What is CarrierScreen?

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.

What is a genetic disorder

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.

How are genetic diseases inherited?

Genetic disorders are passed down in different ways. CarrierScreen looks at disorders which has been passed down in an “autosomal recessive” or “X-linked manner”.

1. Autosomal Recessive conditions

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.


2. X-linked Conditions

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.


What is screened for?

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:

  • Cystic Fibrosis
  • Spinal Muscular Atrophy
  • Fragile X Syndrome
  • Sickle-Cell Disease

Why consider testing?

80% of babies born with a genetic disease have no family history of that condition

next-carrier-screeningThe average person is a carrier of 3-5 disease-causing genetic variants

next-carrier-screening45% of those screened are identified as carriers of one or more conditions

next-carrier-screening3.5% of those screened are identified as having an increased risk of passing on a genetic disease

The Process

  1. If you are requesting this test without a Healthcare Professional (HCP), a Genetic Counselling Session must set up with one of the Genetic Counsellors (GC)* in our preferred provider network. This session is either conducted face-to-face, via Skype or telephonically. Please note that this session is an hour in duration and the cost is not included in the test fee. The cost of this session is R950 and it must be paid directly to the Genetic Counsellor.
  2. If the CarrierScreen test is recommended by your HCP or the GC, they must complete the Test Requisition Form and send it through to Next Biosciences.
  3. Next Biosciences will send you an invoice for payment.
  4. Once payment is received, Next Biosciences will courier a CarrierScreen kit to you for the saliva test to be conducted (instructions provided in the kit).
  5. Once the kit is ready for collection, please contact Next Biosciences and we will arrange for a courier to collect the sample and ship it to the laboratory in the United States. Results can be expected in 3-4 weeks.
  6. Once your results are ready, they will be sent to your HCP or the GC, who will explain your results to you and help you understand what your reproductive options are.
  7. A post-test counselling session may be recommended with a Genetic Counsellor in cases of a positive result. This will be for your own account.

What is the CarrierScreen Test

CarrierScreen screens a total of 287 genetic disorders. Together with your Genetic Counsellor or Healthcare Professional, you can select all or the most appropriate disorders to be included in your test in order to better understand your specific risk. The types of conditions include:

  • Pan-Ethnic disorders
    For disorders found in people of all ethnic backgrounds. Examples of this type of disorder includes Cystic Fibrosis, Spinal Muscular Atrophy and Fragile X Syndrome.
  • Ethnicity Specific disorders
    These are disorders with are found more commonly in individuals of specific ethnic backgrounds. For example, there are over 20 disorders more commonly found in individuals of Ashkenazi Jewish decent and around 10 disorders commonly found in individuals of African descent.

The role of genetic Counselling

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.

Frequently Asked Questions

What results will I get?

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.

What if a get a positive result?

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.

How and when will I get my results?

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.

What are the risks associated with the test?

There are no physical risks associated with test as all that is required for the sample is a bit of saliva.

What is the relevance of genetic-disorders screened for in the South African Population?

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:

  • Cystic Fibrosis (carrier rate in Afrikaans South Africans 1 in 30)
  • Autosomal recessive polycystic disease (ARPKD) (carrier rate in Afrikaans South Africans 1 in 53)
  • Fanconi Anaemia Type A (carrier rate in Afrikaans South Africans 1 in 77)
  • The hemoglobinopathies (Sickle-cell disease, and the Thalassemia’s)
  • Gaucher Disease (carrier rate in in black South Africans 1 in 66)