Homozygous hemoglobin E mimics beta-thalassemia minor without anemia or hemolysis: hematologic, functional, and biosynthetic studies of first North American cases.

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.