Two different theta (theta) globin gene deletions observed among black newborn babies.

Two different theta 1 globin gene deletions have been detected in the Black population of the southeastern U.S.A. Restriction mapping of the alpha globin gene cluster indicated that one deletion removes approximately 1.8 kb of DNA including most of the theta 1 globin gene, while the second removes approximately 6 kb of DNA including the entire theta 1 globin gene. These defects do not cause haematological alterations in the newborn or in the adult (established for the smaller deletion only), nor were changes observed in polypeptide chain patterns at birth.