Hemoglobin gene therapy for β-thalassemia.

Allogeneic stem cell transplantation currently is the only curative option for severe β-thalassemia and sickle cell disease. Human globin gene therapy with autotransplantation of transduced human hematopoietic stem cells is an exciting alternative approach to a potential cure. One patient with thalassemia has recently been reported to have clinical benefit after lentiviral human β-globin gene therapy. He has not required blood transfusions for almost 2 years. Most of the patient's gene correction and new human β-globin gene expression is caused by the expansion of a single clone in which the corrective transgene is inserted into an Hmga2 gene.