SUBTYPE DISTRIBUTION AND MUTATION SPECTRUM THALASSEMIA IN CHILDREN UNDER 10 YEARS IN NORTHERN VIETNAM

Background: Thalassemia is a common hereditary hemoglobin disorder in Vietnam. Elucidating the epidemiological and genetic patterns in children is essential for developing screening and prevention strategies. Methods: A retrospective analysis of 1,240 children under 10 years of age with Thalassemia treated at the National Institute of Hematology and Blood Transfusion in Vietnam, between 2014 and 2023. Results: The median age at treatment initiation was 1 year (range 0-9 years), with 94.5% of patients being the age 0-5 years. Children born after 2020 were diagnosed and treated earlier than those born before 2020 (0 year (range 0-2 years) vs 1 year (range 0-9 years); p < 0.0001), concurrent with the implementation of the national prenatal screening program. β-thalassemia and β-thalassemia/HbE accounted for nearly 90% of cases, with subtype distribution varying by ethnicity and region. β-thalassemia/HbE predominated in the Northwest and North Central regions, particularly among the Thai and Muong populations. In contrast, β-thalassemia was more prevalent in the Northeast, notably among the Tay and Nung populations. Eight α-globin and thirteen β-globin mutated types were detected. The common β-globin variants (Cd17, Cd41/42, Cd71/72, -28, and IVSI-1) and HbE (Cd26), mirror patterns reported in neighboring Laos and Guangxi Province, China. For α-globin genotypes, --SEA (49.83%), HbCS (31.53%), and -α3.7 (8.47%) were most frequent. Conclusion: Geography, ethnicity, and genetic background strongly shape Thalassemia epidemiology in Northern Vietnam. Targeted genetic counseling, early carrier screening, and region-focused community programs are urgently needed to reduce disease burden in high-risk populations.