An important part of pre-pregnancy planning
Whilst recognising the clinical and medico-legal significance of reviewing family histories, the reality is that most children with a familial genetic disorder do not have a family history of that disorder. The presence of a family history of a disorder is an important clue; the absence of such a history provides little information. A test to screen for genetic carriers can provide information about the risk of a familial disorder that is not evident from reviewing the family history.
Reproductive carrier screening
There are hundreds of inherited genetic disorders which cause serious illness in babies and children. The abnormal genes responsible for these disorders have often been inherited from couples who have no idea that they are at risk of having an affected child. These inherited disorders are individually rare, but together they are more common than the chromosome disorders which have long been the focus of genetic screening in pregnancy. Click here to download a summary information sheet.
Types of reproductive carrier screening provided by Sonic Genetics
There are two options:
- A three-gene panel looks for mutations responsible for three common genetic disorders: cystic fibrosis, spinal muscular atrophy and fragile X syndrome. Approximately 5% of people in Australia will be identified as carriers for one or more of these disorders, and one in 240 couples will be found to be at risk of having an affected child. If a female is tested first and found to be a carrier of either cystic fibrosis or spinal muscular atrophy, a free of charge test of the relevant gene will be offered to her partner (full details will accompany the test report).
- The Beacon expanded carrier screen is a screening test that looks for mutations in >350 autosomal recessive genes and >50 X-linked genes which cause serious disorders affecting babies and children. Approximately 75% of people in Australia will be identified as carriers for one or more of these disorders, and one in 20 couples will be found to be at risk of having an affected child.
Note: Males are not routinely screened for X-linked disorders.
Click here to download a quick reference guide to assist your patients with understanding these reproductive carrier screening options
Timing of carrier screening
The ideal time for testing is before pregnancy. This gives the couple and their doctor time to consider the issues arising from the test and make informed choices about their reproductive plans.
Reproductive carrier screening can also be done in early pregnancy. This is less suitable, as there is less time for issues to be considered and decisions made, and there are fewer options available to the couple.
As with all pregnancy-associated tests, reproductive carrier screening can raise questions of ethics and autonomy that require time to resolve. A couple must feel free to accept or decline the offer of this test. Some people will not want to have this information – and some will insist on having it.
If both parents are found to be carriers of mutations in the same autosomal recessive gene, or if the woman is found to be carrying an X-linked disorder, it is important to discuss what it might mean for them individually and as a couple. Full details on how to refer eligible carrier couples to Sonic Genetics for free counselling^ will accompany the results. A list of private and public providers of clinical genetics and genetic counselling services is available on request or visit www.sonicgenetics.com.au/doctors/resources.
^Terms and conditions apply. Please refer to www.sonicgenetics.com.au/rcs/gc