What is carrier genetic screening test?
Carrier screening test is a type of genetic test that can tell you, if you carry a gene for certain genetic disorders. When done before or during pregnancy, it lets you know your chances of having a baby with a genetic disorder.
The sample types for the genetic carrier screening are blood, saliva, or tissue from the inside of the cheek
Test results can be negative (you don’t have the carrier gene) or positive (you do have the gene).
The most likely genetic carrier partner is usually tested first. If the test results show that the first partner is not a carrier, then no further testing is required.
If the test results show that the first partner is a carrier, the other partner is tested. Once you have had carrier screening for the specific disorder, you do not need to be tested again for that disorder.
In recent days we are often listening among our nearest or dearest about the children requiring blood transfusions. Have you ever thought of why such blood transfusions are required?? Which disease are they suffering from??
They are suffering from a genetic disorder called Thalassemia. Children with thalassemia will suffer anemia because of less hemoglobin resulting in fatigue, pain, and several other complications.
There are many such genetic disorders prevalent and rising among our Indian newborns and infants. The most prevalent other genetic disorders are
- breathing and digestion disorder (cystic fibrosis),
- stammering, mental disability and congenital abnormalities (Down’s syndrome),
- severe weakness, and lack of muscle development (spinal muscular atrophy).
Let’s discuss and learn why such diseases occur and what can be done to be more aware of these kinds of scenarios.
Genetic Carrier, Who can be?
Human has two copies of each gene, inherited from biological parents. For a genetic disorder to be present there must be an inheritance of two copies of genes.
Any person, who has only one gene for a disorder, is considered, a “carrier”. The genetic carriers will not be suffering from disease nor have any symptoms of genetic disease.
India is a homeland for many cultural and ethnic groups. The population of India is diverse based on their region, religion, linguistic and socioeconomic backgrounds. The fixed marriage patterns among their nearby region and marriages between the closely linked relatives within the community pose a risk of being a carrier partner.
Genetic Testing Before Pregnancy
Generally, the married couple who are planning for a pregnancy should undergo a “Carrier screening test before pregnancy”. This is done from the blood/saliva sample of the individual. Your gynecologist can order this test. The results can be delivered in a couple of days.
This screening test can be done at different life stages and its implications have advantages as well as disadvantages at each particular stage.
- School screening: Carrier screening is performed at the premarital or pre-relationship stage.
- Pre-conception screening: Carrier screening is performed before the couple decides to conceive. This is the ideal time for carrier screening.
- Pregnant mother screening: Every pregnant woman should get done the carrier screening test at this stage.
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Chances of having a baby with a genetic disorder
If the pregnant mother is found to be a positive genetic carrier then her partner should also be tested. If both the partners were found to be carriers, they will have a 25% chance of having an unaffected child, a 50% chance of having an unaffected child who is also a carrier, and a 25% chance of having a child with a genetic disorder.
It is highly recommended for the couples that if they have doubt about their genetic carrier status such as any previous delivery of a baby with a genetic disorder, family history of any genetic disease, It’s better to undergo genetic carrier tests at a better early time point to prevent genetic disorders. This will give the couple a chance to understand and take necessary preventive steps.
If one of the partners were found to be a carrier, they can have the pregnancy and the mother can undergo prenatal screening tests before delivery. If both the partners were found as carriers, they can discuss the other ways of having the childlike IVF, etc.,
All couples should seek counseling from an obstetrician or genetic counselor before pregnancy so that a couple could learn about the risk of having a genetically defective baby.
Keep following for much more information on health and genetic updates.
Frequently Asked Questions – FAQ
- What does genetic carrier screening test for?
Ans :- Genetic carrier screening test is for those individual who have no sign and symptoms of genetic disease or disorder but suspect of one copy of carrier gene in him or her. Experts recommend this test should be taken by every pregnant woman.
(Disclaimer: Information provided in this piece of article is purely for educational purposes only. All results must be clinically correlated with the patient’s data to make an accurate diagnosis.)