Interactions of hemoglobin Lepore (deltabeta hybrid hemoglobin) with various hemoglobinopathies: A molecular and hematological characteristics and differential diagnosis

Abstract

Hemoglobin (Hb) Lepore is a variant consisting of two alpha-globin and two deltabeta-globin chains. In heterozygote, it is associated with clinical findings of thalassemia minor but interactions with other hemoglobinopathies can lead to various clinical phenotypes. Using a combination of Hb-HPLC, Hb-capillary electrophoresis and DNA analyses, we have identified 14 patients with Hb Lepore-Hollandia including eight heterozygotes, two double heterozygotes with alpha(+)-thalassemia, two compound heterozygotes with Hb E (initially diagnosed as Hb E-beta-thalassemia) and two previously undescribed conditions of double heterozygote for Hb Lepore/Hb Constant Spring and Hb Lepore/alpha(0)-thalassemia, both associated with higher levels of Hb F and lower levels of Hb Lepore. Hematological and molecular features of these patients are presented along with those observed in four other Thai individuals encountered with heterozygous Hb Lepore-Washington-Boston. Haplotype analysis of the beta-globin gene cluster showed that all Hb Lepore-Hollandia genes were associated with a single haplotype not described previously in other populations, (- + - + + - +) whereas the four Hb Lepore-Washington-Boston genes were associated with haplotypes (+ - - - - + -/+) (N=1) and (+ - - - - - +) (N=3), data indicating multiple origins of these two variants. Hb Lepore may not be uncommon in the Thai and other Asian populations and both hematological and molecular studies are required for accurate diagnosis. To facilitate rapid epidemiological, diagnostic screening and differentiation of the two Hb Lepore defects, a simple assay based on multiplex PCR has been developed.