Nikita and Harley Hunter were dealt a heartbreaking blow in April this year when they were told the youngest of their three children - two-year-old Isla - had a rare and incurable neurodegenerative disorder known as Batten disease.

But experimental gene therapy being developed in the US is providing a beacon of hope for the Hunter family.

Texas-based Taysha Gene Therapies is currently seeking FDA approval for an investigative new drug application that would allow them to run a gene therapy clinical trial for children with CLN1 - the form of Batten disease that Isla has.

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Gene therapy for CLN1 disease is a one-time treatment in which a healthy copy of the defective gene is delivered into the brain inside a viral 'transporter'. The healthy gene copy leads to production of the deficient key brain enzyme, thereby slowing or preventing further brain degeneration.

"To think that Isla could be part of something like this, which not only has the potential to help her but other children with CLN1 is amazing," Nikita said.

"We would love for Isla to be given the opportunity to take part in a clinical trial. We would go anywhere. It would be a game changer for our family."

The Batten Disease Support and Research Association Australia is advocating strongly on behalf of Isla and another young Victorian girl with CLN1, whose family reached out to them after reading Isla's story.

BDSRA Australia Head of Research, Medical and Scientific Affairs Dr Ineka Whiteman said while the trial was not yet open for patient recruitment, she was in regular contact with Taysha.

"We're not sitting idle waiting for them to approach us to see if the girls would like to participate in the trial, we just don't think that will happen. We have to be proactive," she said.

"I am reaching out to them regularly and the (BDSRA Australia) advisory board members here to keep the conversation going and to ensure the girls remain on Taysha's radar."

But Dr Whiteman said time was of the essence.

"Time is neurons. The further a patient has progressed, those neurons that have been lost generally can't be regenerated. Treatment will potentially only halt the disease or slow it's progression from the point that the therapy starts," she said.

"It's a race against the clock."

Dr Whiteman said two Australian children with another form of Batten disease had travelled overseas in the past to take part in different clinical trials.

But acceptance into trials was not easy, with many variables such as the number of available places, level of disease progression and other selection criteria, exclusion criteria and site location, all potentially affecting the girls' eligibility.

That said, the prospect of gene therapy was "real hope" for families like the Hunters.

"It is exciting and it's given them more hope than families before them had when they were diagnosed with CLN1 disease," Dr Whiteman said.

"For BDSRA Australia, it would be a wonderful outcome for the families that we represent."

While the family's anxious wait continues, Nikita said she had been overwhelmed by the community's response to Isla's story.

"I've had people I don't know hug me, cry with me, people I wouldn't have expected reach out to both Harley and I to send their love, regards and thoughts," she said.

"We have had donations and fundraisers in our beautiful daughter's name so from the very bottom of our hearts thank you to everyone who has made a difference and shown us what community love and spirit is really about.

"It's easy to lose faith in a situation like ours, but we will never give up fighting to give Isla all she deserves. Thank you to everyone who has had our back along the way, none of it has gone unnoticed."

- A GoFundMe page has been created to help the Hunter family. To read more or to donate, click here.