Nature of Foetal Haemoglobin in F‐Thalassaemia

Abstract

S ummary The nature of Hb‐F was studied in 32 heterozygotes for F‐thalassaemia, in four homozygotes, and in four persons who have F‐thalassaemia in combination with β‐thalassaemia or Hb‐S. Analysis of the cyanogen bromide fragment γCB‐3 indicated that, in all heterozygotes, both G γ and A γ chains were present in Hb‐F in an average ratio of about 2:3. In the homozygotes and the double heterozygotes, both G γ and A γ chains were observed in an approximate ratio somewhat higher than 1:1. This pattern of γ chain synthesis is nonspecific for F‐thalassaemia but similar to that observed in the traces of Hb‐F of normal adults. In conjunctionwith existing information from other genetic studies, it may be concluded that the mutation in F‐thalassaemia is associated with a complete deficiency of β and σ chains from cis position together with an increased synthesis of γ chains that is directed by both A γ and G γ loci.