Homozygous hemoglobin E mimics β‐thalassemia minor without anemia or hemolysis: Hematologic, functional, and biosynthetic studies of first north American cases

Abstract

A young American woman of Thai ancestry living in Ohio and a man of Vietnamese origin living in Iowa are believed to be the first recognized hemoglobin E homozygotes residing in the western hemisphere. Both were clinically well and exhibited neither pallor nor icterus nor splenomegaly. Their blood exhibited marked microcytosis and mild erythrocytosis. Hemoglobin was 99% E and 1% F, 97% E and 3% F, respectively. These features were similar to those previously reported from Southeast Asia and Madagascar in the few well-documented reports of homozygous hemoglobin E. A 51Cr erythrocyte survival study indicated a normal t1/2 of 28 days. Also demonstrated were minimal decrease in whole blood O2 affinity and increased ratio of alpha/non-alpha globin chain synthesis. Mild hemolytic anemia is not, as usually stated, a feature of this condition, which closely mimics a very mild thalassemia minor. Anemia, when found with high proportions of hemoglobin E, should not be attributed to the homozygous hemoglobinopathy. Persons with homozygous hemoglobin E should be reassured as to its benign implications.

Impairment of the Growth of Plasmodium Falciparum in HbEE Erythrocytes

“…corpuscular volume) but have a normal mean cellular concentration of Hb. As expected from these observations, the mean corpuscular hemoglobin (the total amount of Hb per cell) is low (7). Because the carriers of this genetic condition are not anemic and no hemolysis has been detected in the absence of other diseases, the number of erythrocytes is elevated.…”

Adaptation to anemia in hemoglobin E-β thalassemia

“…[12][13][14] In a single case of HbE ␤ thalassemia, the P 50 was remarkably elevated although the level of HbF in this patient, approximately 2%, was unusually low. 14 The present study shows that, overall, patients with HbE ␤ thalassemia are able to adapt to anemia by reducing the oxygen affinity of their red cells.…”

Hematologic genetic disorders among Southeast Asian refugees

“…The three adult women with homozygous HbE had blood hemoglobin concentrations of 11.4, 11.7, and 13.4 gm/ dl, MCVs of 59-67 fl, and HbE range 96-99%. The criteria used to diagnose and the results obtained in the homozygous E cases are very like those previously described [15]. Very minimal anemia (hemoglobin concentration 11-12 gm/dl) may occur in women homozygous for HbE without other demonstrable cause.…”