated that Wendell could be Swiss girl Livia Schepp, who disappeared in 2011 with her twin Alessia, aged six.

“Julia is very open to the idea she may indeed be another missing child and they are hoping to carry out a DNA test with her family,” Dr Johansson recently told The Sun.

“I’ve spoken to her about this and she is open to the fact she could be any missing child out there – not just Madeleine. Julia just wants to know the truth about who she is.

“One of the reasons she made the connection to Madeleine is because one of the suspects in Madeleine’s case looks very much like a man who she says abused her as a child.

“But the same man could be connected to Madeleine and other missing children – this is how predators and traffickers work.

“Julia has taken a DNA test and we are investigating if it’s possible to check her DNA with that of missing Livia.

“We are investigating all possibilities at this stage.”

Wendell’s family in Poland, meanwhile, have spoken of their “devastation” at her claims.

“For us as a family it is obvious that Julia is our daughter, granddaughter, sister, niece, cousin and step niece. We have memories, we have pictures,” the family said in a Facebook statement, via Polish missing persons organisation Missing Years Ago.

“Julia also has these photos, because she took them from the family home with the birth certificate, as well as numerous hospital discharges.

“We always tried to understand all situations that happened with Julia. Numerous therapies, medicines, psychologists and psychiatrists – Julia had it all guaranteed. She wasn’t left alone.

“Threats to our address from Julia, her lies and manipulations, activity on the internet. We’ve seen it all and we’ve tried to prevent it, to explain, we’ve asked her to stop.”

The family hinted at Wendell’s motivations, writing that she “always wanted to be popular”.

But, Dr Johansson urged the family to consider a DNA test, and to “get in touch with us directly so we can discuss the case with them rather than releasing statements online”.

“Some of the information Julia has told us and the evidence we’ve seen doesn’t match what the family are saying so we would like to talk about it directly with them,” she told The Sun.

“It seems suspicious to me that Julia’s family will not take a test, which could clear these claims up very quickly.”