HBA2 and thalassemia: This suggested three possibilities: HbSS with an uncommon (and therefore untested) alpha globin chain mutation; HbS/δβ-thalassemia; and HbS with HPFH with an incomplete increase in gamma globin chain production (HbS-HPFH syndrome). In the present case, the absence of anemia and the patient’s relatively benign clinical course made HbS-HPFH syndrome the most likely diagnosis [8].