Sickle Cell Disease Carrier Screening & NIPT

What is UNITY Fetal Risk Screen(™) for sickle cell disease?

UNITY Screen (™) is carrier screening and a risk assessment for your pregnancy all in one convenient blood test. The first step is identifying if you are a carrier for sickle cell disease, or certain other recessive conditions. If you are not a carrier for sickle cell disease, your baby’s risk of having sickle cell disease is extremely low. If you are a carrier and currently pregnant, UNITY Screen (™) will automatically perform single-gene NIPT to tell you if your baby’s risk of having sickle cell disease is high or low.

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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 sickle cell disease.

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What is sickle cell disease?

Sickle cell disease (SCD) is an inherited condition affecting the red blood cells' ability to carry oxygen in a molecule called hemoglobin. The genetic instructions for making hemoglobin are found in a pair of HBB genes. In sickle cell disease, mutations, or changes, in the HBB genes cause the body to produce abnormal hemoglobin types, such as hemoglobin S, C, or E, instead of the healthy hemoglobin A. These abnormal hemoglobins cause red blood cells to become sickle-shaped, instead of round, which can’t move as easily through blood vessels. This can lead to painful blockages in blood vessels, shortness of breath, frequent infections, or more serious complications like organ damage or stroke. Lifelong treatment typically includes pain medication, hydration, and blood transfusions.

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How is sickle cell disease inherited?

Sickle cell disease is an autosomal recessive condition, meaning a person must inherit a specific genetic change in the HBB gene from both parents to be affected. If both parents are carriers (also called sickle cell trait), they can pass on either a working or non-working copy of the HBB gene. If a child inherits non-working copies from both parents, they will have sickle cell disease.

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Who should consider sickle cell disease screening?

Carrier screening for sickle cell disease and other beta-hemoglobinopathies is recommended for all pregnant individuals or those considering pregnancy. With UNITY Screen (™) one test can tell you if you are a carrier for sickle cell disease and if your baby has a high risk or low risk of having sickle cell disease through our unique single-gene NIPT. Depending on your results, your provider may discuss additional confirmatory testing that can be done either before or after delivery.

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UNITY Screen (™) Carrier Screening & sgNIPT workflow

With UNITY Screen™, carrier screening is performed first to see if you’re a carrier for sickle cell disease. If you're not a carrier for SCD, the chance your baby is affected is extremely low. If you are found to be a carrier, the second step is to assess your baby's risk for SCD. All it takes is a blood sample after 10 weeks in pregnancy.

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.

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What do sickle cell screening results mean?

Your UNITY Screen (™) results will tell you if you are a carrier for sickle cell disease, or other recessive conditions. Then, if you are currently pregnant and a carrier for one or more of the conditions screened, single-gene NIPT will automatically be performed on your sample. Your report for UNITY Screen (™) will show what your baby’s risk of having sickle cell disease is.  

If your results show a high-risk, your healthcare provider will discuss the recommended confirmatory testing that can be performed before or after delivery.

UNITY Screen (™) results are not diagnostic, so there is always the option for additional confirmatory testing to be performed. You can discuss your options and recommendations with your provider or one of our Genetic Counselors:

• Before Birth: Testing 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 in pregnancy while an amniocentesis is typically performed between 15 to 24 weeks in 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.  In addition, all babies born in a hospital in the United States are automatically screened for sickle cell disease and other beta-hemoglobinopathies. The majority of babies with sickle cell disease/beta-hemoglobinopathy will be diagnosed through this screening process. However, in rare cases, a diagnosis may be missed or incorrectly diagnosed.

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Cord Blood Banking: Hematopoietic stem cells from umbilical cord blood, which can only be collected at the time of delivery, may be used to treat certain genetic conditions. BillionToOne’s cord blood banking program will cover the costs associated with the collection and first year of storage of cord blood for patients with high risk HBB sgNIPT results. Interested patients should schedule an appointment with a BillionToOne genetic counselor to learn more.

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Frequently Asked Questions

What is the difference between sickle cell trait and sickle cell disease?

Sickle cell trait occurs when a person inherits one normal HBB gene that makes hemoglobin A and one abnormal HBB gene that makes hemoglobin S. People with sickle cell trait are carriers and usually do not experience symptoms, but they can pass the HBB gene for abnormal hemoglobin to their children.

Sickle cell disease, on the other hand, occurs when a person inherits two abnormal HBB genes from both parents and can only make hemoglobin S. This leads to the production of sickle-shaped red blood cells, causing symptoms like severe pain, anemia, and organ damage.

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How can sickle cell disease affect pregnancy and childbirth?

Sickle cell disease can complicate pregnancy and childbirth. Pregnant people with sickle cell disease are at higher risk for complications such as severe pain episodes, infections, and preeclampsia. They are also more likely to experience preterm labor and have low birth weight babies. Close monitoring by healthcare providers, specialized prenatal care, and managing the condition during pregnancy are crucial to ensure the health of both mother and the baby.

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Is there a cure for sickle cell disease?

A bone marrow or stem cell transplant, which can replace the defective blood-forming cells with healthy ones, is one curative option for those with sickle cell disease. However, this procedure carries significant risks and is not suitable for everyone. There are several newly FDA-approved gene therapies that modify a patient’s own blood stem cells to make Hemoglobin A and then give this modified version back to a patient through a single-dose infusion. This one-time therapy may be curative for those with sickle cell disease that respond well to the treatment.

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What is cord blood banking?

Cord blood banking occurs at the time of delivery and collects and stores hematopoietic stem cells from umbilical cord blood. For expecting parents, banking cord blood can provide a valuable resource for potential future medical treatments for their child or family members. Coordinating logistics prior to delivery ensures that the collection process is smooth and the cord blood is properly preserved for potential use. BillionToOne’s cord blood banking program will cover the costs associated with the collection and first year of storage of cord blood for patients with high risk HBB sgNIPT results. Interested patients should schedule an appointment with a BillionToOne genetic counselor to learn more.

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Treatments & Resources

• Sickle Cell Disease Association of American, Inc. https://www.sicklecelldisease.org/ 
• CDC: Sickle Cell Disease : https://www.cdc.gov/sickle-cell/ 
• National Organization for Rare Disorders (NORD): https://rarediseases.org/rare-diseases/sickle-cell-disease/ 
• American Society of Gene + Cell Therapy: Gene Therapy sickle cell disease: https://patienteducation.asgct.org/disease-treatments/sickle-cell-disease