[1st instance of the absence of an erythrocyte membrane protein (band 4(1)) in a case of familial elliptocytic anemia].

In four members of a family presenting hereditary elliptocytosis erythrocytes were studied, membranes were extracted and proteins were analysed by gel electrophoresis in a polyacrylamide gradient. In one of the patients suffering from severe haemolytic anaemia successfully treated by splenectomy, an almost complete deficiency in band 4(1) was discovered. Endogenous protein kinase activities revealed the absence of radioactivity of band 4(1) in the proband, a result not modified by cAMP. The kinase activity was normal in the parents, which confirms the almost complete absence of protein 4(1) seen in the stained gel of the proband. A moderate increase in the phosphorylation of band 3 was observed in all the members of this family. Deformability was measured by a visco-diffractometric method (Ektacytometry) in a medium of low viscosity (11 cp at 22 degrees C), allowing the recording of curves characteristic of elliptocytosis and revealing a markedly reduced deformability index (DI). At low shear stress, elliptocytes were oriented perpendicular to the flow (a result common to all elliptocytosis). In the proband several years after splenectomy, the DI was extremely reduced at high shear stress, which can be explained by the simultaneous presence of elliptocytes, schizocytes and spherocytes. A more detailed comparative study of the proteins of the various members of the family could lead to more precise information on the possible role of band 4(1) as a linkage protein maintaining the erythrocyte membrane stability.