Compound Heterozygosity for Hb D-Ibadan (HBB: c.263C>A) and Hb C (HBB: c.19G>A)

Abstract

We report an individual with a compound heterozygosity for Hb D-Ibadan (HBB: c.263C>A) and Hb C (HBB: c.19G>A), a hemoglobin (Hb) combination not previously identified. The compound hemoglobinopathy was detected in a young woman during routine prenatal screening. Variant Hbs were identified and confirmed by high performance liquid chromatography (HPLC) and capillary electrophoresis (CE) followed by Sanger DNA sequencing. Hb D-Ibadan was present in significant excess over Hb C (70.3 to 24.4%). A complete blood count (CBC) revealed moderate microcytosis with slight anemia. The history suggests the Hb combination is clinically silent. The findings indicate the compound hemoglobinopathy demonstrates thalassemia minor-like red cell indices with an unequal distribution of the variant Hbs. Comparison with other Hb D-like heterozygous conditions is reviewed.

Keywords:

• Hb C
• Hb D-Ibadan
• hemoglobinopathy

Acknowledgements

The authors would like to thank Chris Dillman and the medical technologists in the hematology section of University Hospitals Cleveland Medical Center, Cleveland, OH, USA for performing the Hb screening assays. The authors would also like to thank the Mayo Clinic Reference Laboratory (Rochester, MN, USA) for performing the sequencing analysis and providing sequencing chromatograms.

Disclosure statement

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