High Hb A2 β-Thalassemia Due to a 468 bp Deletion in a Patient with Hb S/β-Thalassemia

We describe a case of Hb S/beta-thalassemia (thal) involving a 468 bp deletion that removes the beta-globin gene promoter but leaves the coding regions intact. This is the second report of this deletion, and our family study establishes that this deletion causes beta0-thal with unusually high levels of Hb A2 and Hb F. As with other genotypes involving deletions of the 5' region of the beta-globin gene, our patient had a mild form of Hb S/beta-thal.