Common deletions in the ζ-α-globin gene cluster.

The 3 red boxes represent the 3 active globin genes, the one embryonic ζ2-globin gene, and the α2- and α1-globin genes. They span approximately 26 Kb in length from ζ2 to α1 globin genes. The blue lines represent the common α-thalassemia deletions. Figure adapted with permission from Cambridge University Press2 andBlood.5