Hb Tianshui (HBB: C.119A > G) in Compound Heterozygosity with Hb S (HBB: C.20A > T) from Odisha, India

Abstract

We describe here a rare β-globin gene variant, Hb Tianshui [β39(C5)Glu→Arg; HBB: c.119A > G], detected during routine screening in Odisha, India. This is the second report of Hb Tianshui and the first to describe the cation exchange high performance liquid chromatography (HPLC) and DNA studies of two cases of this variant. Both cases had coinherited Hb S (HBB: c.20A > T) but none presented with typical symptoms of sickle cell disease. One of the cases was heterozygous for a common α-thalassemia (α-thal) allele (−α^3.7) (rightward) (NG_000006.1: g.34164_37967del3804) and marginally raised Hb F percentage, while the other Hb S/Hb Tianshui case was completely benign and healthy. An atypical Asian Indian haplotype [+ − + − +] could be assigned to the Hb Tianshui variant. Hb Tianshui seems to mimic a few other Hb variants in cation exchange HPLC. However, we report two specific patterns in the chromatograms that are characteristic to Hb Tianshui. Combining an alkaline electrophoresis result with cation exchange HPLC at screening would be preferred to detect this rare variant, especially in regions with considerable frequency of Hb E [β26(B8)Glu→Lys; HBB: c.79G > A] or Hb S.

Keywords:

• Cation exchange high performance liquid chromatography
• direct HBB gene sequencing
• haplotype
• Hb Tianshui
• sickle cell disease

Acknowledgements

Thanks are due to Professor Sonamali Bag, Director, VIMSAR, Burla, Sambalpur, Odisha, India. The authors are indebted to late Dr. Dilip Kumar Patel, Ex-Associate Professor, Department of Medicine, Veer Surendra Sai Medical College, Burla, Sambalpur, Odisha, India, and Ex-Project Coordinator, Odisha Sickle Cell Project, NHM, District Headquarters Hospital, Deogarh, Odisha, India for his inestimable contribution in this study.

Declaration of interest

The study was performed under the Odisha Sickle Cell Project, funded by the National Heath Mission, Odisha, India. The authors acknowledge the support of the Director, Anthropological Survey of India, Ministry of Culture, Government of India for sanctioning the collaboration program (Vide letter No. 18-22/PMI/2011, dated June 15 2013). The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.