A Family With a Hemoglobin E Variant Including a Thai Immigrant Woman in Korea

Abstract

Dear Editor, A 33-yr-old Thai woman visited Wonkwang University Sanbon Hospital, Korea, with chief complaints of fatigue and dizziness. Peripheral blood smear examination revealed microcytic hypochromic anemia with target cells (Fig. 1). Routine laboratory analysis results were within normal limits (bilirubin, haptoglobin, reticulocyte, lactate dehydrogenase, iron, total iron binding capacity, ferritin, Coombs’ test) except for mild anemia and abnormal Hb electrophoresis (Table 1). Hepatosplenomegaly was absent. Hb electrophoresis was performed on an alkaline agarose gel using a Hydrasis 2 (Sebia, Lisses, France), which revealed markedly increased Hb A2 and Hb F fractions with a severely decreased Hb A1 fraction. Hb E, Hb C, and Hb O migrated at the Hb A2 position during alkaline Hb electrophoresis. To rule out hemoglobinopathy, Homo sapiens Hb β (HBB) (NM_ 000518.4) gene sequencing was performed. Genomic DNA was extracted from peripheral blood by using a QIAamp DNA mini kit (QIAgen, Hilden, Germany). Two primer sets were utilized that included all exons, splice sites, and adjacent intron regions of the HBB gene. DNA was amplified by using a DNA Engine Tetrad 2 Peltier Thermal Cycler (BIO-RAD, Hercules, CA, USA) and sequenced by using an ABI PRISM 3730XL analyzer (Applied Biosystems, Foster City, CA, USA). Sequencing data were analyzed by using Variant Reporter Software Version 1.1 (Applied Biosystems). The proband’s sequencing data revealed a homozygous c.79G>A; p.Glu27Lys (Hb E) variant. A family study revealed Hb E heterozygosity in the proband’s two children (Fig. 1).