Spectrum of HBB gene mutations among 696 β-thalassemia patients and carriers in Southern Vietnam

Abstract

Background: Thalassemias are common inherited blood disorders that have been extensively studied in Asia. Thus far, data on mutations of the HBB gene in Vietnamese patients with β-thalassemia are limited to small studies.

Methods: We recruited 696 β-thalassemia patients and carriers in southern Vietnam and analyzed for the HBB gene mutations using Sanger sequencing technology.

Results: We documented 27 types of known mutations and 10 types of novel variants on 737 alleles out of 1392 surveyed alleles. The three most common mutations, which account for more than ¾ of all mutant alleles, were c.79G > A (HbE), c.124_127delTTCT, and c.52A > T. The novel variants were mainly located in 5' untranslated region (c.-92delC and c.-67A > G) and 3' untranslated region (c.*4C > T, c.*116_*117insA, c.*142 T > C, c.*156G > C, c.*176_*177insA, and c.*247 T > C), except for one in intron 2 (c.316-99 T > G) and one in exon 3 (c.385delG).

Conclusion: We provide here a comprehensive mutation spectrum of the HBB gene in Southern Vietnam, which is crucial for carrier screening and prenatal diagnosis in the future.

Keywords: HBB; Sequencing; Vietnamese; β–thalassemia.