The Proportion of HB A₂ is Higher in Sickle Cell Trait Than in Normal Homozygotes

Abstract

The proportion of Hb A₂ was 3.53 ± 0.94 per cent in the blood of 69 persons with sickle cell trait (A/S) and 2.88 ± 0.69 per cent in a like number with a normal (A/A) genotype using a radial immunodiffusion assay. This differs significantly at the 0.1% level by the paired comparison technique. It is proposed that this effect is due to the impaired association of βS with αA chains allowing more of the latter to combine with δ-chains. A similar phenomenon may account for the increased proportion of Hb A₂ observed in β-thalassemia. The proportion of Hb F did not differ in the two genotypes.