Functional activity of the triplicated alpha alpha alpha 4.2/gene rearrangement

Function of the triplicated alpha alpha alpha 4.2/gene rearrangement was assessed by measurement of Hb Bart's and hematological phenotype including alpha/beta biosynthesis ratio. Increased output of alpha globin chains in alpha alpha alpha 4.2/-- compared to alpha alpha/-- was found in a cord blood. In contrast, hematological phenotypes in two family members with the alpha alpha alpha 4.2/-- genotype were consistent with that expected in alpha alpha/--. This would suggest that the additional alpha gene in the alpha alpha alpha 4.2/rearrangement has variable expression.