Clinical Severity of β-Thalassemia Pediatric Patients in Myanmar.

β-Thalassemia (β-thal) is highly prevalent in Myanmar, but limited data are available on the molecular basis and the clinical manifestations in Myanmar patients. In this study, we investigated the clinical features and β-globin gene abnormalities in 15 homozygous β-thal and 60 Hb E (: c.79G>A)/β-thal pediatric patients who attended Yangon Children Hospital, the biggest thalassemia day care unit center in Myanmar. Eight different β-thal mutations were identified, with four accounting for 88.9% of alleles studied (excluding the Hb E variant). A genotype-phenotype correlation was found; all homozygous β-thalassemias had severe clinical courses, whereas the highly variable disease severity was demonstrated among Hb E/β-thal patients. Interactions of IVS-I-1 (G>T) (: c0.92+1G>T) β-thal with Hb E are associated with milder clinical symptoms. The number of mildly affected Hb E/β-thal patients was lower than expected, suggesting that there may be a considerable number of patients in the population who have either not been admitted to hospital or diagnosed with carrying the disease. Although the clinical severity in the Myanmar β-thal patients seems to be similar to that in other populations, the levels of hemoglobin (Hb) appears to be very low. These findings indicate the need for the improvement of patient management and the development of prevention and control programs for β-thal in Myanmar.