What Does NxGen MDx Screen For?
We screen for up to 120 genetic disorders that can affect your pregnancy, the health of your baby, and your family's future. You can learn more about our various screens — and which sets of screens (or "panels") align with where you are in your reproductive journey.
What Your Test Results Mean:
There are two types of alpha-thalassemia carriers: alpha-thalassemia silent carriers or alpha-thalassemia trait carriers. Individuals who are silent carriers of alpha thalassemia are not expected to show symptoms. Individuals with alpha thalassemia trait may be identified to have mild anemia in the presence of normal iron levels. Individuals with alpha-thalassemia trait typically do not require any medical management or treatment. You and your partner would both have to be carriers of alpha thalassemia to have an increased chance to have a child with symptoms. This is known as autosomal recessive inheritance. Carrier testing of your partner or donor is recommended in addition to consultation with a genetic counselor for a more detailed risk assessment.
When an individual has more than four alpha-globin genes, this is referred to as an alpha-globin triplication. Extra alpha-globin genes can cause alpha/beta hemoglobin imbalance in the presence of beta-thalassemia or beta-thalassemia trait. Individuals with an alpha-globin triplication without beta-thalassemia or beta-thalassemia trait are not expected to show symptoms. Your partner would have to be a carrier of beta-thalassemia for there to be an increased chance to have a child with symptoms. This is known as autosomal recessive inheritance. Carrier testing of your partner or donor is recommended in addition to consultation with a genetic counselor for a more detailed risk assessment.
We recommend that you share and discuss this information with all of your health care providers. Since this is an inherited gene change, this information may be helpful to share with family members as it may impact their family planning.
What is Alpha-Thalassemia?
Alpha-thalassemia is an inherited disorder caused by decreased synthesis of hemoglobin alpha chain, a protein in the red blood cells required for oxygen delivery. The clinical features of alpha thalassemia can be explained by deletions or variants in the HBA1 or HBA2 alpha-globin genes. Typically, individuals have two copies of the HBA1 and HBA2 genes, for a total of four alleles encoding for the alpha chain component of hemoglobin in red blood cells. There are two types of alpha thalassemia: Hb Bart syndrome (hydrops fetalis) and HbH disease. In the most severe type, Hb Bart syndrome (0 copies of HBA1 or HBA2), pregnancies may result in stillbirth or early infant death. Anemia, enlargement of the spleen and liver, mild jaundice, and skeletal changes (particularly in the face) are general features of HbH disease (1 copy of HBA1 or HBA2).
Prognosis of alpha thalassemia depends on which type an individual is diagnosed with. The prognosis of Hb Bart syndrome is poor; it is known to be fatal and can often result in miscarriage or stillbirth. For HbH disease, prognosis is typically fair; however, it depends on the severity of the signs and symptoms which can vary in each individual. If individuals with HbH disease are receiving proper treatment, they can live well into adulthood.
Management of Hb Bart syndrome is focused on care of the mother during pregnancy as well as supportive care in infancy. Individuals with HbH disease require annual follow up with a hematologist and may require red blood cell transfusions. Other complications such as splenomegaly, gallstones, and leg ulcers may require appropriate medical or surgical treatment.
What is Beta-Thalassemia Due to Alpha/Beta Hemoglobin Imbalance?
Individuals with more than four alpha-globin genes and beta-thalassemia or beta-thalassemia trait would have a diagnosis of beta-thalassemia intermedia. Beta thalassemia is a blood disorder that reduces the production of hemoglobin. Hemoglobin is the iron-containing protein in red blood cells that carries oxygen to cells throughout the body. As a result, affected individuals have mild to moderate anemia and may also have slow growth and bone abnormalities.
Prognosis of beta-thalassemia due to alpha/beta hemoglobin imbalance is typically fair, though severity
of the signs and symptoms vary in each individual. If individuals with an alpha/beta hemoglobin imbalance
are receiving proper treatment, they can live well into adulthood.
The most common treatment for beta thalassemia due to alpha/beta hemoglobin imbalance is blood transfusions, which provide a temporary supply of healthy red blood cells to bring oxygen to the body. If transfusions occur frequently, they may result in a toxic buildup of iron in the blood. To counteract this side effect, individuals with beta thalassemia require chelation therapy, which helps eliminate excess iron from the body.
Talk to a Genetic Counselor
As a NxGen client, you'll have access to personal genetic counselors who can help explain the results of your screens and provide insight on how to move forward. To schedule a personal conference to discuss your screen results, call (855) 776-9436. or click the link below.Discuss Your Screening Results