Hemoglobin Duarte: (α₂β₂^{62(E6)Ala→Pro}): A New Unstable Hemoglobin With Increased Oxygen Affinity

A patient with a normal blood hemoglobin level, but with evidence of brisk hemolysis, was found to have an unstable hemoglobin with a left-shifted oxygen dissociation curve. Two sisters of the patient had a history of hemolytic anemia. Both died of thromboembolic complications following splenectomy. Our patient was found to be heterozygous for a new β-chain mutation and β-thalassemia. All of the hemoglobin in his red cells was of the abnormal type, designated hemoglobin Duarte, and was shown to contain proline at the β62 (E6) position instead of alanine.