Sickle cell beta-thalassemia refers to an inherited condition that impacts hemoglobin. People with the condition have different changes in each copy of their hemoglobin gene. One causes red blood cells (RBCs) to form a sickle shape and another reduces the amount of hemoglobin.

Sickle cell beta-thalassemia is a type of RBC disorder known as a hemoglobinopathy. These are conditions that cause abnormal hemoglobin production or a change in its structure. Hemoglobin is the protein in RBCs responsible for carrying oxygen around the body.

Both sickle cell disease and beta-thalassemia are genetic conditions that affect hemoglobin. A person with sickle cell beta-thalassemia inherits a trait for both conditions, impacting the shape and number of hemoglobin.

In this article, we will discuss the causes and risk factors for sickle cell beta-thalassemia, as well as symptoms and treatment options for the condition.

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Sickle cell beta-thalassemia is a genetic condition and a type of sickle cell disease that features symptoms of both sickle cell disease and beta-thalassemia. It causes RBCs to take on a sickle shape, making them unable to flow through the blood vessels as smoothly. It also affects the amount of normal hemoglobin a person has in their blood.

It is an inherited condition, meaning that parents pass it on to their children. Researchers estimate that 5–7% of the global population are carriers of a significant hemoglobin mutation. People with sickle cell beta-thalassemia inherit a sickle trait from one parent and a beta-thalassemia trait from the other.

There are two types of sickle cell beta-thalassemia: plus (HbS beta+) and zero (HbS beta0). The former is the milder variant. The “plus” indicates that the blood contains a lower-than-average amount of normal hemoglobin. This differs from the latter, in which a person has no normal hemoglobin.

Sickle cell beta-thalassemia results from a change in the beta-hemoglobin (HBB) gene. The beta-hemoglobin gene is responsible for forming the hemoglobin subunit beta component of the hemoglobin protein.

A person develops sickle cell beta-thalassemia when they inherit one sickle cell trait from one parent and one beta-thalassemia trait from the other. The beta-thalassemia gene can be either beta+, which results in a lower production of normal hemoglobin, or beta0, which leads to a complete absence of normal hemoglobin.

Risk factors for a person developing sickle cell beta-thalassemia include having parents that may be carriers of the sickle cell, HbS beta+, or HbS beta0 gene. The condition follows an autosomal recessive inheritance pattern. This means that if a person has a beta-thalassemia trait and their partner has a sickle cell trait, there is a 25% chance with each pregnancy that their child will have sickle cell beta-thalassemia.

The symptoms a person may experience will depend on whether they have HbS beta+ or HbS beta0. The amount of normal hemoglobin a person can produce largely determines the severity of the condition.

A person with HbS beta+ will likely have milder symptoms, as while they produce less functioning hemoglobin than is typical, they can still produce normal hemoglobin. Individuals with either type will produce sickle-shaped RBCs that can block circulation and cause cell damage and pain.

A person with HbS beta+ may experience:

The symptoms of HbS beta0 are typically similar but with a more severe case of anemia.

Some newborn screenings include testing for sickle cell disorders such as sickle cell beta-thalassemia. Screening involves taking a blood sample and looking at the types of hemoglobin present in the newborn’s blood. However, newborn screenings only suggest the possibility of sickle cell beta-thalassemia and require further confirmatory tests. This may include the parents and any siblings having tests.

These tests may include:

  • Molecular gene testing: These aim to detect changes within the HBB gene.
  • High performance liquid chromatography: This test identifies what type of hemoglobin is present in the RBC. It does this by separating each component of the RBC.
  • Hemoglobin electrophoresis: This test also measures the different types of hemoglobin in the blood. Electrophoresis uses an electrical current to move molecules in RBCs through a gel based on their size and electrical charge.

Treatment aims to prevent complications from occurring and treat the symptoms a person may experience. This generally involves continuous care to prevent and manage potential problems.

In addition to the treatments below, a person may receive pain relief medications and antibiotics to help reduce pain and infections. The spleen usually helps prevent infections, but many people with sickle cell beta-thalassemia may lose spleen function. As such, children may receive penicillin prophylaxis to prevent pneumococcal sepsis.

Treatment options for sickle cell beta-thalassemia may include:


People may require hydroxyurea if they experience frequent periods of pain. Hydroxyurea is a drug that makes RBCs bigger and changes their shape to the typical round and flexible composition. This can help slow or prevent complications.

Hydroxyurea increases the level of fetal hemoglobin (HbF) in the body. HbF is present in higher quantities in newborns and can help protect against sickle cell complications. With higher levels of HbF, RBCs are less likely to become sickle-shaped.

According to the American Society of Hematology, people with sickle cell beta-thalassemia who take hydroxyurea also have fewer:

Blood transfusions

Some people with sickle cell beta-thalassemia may require blood transfusions. This is when a healthcare professional infuses healthy donor blood into the body of a person with sickle cell beta-thalassemia via a tube. The donor blood will need to have matching antigens to the blood of the person receiving the transfusion. These antigens, known as human leukocyte antigens, are proteins present on the surface of RBCs.

If the antigens do not match, the immune system of the person receiving the blood donation is more likely to reject the transfusion, and it may lead to a reaction that can cause health problems.

Bone marrow transplantation

The bone marrow in the body produces blood cells. A person with dysfunctional bone marrow, such as in sickle cell beta-thalassemia, may receive hematopoietic stem cells from a healthy donor. This may help improve bone marrow function and reduce the symptoms of sickle cell beta-thalassemia. A hematopoietic stem cell transplant is currently the only cure for this condition.

Sickle cell beta-thalassemia is a type of sickle cell disease. Some evidence suggests the life expectancy of a person living with sickle cell disease is reduced by 20–30 years compared with a healthy individual. Similarly, a 2019 study suggests a person with sickle cell disease may live roughly 22 fewer years than a person without the condition.

Advances in therapy and treatment options are helping to improve the outlook of people with sickle cell disease. However, statistics like these highlight the necessity to further develop approaches to improve the underlying morbidity and mortality of individuals with the condition.

Most often, a person will receive a diagnosis of sickle cell beta-thalassemia shortly after birth. Later in life, if they believe their current treatment regime is not suitable or notice worsening symptoms, they should contact their doctor.

If a person is aware of a family history of sickle cell disease, they may wish to consider undergoing genetic screening before attempting to have children.

Sickle cell beta-thalassemia is a type of sickle cell disease. It occurs when a person inherits a sickle cell trait and a beta-thalassemia trait from their parents. It results in a person having sickle-shaped RBCs and either producing a low amount of hemoglobin or none at all.

Symptoms of the condition can include mild to severe anemia, tiredness, weakness, pain, and possible organ damage. Treatment may involve pain relief medications, antibiotics, hydroxyurea, and blood transfusions. Some people may also receive a bone marrow transplant to help them produce healthy hemoglobin.