AlphaThalassemia Carrier Screening & NIPT

Unity Screen offers a single blood draw as early as 10 weeks into pregnancy, combining carrier screening and non-invasive prenatal testing (NIPT) to assess the risk of alpha-thalassemia and other genetic conditions.

Incidence at Birth

Occurs in up to 1 in 10,000 births and is more common in individuals of Asian ancestry

Carrier Rate

1 in 20 people are carriers of a form of alpha-thalassemia.

Inheritance

Alpha-thalassemia is a recessibe condition that can be passed down in famamilies.

Incidence at Birth

Occurs in up to 1 in 10,000 births and is more common in individuals of Asian ancestry

Incidence at Birth

Occurs in up to 1 in 10,000 births and is more common in individuals of Asian ancestry

Incidence at Birth

Occurs in up to 1 in 10,000 births and is more common in individuals of Asian ancestry

What is UNITY Screen™ for Alpha-Thalassemia?

The American College of Obstetricians and Gynecologists (ACOG) recommends carrier screening, including for alpha-thalassemia, for all pregnant individuals. UNITY Screen™ starts with alpha-thalassemia carrier screening to identify carriers, potentially increasing the chance of an affected baby.

If you're not a carrier, the risk to your baby is minimal. If you are, the next step is single-gene NIPT within UNITY Screen™ to assess alpha-thalassemia risk. While not diagnostic, UNITY Screen™ offers crucial information for planning and may lead to additional genetic testing pre or postnatally.

How unity for Alpha-Thalassemia Works

The American College of Obstetricians and Gynecologists recommends that anyone planning to start a family or those who are already pregnant be offered carrier screening for inherited conditions, including alpha-thalassemia.

What is Alpha Thalassemia?

Alpha-thalassemia is an inherited condition that affects the red blood cells’ ability to carry oxygen around the body in a molecule called hemoglobin. Hemoglobin is a protein made up of several parts, or subunits, called alpha and beta chains. The genetic instructions to make alpha-chains of hemoglobin are contained in the HBA1/HBA2 genes. If a person has large deletions or smaller changes (non-deletions) in these genes, they can have alpha-thalassemia. The type and severity of symptoms depends on how many copies of the HBA1/HBA2 genes are working. There are two types of alpha-thalassemia that can cause clinical symptoms: 

Hemoglobin H disease:
This is a milder form of alpha-thalassemia caused by a person only having one out of four working copies of their alpha-thalassemia genes. Symptoms can vary from person to person, and some do not have any symptoms or are mildly affected. Others can develop an enlarged spleen, mild jaundice, and mild changes to facial features. In very rare cases, individuals with HbH may require regular blood transfusions. 

Alpha-thalassemia major (Hemoglobin Bart disease):
This is the most severe form of alpha-thalassemia and is caused by a pregnancy having zero working copies of their alpha-thalassemia genes. Signs of this condition, such as the accumulation of fluid in different areas of the pregnancy (hydrops), are usually seen on second and third trimester ultrasounds.

How is Alpha-Thalassemia Inherited?

Alpha-thalassemia inheritance is complex, with up to four copies of the HBA1/HBA2 genes inherited instead of the usual two. The number of functional copies influences the condition's severity, and testing helps assess the risk for affected offspring.

Who Should Consider Alpha-Thalassemia Carrier Screening?

With UNITY Screen™, if your test indicates an elevated risk of alpha-thalassemia in your pregnancy, you can explore further alpha-thalassemia genetic testing options with your healthcare provider for confirmation either before or after birth.

With UNITY Screen™, if your test indicates an elevated risk of alpha-thalassemia in your pregnancy, you can discuss further genetic testing with your healthcare provider for confirmation either before or after birth.

Carrier Frequency for Alpha Thalassemia: Gene: HBA1 / HBA 2
The gene HBA1/HBA2 is associated with carrier frequencies for alpha thalassemia across various ethnicities.

  • In African American populations, carrier frequencies are as follows: aa/a (1 in 3), aa/- (1 in 5,000), and aa/aaCS (1 in 10,000).
  • Among Asian populations, carrier frequencies are: aa/a- (1 in 16), aa/- (1 in 93), and aa/aaCS (1 in 93).
  • Northern European populations exhibit carrier frequencies of: aa/a- (1 in 44), aa/- (1 in 3,807), and aa/aaCS (1 in 10,000).
  • In the general population, carrier frequencies are: aa/a- (1 in 16), aa/- (1 in 570), and aa/aaCS (1 in 10,000). Understanding these carrier frequencies is essential for targeted healthcare interventions and genetic counseling efforts.

UNITY Screen™ Alpha-Thalassemia Screening Workflow

Carrier screening can be done prior to or during pregnancy. If you're pregnant, your doctor can order carrier screening and NIPT at the same time to understand your carrier status and if the baby is at high-risk for any conditions you are a carrier for along with screening for chromosome conditions.

Consult
The UNITY Screen™ NIPT is ordered through your healthcare provider. You can schedule a complimentary genetic counseling session to answer any questions about the test before or after your blood is drawn.

Test: As early as week 10
Your blood sample can be collected in the doctor’s office, at a local lab, or through our mobile services. Your blood sample is shipped to our CAP/CLIA certified laboratory in northern California.

aneuploidy NIPT + fetal antigen results: As early as week 11
Within about one week from lab receipt, your doctor will receive the baby’s risk score for aneuploidies (chromosome conditions) and fetal antigens (if added). You will receive a text or email indicating your results are available on our portal, or your healthcare provider may call you with the results.

carrier status + single-gene NIPT results: As early as week 12
Within about two weeks from lab receipt, your doctor will receive the results of your maternal carrier status testing and single-gene NIPT. If you were found to be a carrier for any of the recessive conditions, single-gene NIPT is automatically run to determine your baby’s risk of being affected. You will receive a text or email indicating your results are available on our portal, or your healthcare provider may call you with the results.

What Do Alpha-Thalassemia Screening Results Mean?

Alpha-thalassemia blood test results can be complex to interpret because there are several forms of alpha-thalassemia and the risk for disease depends on a variety of factors. If your alpha-thalassemia carrier screening shows that you're a carrier, UNITY Screen™ will assess your pregancy's risk for Hemoglobin H disease or Hemoglobin Bart disease and provide the result on the same report.

View sample results

If UNITY Screen™ shows an increased or high-risk for alpha-thalassemia, your doctor or genetic counselor will discuss next steps and additional testing options with you.

Before Birth
Testing for alpha-thalassemia during pregnancy can be performed by obtaining a sample of placenta (chorionic villus sampling or CVS) or fluid around your baby (amniocentesis) which both contain DNA that is representative of your baby. A CVS is ideally performed between 10 to 13 weeks pregnancy while an amniocentesis is typically performed between 15 to 24 weeks pregnancy. Both procedures are generally safe, but have a small risk for pregnancy complications, including miscarriage.

After Birth
Testing for your baby can be performed after birth through a blood test. All babies born in a hospital in the United States are automatically screened for alpha-thalassemia.

Your healthcare provider or a genetic counselor can help you understand the next best steps for you and your family if you receive a high-risk result. At BillionToOne, we offer complimentary genetic counseling services to discuss test results with patients or providers.

Schedule a genetic consultation

Frequently Asked Questions.

Explore our additional resources and find answers to common questions.

How is alpha-thalassemia treated?

Medical management of alpha-thalassemia includes folic acid supplementation, blood transfusions, medications to reduce extra iron in organs and bone marrow transplants for some patients. Advanced therapies include in-utero blood transfusion and stem cell transplantation

What is materal mirror syndrome?

In pregnancies with a severe form of alpha-thalassemia (Hemoglobin Bart disease/ alpha-thalassemia major) an affected baby develops anemia, which can lead to heart failure. When the baby's heart is working too hard, excess fluid can begin to build up around the heart, lungs, intestines, or under the baby's skin, this is called fetal hydrops. Hydrops can be seen on second and third trimester ultrasounds.

When a baby develops hydrops, a mother can mirror these symptoms and develop life-threatening complications like hypertension, swelling in the hands and feet, protein in the urine, fluid in the lungs, and possibly hemorrhage. Babies are typically delivered immediately if this severe condition occurs.

A doctor

Contact Us

Our Genetic counselors are available to answer your questions and help understand your results.
Contact Us
Mother with her baby smiling

Find a Provider

To find a provider you may be able to order UNITY Screen for you, explore local providers today.
Find a Provider