Clinical and hematological evaluation of two delta 0 beta 0-thalassemia homozygotes.

Two homozygous delta 0 beta 0-thalassemia patients, one with the G gamma A gamma type and the other with the G gamma type, and their heterozygous parents are described. Red cell indices among the heterozygotes with the G gamma A gamma type of delta 0 beta 0-thalassemia were markedly different from those in heterozygotes with the G gamma type. However, the imbalance in in vitro hemoglobin synthesis was quite similar in the two heterozygous conditions. The same was observed for the homozygous patients; the in vitro chain synthesis was severely imbalanced as seen in beta-thalassemia major. The clinical and some of the hematological findings were milder in the G gamma-delta 0 beta 0-thalassemia homozygote than in the G gamma A gamma-delta 0 beta 0-thalassemia homozygote. The death of a sibling of the G gamma-delta 0 beta 0-thalassemia homozygote with a diagnosis of thalassemia major suggests that both types of delta 0 beta 0-thalassemia could follow a severe clinical and hematological course. The discovery of the G gamma type of delta 0 beta 0-thalassemia in a Turkish child shows that two types of delta 0 beta 0-thalassemia can be found in that country. Differentiation between the two types can only be made through structural analyses of Hb F.