A ground-breaking Australia study has added weight to the prospect of government-funded genetic carrier screening for couples wanting to have children.
The Mackenzie’s Mission study, published in the New England Journal of Medicine, looked at the feasibility of screening for the chance of having children with one or more of hundreds of genetic conditions at a national level.
It is the first time a genetic carrier screening project of this scale has been attempted in Australia and one of the first in the world. It was co-authored by WA’s Professor Nigel Laing from the Harry Perkins Institute of Medical Research.
The study, administered by Australian Genomics, tested 9107 couples to see if they had an increased chance of having children with one or more of about 750 severe childhood-onset genetic conditions.
Researchers from WA, NSW and Victoria concluded routine genetic carrier screening should be available to all Australians planning a family.
They also found that GPs and other medical professionals would play an important role in encouraging uptake of a national reproductive genetic carrier screening program.
Professor Laing said doctors have an important role to play in informing future parents about screening that is available.
“One of the challenges of implementing a national screening program in Australia is delivering it across our diverse and geographically dispersed populations,” he said.
“The study demonstrated that this is possible by recruiting in all states and territories and in metropolitan, inner regional, remote and very remote locations, collaborating with a wide network of hospitals. In Western Australia this included working with the Royal Flying Doctor Service to take carrier screening to remote areas.”
Mackenzie’s Mission was named after Mackenzie Casella who died of spinal muscular atrophy at just seven months old.
Mackenzie’s parents Rachael and Jonathan Casella had no family history of the genetic condition and were not aware they were genetic carriers. After Mackenzie’s death in 2017 they launched a campaign calling for reproductive genetic carrier screening to be routine and free for all prospective parents in Australia.
The three-year study – undertaken as part of Mackenzie’s Mission – tested 9,107 couples to see if they had an increased chance of having children with one or more of about 750 severe childhood-onset genetic conditions.
Of the couples tested, 175 – almost one in 50 – were found to be at “increased chance”. Three quarters of them used that information to inform their decisions about having children, including using IVF and selecting embryos unaffected by the genetic condition.
It is the first time a genetic carrier screening project of this scale has been attempted in Australia and one of the first in the world.
Prof Laing said there is “huge potential” for genetic carrier screening in Australia to give parents more power over their genetics.
“Most of us have no idea what recessive diseases we’re carrying or what our significant other is carrying,” he said.
“Most of the time a couple has a child with a severe recessive disease there is, in fact, no family history, it comes completely out of the blue.
“Knowledge is power, that’s the way I look at it. It gives people choices; it gives people options.”
In November 2023 the Federal Government included free reproductive carrier screening for spinal muscular atrophy, cystic fibrosis and fragile X syndrome on the Medicare Benefits Schedule.
But in the Mackenzie’s Mission study 80% of the couples found to have an increased chance of bearing children with a severe genetic condition were carriers for conditions other than those three.
Royal Australian College of GPs guidance states all couples should be offered information about genetic carrier screening during pre-conception or in the early stages of pregnancy. Those deemed at high risk of having a child with a genetic condition should be referred to a specialist for further treatment, often at their own expense.
Researchers are now working with the Federal, state and territory governments to establish what a national genetic screening program might look like and how it could be rolled out.