Identification of β‐globin gene mutations in Thailand using an automated fluorescence‐based DNA sequencer

Abstract

Fluorescence-based DNA sequence analysis was developed for identification of beta-globin gene mutations in the Thai population. The beta-globin gene was directly sequenced in two runs and the sequencing electropherogram allowed unambiguous detection of nucleotide substitutions, frameshifts, and small insertions/deletions in heterozygote and homozygote. The method was validated and successfully applied in routine analysis of 416 individuals with beta-thalassemia disease, beta-thalassemia/hemoglobin (Hb) E and Hb variants. Twenty-five different beta-globin gene mutations were identified. Two Hb variants, Hb Tacoma [codon 30 (G-T)] and Hb Tende [codon 124 (C-T)], were also identified for the first time in a Thai population. Automated fluorescence-based DNA sequence analysis provides a rapid and reliable method for identification of common, rare and unknown beta-globin gene mutations, which is essential for prevention and control of thalassemia and hemoglobinopathy in Thailand.

Molecular basis and hematological features of hemoglobin variants in Southern Thailand

“…As there is a high prevalence of Hb C in the southern Thai population, nearly 50% of it was found in the samples in spite of very few cases being found in other parts of Thailand [16,32]. This finding also suggests that the history of population admixture may have contributed to the present distribution pattern of the variants.…”

“…Another 7 variants, Hb C, Hb D-Punjab, Hb G-Makassar, Hb Q-Thailand, Hb Lepore-Hollandia, and Hb Hope, have been reported in all parts of Thailand [14,16,[27][28][29][30][31], but due to difference in race and ethnicity, the prevalence differs (data were shown in Table 4). As there is a high prevalence of Hb C in the southern Thai population, nearly 50% of it was found in the samples in spite of very few cases being found in other parts of Thailand [16,32].…”

“…However, many uncommon hemoglobin variants have been found. The spectrum and prevalence of hemoglobin variants in each region is different and depends on ethnic group and geographical location, including each part of Thailand [10][11][12][13][14][15][16][17][18]. This study aimed to investigate the prevalence of hemoglobinopathy in southern Thailand using DNA sequencing and study the severity of each hemoglobin variant.…”

Unstable abnormal hemoglobins found in Russia in the past 10 years

“…Выявленные нами формы НГ описаны у пациентов различных национальностей. Так, например, Hb Tacoma был обнаружен в североевропейских семьях, в Африке и Японии [3][4][5][6]. Клинические признаки у выявленных нами пациентов русской национальности аналогичны ранее описанным и характеризуются гипохромной микроцитарной анемией I-II степени, как правило, не требующей проведения заместительной терапии.…”