**1.3 Hemoglobin E**

HbE is abnormal hemoglobin resulted from the G-A substitution at codon 26 of β-globin gene. This missense mutation partially activates a cryptic splice site toward the 3′ end of exon 1, resulting in a proportion of abnormally splice mRNA. Thus, less β<sup>E</sup> globin is synthesized, leading to a mild thalassemia phenotype. HbE is becoming the common β-globin structure variant across the world as a result of migration and inter racial marriage [2, 10]. It has been realized to be the hallmark of Southeast Asian region. In Thailand, HbE is very common accounting for approximately 8–70% of population [11].
