Phan Thị Xinh1,2, Ho Quoc Chuong3, Nguyen Thi Thanh Ha4, Huynh Duong Bich Tram5, Cao Van Dong2, Le Vu Ha Thanh2, Nguyen Thi Hong Hoa2, Huynh Nghia1,2, Nguyen Tan Binh2,6, Phu Chi Dung2, Hoang Anh Vu7. 1. Department of Hematology, Faculty of Medicine, University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City, Vietnam. 2. Ho Chi Minh City Blood Transfusion and Hematology Hospital, Ho Chi Minh City, Vietnam. 3. Center for Molecular Biomedicine, University of Medicine and Pharmacy at Ho Chi Minh City, 217 Hong Bang Street, District 5, Ho Chi Minh City, Vietnam. 4. Department of Molecular Biology, Dai Phuoc Clinic, Ho Chi Minh City, Vietnam. 5. Department of Hematology, Cho Ray Hospital, Ho Chi Minh City, Vietnam. 6. Department of Hematology, Pham Ngoc Thach University of Medicine, Ho Chi Minh City, Vietnam. 7. Center for Molecular Biomedicine, University of Medicine and Pharmacy at Ho Chi Minh City, 217 Hong Bang Street, District 5, Ho Chi Minh City, Vietnam. hoanganhvu@ump.edu.vn.
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.
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.