Preimplantation genetic testing for genetic conditions
Many conditions or disorders tend to run in families. These hereditary conditions are passed down from parents to their children in the form of gene or chromosomal variations.
When planning a family, if you are concerned about the risk of passing on genetic conditions that have affected you or other family members, you may want to consider genetic counselling and subsequent testing.
What is single-gene preimplantation genetic testing (PGT)?
Preimplantation genetic testing is a highly sophisticated scientific technique used to test embryos for specific genetic or chromosomal variations. It allows the potential selection and transfer of unaffected embryos to improve the chance of implantation and pregnancy.
Since its introduction, single-gene PGT has helped thousands of couples conceive healthy babies despite a family history of serious heritable diseases.
Who would consider preimplantation genetic testing?
It is recommended that you consider PGT if you are concerned or can relate to any of the following:
- risk of having a child with an inherited genetic condition
- either partner having a known family history of chromosomal rearrangement
- previous chromosomal variations in a pregnancy
- advanced maternal age (usually to test for Down’s Syndrome where the mother is over 38yrs old)
- experienced recurrent miscarriage (3 or more miscarriages)
- repeated unsuccessful standard IVF where embryo transfers have not resulted in a pregnancy.
What does PGT involve?
PGT testing involves the removal of (possibly) just one cell from an embryo and testing for a specified condition such as cystic fibrosis or Down’s syndrome. The embryos diagnosed as unaffected will then be transferred in an IVF cycle, maximising the chance of a healthy baby.
What can PGT test for?
PGT can test for a large number of single gene disorders. Common conditions being tested for include:
- Huntington’s disease
- Cystic Fibrosis
- Duchenne muscular dystrophy
- Hereditary cancers
It is important to note that single gene PGT is only possible where an exact genetic diagnosis has been obtained.
If you have concerns regarding inheritable genetic conditions, you should discuss them with a doctor to refer you to a clinical geneticist or a fertility specialist to discuss how a genetics consultation might help you.
Genetic counselling can provide individuals and families with current information about hereditary conditions. In many cases, genetic counselling can reassure couples that there is no increased risk, or that there is a lower risk of their child inheriting the condition than they had originally thought.
Cystic Fibrosis (CF) is a common preventable genetic condition
Cystic Fibrosis is the most common life threatening genetic condition affecting Australian newborns. It is estimated that 1 in every 20 Caucasian Australians are carriers of CF, although they have no symptoms of the disease. For a child to have Cystic Fibrosis, both parents must be carriers of the gene fault responsible for CF (1 in 400 couples are at high risk of having a child affected by CF). When two CF carriers have a child there is a 1 in 4 chance their child will be affected by CF.
A simple blood test of one partner will provide a fast result. If the test is negative, the risk of your child being affected by CF is very low and there is no need for any further concern.