CarrierScreen is a screening test which looks for changes in your DNA to assess your risk of having a child with a genetic disorder.
Everyone is at risk of having a child affected by a genetic disorder, even if you have no family history or symptoms of disease. CarrierScreen tells you if you are a carrier for a genetic disorder, which you have a chance of passing on to your children.
CarrierScreen helps empower you to make informed reproductive decisions.
Your DNA is sectioned into genes that provide important instructions for the body to grow and function.
Sometimes changes, or mutations, in genes lead to genetic conditions which can significantly impacts one’s health and well-being. We have two copies of most genes in our body. Carriers of a particular condition have one normal gene copy and one non-working copy. Carriers are typically healthy, but they may be at an increased risk of having a child with the condition they carry.
The TriScreen Non-Invasive Prenatal Test (NIPT) is a simple blood test that analyses the DNA of an unborn baby, found in the mothers’ blood, to detect certain chromosomal conditions in a pregnancy.
The TriScreen NIPT can be done from as early as 10 weeks and is more accurate than an ultrasound and the maternal blood test to detect chromosomal conditions, providing a greater sense of comfort.
If both partners are carriers of an autosomal recessive genetic disorder, their child has a 1 in 4 (25%) chance of having that disorder.
If only one partner is a carrier, the chance of having an affected child is significantly reduced but not eliminated.
Every individual has two sex chromosomes, a male has an X and a Y chromosome and a female has two X chromosomes. If the female partner is a carrier of an X-linked genetic disorder, her male child has a 1 in 2 (50%) chance of having that disorder, and her female child has a 1 in 2 (50%) chance of being a carrier.
CarrierScreen screens for a wide variety of clinically relevant disorders found in people of all different ethnic backgrounds, and disorders commonly found in specific ethnicities. These conditions are selected based on incidence, impact and availability of treatment options.
Examples of conditions screened for are:
80% of babies born with a genetic disease have no family history of that condition
The average person is a carrier of 3-5 disease-causing genetic variants
45% of those screened are identified as carriers of one or more conditions
3.5% of those screened are identified as having an increased risk of passing on a genetic disease
CarrierScreen offers 3 different test panels to choose from; your HCP or the GC will advise you as to which one is best suited for you. These panels are
For disorders found in people of all ethnic backgrounds. The panel includes Cystic Fibrosis, Spinal Muscular Atrophy and Fragile X Syndrome
For disorders found commonly in people of African, Asian and Hispanic descent. The panel includes Sickle-Cell Disease, Alpha-Thalassemia and Beta-Thalassemia.
For disorders found commonly in people of Ashkenazi Jewish decent. This panel includes 19 disorders.
All of the above panels can be done alone or in conjunction with each other
Genetic Counsellors are Healthcare Professionals who know about genetics and specialise in counselling.
They use these skills to inform you about the complicated world of genetics so you understand genetic illnesses, how they affect your health, how they are inherited and what the risks are of passing them on to your children. Genetic counselling is valuable both before and after testing. Pre-testing counselling is used to evaluate your risks of (inheriting) a genetic condition based on personal and family medical history. Based on this risk profile Genetic Counsellors can determine whether a Genetic test is necessary for you. Post the Genetic test, they will help you understand your results and what they mean for you and your family; and provide you with the emotional support needed to help you come to terms with your risk and make decisions that are right for you. With the help of Carrier Screening they can help empower you make informed reproductive decisions.
The cost of a Pre-Test Genetic Counselling Session is not included in the above test fees. It is a separate cost which must be paid directly to the Genetic Counsellor, and it can be reimbursed from your medical aid. The cost is R950.00.
In your results you may be identified as a carrier of a genetic disorder. This result usually doesn’t affect your health but it means you have an increased chance of having a child with that specific condition, who will be affected. You may also be identified as a non-carrier of a specific genetic disorder. This means that the chances of you having a child with that specific condition are significantly reduced, but NOT eliminated.
For each genetic disorder in your selected panel, your CarrierScreen results will identify you as a carrier or a non-carrier. Being identified as a carrier is common. It is a combination of your results, your partner’s results, and the manner in which the condition is inherited that contributes to your overall risk of having an affected child.
If a positive result for a Genetic condition is found this will be explained to you by the Healthcare Professional. They will help you understand your results and what they mean for you and your family.
Your results alone however may not provide enough information for your Healthcare Professional to determine your overall risk of having an affected child. They may then require your partner to be screened as well to give a more comprehensive view of your combined risks.
Positive results are overwhelming, emotional and difficult to understand so a Genetic counsellor will provide you with the emotional support needed to help you come to terms with your risk and guide you in how to make decisions that are right for your specific situation.
It takes 3-4 weeks to receive your results from when the parcel is collected by the courier. Your results are sent to NextBiosciences who then pass it on to your Healthcare Professional for them to be explained to you.
There are no physical risks associated with test as all that is required for the sample is a bit of saliva.
Given the history of colonization in South Africa, a number of ethnic groups need to be accounted for in the range of disorders to be tested. Your Healthcare Professional will be able to guide you as to which panel you should choose based on your family history and ethnicity. The full panel is the most representative of our diverse population, it also includes prevalent conditions facing the Black and Afrikaans populations which are likely to be less represented by a US based test. These conditions include:
