a group of abnormal Hb's with normal α chains, but the non-α chains consist of the
N-terminal portion of the δ chain joined to the C-terminal portion of the β chain, apparently as the result of nonhomologous pairing and crossing over between the genes for β and δ chains. The major types are Hb Lepore
Boston (identical to Hb Lepore
Washington), Hb Lepore
Hollandia, and Hb Lepore
Baltimore, which differ in the region of crossing over (δ87-β116, δ22-β50, and δ50-β86, respectively). Heterozygotes form about 10% Hb Lepore, normal amounts of Hb A
2, and moderately increased amounts of Hb F and usually have mild anemia, microcytosis, and hypochromia; homozygotes form only Hb Lepore and Hb F and have severe anemia. Compare:
hemoglobin anti-Lepore.