Patients & Families


  • β-thalassemia is an inherited blood disorder caused by a mutation in the beta-globin gene which causes ineffective red blood cell production leading to severe anemia, a condition where there are not enough healthy red blood cells in the blood
  • Depending on clinical severity and need for transfusions, β-thalassemia is broadly classified into 2 types
    • Transfusion-dependent β-thalassemia (TDT) is the most severe clinical presentation of β-thalassemia and requires regular lifelong blood transfusions for survival. It includes β-thalassemia major (Cooley’s anemia) and some forms of β-thalassemia intermedia.
    • Non-transfusion-dependent β-thalassemia (NTDT) requires occasional blood transfusions, but does not require regular transfusions indefinitely for survival. This includes less-severe forms of thalassemia intermedia
  • Symptoms of TDT often appear within the first 2 years of life, these include:
    • Severe anemia
    • Slow growth
    • Failure to thrive
    • Yellowing of the skin and eyes

People living with TDT require a lifelong regimen of regular blood transfusions for survival. The blood transfusions deliver healthy red blood cells to the body to address the severe anemia and associated complications.

However, blood transfusions can cause too much iron to build up in the body which can damage organs, such as the heart and liver, and lead to symptoms including abdominal pain, weakness, fatigue and joint pain. Because iron build up cannot be eliminated naturally, patients who receive ongoing blood transfusions must also take medicines, called iron chelation therapy, to remove the excess iron.

Currently, the only potentially curative treatment option for TDT is a bone marrow transplant (BMT, also called a stem cell transplant or allogeneic hematopoietic stem cell transplant). You can find more information about BMT using the resources below.

bluebird bio clinical studies in TDT:

Two phase 3 global clinical studies are underway to determine if the one-time gene therapy can decrease or eliminate the need for continued blood transfusions in people living with transfusion-dependent β-thalassemia, while also being safe and well-tolerated. To learn more about these clinical investigational studies visit

The following organizations offer resources and information for patients with transfusion-dependent β-thalassemia, their families and caregivers:

Bone Marrow Transplant Resources

Thalassemia Resources