ANNETTE Saurine started worrying about her daughter Maddy when, at six months old, she still wasn't sitting up.
"We had a lot of tests done. They were very scary times," the Ballina woman said.
"Within a week, my world changed forever.
"She had cerebral palsy, epilepsy, she was profoundly deaf and she was aspirating, which meant her fluids were going down the wrong pipe," she said.
"I thought I was going to have my baby forever.
"Maddy was in and out of hospital with pneumonia. She died two weeks before her third birthday, in May 2005."
Doctors couldn't give Ms Saurine a reason for her daughter's death.
"It was horrific," she said.
"We had to bury our Maddy. But despite everything she went through, she was always happy.
"People didn't see her disabilities. They saw that she was amazing."
Seventeen months later, Ms Saurine gave birth to another girl, Charley, and this time doctors - after extensive tests - diagnosed mitochondrial disease at six months.
It is a genetic disorder that impairs the body's ability to convert food into the energy needed to power muscles and major organs.
"Charley was severely affected. She really struggled day to day," Ms Saurine said.
"But we realised that we were lucky for every day we had with her."
Charley died in 2009 at two-and-a-half years old.
Ms Saurine said one of the most difficult things in coping with her daughters' illnesses and deaths was that no one understood what she was going through.
Few know about mitochondrial disease, but the Australian Mitochondrial Disease Foundation hopes that will change.
Tomorrow the foundation is raising awareness with its Stay in Bed Day.
People with mito often spend a lot of time sleeping.
Stay in Bed Day started in 2009 and is the perfect excuse for doing nothing.
Fundraising opportunities include donating or sponsoring people to have a sleep-in, hosting a pyjama party or having a bed relay.
"I hope one day we can find a cure for this disease," Ms Saurine said.
"My daughters are angels. Even though I lost them, I would go through it again and again just to be their mum."