The epidemiology of thalassaemia syndromes in Southeast Asia.

Thalassaemia syndromes are inherited haemoglobin disorders caused by mutations affecting α- and β-globin chains, ranging in severity from asymptomatic to transfusion-dependent. This Series paper synthesises epidemiological data across ten WHO Southeast Asia Region (SEAR) countries, combining local expertise with a rapid literature review. Due to the high prevalence of α- and β-thalassaemia variants, as well as haemoglobin E, the SEAR carries a disproportionately high burden and faces specific challenges. Although a small number of mutations tends to dominate in each country, the range of underlying mutations and deletions is complex. Beyond molecular studies, epidemiological data remain limited in most SEAR countries. Key challenges include blood supply shortages, consanguinity, gender-based disparities in healthcare access, population migration redistributing mutation profiles, and poor awareness. Recommendations to reduce the health burden of thalassaemia syndromes in the SEAR include setting up national registries, expanding premarital and prenatal screening, improving blood supply coordination, and promoting culturally sensitive education. Without targeted investments and policy commitment, most SEAR populations will remain unable to benefit from recent therapeutic advances, including emerging gene therapies.