Autologous hematopoietic stem cell (HSC)-targeted gene therapy provides a one-time cure for various genetic diseases including sickle cell disease (SCD) and ?-thalassemia.In HSC gene-addition therapy, patient CD34+ HSCs are genetically modified by adding a therapeutic ?-globin gene with lentiviral transduction, followed by autologous transplantation.Alternatively, novel gene-editing therapies allow for the correction of the mutated ?-globin gene, instead of addition.