You may be wondering what the difference is between Genetic Carrier Screening and Non-Invasive Prenatal Testing (NIPT). These are two different genetic tests that have different purposes and screen for different things.
Genetic Carrier Screening vs. NIPT – What’s the difference?
It is important to understand the purpose of Genetic Carrier Screening and Non-Invasive Prenatal Testing (NIPT) and what this means for you. NIPT screens a developing pregnancy for extra or missing chromosomes using a maternal blood sample. Maternal and fetal DNA is screened for common chromosome conditions. In contrast, carrier screening screens healthy adults for inherited genetic conditions that have little or no impact on their own health, but may increase the chance of having a child with an inherited genetic condition.
Genetic Carrier Screening
Carrier screening is ideally performed prior to conception, or during early pregnancy. This determines the likelihood that you are a carrier of specific genetic conditions that could be passed on to your child.
It is important to know that we are all carriers of 2-3 recessive genetic conditions. Most people are unaware that they carry these conditions. Most carriers have no family history of the conditions they carry. For this reason, all couples or individuals should consider carrier screening as a child can have a genetic condition regardless of their parent’s family history, ethnicity or age. Having carrier screening early on gives you time to consider your reproductive options if you have been identified as a carrier.
Our carrier screening test screens for over 400 inherited genetic conditions. Australian guidelines state that this test should be offered to everyone planning a pregnancy or in early pregnancy, irrespective of age, family history or ethnicity.
Non-Invasive Prenatal Testing (NIPT)
NIPT screens for the most common chromosome conditions in pregnancy including Down syndrome (trisomy 21), Edward syndrome (trisomy 18), Patau syndrome (trisomy 13) and sex chromosome aneuploidies – Monosomy X (Turner Syndrome), Triple X syndrome (XXX), Klinefelter syndrome (XXY) or Jacob syndrome (XYY).
NIPT requires a maternal blood sample from 10 weeks gestation which will provide information about whether there is a low or increased chance of the current pregnancy being affected with a chromosome condition. These conditions are most often caused by a sporadic event at the time of conception and are not usually inherited.
The below table compares the two tests in further detail:
Genetic Carrier Screening
|Screens egg and sperm contributors for inherited single gene conditions that can significantly affect the health of future children.
|Screening for common chromosome conditions in pregnancy.
|Although these conditions are inherited, there is usually no known family history of the condition.
|These chromosome conditions are not inherited and caused spontaneously.
|Prior to conception (ideally) or in the first trimester of pregnancy.
|Screening is performed early in pregnancy from 10 weeks.
Still have questions?
If you still have questions about the difference between Genetic Carrier Screening and NIPT, please get in touch with one of our Genetic Counsellors by calling any of our MUFW clinics.