Reproductive carrier screening: What is the GP’s role?

‘GPs routinely ask questions to ascertain a good medical history. This is bread and butter work. But for couples who are planning a pregnancy or who are in the early stages of pregnancy, it’s good to expand to a full family history.’
 
That is Kate Dunlop, director of the Centre for Genetics Education in NSW, talking about the key role GPs can play in doing a risk assessment before referring a patient for reproductive carrier screening.
 
Ms Dunlop was on the advisory group for the RACGP’s new Genomics in general practice guidelines.
 
By taking a comprehensive family history stretching back one or even two generations, a GP can act as something of a genetic detective. Is there a condition that’s affected more than one relative? Have there been health or learning problems? Has anyone had more than three miscarriages or stillbirths?
 
The goal of such a line of questioning is to find out whether there are any recessive disorders that might be expressed in the next generation.
 
‘A family history can alert you to the chance that this family might be carriers of a gene variant,’ Ms Dunlop told newsGP.
 
‘However, many parents who have a child with one of these disorders do not have a family history and so there is always a possibility for all couples.
 
‘Some experts recommend women and couples planning a pregnancy start a conversation with their doctor about the possibility of carrier screening.’
 
While it’s best to do this kind of family screening before a pregnancy, it’s often only after conception that prospective parents come in to see their GP.
 
Genomics in general practice states that information about carrier screening can be offered prior to conception, as identifying carrier couples before pregnancy gives more reproductive options, such as IVF with pre-implantation genetic diagnosis, use of donor gametes or prenatal diagnostic testing. Information about carrier screening can also be offered in early pregnancy.
 
‘GPs are well placed to help with reproductive carrier screening. They work closely with their patients and many have established relationships,’ Ms Dunlop said.
 
Genetic testing of people possibly carrying gene variants has traditionally been very expensive. As a result, Australia’s healthcare system has focused on screening in particular ethnic groups with a high incidence of a gene variant of concern.
 
‘However, given the multicultural nature of society and marriage between people of different ethnic backgrounds, ethnicity is less strongly predictive of carrier frequency in Australia. Therefore, carrier screening panels increasingly test for multiple conditions, irrespective of ethnicity,’ the guide states.
 
Significant research is being undertaken in this area and now that the cost of testing has gone down, Ms Dunlop said it is becoming more common to screen and test the wider population – even though most genetic conditions are very rare.
 
There has been increased public awareness of three genetic conditions – spinal muscular atrophy (SMA), cystic fibrosis and Fragile X – in the wake of a call to make this testing free by the parents of a child born with SMA.
 
For carrier screening in couples at low risk, the patient must pay the cost.
 
Genomics in general practice states that the, ‘decision to undertake carrier screening is a personal choice to be made by the individual or couple … [w]omen or couples should be informed of the benefits, limitations and cost of screening’.

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