Complex Interaction of Hb E [β26(B8)Glu→Lys], Hb Korle-Bu [β73(E17)Asp→Asn] and a Deletional α-thalassemia-1 in Pregnancy

Abstract

A pregnant Thai woman with mild hypochromic microcytic anemia caused by α- and β- globin defects is described. The proband was a 26-year-old pregnant woman discovered through our ongoing thalassemia screening program. Initial hemoglobin (Hb) high performance liquid chromatography (HPLC) analysis revealed a homozygosity for an unknown variant at the D window, inconsistent with results of family analyses. Further Hb analysis using automated capillary zone electrophoresis identified that the proband was in fact a compound heterozygote for Hb E [β26(B8)Glu→Lys, GAG>AAG] and another β chain variant. DNA analysis demonstrated that she carried the Hb Korle-Bu mutation [β73(E17)Asp→Asn (GAT>AAT)] in trans to the Hb E and an α-thalassemia-1 (α-thal-1) with the Southeast Asian (− −^SEA) deletion. Family studies identified that her father and sister were double heterozygotes for Hb Korle-Bu and α-thal-1, whereas her mother was a double heterozygote for Hb E/Hb Constant Spring [Hb CS; α142, Term→Gln (TAA>CAA in α2)]. The genotype-phenotype relationship observed in this Thai family with complex hemoglobinopathies and methods for characterization are presented.

Keywords:

• Hb E
• Hb Korle-Bu
• α-Thalassemia (α-thal)

ACKNOWLEDGMENTS

This study was supported by the Regional Health Centre 8, Nakornsawan, Ministry of Public Health, Khon Kaen University, and the Commission of Higher Education (CHE), Ministry of Education, Thailand.

Declaration of Interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.