DNA is the building block for all living things and as such, dictates our genetics. We don't tend to give it much thought unless there’s something wrong. But for most of us, our DNA isn’t perfect - it can have ‘secret’ errors which can harbour potential disease-causing issues even though we look and feel fine. Mostly, our bodies are protected from these potential disease-causing errors as we have two copies of most of our genes, so one functional copy is often enough to override the ‘faulty’ copy and keep us healthy.
However, these hidden errors can surface when we have children if our reproductive partner also carries an error in that same gene. If you and your partner are both carriers, when you reproduce your child will inherit from each of you either the gene with the faulty code or the normal gene. This means that statistically, there is a 25% chance that your child will inherit both faulty copies, which will show up and cause disease, and even healthy siblings can be carriers of the damaged genes and go on to affect future generations.
Carrier Screening is a process that looks for the faulty code in several hundred genes that have the potential to cause serious diseases such as cystic fibrosis and thalassemia.
Most of us will discover that we are carriers of one or more errors in these genes, but as long as our reproductive partner doesn’t have a fault in the same genes, that disease will not turn up in our children. In fact, only 30% of people do not have any errors detected in the few hundred genes screened. If in a reproductive couple one partner does not have any faulty genes, the other partner doesn’t need to be tested. We usually recommend testing females first as they carry two copies of the X chromosome. Females can be secret carriers of X chromosome-linked errors such as hemophilia A, Duchenne muscular dystrophy, and fragile X, which can cause disease if inherited by their sons.
We would love for all women and couples planning pregnancy to be offered screening for genetic conditions irrespective of the presence or absence of a family history of a genetic condition, however today, this is not subsidised through Medicare.
We strongly suggest that if you have a familial history on either side of your family of inherited disease that you discuss with your doctor whether reproductive genetic screening may be appropriate.
If you undertake carrier screening and you discover you and your partner both carry an error in the same gene, you can consult with a genetic counsellor about your options.
There are many private providers of Reproductive Carrier Screens. They can vary in the number of genes tested, their cost (typically around $600) and some include genetic counselling.
Some companies will offer a discount for couples if they are screened at the same time. Speak to your doctor or specialist about which test they would recommend for you.
All new sperm donors at our clinic are now genetically screened. If the donor is found to be a carrier of any disease-causing gene, we require that the recipients be tested for the same panel of genes so you have the best chance of having a healthy baby.
If you have any questions or think you require genetic screening (such as if you have a family history of the diseases mentioned above), please speak to your doctor.