Hb D-Los Angeles [beta121(GH4)Glu>Gln] and Hb Beograd [beta121(GH4)Glu>Val]: Implications for their laboratory diagnosis and genetic origins.

OBJECTIVE The aim of this study was to determine the laboratory diagnosis and genetic origins of the hemoglobin (Hb) variants, Hb D-Los Angeles and Hb Beograd observed frequently in our region. MATERIAL AND METHODS Hb variants were investigated in one Hb D-Los Angeles and two Hb Beograd families. These families were unrelated with each other. For the determination of Hb variants, alkaline/acid electrophoresis, HPLC, DE-52 micro-column chromatography procedures were applied. Mutations were determined by non-radioactive fluorescence automated DNA sequencing. Beta globin gene cluster haplotypes were identified by RFLP analysis at seven loci known as ε-Hinc II, Gγ-Hind III, AΨβ-Hind III, 5'Ψβ-Hinc II, 3'Ψβ-Hinc II, β-Ava II ve 3'β-Hinf I. RESULTS Three novel beta globin gene cluster haplotypes were identified as in relation with Hb D-Los Angeles [--+-+++], Hb Beograd [+----++ and -+-(+/-)(+/-)+(+/-)]. These haplotypes were reported for the first time in the world population Conclusion: In this study we emphasize the importance of DNA seqeuncing and other laboratory procedures for the identification of Hb variants in premarital diagnosis. On the other hand we discuss also the genetic origins of these Hb variants.