Genetic Carrier Screening | Get your kit online today!

How common is it to be a carrier?

Everyone is a carrier for genetic conditions. Most people are completely unaware of the conditions they carry and do not have anybody in their family with the genetic condition. For these reasons, it is recommended that healthcare providers offer carrier screening to anybody planning a pregnancy or in early pregnancy.

How do these conditions occur?

Carrier screening tests for genetic conditions inherited in ‘autosomal recessive’ and ‘X linked’ patterns.

Autosomal recessive – Babies inherit half of their genes from each biological parent. If the parents are both carriers for a change in the same gene, for each pregnancy they concieve together there will be a 1 in 4 or 25% chance of having a child with the condition. Most of the conditions screened through carrier screening are autosomal recessive conditions. Common autosomal recessive conditions are: cystic fibrosis and spinal muscular atrophy.

If only one prospective parent has been screened and is a carrier for an autosomal condition, carrier screening for the other prospective parent will be needed to check whether they are also a carrier for the same condition.

X-linked – Some genetic conditions are caused by faults in genes on the X chromosome. A female who is a carrier for an X-linked condition has a 1 in 2 or 50% chance of passing the fault on in each pregnancy. For X linked conditions, males who inherit the fault are usually affected by the condition, but there are some conditions where a female who is a carrier for the condition may also have symptoms. Fragile X syndrome is an example of a common X-linked condition. For X-linked conditions, only the female prospective parent needs to be offered carrier screening.

Is carrier screening Medicare funded?

Carrier screening for Cystic Fibrosis (CF), Spinal Muscular Atrophy (SMA) and Fragile-X Syndrome (FXS) is funded through Medicare (MBS items 73451 & 73452) for people who are planning a pregnancy or already pregnant. If the female partner tested is a carrier for CF or SMA funded screening is available for their partner.

Carrier screening for Bloom syndrome (BS), canavan disease, cystic fibrosis(CF), Familial dysautonomia (FD), fanconi anaemia type C (FA-C), Fragile-X Syndrome (FXS), Gaucher disease (GD), Glycogen storage disease Type 1 (GSD1), Mucolipidosis IV (ML IV), Niemann-pick disease (NPD) Type A 7, spinal muscular atrophy (SMA), Tay Sachs disease (TSD) is funded through Medicare (MBS item 73453) for people of reproductive age who are of Ashkenazi Jewish descent. If both members of the reproductive couple are of Ashkenazi Jewish descent and are already pregnant, it is recommended that they are both tested at the same time.

Currently there are no out of pocket costs to people who meet criteria for Medicare funded carrier screening. Larger panel carrier screening is not funded by Medicare. Out of pocket costs vary by test.

THINKING ABOUT CARRIER SCREENING?

1.

Carrier screening is usually requested by general practitioners, obstetricians, fertility specialists, midwives, genetic counsellors or medical geneticists. Let your healthcare provider know that you wish to have carrier screening. Your healthcare provider will need to complete a test request form.
2.

Carrier screening can be performed on one or both prospective biological parents at the same time. Testing both prospective parents will give the most informative result. If only one prospective parent is screened, it is recommended that the female prospective parent is screened as this will include screening for conditions on the X chromosome. Carrier screening can be performed on blood or saliva samples. Carrier screening kits can be ordered online (click here to see list) and returned by mail to the genetic testing laboratory. We recommend you ask for your carrier screening to be performed by a specialist genetic testing laboratory.

Download the Genetic Carrier Screening – How to be tested brochure
3.

Depending on the carrier screening test you have, results are usually available approximately 2-6 weeks after the sample was received by the laboratory. Results are issued to the healthcare provider who requested the screening. The healthcare provider will discuss the results and may make a referral for genetic counselling if the results show there is an increased chance of having a child with a genetic condition. If only one prospective parent has been screened and is a carrier for an autosomal recessive condition, the healthcare provider will order carrier screening for the other prospective parent to check whether they are also carrier for the same condition.

Download the Genetic Carrier Screening – If you find out you are a carrier brochure

What types of conditions are screened?

Larger carrier screening panels can include hundreds of genetic conditions. These include conditions which cause: shortened lifespan, intellectual disability, serious physical disability. For some of the conditions screened early treatment may substantially improve outcomes, for others, there is no cure or effective treatment or the treatment is very burdensome.

All carrier screening panels include three of the most common inherited conditions:

Spinal Muscular Atrophy (SMA)

SMA is a condition that affects nerves in the spinal cord and causes muscles to get weaker. There are four types of SMA with SMA type 1 being the most common and the most severe. Babies with SMA type 1 have weak muscles from birth and usually do not live past two years of age. There is no cure for SMA but new treatments are showing promise in improving symptoms and quality of life.

Fragile X Syndrome (FXS)

FXS is the most common cause of inherited intellectual disability. People with FXS can have delayed development, learning difficulties, anxiety, autism and epilepsy. The features of FXS vary from mild to severe with males more likely to be severely affected than females. There is no cure for FXS although some educational, behavioural and medical interventions can improve outcomes for people with FXS. Some females who are carriers of FXS may have early menopause, neurological (brain and movement) symptoms, including anxiety, depression, ADHD, social deficit, autism spectrum disorders (ASD) or develop unsteadiness (ataxia), intention tremor (shaking) and memory problems in later life.

Cystic Fibrosis (CF)

CF is an inherited condition affecting breathing and digestion. CF causes thick mucus which traps bacteria, resulting in recurrent infections that damage the lungs. Thick mucus in the gut also makes digestion of food difficult. Infants, children and adults with classical/ typical CF require daily chest physiotherapy to clear mucus from their lungs, frequent courses of antibiotics, and need to take medicine to help with digestion. CF is a life shortening condition. There is no cure, but better treatments are being developed.

Frequently Asked Questions

Carrier screening is available in Australia. There are a variety of carrier screening options which include:

A small (3- gene) panel, which screens for carriers of three of the most common inherited conditions – cystic fibrosis, spinal muscular atrophy and fragile X syndrome
A larger gene panel, which screens for carriers of a wider range of common and rare inherited conditions

If you do not meet the criteria for Medicare funded carrier screening under item numbers 73451, 73452 or 73453 carrier screening is still available to you and there will be a fee for the test. The laboratory doing your testing can provide information about test fees.

If both prospective parents are carriers for the same autosomal recessive condition or the female prospective parent is a carrier for an X-linked condition, there is an increased chance of having a child with a genetic condition. Genetic counselling is recommended. Depending on the carrier screening service used, genetic counselling may be available through that service. Alternatively, a healthcare provider can refer them to a local clinical genetics service.

Genetic counselling involves speaking to an expert in genetics about what the results mean and family planning options available to them. Some people may choose to reduce the chance of having a child with the genetic condition whereas others may choose not to alter their path. These choices are entirely up to the prospective parents, and genetic counselling services can support them in making these decisions.

A number of options are available to people who have an increased chance of having a child with a genetic condition. For those who are pregnant, genetic testing can be done during early pregnancy to see if the fetus has the condition. If this testing diagnoses the condition, the parents have a choice about whether to plan for the birth of a baby with the condition or to have a termination of pregnancy. If the prospective parents are not yet pregnant, there are a range of family planning options available including in vitro fertilisation (IVF) with genetic testing of the embryos (known as pre-implantation genetic testing (PGT)). Through genetic counselling detailed information will be given and individuals or couples will be supported to consider which options are right for them.

Genetic counselling also involves speaking about what the carrier screening results might mean for other biological relatives. It is important that biological relatives are told about these carrier screening results so that they can access screening themselves if they choose.

If a person or a both prospective parents receive a ‘low risk’ or ‘negative’ result from carrier screening, this means they have a low chance of having a child with a genetic condition. Genetic testing technologies detect the majority of carriers but cannot detect every gene change that causes these conditions. If no gene change is found, there is still a small chance for each condition screened that the person is a carrier of a rarer gene change that has not been detected.

Although carrier screening is relevant to everyone, it is especially important for those who have a family history of a genetic condition. People with a family history should let their healthcare provider know prior to carrier screening and the healthcare provider should include the family history information (including the specific family gene fault if known) on the test request form so that the testing laboratory can ensure the appropriate testing is being performed.

For most of the genetic conditions screened for through carrier screening, carriers do not develop symptoms. However for some genetic conditions, carriers may experience health effects. In these situations, it is recommended that carriers for these conditions are referred for genetic counselling to discuss their results further.

If you have specific questions about carrier screening, we suggest you contact a specialist genetic testing provider and ask to speak to a genetic counsellor.