Prenatal diagnosis for Tay‐Sachs disease using chorionic villus sampling

Prenatal diagnosis for Tay-Sachs disease was performed on 25 patients using chorionic villus sampling (CVS). Nineteen were diagnosed as normal, and six were affected. Normal villus extracts had both hexosaminidase (hex) A and B activity, as determined by Cellogel and polyacrylamide gel electrophoresis, while extracts from affected fetuses had only hex B activity. Compared to cultured amniotic fluid cells or fibroblasts, villi contained less hex A. Hex A levels in fresh villi and cultured trophoblasts were roughly comparable.