Hemoglobin--from F to A, and back.

Worldwide, millions of peoples' lives are affected directly or indirectly by inherited abnormalities of the beta-globin chain. Most prominent among these abnormalities are sickle-cell anemia and beta-thalassemia (in which production of the beta-globin chain is vastly reduced or absent). Homozygous persons suffer from ineffective red-cell production and accelerated hemolysis. The markedly increased rate of erythropoiesis results in abnormalities of bone and extension of marrow into both bony and extramedullary sites that are not normally involved in hematopoiesis; in beta-thalassemia, there is massive hepatosplenomegaly. Although a great deal is known about these diseases at the molecular level and improvements in antenatal . . .