Genetic Carrier Screening
Genetic carrier screening gives individuals and couple’s information about their risk of having a child with a genetic condition.
It will tell you if you are a carrier for three common inherited conditions:
- Cystic Fibrosis (CF)
- Fragile X Syndrome (FXS)
- Spinal Muscular Atrophy (SMA)
Many people are carriers of CF, FXS and SMA even though they do not have anybody in their family who has the condition.
The test is conducted through Victorian Clinical Genetics Services (VCGS) involving an initial test of the female partner for all three conditions. If she is found to be a carrier for CF or SMA then the male partner will need to be tested.
The test is able to identify about 90% of people who are carriers of CF, 95% of people who are carriers of SMA and over 99% of people who are carriers of FXS. However, the test will not detect every person who is a carrier.
To access Genetic Carrier screening for your patients we recommend an appointment with a Genetic Counsellor or a Fertility Specialist. This way your patient is supported throughout the preparation and results stage of the screening.
We have Genetic Counsellors in both Auckland and Christchurch, all other regions would need a fertility specialist first consultation appointment.
If you are referring patients for the test, you can refer using your preferred referral method - or your patient can request an appointment directly online here
How the test process works:
- Decide whether or not to have the test: It is your choice whether or not to have the
test. Read through the information provided and discuss the test with your doctor or genetic counsellor. It is recommended that the female member of the couple is screened first as FXS testing is not necessary for the male partner.
- Consider whether it is the right time to have the test: To ensure there is time to make decisions it is best to have this test either before pregnancy or early in pregnancy. If you are pregnant, we recommend having screening before 12 weeks of pregnancy.
- Request the test: If you would like to have the test, your doctor or genetic counsellor will need to complete a test request slip.
- Sample collection: Your doctor will arrange for you to have a blood or saliva sample taken. Your sample will be sent to VCGS where it will be processed.
- Receive your results: It will take approximately 10 working days (from receipt of sample) for your test to be processed and your results to be sent to your doctor or genetic counsellor. Your doctor or genetic counsellor will discuss your results with you.
- Next steps: If the test shows you are a carrier, talk to your doctor or genetic counsellor: Your result will tell you if you are a carrier of CF, FXS or SMA. If you are a carrier, your partner may need to have carrier testing and it is recommended that you speak to your doctor of genetic counsellor.
Accessing the test
Video about Genetic Carrier Screening
- Information on costs can be found on our pre treatment section of our price sheet here.
About the conditions 'cystic fibrosis, fragile X & spinal muscular atrophy
What is cystic fibrosis (CF)?
Cystic fibrosis is an inherited condition affecting breathing and digestion. CF causes the build-up of thick mucus which traps bacteria, resulting in recurrent infections that damage the lungs. Thick mucus in the gut also makes digestion of food difficult.
What is fragile X syndrome?
FXS is the leading cause of inherited intellectual disability. People with FXS can have developmental delay, learning difficulties, anxiety, autism and epilepsy. FXS is caused by a change in the length of the FXS gene (FMR-1), located on the X-chromosome. There are three classes of gene length: short (normal), medium (premutation) and long (full mutation). Females at risk of having a child with FXS carry either the premutation or full mutation.
Features of FXS vary from mild to severe with males more likely to be severely affected than females. Females with a premutation do not have FXS, but may experience early menopause (before age 40). Females with a full mutation may not show obvious features of FXS. There is no cure for FXS although some educational, behavioural and medical interventions can improve outcomes for people with FXS.
What is 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. Carrier screening looks for SMA type 1. This is the most common and 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.