Restriction fragment length polymorphism in the interzeta hypervariable region for prenatal diagnosis of non-deletion α thalassemia

Abstract

A Bam Hi restriction fragment length polymorphism in the interzeta hypervariable region (IZ HR+) of the ζ-α gene cluster was used for the prenatal diagnosis of a pregnancy at risk for Hb H hydrops fetalis. The parents had ζ-α thalassemia 1 and non-deletion α thalassemia, respectively, and a previous hydrops was missed using the conventional method of gene detection. In this prenatal diagnosis, linkage to IZ HVR was used to exclude non-deletion α thalassemia, and the numbers of ζ and α genes in the fetus were quantitated to predict the exact genotype. Confirmation was made by analysis of cord blood at delivery.