Usefulness of HbA2 for Screening of δ-chain Variant Hemoglobin, Hb A2-Niigata [δ1Val→Ala]

Abstract

We reported several cases of Hb A2-Niigata [δ1Val→Ala] with δ-chain variant hemoglobin (Hb) with falsely high HbA1c levels. HbA2 (α2δ2) is estimated to be low in heterozygous mutations of δ-chain variant hemoglobin, but no reports have described the measurement of HbA2 in Hb A2-Niigata. In this study, we measured HbA2 in five patients with Hb A2-Niigata via cellulose acetate electrophoresis (CAE) and high-performance liquid chromatography (HPLC). Although the HbA2 levels measured by CAE in all patients with Hb A2-Niigata were within the reference range, those measured by HPLC (HA-8180T) were <2.2 % of the lower limit of the reference range in all patients. We demonstrated for the first time that the HbA2 levels in patients with Hb A2-Niigata were low. HbA2 measured by HA-8180T is useful for screening δ-chain variant hemoglobin, Hb A2-Niigata.