Detection of phosphohexose isomerase deficiency in human fibroblast cultures
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).