Clinical and molecular genetic features of Hb H and AE Bart's diseases in central Thai children.

Background: α-Thalassemia, one of the major thalassemia types in Thailand, is caused by either deletion or non-deletional mutation of one or both α-globin genes. Inactivation of three α-globin genes causes hemoglobin H (Hb H) disease, and the combination of Hb H disease with heterozygous hemoglobin E (Hb E) results in AE Bart's disease.

Objective: This study aimed to characterize the clinical and hematological manifestations of 76 pediatric patients with Hb H and AE Bart's diseases treated at Phramongkutklao Hospital, a tertiary care center for thalassemia patients in central Thailand.

Patients and methods: Seventy-six unrelated pediatric patients, 58 patients with Hb H disease and 18 patients with AE Bart's disease, were enrolled in this study. Their clinical presentations, transfusion requirement, laboratory findings, and mutation analysis were retrospectively reviewed and analyzed.

Results: A total of 76 pediatric patients with Hb H and AE Bart's diseases who mainly lived in central Thailand were included in this study. The clinical severities of patients with non-deletional mutations were more severe than those with deletional mutations. Eighty-six percent of patients with non-deletional AE Bart's disease required more blood transfusion compared to 12.5% of patients with deletional AE Bart's disease. Non-deletional AE Bart's disease also had a history of urgent blood transfusion with the average of 6±0.9 times compared to 1±0.3 times in patients with deletional Hb H disease. The difference was statistically significant.

Conclusion: This study revealed the differences in clinical spectrum between patients with Hb H disease and those with AE Bart's disease in central Thailand. The differentiation of α-thalassemia is essential for appropriate management of patients. The molecular diagnosis is useful for diagnostic confirmation and genotype-phenotype correlation.