Rare hemoglobin variant Hb yaizu observed in Turkey

ABSTRACT

To determine the characteristic features of the rare hemoglobin [Hb] variant Hb Yaizu to enable laboratory diagnosis of the hemoglobin variants during screening programs. Genomic DNA was obtained from the 4 members of a family living in Denizli province, an Aegean region of Turkey. Blood cell counts, hemoglobin composition, hemoglobin electrophoresis [both alkaline and acid], HPLC analysis, DNA sequencing and beta globin gene cluster haplotypes were done. Hb Yaizu carriers were apparently healthy individuals. Hb Yaizu was slightly faster than Hb S at alkaline pH, but slower than Hb S at acidic pH in hemoglobin electrophoresis. An abnormal hemoglobin peak was observed with a retention time of 4.77 mm in HPLC analysis attributed to Hb Yaizu. Two members of the family were heterozygous Hb Yaizu [beta 79 [EF3] Asp>Asn] confirmed by DNA sequencing. The mutation was found to be linked with the Mediterranean haplotype I [+----++]. We have presented the details of Hb Yaizu, a rare hemoglobin variant that may be important to hemoglobinopathy screening programs, although its clinical significance is unclear