Carrying or Inheriting the Beta Thalassemia Minor Trait
Carrying or Inheriting the Beta Thalassemia Minor Trait
The beta thalassemia trait is present at birth. It is inherited in an autosomal recessive pattern involving the HBB (hemoglobin subunit beta) gene. Your chances of carrying or inheriting the beta thalassemia minor trait depend on whether one or both of your parents are carriers.
In an autosomal recessive condition like beta thalassemia minor, inheriting one normal HBB gene can compensate for inheriting one mutated (defective) gene. In this scenario, the baby will be a carrier (because they have the trait) but usually without symptoms (due to the work of the normal HBB gene).
If both parents have beta thalassemia trait, each child has the following risk:
- 25% chance of being affected with beta thalassemia trait
- 50% chance of being an asymptomatic carrier
- 25% chance of being unaffected and not a carrier
Diagnosis
An official diagnosis of beta thalassemia minor can be confirmed only by a healthcare provider. Diagnosis is usually done using the following laboratory tests:
- Complete blood count (CBC): A blood test that measures the size, shape, and number of your red blood cells
- Hemoglobin electrophoresis: A specialized blood test that measures the different types of hemoglobin in your blood
- Iron studies: Such as free erythrocyte protoporphyrin and ferritin blood tests
- State-mandated newborn screening: Depending on whether your state tests for hemoglobin disorders at birth
- Chorionic villus sampling (CVS) or amniocentesis: For a fetus in which beta thalassemia is suspected
Molecular genetic testing can detect mutations of the HBB gene. However, this type of testing is typically reserved to identify people at risk of having the trait and those who are asymptomatic carriers. It may also be used in prenatal testing.
Knowing whether you have the thalassemia trait is important for family planning and your own health. Two people with the trait increase their risk of passing two defective HBB genes to their baby, which can result in beta thalassemia major, also known as Cooley’s anemia, a potentially life-threatening form of thalassemia.
Getting tested for this trait can provide the following benefits:
- Understanding the risk of having a child with this disease, especially if both partners are carriers
- Identifying possible risk of anemia during pregnancy
- Knowing whether your children are at risk of being carriers for future family planning
- Preventing a misdiagnosis of iron deficiency anemia and the unnecessary prescription of iron supplements
Mild Anemia: Symptoms of Beta Thalassemia Minor
Beta thalassemia minor symptoms may not be apparent in everyone affected by this condition. When they occur, symptoms of mild anemia are subtle and can often be overlooked. You may not know you have this disorder until your blood is tested.
When beta thalassemia minor results in mild hemolytic anemia (early breakdown of red blood cells), symptoms can include:
- Being moody
- Fatigue
- Being more weak or tired than usual
- Frequent headaches
- Problems concentrating
If anemia becomes worse, the following symptoms may also develop:
- Mild anemia with it, Symptoms are often mild. Though rarely needed, treatment can involve taking folic acid, having blood transfusions, and managing iron levels in your blood.
Finding out whether you have this disorder can help you gauge your risk of passing it on. When two parents have the damaged gene, it raises the risk of a more severe form of thalassemia in their children.
