Reproductive genetic carrier screening (RGCS) is testing offered to couples planning a pregnancy, or in the early stages of pregnancy for conditions inherited in an autosomal recessive or X-linked manner. The testing aims to identify those couples who are at risk of having a child with a serious childhood onset condition. Identifying these couples offers them information on which to base reproductive decision making.
To quote the RANZCOG: “Information on available reproductive genetic carrier screening should be offered to all women planning a pregnancy or in the first trimester of pregnancy. Options for carrier screening include screening with a panel for a limited selection of the most frequent conditions (e.g. cystic fibrosis, spinal muscular atrophy and fragile X syndrome) or screening with an expanded panel that contains many disorders (up to hundreds).”
Genetic conditions are a major cause of death and chronic illness in children. Estimates suggest one in 50 Australian couples have an increased chance of having a child with a severe autosomal or X-linked recessive condition such as cystic fibrosis (CF), spinal muscular atrophy (SMA) or Fragile X syndrome. This equates to more than one in 400 children being born with one of these conditions. The impact on families cannot be overstated and nearly 90% of parents with affected children have no prior family history.
The advent of genomic testing has focused on diagnosing those individuals who already have symptoms of genetic conditions. Known as the diagnostic odyssey, the journey to a diagnosis can be both lengthy and challenging, placing additional burdens on the affected individual and their family.
RGCS is relevant to all couples regardless of ethnicity or family history and offers the chance to get ahead of the diagnostic odyssey and be informed of their risk of having a child with a severe genetic condition before pregnancy, or during early pregnancy. This allows couples the opportunity to then make reproductive decisions in line with their own beliefs and values. Options such as IVF and preimplantation genetic diagnosis (PGT), early intervention and prenatal diagnosis are all open to couples.
Genetic Services of Western Australia gladly accepts referrals, via the Central Referral System for couples where there is a family history of a known genetic condition; other couples can explore options available with their GP, obstetrician, or private genetic counselling services.
As there are several providers of RGCS who offer a wide range of services, some of the issues to consider when selecting providers and offering RGCS include: whether or not to test both members of the couple at the same time or sequentially, which panel of genes to select, how the samples are collected (blood or saliva) and the cost of the test. The turnaround time for results and whether or not the couple are currently pregnant will impact the decision on whether or not to test at the same time. The decision about whether or not to pursue RGCS is one for each couple to make once the above issues have been considered.
Mackenzie’s Mission is a federally funded national research study investigating how to best implement a population genetic carrier screening program in Australia. Reproductive genetic carrier screening for approximately 1300 genes will be offered to more than 8000 couples nationwide free of charge. Issues such as health economics, ethical considerations, screening uptake, incidence of increased chance couples, gene selection and clinical considerations will all be assessed.
In Western Australia, Mackenzie’s Mission is still looking for health care professionals (midwives, GPs, obstetricians, GP/Obst.) in northeast metropolitan Perth, rural and remote regions to recruit their patients. If you are interested in being involved, please phone 1800 466 466 or email the WA study team on mackenziesmissionwa@perkins.org.au.
For more information Mackenzie’s Mission | Home (mackenziesmission.org.au).
Key messages
- Reproductive genetic cancer screening should be offered to all women planning a pregnancy or in the early stages of pregnancy.
- Reproductive genetic carrier screening is relevant for all couples regardless of family history or ethnicity
- Further information and education (Cat.2 CPD activity) can be found at RACGP Beware the Rare website.
ED: This article was written with the input of Dr Sarah Smith – KEMH Liaison GP and Ms Samantha Edwards –Project Officer and Associate Genetic Counsellor Mackenzie’s Mission
Author competing interests – nil