Homozygous Delta-Thalassemia First Discovered in Japanese Family With Hereditary Persistence of Fetal Hemoglobin

A family with δ-thalassemia has been discovered, in which five members are thought to be δ-thalassemia homozygotes with complete deficiency of Hb A₂, and three members are probably heterozygotes with low levels of Hb A₂ (1.2-1.6%). In four members among these, persistence of fetal hemoglobin of Swiss type was observed. The formal genetics of these two entities was discussed. The proposita showed first thalassemia-like stigmata with iron deficiency anemia, but after iron therapy administered over 2 months, the stigmata disappeared. All the other members of the family were free from clinical symptoms with normal morphology, MCH, and osmotic fragility of the red cells.