Intrauterine Diagnosis

The specific activities of three disease-related lysosomal enzymes were compared in cultured skin fibroblasts from seven normal women (M), their fetuses (F), and cells cultured from corresponding amniotic fluid cells (A). All samples were obtained in weeks 17–21 of pregnancy. Highly significant differences in the mean specific activities of β-galactosidase (β-Gal), β-D-N-acetylglucosaminidase (Hex), and arylsulfatase A (ARA) are evident in control cells developed from each of these sources. In addition, the pattern of differences in the three cell types was dissimilar for each enzyme. The mean activities in nanomoles of product produced per hour per milligram of soluble cell protein were: β-Gal: F = 248, A = 676, M = 375; Hex: F = 3412, A = 6548, M = 6781; and ARA: F = 143, A = 244, M = 458. The differences in enzyme specific activities between the three cell types studied indicated significant differences in the enzymology of these cells under defined culture conditions. In light of these findings the prerequisites necessary for antenatal diagnosis of inherited metabolic disorders are recommended.