α0-Thalassemia due to recombination between the α1-globin gene and an AluI repeat

Abstract

A form of α0-thalassemia found in subjects of Mediterranean origin has been analyzed by gene mapping and DNA sequencing. Homozygotes have the hemoglobin Bart's hydrops fetalis syndrome, while compound heterozygotes for this defect and α+-thalassemia have hemoglobin H disease. It results from a deletion that removes 20.5 kilobases of DNA from within the α-globin gene cluser. Sequence data from the regions adjacent to the breakpoint indicate that the recombination event that caused this deletion occurred between the α1-gene and an unusual AluI sequence located between the embryonic ζ genes.