Variations in Globin Synthesis in Delta-Beta-Thalassaemia

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Abstract
Peripheral blood globin synthesis studies were done in 11 patients with δβ‐thalassaemia trait, Hb S‐δβ‐thalassaemia or δβ/βº‐thalassaemia from two black and two Caucasian families. All patients had elevated Hb F and normal or decreased Hb A2 levels and 10 had family studies confirming the diagnosis. In addition, four unrelated non‐thalassaemic patients with elevated Hb F levels also had peripheral blood globin synthesis studies. The β/α specific activity globin synthesis ratios in the three blacks with δβ‐thalassaemia trait were 0.60–1.04. In the four Caucasians with δβ‐thalassaemia trait, the β/α ratios were 0.58–1.02. These results demonstrate a wide range of ratios overlapping those of normal controls (0.99 ± 0.06). The βs/α ratios in three blacks with Hb S‐δβ‐thalassaemia ranged from 0.66 to 1.00, similar to those of patients with δβ‐thalassaemia trait. In the black patient with δβ/βº‐thalassaemia, the γ/α ratio was 0.67. The β/α peripheral blood ratios in the four non‐thalassaemic patients with elevated Hb F ranged from 1.00 to 1.1, similar to those of normal controls. These studies indicate that a decreased β/α ratio is not an invariable finding in δβ‐thalassaemia in blacks or Caucasian patients and that globin synthesis data alone is insufficient to diagnose definitively heterozygotes for δβ‐thalassaemia or to distinguish this trait from non‐thalassaemic haematological disorders associated with a normal percentage of Hb A2 and an elevated level of Hb F.