A video report by Granada Reports Reporter Mel Barham
A nine-year-old girl born with a rare genetic condition, who underwent experimental brain surgery in Poland, is amazing doctors with her progress.
Hallie Campbell from Wigan was diagnosed with AADC deficiency as a baby. The life-limiting condition meant she could not walk, talk or even sit up by herself.
The debilitating condition also caused her to suffer from excruciating seizures every day, sometimes lasting for hours at a time.
Hallie's mum Lucy said: "When I think about it, I almost like can't believe how poorly and fragile that she was.
"She used to feed through a tube 20 hours a day. She couldn't hold her head up. We'd have to sit her on our knee and prop her up and hold her head.
"And the seizures, that was probably the worst one for us - hours and hours a day of her just being in excruciating pain. It was just awful."
The prognosis for those with AADC deficiency was not good, so in 2019 Hallie's family decided to take a leap of faith and put her forward for experimental surgery being offered in Poland.
The gene therapy brain surgery was still being tested and was therefore unlicensed which meant it wasn't available on the NHS.
The family had to raise £70,000 in just a few weeks, and thanks to the generosity of viewers after appealing for help on Granada Reports, they were able to travel to Poland in November 2019 for what they hoped would be life-changing surgery.
"I just felt like if there was something that we could do, we needed to do it." said Hallie's mum.
"And there was just something in me that I just knew that, you know, I needed to do this.
"And I'm so glad that we did. I just felt like the universe had our back."
Three years on, ITV Granada Reports correspondent Mel Barham, who originally filmed with the family in Poland, went back to see Hallie's progress.
Lucy told ITV News: "I can't even explain what it's like, it is just so lovely to see her just loving and enjoying life and interacting with everybody and playing like a child.
"And she absolutely just loves life. She's a really happy little girl."
Hallie is now able to sit unaided, feed herself and play with dolls and toys. She is also learning to walk, talk and use sign language
Lucy explained: "She's just started signing, she can sign her friends's names, oh and 'hungry'.
"That is one of her favourite signs, hungry. And so it's really nice that she can communicate that way as well with us."
The family admit it was a huge decision to put Hallie forward for unlicensed treatment, but seeing her progress they have no regrets.
"It was just really hard, you know, to see Hallie in so much pain.
"And, you know, I think without gene therapy, this could have been a completely different story.
"But the story now, I feel like it's just a lovely story of like hope, healing and happiness. Really. It's lovely."
And as for those who helped them, the family say they can't thank people enough.
"Absolutely. Forever grateful to everybody that made this possible for Hallie because, you know, without the generous Granada Reports viewers, and everybody that helped make this possible, everybody that donated and has absolutely changed Hallie's life for the better and just made her who she is today."
All they wanted was to stop Hallie's painful seizures, the bonus has been unlocking their little girl's potential.
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