What is Carrier Screening?
Carrier screening is a type of genetic test that can tell you if you carry the gene for a particular genetic disorder. When done before or during pregnancy, it can determine your chances of having a child with a genetic disorder.
What is Recessive Disorder?
Most carrier screening is done for recessive diseases. For a person to have a recessive disease, they need both the gene from the mother and the gene from the father. If a person has only one gene for a disease, he or she is called a carrier. Carriers are often unaware that they carry the disease gene. They usually have no symptoms or only mild symptoms.
What are the odds of having a child with a recessive disorder?
If both parents carry the recessive gene for the disorder, there is a 25% (one in four) chance that the child will inherit the gene from both parents and develop the disorder. There is a 50% (1 in 2) chance that the child is a carrier of the disorder. Same as the carrier parents. If only one parent is a carrier, there is a 50% (1 in 2) chance that the child will be a carrier of the disease.
What Does Will Carrier Screening Find?
The Carrier Screening Panel contains a large list of genetic disorders such as:
- Fragile x syndrome
- Spinal muscular atrophy
- Alpha thalassemia
- Cystic fibrosis
Though there is no known cure yet for genetic disorders like Fragile x syndrome, pharmaceutical companies like Zynerba are already on it’s third phase in conducting a Fragile X Syndrome clinical trial.
How can Carrier Screening be done?
Carrier screening involves testing a blood, saliva, or tissue sample taken from the inside of the cheek. The test result is negative (doesn’t have the gene) or positive (have the gene). The partner most likely to be the carrier is usually tested first. If the test results indicate that the first partner is not the carrier, no further testing is required. If the test results indicate that the first partner is the carrier, the other partner is tested. Once you have been tested for carrier screening for a particular condition, you do not need to be tested again for that condition.
When can carrier screening be performed?
Some choose to have carrier screening before birth. At the time of pregnancy carrier screening can also be done. Getting tested before pregnancy gives you more options and more time to make decisions.
Should I do carrier screening?
Carrier screening is your choice. You can choose w hether or not to do carrier screening. There are no choices of right or wrong.
Who should undergo carrier screening?
All women who plan to become pregnant or have become pregnant are offered carrier screening for cystic fibrosis, hemoglobinopathy, and spinal muscular atrophy (SMA). You may also be tested for other disorders. There are two methods of carrier screening for other disorders:
1) targeted screening
2) extensive carrier screening.
Hemoglobinopathy:- A genetic disorder that affects the number or shape of red blood cells in the body. Examples include sickle cell anemia and various forms of thalassemia.
Spinal Muscular Atrophy (SMA):- It is an inherited disorder that causes muscle wasting and severe muscle weakness. Spinal muscular atrophy (SMA) is the genetic cause of death in infants.
What is targeted carrier screening?
In targeted carrier testing, you are screened for disorders based on your ethnicity or family history. If you belong to an ethnic or racial group with a high carrier rate for a particular genetic disorder, carrier screening for those disorders may be recommended. This is also known as ethnic carrier screening. If you have a family history of a particular disorder, screening for that disorder may be recommended, regardless of your race or ethnicity.
What is Extended Carrier Screening?
In extensive carrier testing, multiple disorders are screened with a single sample. This type of screening is done regardless of race or ethnicity. Companies that offer extensive carrier screening create lists of disorders that they test for. This list is called a selection table. Some tables examine more than 100 different disorders. Screening panels often focus on serious medical conditions that affect a person’s quality of life from an early age.
Is one approach better than the other?
Before testing, you and your obstetrician-gynecologist (obstetrician-gynecologist) can discuss the advantages and limitations of each carrier screening method. You can also discuss this with your genetic counselor. In some cases, targeted screening and extended screening can be tailored to your circumstances.
Obstetrician-gynecologist :- A physician with special education and training in women’s health.
What options do my partner and I have if we are carriers of a genetic disorder?
You can choose in vitro fertilisation (IVF) to conceive using donor eggs or donor sperm. This option allows embryos to be tested before being transferred to the uterus.
You can choose not to get pregnant.
You may choose to adopt a child.
If you are being screened for carriers after pregnancy, your options are more limited. In either case, your OB-GYN or genetic counselor can explain the risks of having a child with a disability
Consult your doctor.
The information you get from genetic testing can have a huge impact on your life. Before genetic testing, we strongly recommend that you seek genetic counseling to learn more about which testing options may benefit you and your family. Genetic counseling is also recommended to help people understand genetic test results and how they affect other family members.
