Rare β Chain Hemoglobin Variants Found in Swedish Patients During HBA_1c Analysis

Abstract

Here we report the occurrence of five different β chain hemoglobin variants not previously described in Sweden. The variants were found during quantification of HbA1 using ion exchange high performance liquid chromatography (HPLC) or isoelectrofocusing. Samples were examined either at protein level by separation of globin chains on c₈ reversed phase HPLC, digestion with trypsin or lysylendopeptidase and separation of peptides by C₁₈ reversed phase HPLC, or at DNA level by direct nucleotide sequencing of double-stranded DNA fragments amplified from exon 1+2 of the β-globin gene. The variants were: Hb Raleigh [β1(NA1)Val→Ac-Ala], Hb J-Baltimore [β16(A13)Gly→Asp], Hb Tacoma [β30(812)Arg→Ser], Hb K-lbadan [β46(CD5)Gly→Glu], and Hb Fukuyama [β77(EFl)His→Tyr]. Hb Tacoma, Hb K-Ibadan, and Hb Fukuyama were slightly unstable in the isopropanol test, but no signs of hemolysis were found in the patients who all had normal hematological findings.