Genetic counselling | Aurora Imaging

Genetic Counselling

Aurora Imaging can assist you to understand the rapidly changing range of genetic screening that is now available before and during pregnancy. These tests are designed to determine the chance of you passing on an inherited condition to your children, to determine whether your current pregnancy may be affected by Down syndrome or other chromosome conditions, or to know whether a chromosome condition that you carry has affected your pregnancy.

Our experienced genetic counsellor - Karen at Private Genetics can provide information on the tests available and which of these, based on your particular circumstances, may be suitable for you.

https://privategeneticswa.com.au/

Reproductive carrier screening

What is reproductive carrier screening?

Reproductive carrier screening is genetic testing for couples which aims to identify if there is an increased chance of passing on a genetic condition to their children. These conditions do not cause problems for the parents themselves as they are unaffected "carriers", but if two carrier parents conceive a child their is a possibility that the child will be affected by the disease.

The most common of these conditions in Australia is cystic fibrosis, a condition which affects the lungs, pancreas, and digestive system. Around one in 20 people carry a change in the CFTR gene. Individually, this is of no significance, but for a couple who both carry such changes, one in four of their children will have cystic fibrosis.

Reproductive carrier screening aims to identify couples in this situation and can test for anywhere between one and over 1,000 different genetic conditions. Testing involves a simple blood or saliva test.

Who should have reproductive carrier screening?

It is now recommended by the Royal Australian and New Zealand College of Obstetricians and Gynaecologists and the Human Genetics Society of Australasia that reproductive carrier screening is offered to all couples planning a pregnancy. Not all couples will elect to have screening and the choice remains yours.

It can be difficult to decide whether to have screening and which tests to have. It is important that thorough pretest counselling is provided before the test is done. This ensures that you understand what is being tested for, what it means if the test shows an increased chance of passing one a condition, and what are the options if you screen at increased risk. Our experienced genetic counsellor can provide this counselling and assist you in your decision making.

The best time to have reproductive carrier screening is before you become pregnant as this allows the most time to make decisions and gives the most options to the couple. It can be done in pregnancy but should be done as early as possible.

How do I access reproductive carrier screening?

This testing is provided by most private pathology companies. It requires a request form signed by a doctor who has provided pretest counselling. Our genetic counsellor can provide this counselling and discuss the options with you, and arrange testing if you choose to go ahead. To make an appointment, contact us here.

Aneuploidy screening

What is aneuploidy screening?

Our genetic material (DNA) is packaged into 23 individual compartments called chromosomes. Each cell has two copies of each chromosome for a total of 46. Aneuploidy is the situation where our cells have too many or too few chromosomes. For example, Down syndrome occurs when there is an extra copy of chromosome number 21 (trisomy 21). Aneuploidy screening is a test in pregnancy that aims to determine whether there is an increased chance that the baby is affected by one of a number of chromosome conditions.

What does aneuploidy screening involve?

It is recommended that all couples be offered aneuploidy screening in early pregnancy. Some couples elect not to undergo screening at all.

There are several methods of aneuploidy screening. The two most common methods are:

1. The first trimester screen or combined test. This is a combination of an ultrasound scan and a blood test. If the baby is affected by Down syndrome, the test will show an increased probability about 90% of the time but it cannot predict all babies with Down syndrome. This test also assesses the chance of trisomy 18 and trisomy 13. About 5% of women will screen at increased probability of Down syndrome with this test, but most will not be affected.

2. Non-invasive prenatal testing (NIPT). This is the most effective screening test currently available for chromosomal conditions such as Trisomy 21 – Down syndrome; Trisomy 18 and 13. It is also very accurate at determining the sex of your baby. NIPT can also check for a range of other conditions, explained below. NIPT is a screening test and not diagnostic. If you receive an increased probability result, this does not always mean your baby has the condition in question and further testing is usually indicated.

There are several companies offering NIPT in Australia, nearly all of whom offer maternal blood collection through the clinical laboratories in Western Australia (eg. Percept NIPT through PathWest, Harmony NIPT through Australian Clinical Labs, Generation NIPT through Western Diagnostic Pathology). Aurora Imaging is independent of the NIPT providers.

If required, Aurora Imaging will take maternal blood for the Natera-based NIPT (Panorama and Vistara) from 9 weeks gestation onwards: all of the other NIPT companies now provide a phlebotomy service through the clinical laboratories in Western Australia. It is important to know your gestation accurately and whether you have a multiple pregnancy prior to having NIPT: an early pregnancy ultrasound can provide this information for you. Most companies will offer NIPT after 10 weeks gestation (exception Natera who will offer testing from 9 weeks gestation onwards).

There is currently no Medicare rebate for NIPT.

Panorama (Natera) – checks for Trisomy 21 (Down Syndrome), Trisomy 13 and Trisomy 18. In addition Panorama is able to identify triploidy (where there is a whole extra set of chromosomes). This test is suitable for single and twin pregnancies. Optional micro-deletion testing is available. Gender determination and zygosity (identical or non-identical twinning) is available for twin pregnancies. Further information is available at https://www.natera.com.

Panorama is performed from 9 weeks gestation, costs from $425 (standard panel) to $580 (full microdeletion panel) and takes up to 10 working days as this testing is performed in the USA.

Vistara (Natera) – screens for 31 single gene conditions (including conditions such as achondroplasia, osteogenesis imperfecta, craniostenosis syndromes, Noonan syndrome) and can be combined with Panorama to also check your baby’s chromosomes. The specific genetic conditions screened for with Vistara are available at https://www.natera.com. We would strongly recommend you have a counselling session with a genetic counsellor before you decide to embark upon single gene NIPT.

Vistara is performed from 9 weeks gestation, costs $1300.00, and takes ~20 working days.

Pre and post-test counselling is important to help you understand these options and the possible outcomes.

Most women will receive a low probability result following NIPT. If, however, testing is reported as an increased probability for a chromosome problem, your doctor can arrange a referral to our practice. The medical staff at Aurora Imaging can assist you with counselling and specific diagnostic testing (eg. CVS or amniocentesis) in the setting of an increased probability NIPT to clarify the result.

To make an appointment for genetic counselling or the first trimester screen, contact us here.

Reproductive counselling for identified conditions

Aurora Imaging's expert genetic counsellor can provided tailored counselling for couples with identified genetic conditions. This may include conditions such as:

Balanced translocations, including targeted non-invasive prenatal testing for translocations
Family history of inherited genetic conditions
Known carriers of recessive conditions through previous testing or reproductive carrier screening
Genetic abnormalities identified at amniocentesis for structural fetal anomalies.

To make an appointment to see our genetic counsellor visit https://privategeneticswa.com.au/