Molecular analysis of β‐thalassemia in South Vietnam

• Published in: American journal of hematology 2002-10, Vol.71 (2), p.85-88
• Main Authors: Svasti, M.L. Saovaros, Hieu, Tran Minh, Munkongdee, Thongperm, Winichagoon, Pranee, Van Be, Tran, Van Binh, Tran, Fucharoen, Suthat
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Anemias. Hemoglobinopathies; beta-Thalassemia - epidemiology; beta-Thalassemia - genetics; Biological and medical sciences; Child; Child, Preschool; Diseases of red blood cells; DNA Mutational Analysis; Family Health; Frameshift Mutation; Gene Frequency; Genetic Linkage; Globins - genetics; haplotype analysis; Haplotypes; Hematologic and hematopoietic diseases; Humans; Infant; Medical sciences; molecular basis; Mutation; South Vietnam; thalassemia; Tropical medicine; Vietnam - epidemiology
• ISSN: 0361-8609; 1096-8652
• DOI: 10.1002/ajh.10193

In Vietnam, the carrier rate for β‐thalassemia varies from 1.5% to 25% depending on the ethnic groups of the population. The molecular basis of β‐thalassemia in South Vietnam was studied in 50 unrelated β‐thalassemia patients. Of these, 31 had β‐thalassemia/Hb E, 18 were homozygous for β‐thalassemia, and 1 carried the β‐thalassemia trait. The majority of the patients were Kinh, four were Chinese, and two were Kinh–Chinese. All had severe anemia and received blood transfusions regularly, every 1–3 months. Hepatosplenomegaly was found in all patients, and splenectomy had been done in six patients. Normal α‐globin genotype (αα/αα) was found in all subjects. Reverse dot‐blot hybridization using oligonucleotide probes specific for Southeast Asian mutations can detect β‐thalassemia in 60 chromosomes in addition to 31 chromosomes with βE mutation. Excluding the βE gene, six previously reported Thai and Chinese β‐thalassemia mutations were found, including codons 41/42 (−TCTT) 35.3%, codon 17 (A→T) 25.0%, −28 (A→G) 7.3%, codons 71/72 (+A) 7.3%, IVS‐II nt 654 (C→T) 7.3%, and IVS‐I nt 1 (G→T) 6.0%. The Vietnamese frameshift mutation at codon 95 (+A) was detected by ARMS in seven chromosomes (10.3%). DNA polymorphism of the β‐globin gene cluster carrying the codon 95 mutation was − + − − − − − + for Gγ/XmnI, ϵ/HincII, Gγ/HindIII, Aγ/HindIII, ψβ/HincII, 3′ ψβ/HincII, β/AvaII, and 3′β/BamHI, respectively. The remaining mutation detected by the gap PCR was a large deletion known as the Chinese Gγ(Aγδβ)0‐thalassemia. The two most common mutations were the frameshift at codons 41/42 (−TCTT) and the nonsense mutation in codon 17 (A→T). Thus β‐thalassemia mutations in South Vietnam is similar to the previous report from the North, although at different frequencies. This result will help to establish a center for prenatal diagnosis and for prevention and control of thalassemia in Vietnam. Am. J. Hematol. 71:85–88, 2002. © 2002 Wiley‐Liss, Inc.