An unusual case of hemoglobin Bart's hydrops fetalis.

A baby with alpha-chain thalassemia hydrops fetalis was born to an Iraqian Jewish couple of Iraqi-Kurdish extraction. Hemoglobin Bart's constituted only 40% of the total hemoglobin, much less than usually found in alpha-thalassemia hydrops fetalis. That this is a particular expression of hemoglobin H disease is considered. The likelihood of two alpha-chain loci, rather than one alpha-chain locus, in this family, is also discussed.