Hemoglobin Zeta (HBz)

Zeta-globin is an alpha-like hemoglobin. The zeta-globin polypeptide is synthesized in the yolk sac of the early embryo, while alpha-globin is produced throughout fetal and adult like. The zeta-globin gene is a member of the human alpha-globin gene cluster that includes five functional genes and two pseudogenes. The order of genes is: 5' - zeta - pseudozeta - mu - pseudoalpha-1 - alpha-2 -alpha-1 - theta1 - 3'.Its composition was found to be gamma(2) X(2). It was originally thought that the X-chain might be the epsilon chain whose synthesis persisted until after birth because of the chromosomal anomaly; later work indicated that the X-chain is indeed different from epsilon and therefore it is now called zeta. Hb Portland-2 is the designation for zeta(2)-beta(2) found in stillborn infants with homozygous alpha-thalassemia .