A type of genetic testing called carrier screening test is a blood examination conducted to determine whether one of the couples is carrying a gene that has mutated and may predispose their offspring to serious inherited disorders. Sickle cell disorder, Tay-Sach’s disease, cystic fibrosis and thalassemia are the most common disorders caused by genetic mutations. Most of these genetic health problems are recessive, which means the baby inherits the condition from both parents.
Each person has two copies of a gene, one of each inherited from a parent. Being a carrier means that the individual carries one copy of a gene that has a change or has mutated. A gene that has mutated means the gene is not working properly. However, carriers will not suffer from the disorder because they still have one gene that works properly. But, being a carrier would predispose his or her offspring to an increased chance of being born with a genetic disease. On the other hand, if both couples are carriers of one of the disorders, then there is one in four chances that their child will inherit a defective gene.
Carrier Screening Test: How It Is Done?
To perform a carrier screening test, the doctor asks the couple questions related to the family history of both the husband and the wife. This usually occurs during preconception or the initial prenatal visit. If the husband happens to be a carrier of a certain disease, the doctor likewise highly recommends the wife or the pregnant woman to undergo the carrier screening test as well. Since these diseases are inherited, heredity is one important factor that predisposes a generation to these diseases.
Carrier screening test is performed by obtaining a saliva or blood sample and is tested in the laboratory. As mentioned previously, if anyone of the couple is a potential carrier, the screening test is done.
However, if the husband and the wife are carriers of a genetic disease, they will be given the priority to undergo a carrier screening test even before the wife conceives.
If the test confirms the genetic disorder, the couple can do the following:
- Consult An Expert: An expert on this matter would be a genetic counselor. A genetic counselor is a health expert who deliberately plans for a safe pregnancy despite the risk of birth defect.
- Choose Not To Have A Child Through Natural Conception: Knowing that there is an increased risk for the offspring to develop genetic anomalies, a couple may decide not to have a child through natural conception.
- Artificial Insemination: Artificial insemination is an expensive way of conceiving through the use of a donor sperm.
- In-Vitro Fertilization: This is another method of conceiving which allows testing of the embryo’s genes before being implanted.
Cystic Fibrosis Screening
One of the most common and known fatal genetic diseases is cystic fibrosis. People diagnose with cystic fibrosis are prone to digestive problems, difficulties in breathing, lung infections, lung damages and other complications.
Focus on Health: Cystic Fibrosis Carrier Testing
Cystic fibrosis screenings are available regardless of the level of risks, although there are those who prioritize the most vulnerable groups such as Caucasian people and carriers. It should be noted that a negative result in cystic fibrosis screening does not ensure absolute exception of the disease. This is because there is still a high chance for the baby to develop the disease. Science explained that on very rare occasions, other forms of mutations are not detected by the screening tests.
Sickle Cell Screening
Sickle Cell Disorder is a genetic disease that primarily affects the red blood cells. An individual with Sickle Cell disease has abnormal and weak red blood cells. There is a problem with red blood cell production and so, circulation is affected. Races belonging to the African, Central or South American, Caribbean, Mediterranean, Arabian and Indian descents are highly predisposed to this disease. An amniocentesis may be performed in a pregnant woman who is a carrier of the said genetic disorder to find out if her fetus has the sickle cell disorder.
Thalassemia is a group of blood disorders primarily characterized by an abnormal form of hemoglobin. Another form of the genetic disorder, people with Thalassemia suffer from severe anemia. In the United States, more than 2 million individuals carry this trait. Aside from the United States, other races in regions, such as Southeast Asia, China, East India, Africa, Middle East, Italy, Greece, and Turkey are predisposed to carry traits of this disease.
Thalassemia screening in pregnancy involves a series of blood test for assessment. Apart from blood exam, pregnant mothers are prescribed with 5mg folic acid daily to prevent the occurrence of iron deficiency anemia caused by Thalassemia.
The genetic disorder known as “Tay-Sachs disease” is a life-threatening disease that mainly targets the central nervous system. Racial groups predisposed to this disorder belong to the Eastern or Central European Jews, Cajuns, French Canadians, Irish Americans.
Mothers with Tay-Sachs disorder may undergo Tay-Sachs screening test in the form of amniocentesis or chorionic villus sampling.