The choice of HSCT protocol will depend on the availability of an identical donor, the patient's age, the severity of SCD, and its consequences on the degree of organ dysfunction. TCD indicates transcranial Doppler; VOC, vaso-occlusive crises; ACS, acute chest syndrome; TP, transfusion program; HU, hydroxyurea; BMT, bone marrow transplantation; CBT, cord blood transplantation; PBSCT, peripheral blood stem cell transplantation; TBI, total body irradiation; Fluda, Fludarabin; MMF, mycophenolate mofetil; BU, busulfan; CY, cyclophosphamide; MTX, methotrexate; and ATG, antithymoglobulin.