The results of a study of ten members of an unusual family are presented; the mother and four children were found to have homozygous Hgb E disease, the father and three childrens either thalassemia-heterozygous Hgb E or thalassemia-homozygous Hgb E disease. It was impossible to make a definite diagnosis in one boy who might have had any one of the three conditions presented by the rest of the family.
It is not possible from the genetic, clinical and hematologic data to differentiate thalassemia-homozygous Hgb E from thalassemia-heterozygous Hgb E disease in the various members of the family.
The difficulty of differentiating mild thalassemia-heterozygous Hgb E from homozygous Hgb E is presented. Confusion arises in the overlapping of values obtained in the laboratory for the two conditions.
The presence of large numbers of target cells in the peripheral blood is a striking feature in the family. A consideration is made that the abnormality accompanying the Hgb E disease may be a hereditary defect in target cell production which may or may not be a variant of thalassemia.
Suggestive evidence is presented for a minimal hemolytic component in homozygous Hgb E disease manifested by a slightly shortened red cell survival time and a moderate increase in erythrocytic elements in the bone marrow.