Everything you need to know about the study

To take part in Mackenzie’s Mission, couples were invited by a participating healthcare provider. General practitioners, obstetricians, midwives, genetics health professionals and fertility specialists at selected sites across Australia invited people to participate in the study.

The study started recruiting couples through participating healthcare providers in Victoria, Western Australia, New South Wales and the ACT in 2020. The study then opened in all other states and territories in early 2021. Participant involvement in the study ended in March 2022.

More than 10,000 couples were offered reproductive genetic carrier screening through the study. We aimed to enrol a broad range of couples to reflect Australia’s diversity. This was important to ensure the outcomes of our research were applicable to the whole population.

No, this was a research study and participation was optional.

The healthcare providers who invited people to participate provided information and support to help prospective participants make an informed choice about whether or not to take part.

People who weren’t invited to take part in Mackenzie’s Mission by a participating healthcare provider or were not eligible for the study, and would still like to access genetic carrier screening, can find information about other available options here.

Mackenzie’s Mission screened couples to find out if they had an increased chance of having a child with a severe genetic condition that occurs in childhood and has a significant impact on lifespan and/or quality of life. For some of these conditions, early diagnosis and treatment can improve a child’s health.

The study screened for about 1300 genes associated with more than 750 severe childhood-onset genetic conditions, including spinal muscular atrophy (SMA), cystic fibrosis (CF) and fragile X syndrome (FXS).

For more information about the conditions screened for in this study, click here.

Reproductive genetic carrier screening in this study screened the biological mother and father’s genes together.

The result provided told couples if, together, they had an increased chance of having a child with any of the genetic conditions screened. Individual carrier results were not reported through the study.

The best time for prospective parents to have reproductive genetic carrier screening is when they are planning on having a child, and are not yet pregnant.

If a couple find out they have an increased chance of having a child with any of the genetic conditions the study tests for, there will be time for the couple to discuss the result with a genetic counsellor and explore their family planning options. Knowing this information before becoming pregnant provides more options than learning it when the couple is already pregnant.

Reproductive genetic carrier screening can also be done in pregnancy. It is important the results are received as early as possible in pregnancy. If the results show an increased chance of having a child with a genetic condition, and further testing finds that the developing baby will have the condition, this allows more time for the couple to consider the result and make an informed decision about how to manage the pregnancy.

The reproductive genetic carrier screening provided through this study tested the DNA taken from a mouth swab.

No, it was not possible to tell each member of the couple what conditions they are individually genetic carriers for. This is because the genes from both members of the couple were analysed by the laboratory together.

Only couples who had an increased chance of having a child with any of the genetic conditions screened were told that they are genetic carriers for that condition.

There are a number of options available if a couple is found to have an increased chance of having a child affected by any of the genetic conditions screened.

Some things to consider are:

• What the genetic condition is
• The severity and impact of the condition
• Whether treatment is available for the condition
• What reproductive options are available when planning or having a baby
• The couple’s values

The following options are available:

• Become pregnant naturally and have testing in early pregnancy, known as chorionic villus sampling (CVS) or amniocentesis, to see if the developing baby will have the condition. If this testing shows that the baby will have the condition, the couple has the choice of whether they want to continue with the pregnancy or have a termination of pregnancy.
• Undertake in vitro fertilisation (IVF) and have the embryos tested for the genetic condition through preimplantation genetic testing (PGT) before being transferred into the mother’s uterus. Couples who were not pregnant and were found to have an increased chance of having a child with any of the genetic conditions screened through Mackenzie’s Mission (where this was not already known to the couple before enrolling in the study) were offered one free cycle of IVF with PGT.
• Use donor eggs, sperm or embryos to achieve a pregnancy.
• Consider adoption.

Couples who have an increased chance of having a child with any of the genetic conditions screened can explore all these options in detail with a genetic counsellor. The purpose of reproductive genetic carrier screening is to assist couples in making informed decisions about their family planning. There are no right or wrong decisions, and it is up to the couple to decide which options are most suitable for them.

If a couple had reproductive genetic carrier screening through Mackenzie’s Mission, and in the future, either member of the couple wants to have children with a different person, the previous results will not be applicable to the new couple.

Reproductive genetic carrier screening would need to be repeated with the new partner to provide information about the chance of having a child with an autosomal recessive or X-linked genetic condition.