Detection of phosphohexose isomerase deficiency in human fibroblast cultures

Summary Fibroblasts cultured from two patients afflicted with nonspherocytic hemolytic anemia due to phosphohexose isomerase (PHI) deficiency show on the average 53% of the normal PHI-activity. The presence of the defective enzyme in cells derived from the heterozygous relatives of the patients is revealed by an intermediate average specific activity; the wide range of PHI-activities observed in these cells, however, precludes the detection of heteozygotes. The PHI-genotypes of the patients and of their heterozygous and normal relatives respectively, can be distinguished by starch gel electrophoresis and by heat-inactivation studies with fibroblast-homogenates. These latter experiments confirm the results obtained with hemolysates (Tariverdian et al., 1970).D-Glucose-6-phosphate-ketol-isomerase, E.C.5.3.1.9.Supported by the Deutsche Forschungsgemeinschaft.Supported by the Stiftung Volkswagenwerk.