Many of the children were diagnosed in a Melbourne Genomics project led by clinical geneticist Dr Sue White from Murdoch Children's Research Institute (MCRI), which investigated the benefit of genomic sequencing for children with undiagnosed genetic disorders.

The findings of this Australian-first study show that for children like many of the 100 diagnosed, genomic sequencing resulted in five times more diagnoses at 75 per cent % less cost per diagnosis when compared to standard testing approaches. Changes to medical care were made for 28 per cent of children because their condition could be more precisely pinpointed.

"Some of the diagnoses have meant a change in care which is a significant benefit for children and their families," said Dr White, "In some children, ineffective treatments were stopped, while in others, we have been able to put in place early monitoring for related health complications. It's pretty clear that a diagnosis helps doctors take the best care possible of their patients, and this test delivers diagnoses in more than half of the children tested."

One in 12 Australians have a rare condition and many of these are undiagnosed.

"This means fewer tests for kids, better diagnosis more quickly and better use of precious healthcare dollars," said Associate Professor Clara Gaff, Executive Director of Melbourne Genomics Health Alliance. "We've shown that genomic sequencing has strong benefits for these children, and these findings are of interest across Australia and the world."

One of the 100 children to gain a diagnosis is two-year-old Nelle Hookins. Nelle was diagnosed with Cohen Syndrome after undergoing genomic sequencing. Nelle is one of the youngest patients in the world to be diagnosed with Cohen syndrome. She had had 11 admissions to hospital and 15 appointments with specialists over 18 months searching for an answer. The diagnosis means Nelle's family and paediatrician can now focus on managing her condition and help her to achieve her potential.

"We are ecstatic that Nelle's family and another 99 families from across Australia now have answers for their children," said Dr White. "It means so much to have a diagnosis – not only in getting the most appropriate care, but in being able to better understand their child's likely path forward in life."

"I congratulate everyone involved and join in celebrating this significant milestone," said Victoria's Health Minister, The Hon Jill Hennessy. "I am very proud to see Victoria leading the way in bringing genomic sequencing into healthcare, so that more patients like Nelle can benefit."