Efficacy and Safety of Gene Therapy for β-Thalassemia

β-Thalassemia results from insufficient production of the hemoglobin subunit β-globin (β+) or from the absence of β-globin (β0). Low levels of adult hemoglobin (HbA, or α2β2) are exacerbated by excess free α-globin chains in erythroid cells, leading to dyserythropoiesis and shortening red-cell survival. Patients with transfusion-dependent β-thalassemia, the most severe clinical form of this disorder, receive repeated red-cell transfusions in order to prevent severe anemia and increase survival. However, iron overload caused by transfusions often leads to dysfunction in the heart, endocrine glands, and liver. Allogeneic hematopoietic stem-cell transplantation, which is routinely used in children with β-thalassemia, can increase overall . . .