Complex interaction of Hb E [beta26(B8)Glu-->Lys], Hb Korle-Bu [beta73(E17)Asp-->Asn] and a deletional alpha-thalassemia-1 in pregnancy.

A pregnant Thai woman with mild hypochromic microcytic anemia caused by alpha- and beta- 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 [beta26(B8)Glu-->Lys, GAG>AAG] and another beta chain variant. DNA analysis demonstrated that she carried the Hb Korle-Bu mutation [beta73(E17)Asp-->Asn (GAT>AAT)] in trans to the Hb E and an alpha-thalassemia-1 (alpha-thal-1) with the Southeast Asian (- -(SEA)) deletion. Family studies identified that her father and sister were double heterozygotes for Hb Korle-Bu and alpha-thal-1, whereas her mother was a double heterozygote for Hb E/Hb Constant Spring [Hb CS; alpha142, Term-->Gln (TAA>CAA in alpha2)]. The genotype-phenotype relationship observed in this Thai family with complex hemoglobinopathies and methods for characterization are presented.