Occurrence of Defective Hexosephosphate Isomerization in Human Erythrocytes and Leukocytes

Abstract

Deficient activity of erythrocyte and leukocyte glucosephosphate isomerase was found in three siblings with hereditary hemolytic anemia who were unrelated to the single patient previously described. Anemia was more severe in these subjects but was ameliorated by splenectomy. Activities of glucose phosphate isomerase in proband red cells were 14 to 30 per cent of normal mean values despite brisk reticulocytosis, and leukocyte activities were as low as 5 per cent. Cells from both parents, both grandmothers and four siblings, all clinically unaffected, contained approximately half the usual isomerase levels. Enzyme inhibitors were not demonstrable, and glucosephosphate-isomerase reaction kinetics appeared normal. Starch-gel electrophoresis of proband hemolysates demonstrated distinct isozyme patterns unlike any previously noted, including those of the other deficient kindred. Genealogic patterns conformed with autosomal recessive transmission of the genetic defect.