Two brothers are the only people in the world with a genetic disorder called Arts Syndrome.
Teenagers Thomas and Bradley Farrell both suffer from the condition that affects their hearing, sight and muscle tone.
Older brother Bradley, 18, was diagnosed as deaf when he was a year old and Thomas, 17, was diagnosed at five months.
They spent years in and out of hospitals with breathing problems but it took nine years before they were diagnosed with Arts Syndrome because the specific gene related to their condition was only found in 2007.
The brothers, from Sydney, use a breathing machine and they are highly susceptible to infection.
They have very limited vision and have been confined to wheelchairs for several years because their muscles are so weak.
Their mum Sharon told the Mail: "There's no cure and that's just the way it is. Lots of young people who have rare disorders are still waiting to find out what they have.
"There are millions of genes. It's like a needle in a haystack. We were very lucky to find out what it was.
"If we can keep them healthy and happy, that's my main objective. We just want to give them a good quality of life."
The life expectancy for Arts Syndrome, which primarily affects boys, is five years old.
Sharon said: "They had already surpassed the life expectancy when we were told (about the gene).
"Every time we make a visit to the hospital... the doctors don't know and we certainly don't know what to expect.
"We go in with one complaint and there's something else that's happening at the same time. We go in hoping it's only a short stay but sometimes it can be longer.'"
While there is no treatment for the genetic condition, the boys have been taken a drug treatment called SAM for the past six years to help with complications associated with the syndrome.
Their mum said: "They can't dress themselves or feed themselves, but they have electric wheelchairs that's given them good independence around the house.
Money for the modifications for their home were provided by former Australian cricketer Steve Waugh from The Steve Waugh Foundation, which helps raise awareness of rare diseases.
Bradley and Thomas are set to meet Steve, along with other sufferers of rare diseases and their families.
Rare Disease Day on Saturday (Feb 28) marks 10 years since the Steve Waugh Foundation started raising awareness of the two million Australians who suffer from a rare disease.