HBE1 encodes the epsilon globin chain, a beta-type hemoglobin subunit expressed during early mammalian embryonic development 1. This chain functions as part of embryonic hemoglobin, contributing to oxygen transport and binding 2. HBE1 expression is temporally regulated during fetal liver erythropoiesis, with increased expression in fetal liver-derived immortalized erythroid cells compared to cord blood cells, accompanied by downregulation of BCL11A and upregulation of LIN28B and IGF2BP1 2. Clinically, HBE1 variants are implicated in hemoglobinopathies. Deletions involving the HBE1 locus contribute to novel thalassemia categories; εγδβ-thalassemia (deletion of epsilon through beta-pseudogene loci) causes severe transient perinatal anemia, while εγ-thalassemia (deletion of epsilon through pseudobeta loci) presents with distinct phenotypes including increased HbA2 without microcytosis 3. Additionally, an HBE1 SNP (rs72872548) serves as a disease severity predictor in β0-thalassemia/HbE disease populations, demonstrating >85% specificity and 75% accuracy when combined with SNPs in BCL11A and HBS1L-MYB 4. HBE1 also shows signatures of positive selection in North African populations, suggesting adaptive significance in hemoglobin phenotypes 5.