Australian family grapples with daughter's devastating childhood dementia diagnosis

When Rachel Anderson and Elijah Marshall noticed their daughter Hannah struggling to remember things she had just done, they knew something was not right.

"There were things that she used to be able to do that she just didn't seem to be able to do anymore," Anderson said. "Then other people started noticing and saying there's something not quite right with Han."

Just 10 years old at the time, Hannah Anderson-Marshall was eventually diagnosed with childhood dementia.

It was a devastating moment for the family from Leeton in the Riverina region of New South Wales.

There is currently no cure for childhood dementia, and like other forms of dementia, it is a regressive disease that results in death.

"I was making her a dress [at the time of her diagnosis] and I'm suddenly thinking … 'Is this what we would bury or cremate Hannah in?'" Anderson said.

"I just couldn't do a thing without thinking about Hannah actually dying."

Hannah's father has also struggled to grapple with the grim reality of her diagnosis.

"Every once in a while [you] just go, you're not going to do that or you're not going to see that, like being able to celebrate HSC with her … walking her down the aisle," Marshall said.

According to the Childhood Dementia Initiative, one in 2900 babies across the world is born with a condition that causes childhood dementia.

About 50 percent die by the age of 10, and 70 percent will die before they turn 18.

Hannah's form of childhood dementia is an extremely rare neurodegenerative disorder with brain atrophy.

It causes seizures, loss of cognitive and motor skills, and loss of brain cells and neural connections.

The Childhood Dementia Initiative aims to find treatments and cures, provide access to quality care for children with dementia and their families, and to make the disease a global health priority.

Childhood Dementia Initiative director and neuroscientist Peter Schofield said childhood dementia was difficult to diagnose because every case was different.

"In the childhood dementias, there are a bunch of very rare genetic mutations that result in deficits in nerve cell function in the brain and that causes the dementia," he said.

"In general, they all cause some accumulation of a toxic product inside the nerve cells, and that's what kills them."

Dr Schofield said that although the disease was relatively rare, the parents of children with dementia had a "one in four" chance of seeing the disease develop in any subsequent children.

"[But] because disease onset ranges from generally two to 14 years, most couples have already had a second child before the first is diagnosed," he said.

Childhood Dementia Australia aims to increase research into the condition.

Hannah, now 12, attends Gralee School in Leeton, a school for students with special needs.

Her teacher, Lizette Taylor, recently won a Minister's Award for Excellence in Teaching for her work with children with dementia.

"It got to the point where we couldn't really teach [Hannah] new things in school because it wasn't fair … to have to expect her to remember things that were brand new," she said.

"We kind of had to go back over what she had learnt, but kind of extend on it."

Taylor said it was important to adapt her teaching to Hannah's daily needs, and using visual aids had been helpful.

"Creating something called a memory book [has helped] because it has photos in there as well as words that they can go back and read," she said.

"Hannah went on a term-long holiday in term two, and I thought it'd be really cool for her to document it using this app.

"When she came back, she was able to go through it again using photos."

Hannah's family has a similar focus and is determined to make the most of their time with her.

"Hannah remembers being at Uluru … she had a bucket list item of wanting to go," Anderson said.

"To have that dream for our family, to be able to make that dream happen for her, it's memories for all of us."