Delta Beta-Thalassaemia in two yugoslavian families.

Members of two Yugoslavian families were found to have delta-beta-thalassaemia. Interaction of beta-thalassaemia with delta-beta-thalassaemia occured in two young children producing a clinical condition which is somewhat less severe than that of homozygous beta-thalassaemia. Results from biosynthetic analyses indicate that the degree of globin chain imbalance in double heterozygotes for beta- and delta-beta-thalassaemia is similar to that in homozygous beta-thalassaemia. Fetal haemoglobin of all heterozygotes contained G-gamma and A-gamma chains in an average ratio of about 2:3 whereas that in the two double heterozygotes had G-gamma and A-gamma chains in a ratio of 3:2.