Hb Waikato [α127(H10)Lys→Gln; HBA1: c.382A>C]: A Novel High Oxygen Affinity Variant

Abstract

We report the identification of a novel, high oxygen affinity hemoglobin (Hb) variant [α127(H10)Lys→Gln; HBA1: c.382A>C]. The variant was detected in an adolescent male (proband) of Syrian descent by cation exchange high performance liquid chromatography (HPLC), during Hb A_1c analysis. A complete blood count (CBC) showed elevated red blood cells (RBCs) (6.08 × 10¹²/L), Hb (16.1 g/dL) and packed cell volume (PCV) (0.48 L/L). Capillary electrophoresis (CE) revealed the variant was more negatively charged and represented 18.2% of total Hb. Isopropanol stability was normal. Cyanosis in the subject prompted investigation of oxygen affinity, with a reduced p50 of 20.8 mm Hg and a left shifted oxygen dissociation curve demonstrating increased oxygen affinity. We propose the novel variant be named Hb Waikato, which reflects the Hospital Laboratory where the variant was discovered and region where the proband was born and herein describe characterization.

Keywords:

• Capillary electrophoresis (CE)
• high oxygen affinity hemoglobin (Hb)
• novel α-globin variant

Disclosure statement

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

Acknowledgements

We wish to thank Associate Professor Nicholas Ling from Waikato University, Hamilton, New Zealand, for performing the oxygen dissociation studies. We also acknowledge the Biochemistry Department at Waikato Hospital, Hamilton, New Zealand, for undertaking Hb A_1c testing, blood gas analysis and providing technical assistance.