first would-be parents tested for 700 genetic diseases
The would-be parents will be tested for some 1300 genetic mutations linked to more than 700 rare autosomal recessive and X-linked genetic conditions, including spinal muscular atrophy (SMA), cystic fibrosis and fragile X syndrome.
Genetic counsellor Kirsten Boggs said the trial aimed to give would-be parents the information they needed to make informed decisions about family planning and full reproductive choice.
“We see so many families and what they go through when they have children with severe genetic disease. It is incredibly traumatic,” Ms Boggs said.
“There’s the grief and loss of a healthy child, and some children don’t survive for very long. Others are severely affected by their conditions,” she said.
The $20 million federal government-funded project was named after baby Mackenzie Casella, who was diagnosed with the most severe form of SMA. Mackenzie died in October 2017 at seven-months-old.
Commercial companies offer carrier testing for a handful of genetic conditions, usually costing between $300 and $600.
Principal investigator and clinical co-lead, UNSW Professor Edwin Kirk said the goal was to prove wide-scale carrier screening could be a success and ultimately be able to offer it free to any couple who wants it.
“I don’t think I fully appreciated how really complex something like this is and the numbers of decisions we would need to make to work out how best to do it,” Professor Kirk said of the project overseen by the Australian Genomics Health Alliance.
“We are looking at the psycho-social, economic, ethical issues of screening, involving genetic screening – a comprehensive look at every aspect to find any problems and work out how to address them,” he said.
Anna and Chris Pratt are among the first to take part. The couple are planning to have a sibling for their 18-month-old son Freddie who was born with rare chromosome deletion that has caused life-long disabilities.
“We aren’t carriers for what happened to Freddie but having been through this experience we wanted to make sure we covered our bases this time around,” Mrs Pratt said.
“Freddie is amazing. He’s a little chiller, and we are really lucky to have him, despite all the things we have to deal with,” she said.
“Information is power,” Mrs Pratt said. “That is how we approach things with Freddie day-to-day, and having this genetic testing means we can be prepared.”
“Regardless of the results we will be able to arm ourselves with the research to make informed decisions for our next child,” she said.
Couples are provided with educational material and talk through the process, the limitation and potential ramifications with a genetic counsellor.
If they choose to go ahead, they are sent a mouth swab kit to collect a saliva sample that they send back to the lab for DNA testing.
Geneticists estimate everyone carries between three to five recessive genes for serious conditions. It is only when both parents carry the same mutation that their child has a one-in-four chance of developing the corresponding genetic condition, and a one in two chance their child will be a carrier.
Couples will only be told they have a genetic mutation if both individuals carry the same mutation for one of the conditions – roughly 1 per cent of all the couples tested, Professor Kirk said.
They can choose to conceive naturally and undergo prenatal testing or choose to test their child at birth, knowing early diagnosis can lead to better treatments and quality of life for many of these conditions.
They can also opt for subsidised IVF to screen out embryos with a mutation. Some couples might choose to use donor eggs or sperm, adopt or choose not to have children.
Recruitment will ramp up at the end of January through GP clinics and other primary health services that look after would-be parents from across a broad social, economic cultural and geographic spectrum.
The trial expected to finish at the end of 2021.
Kate Aubusson is Health Editor of The Sydney Morning Herald.