Identification of HB Lepore-Mashington-Boston in Association with HB E [βB26(B8)GLU→LYS] in a Thai Female

Abstract

The proposita was a Thai female showing signs of a mild anemia (Hb: 11.4 g/dl; RBC: 4.91 × 10⁶/mm³; reticulocytes: 2.4%; MCV: 70 fl; MCHC: 23.3 g/dl). Hemoglobins were isolated by DEAE-cellulose chromatography in the following relative amounts: Hb E + Hb A₂ = 53%; Hb F₀ = 30.0%; Hb δβ-Lepore = 12.7%; Hb F₁ = 4.3%. The β^E and δβ-Lepore chains were isolated by CM-cellulose chromatography and were subjected to tryptic peptide mapping on paper in comparison to normal β^A chains. Amino acid analysis of selected peptides permitted unambiguous identification of the abnormal hemoglobins as Hb E [β26(B8)GluLys] and Hb Lepore-Washington-Boston, which has a δ chain sequence for residues 1-87, and a β chain sequence for residues 116-146. The presence of a Lepore hemoglobin was further confirmed by Pst I digestion of the proposita's DNA. The association of the two hemoglobin variants gave rise to elevated levels of Hb F.