The role of GPs in genetic testing advice

Amanda Lyons

23/02/2018 4:22:51 PM

The increasing availability of genetic testing means GP involvement with prenatal and antenatal care is becoming more important.

Many now believe genetic testing and screening should be widely available for prospective parents
Many now believe genetic testing and screening should be widely available for prospective parents

Significant advances in the field of genetic testing and screening have led to the question of whether these tests should be made more widely available for patients.
The recent story of Rachael and  Jonny Casella, in which the couple discovered their baby Mackenzie was affected by an extremely rare condition called spinal muscular atrophy type 1, has provided a case study in which such testing may have avoided a tragic situation.
‘Spinal muscular atrophy is just an absolutely devastating condition,’ Dr Wendy Burton, Chair of the RACGP’s Antenatal/Postnatal Care Specific Interests network, told newsGP. ‘I think most parents, if they knew that was the journey that was coming at them, would wonder about the decision they will make.’
Dr Burton believes the growing availability of such testing means general practice involvement with prenatal and antenatal care is vital, but changing structures of care mean GPs run the risk of losing the skills necessary to provide the best help.
‘Then you end up in the unfortunate situation of [the Casellas], devastated and then realising there was something that might have helped them make an earlier decision,’ she said.
It can be difficult for GPs to know how to navigate discussions about genetic testing, especially as it is such a rapidly developing field. According to RACGP President Dr Bastian Seidel, the RACGP is close to completing a resource for GPs, Genomics in general practice, to be released in the first half of this year.
‘The resource will address the need to provide women who are pregnant, or planning a pregnancy, with information about prenatal screening tests for chromosomal conditions so they and their partners can make an informed choice,’ he told newsGP.
He cautioned, however, that pre-pregnancy testing will not be appropriate for all patients.
‘It depends on a variety of circumstances, and requires a comprehensive family history,’ he said.
Discussing genetic testing in consultations can be time-consuming, because the issues and decisions involved are often very complex.
‘You’ve got to do more than just give patients the surface and say, “This is available, do you want it?”’ Dr Burton said.
There are also monetary issues to consider; these tests are not cheap, and are not necessarily funded by Medicare.
‘Patients need to know that the costs of most genetic tests are not MBS-rebatable, except in some cases of Fragile-X syndrome,’ Dr Seidel said. ‘It’s important to consider the out-of-pocket costs presented by these tests.’
Then there can be further complex decisions presented by how to respond to test results.
‘These are not simple conversations to have with patients, because what do you do with what you find?’ Dr Burton said. ‘If a woman tests positive as a carrier for cystic fibrosis, SMA [spinal muscular atrophy] or Fragile X, then it’s recommended that her partner be tested.
‘If they’re both positive, there’s a mathematical probability, typically a one-in-four chance, that the child would be affected.
‘So then do they have an amniocentesis or a scan with a one in 150 chance of the baby miscarrying?’
In Dr Burton’s experience, the decision process is different for every couple.
‘I’ve looked after women who have a Down Syndrome member of the family; one who didn’t want testing because they would not terminate on that basis, and another who went straight for diagnostic testing because they would not proceed with a pregnancy,’ she said.
‘So there’s just not one size that fits all.’

chromosomal-conditions genetic-testing maternity-care

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DR J N Parikh   27/02/2018 11:12:11 AM

Excellent message oabout genetic testing pre and antenatal I wish we can discuss the cost of testing and related information

Manmeet   27/02/2018 1:19:47 PM

Good insight on the upcoming issues regarding genetic testing.

Adj Assoc Prof Bob Davis   28/02/2018 9:38:23 AM

Its good to see the college take a lead in this area. Genetic testing has huge implications for general practice. Costs are coming down dramatically eg genetic sequencing has gone from tens of millions of dollars to a few hundred per test. I suspect that this availability will mean the guidelines may be out dated in a few years . There are huge ethical implications and perhaps the college needs to engage with the wider membership about how we support our patients.