Genetic carrier screening

Identify if you carry genes for certain inherited conditions, enabling informed family planning and early intervention for potential health issues.

What is Genetic Carrier Screening?

Genetic carrier screening is DNA-based testing to identify individuals or couples at increased risk of having children with severe inherited genetic disorders, performed in order to inform reproductive decision-making.

Genetic carrier screening (GCS) is testing to identify couples at increased risk of having children with three of the most common, severe inherited genetic disorders in the Australian population:

  • Cystic fibrosis (CF)
  • Spinal muscular atrophy (SMA)
  • Fragile X syndrome (FXS)

One in twenty Australians will be a carrier for at least one of these conditions. Most will not have a family history of the disease. Carriers are usually unaffected by the condition themselves, but are at increased chance of having an affected child.

Hear from our Chief Scientist, Genomic Diagnostics

Our expert Genomic Diagnostics team will use the DNA from your blood sample to test for the most common inherited genetic changes that cause cystic fibrosis, spinal muscular atrophy and fragile X syndrome.

Genetic testing is the only way to find out whether or not you are a carrier for one of these conditions.

Knowing your carrier status can help you make informed choices. For many people, genetic carrier screening provides peace of mind. For those with a higher risk of having an affected child, it provides the opportunity to consider a range of options.

If you are found to be carriers of a condition, there are several reproductive options you can discuss with your doctor including:

  • natural pregnancy, with or without prenatal diagnosis
  • pre-implantation genetic diagnosis (PGD) with in vitro fertilization (IVF) to test and then transfer embryos that are free of the condition
  • the use of a sperm or egg donor
  • adoption

About the genetic conditions screened

Cystic fibrosis, spinal muscular atrophy and fragile X syndrome can have devastating effects on life-expectancy and quality of life.

  • Cystic fibrosis is the most common inherited disorder in Caucasians.
  • Spinal muscular atrophy is the most common genetic cause of mortality in children under two.
  • Fragile X syndrome is the most common form of inherited intellectual disability.

We provide genetic counselling free of charge for carrier couples when at least one partner has their test at one of our Healius Pathology network collection centres.

Cystic fibrosis and spinal muscular atrophy are autosomal recessive conditions, which means both parents must be carriers to have an affected child. Fragile X syndrome is an X-linked condition, so only the mother must be a carrier to have an affected child.

Hear from a genetic counsellor

If you and your reproductive partner are found to be a carrier couple for any of these conditions, you have the option of being referred by your clinician to a genetic counsellor.

Patients' process

Step 1

See your doctor to get a request

After discussing genetic carrier screening with you, your doctor will complete a request form.

Step 2

Get a blood test

Go to your nearest collection centre with your request form to perform a blood test.

Step 3

See your doctor to get your results

Your genetic carrier screen results will be delivered to your doctor within 10 working days. If you and your partner are identified as a carrier couple, we will offer free genetic counselling to support you with your next steps.

Genetic Carrier Screening patient brochure
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What is Genetic Carrier Screening?

Genomic Diagnostics’ genetic carrier screening tests for three of the most common inherited genetic conditions: cystic fibrosis (CF), fragile X syndrome (FXS) and spinal muscular atrophy (SMA).

One in 20 Australians will be a carrier for at least one of these conditions, however most will have no family history of disease.1 This is due to the relatively rare nature of the conditions and their inheritance patterns, either autosomal recessive or X-linked.

Carrier screening for CF, FXS and SMA is now funded by Medicare and should be offered to those considering pregnancy or in their first trimester.

Why screening is important?

Genetic carrier screening helps to inform reproductive decision-making.It gives carrier couples (where both partners are carriers for CF or SMA or the female partner is a carrier for FXS) the opportunity to consider a range of reproductive options.

When to offer screening?

RANZCOG recommends that information on carrier screening be offered to all women planning a pregnancy or in the first trimester of pregnancy. This includes screening for CF, FXS and SMA. The genetic carrier screening test can be easily added as part of a patient’s routine antenatal blood screening.

There is global consensus that genetic carrier screening is  performed before pregnancy. This gives your patients the widest range of reproductive choices and more time to make important decisions.

Carrier screening can still be offered in early pregnancy, although options will be more limited and time-sensitive.

The recommended screening pathway is to test the female partner first, followed by the male partner if the female is identified as a carrier for CF or SMA.

Genetic conditions screened  

CF, SMA and FXS can have devastating effects on life-expectancy and quality of life. The combined affected pregnancy rate for these disorders is equivalent to the population risk of having a child with Down syndrome.

Cystic Fibrosis

  • Description: most common inherited disorder in Caucasians
  • Carrier risk: 1 in 25
  • People with the condition: 1 in 2,500
  • Testing approach: testing for the 50 most common CFTR variants that are associated with more than 95% of CF cases
  • Inheritance: autosomal recessive; both parents must be carriers to have an affected child

Fragile X Syndrome

  • Description: most common form of inherited intellectual disability
  • Carrier risk: 1 in 200
  • People with the condition: 1 in 3,600 males, 1 in 6,000 females
  • Testing approach: testing for triplet repeat expansions in the FMR1 gene that are associated with more than 99% of FXS cases
  • Inheritance: X-linked; the mother must be a carrier to have an affected child

Spinal Muscular Atrophy

  • Description: most common genetic cause of mortality in children under two
  • Carrier risk: 1 in 35
  • People with the condition: 1 in 10,000
  • Testing approach: testing for the SMN1 gene deletion that is associated with more than 95% of SMA cases
  • Inheritance: autosomal recessive; both parents must be carriers to have an affected child

Accuracy of screening results

Genetic carrier screening tests for the most common genetic changes associated with CF, SMA and FXS.

The assay can detect:

  • >95% of cystic fibrosis carriers
  • >99% of fragile X carriers
  • >95% of spinal muscular atrophy carriers

The tests used for GCS are highly accurate diagnostic tests that reliably identify carriers for these conditions. However, genetic carrier screening cannot identify a small percentage of carriers (1-5%) because some very rare genetic variants cannot be detected by the test.

Clinicians' process

Step 1

Patient consultation
  • Discuss carrier screening with your patient as recommended by clinical guidelines.
  • Order genetic carrier screening on a standard request form, noting any family history or pregnancy, and if the reproductive partner is a known carrier.

Step 2

Blood collection
  • Patient attends collection centre with their signed request form.
  • Blood is collected.
  • Genetic carrier screening is performed.

Step 3

Result discussion
  • Results are delivered to you by your preferred method.
  • Genetic counselling is offered for couples who are identified as carriers.
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