Gene Mapping in Thalassemia

To the Editor: We are pleased to see that detection of specific human globin-gene deletions by restriction endonuclease mapping of the mutants hereditary persistence of fetal hemoglobin and δβ thalassemia, described by us several months ago,¹ has been so quickly applied to the prenatal detection of these disorders.² We should like to add a cautionary note not adequately stressed by the authors. There are substantial differences between the results presented in the Journal article and ours, which may complicate the use of this technic for prenatal diagnosis. For example, our homozygote for δβ thalassemia has two β-like Eco RI…