Author: Mahzabin et al. Summary: The phenotypically diverse presentation of Hemoglobin E/β-thalassemia is often attributed to coinheritance of β-globin (HBB) gene mutations. This study described the phenotype and genetic basis of Hb E/β-thalassemia patients and its relation with clinical severity. A total of 32 Hb E/β-thalssemia patients were included in this cross-sectional study. Cases were confirmed by capillary hemoglobin electrophoresis or high-performance liquid chromatography and further analyzed with clinical information and ancestral data. Data collection period was May 2019 to July 2020. Gene sequencing was performed using Sanger’s sequencing method for mutational analysis, and Mahidol scoring was used to grade