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Thalassemia‐like abnormalities of the red cell membrane in hemoglobin E trait and disease
Author(s) -
Dorléac E.,
Morlé L.,
Gentilhomme O.,
Jaccoud P.,
Baudonnet C.,
Delaunay J.
Publication year - 1984
Publication title -
american journal of hematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.456
H-Index - 105
eISSN - 1096-8652
pISSN - 0361-8609
DOI - 10.1002/ajh.2830160302
Subject(s) - thalassemia , heterozygote advantage , hemoglobinopathy , red cell , hemoglobin e , sickle cell trait , hemoglobin , red blood cell , population , biology , compound heterozygosity , microbiology and biotechnology , chemistry , biochemistry , hemolytic anemia , genetics , medicine , phenotype , gene , immunology , allele , disease , environmental health
In recent studies, we observed a decrease of K Mapp , an abnormally biphasic kinetics of the red cell membrane neutral phosphatase and an increased binding of hemoglobin to the membrane in various forms of β‐thalassemia. Since the gene encoding the β chain (β E chain) of hemoglobin E (HbE) is endowed with some thalassemic characteristics, we studied the erythrocyte membrane in 25 individuals with Hb E trait or disease. The apparent Michaelis‐Menten constant for p‐nitrophenylphosphate (the artificial substrate used) was significantly decreased, as in β‐thalassemia. However, the kinetics was monophasic in all the heterozygotes and in four of the homozygotes. It was biphasic only in the three other homozygotes. V max was also significantly reduced, a fact that is masked, when not reversed in β‐thalassemia, owing to the rejuvenation of the red cell population. In 5 mM phosphate buffer (pH 8.00), the binding of Hb E to the erythrocyte ghosts was increased in the homozygotes. In the heterozygotes, Hb A binding was also increased, as is the case in β‐thalassemia. This latter fact suggests that the membrane binding site(s) of hemoglobin is (are) altered. We found a highly significant increase of Hb F in EE subjects. The present study extends to the red cell membrane the β‐thalassemic phenotype associated with the β E gene.