Molecular Spectrum of β-Thalassemia Mutations in Central to Eastern Thailand

Genetic Background Studies of Eight Common Beta Thalassemia Mutations in Thailand Using β-Globin Gene Haplotype and Phylogenetic Analysis

“…In Thailand, more than 30 β-thalassemia mutations have been reported (ranging from 3% to 9% depending on the region) [ 2 , 4 , 5 ]. In this study, we focused on eight common β-thalassemia mutations and sought to demonstrate their genetic background in Thailand.…”

“…Four intragenic β-globin gene polymorphisms, including codon 2 (C/T), IVS II-16 (C/G), IVS II-74 (G/T) and IVS II-81 (C/T), were genotyped using direct DNA sequencing on an ABI PRISM™ 3130 XLanalyzer (Applied Biosystems, Foster City, CA, USA), as described elsewhere [ 5 ]. Only samples with the codon 41/42 (-TTCT) mutation (four polymorphisms) were genotyped, with multiplexing targeted sequencing, using a barcode and a next-generation sequencing platform.…”

“…There is a high frequency of the β-thalassemia carrier in each region of Thailand (between 3% and 9%). However, it has been reported that eight common β-thalassemia mutations in Thailand (including codon 41/42 (-TTCT), codon 17 (A > T), NT-28 (A > G), IVS II-654 (C > T), codon 19 (A > G), codon 26; HbE (G > A), IVS I-1 (G > C) and IVS I-5 (G > C)) represent more than 85% of the total β-thalassemia mutations [ 3 , 4 , 5 ]. Several previous studies have reported the genetic relationship between populations, chromosome background of the gene and linkage analysis, as well as differences in clinical phenotypic expression using haplotype and phylogenetic analyses [ 6 , 7 , 8 ].…”

Rapid molecular diagnostics of large deletional β0-thalassemia (3.5 kb and 45 kb) using colorimetric LAMP in various thalassemia genotypes

“…In Southeast Asia and Thailand, severe β-thalassemia disease is associated with homozygous β 0 -thalassemia or compound heterozygous β 0 -thalassemia/Hb E [ 7 , 18 ]. Two large deletional β 0 -thalassemia events, including a 3.5-kb deletion and a 45-kb deletion, are prevalent in Thailand, especially in the southern part of the country [ 2 , 3 ]. These deletions are targeted to prevention and control in a fetus at risk of severe disease [ 2 ].…”

“…Most mutations occur by point mutations, and some nucleotide deletions or insertions lead to frameshift mutations. However, large deletions are usually documented in the Thai population, especially in southern Thailand, where the heterogeneity of β-thalassemia mutations is greater than in other parts of the country [ 2 , 3 ]. The frequency of the β-thalassemia trait throughout the country is approximately 3–9% [ 4 , 5 ].…”