Hemoglobin E shows a substitution of lysine for glutamine at position 26 of the beta-chain.
Features of hemoglobin E trait:
(1) It causes microcytosis and hypochromia in the peripheral blood.
(2) The peripheral blood smear often shows target cells.
(3) The patient is typically not anemic or minimally anemic.
(4) Patients may show a mild increase in hemoglobin A2 (typically 2.8 to 3.8%).
(5) It is common in Southeast Asians.
(6) The patient typically does not show clinical evidence of anemia.
It is important to first test the patient for iron deficiency and to replace depleted iron stores before evaluating for hemoglobin E.
Hemoglobin E migrates with hemoglobin C, O Arab and A2 in alkaline (pH 8.4) electrophoresis on cellulose acetate.
Hemoglobin E migrates with hemoglobin A2 in acid electrophoresis.
Hemoglobin E can be separated from hemoglobin A2 in capillary electrophoresis.
