Characterization of an Indian (delta beta)0 thalassaemia.

The molecular basis of delta beta thalassaemia in an Indian family is shown here to be due to a previously undescribed deletion within the beta globin gene complex. Starting 3 kilobases from the 3' end of the A gamma gene, the deletion removes the delta and beta globin genes and continues to an unknown extent in the 3' direction. Heterozygotes for this deletion have about 25% Hb F with a G gamma:A gamma ratio of 70:30 while interaction with beta+ thalassaemia results in the clinical picture of thalassaemia intermedia.