A groundbreaking drug that slows the progression of a rare and fatal childhood illness has been given funding through the Federal Government's Life-Saving Drugs Program.

Key points: Children with Batten disease usually die between the ages of six and 12

Children with Batten disease usually die between the ages of six and 12 Brineura costs $850,000 per person for one year's supply

Brineura costs $850,000 per person for one year's supply It is too expensive to go on the pharmaceutical benefits scheme but will be funded on the Life-Saving Drugs Program

Batten disease is a neurological illness that robs children of their ability to walk, talk, see and eat.

About 35 children have some form of Batten disease in Australia, according to the Batten Disease Support and Research Association.

Tom Strahan, 6, was the first Australian to receive the drug called Brineura, when his family moved to Italy so he could be part of a clinical trial.

Brineura treats one specific form of Batten disease — Late Infantile Batten Disease or CLN2.

Children with CLN2 usually die between the ages of six and 12.

Since the ABC first reported Tom's story in July, he has started prep school, his speech is improving and he has started to swim independently.

Tom's mother, Kate Beattie, said he had come a long way since his diagnosis when he was three years old.

"Where we are [now] is so different from what we expected and what would've been the outcome if he hadn't received any treatment," she said.

Tom's family is thrilled the drug will now be available to anyone affected by CLN2.

"Frankly we felt like it was the right decision … to make sure that children are receiving the best, and indeed only, medical treatment and are receiving the treatment that children in the United States receive, children in Germany and France receive, to make sure Australian children have access to that too," Ms Beattie said.

'Her quality of life was non-existent'

Mia, Peta, Toby, Hamish and Jasper Murchison pictured shortly before Mia died from Batten disease in August 2018. ( Supplied: Julie Adams )

Mia Murchison also had Batten disease, but Brineura has come too late for her.

She died in August last year, three weeks after her ninth birthday.

"Her quality of life was non-existent, it felt like suffering … we're really sad, we miss her, I miss her every day," her mother, Peta Murchison, said.

For years the family has raised awareness of Batten disease through the Bounce4Batten campaign.

A drawing by a friend of Mia Murchison, which now hangs in her room. ( Supplied: Julie Adams )

Peta and husband Hamish said they were relieved the drug had been approved.

"The fact that the Australian Government has now approved a treatment and we're one of the few countries in the world that now has that treatment available means that kids that are diagnosed in the future won't have to go through what Mia went through," Mr Murchison said.

"Mia has always surprised me and I admire that for someone so young she was able to do more than most people do in a lifetime," Ms Murchison said.

"I'm really proud to have a daughter that taught me so much and gave me a lot of strength to be able to play a small part in helping."

Federal Health Minister Greg Hunt said the drug proved effective, and while it was too expensive for the pharmaceutical benefits scheme — it costs $850,000 per person each year — it would be funded on the Life-Saving Drugs Program.

He said he expected about 17 children would receive Brineura in the next five years.