Variation of lysosomal enzyme activity with gestational age in chorionic villi

The activities of 14 lysosomal enzymes in chorionic villi at gestational ages of 6-12 weeks were assayed. Arylsulphatases A and B, alpha-glucosidase and beta-glucuronidase activities increased with advancing gestational age. When compared with the activity in cultured amniotic fluid cells, arylsulphatase A, beta-galactosidase, alpha-glucosidase, heparan N-sulphatase, alpha-L-iduronidase, alpha-mannosidase, neuraminidase, and sphingomyelinase showed significant differences. All except beta-glucuronidase showed lower activity in chorionic villi than in cultured amniotic fluid cells. Prenatal diagnosis using chorionic villi was possible except for alpha-L-iduronidase. Storage at -20 degrees C up to 42 days did not significantly affect activity. The results emphasize the importance of using fresh or frozen age-matched control tissue for diagnosis.