Hb H Disease Caused by Multiple Mutations in the Polyadenylation Signal Site and − −^SEA/αα

Abstract

Thalassemia is the most common monogenic disease, with the highest incidence in Guangxi Zhuang Autonomous Region, People’s Republic of China (PRC). The blood test result was not consistent with α-globin gene testing in one of the patients during daily screening. It was confirmed that there were multiple mutations at the α2-globin gene polyadenylation (polyA) signal site: HBA2: c.*64(T>C), HBA2: c.*68(A>C), HBA2: c.*71(G>A), HBA2: c.*74(C>A), HBA2: c.*82(G>A), HBA2: c.*92(A>G) and HBA2: c.*98(T>C) and compound − −^SEA/αα by sequencing of the HBA1 and HBA2 genes of the proband and core family members. After that, we found a further two cases of unrelated patients with this type of mutation. The mutation is not an accidental phenomenon, and likely to occur with a considerable incidence in Guangxi Zhuang Autonomous Region, PRC. We analyzed the hematological manifestations of this type of thalassemia and showed that it was a Hb H (β4) disease caused by rare mutations. We suggest that it is essential to pay attention to this mutation during future clinical diagnoses and genetic counseling of patients.

Keywords:

• α-Thalassemia (α-thal)
• Hb H disease
• multiple mutations
• polyadenylation (poly A) signal site

Acknowledgments

We thank Dr Dev Sooranna, Imperial College London, London, UK, for editing the manuscript.

Disclosure statement

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

Additional information

Funding

This study was funded by the Guangxi Science and Technology Department [Gui 14124004-1 and Gui 1598012-21], the Health Department of Guangxi Province [Z2014146] and the Natural Science Foundation of China [81260093].