Hb Tarrant [α126(H9)Asp→Asn; HBA2: c.379G > A (or HBA1)] in a Chinese Family as a Cause of Familial Erythrocytosis

Abstract

Hb Tarrant [α126(H9)Asp→Asn; HBA2: c.379G > A (or HBA1)], is a rare high oxygen affinity hemoglobin (Hb) variant that causes erythrocytosis, previously described in a few Mexican–American families. Here we report the first Chinese family with this Hb variant presenting with unexplained familial erythrocytosis. No evidence of hemolysis was seen. A locally adapted approach to the diagnostic process in clinical laboratories is discussed. Molecular analysis has an important role in confirmation of the diagnosis. Proper identification of this rare but clinically significant Hb variant is helpful for family counseling and will help to guide appropriate management of absolute erythrocytosis.

Keywords:

• Chinese
• erythrocytosis
• Hb Tarrant
• high oxygen affinity hemoglobin (Hb)

Acknowledgements

The authors thank the staff at the hematology laboratories of the Prince of Wales Hospital, The Chinese University of Hong Kong and The University of Hong Kong, Hong Kong SAR, People’s Republic of China, for their support. The authors are also grateful to the proband and her family for their contribution to this study.

Declaration of interest

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