Hereditary hemolytic anemia associated with glucosephosphate isomerase (GPI) deficiency--a new enzyme defect of human erythrocytes.

I N RECENT YEARS, specffic inborn erythrocyte enzyme deficiencies have l)een implicated in the etiology of certain hereditary hemolytic anemias not characterized by spherocytosis. This report defines still another instance in which hereditary hemolytic anemia has been found to be associated with a deficiency in a specific glycolytic enzyme. The propositus has had a hemolytic syndrome present since birth. Erythrocytes and leukocytes both exhibit subnormal activity of the enzyme glucosephosphate isomerase ( D-glucose-6phosphate ketol-isomerase, EC 5.3.1.9). The hematologic, biochemical, and genetic studies of the patient and his family constitute the basis of this report.