Abstract

Cystathionine synthase activity was studied in skin fibroblasts from a mother with homocystinuria and her husband and newborn baby. Enzyme studies were also undertaken on a fibroblast cell line derived from amniotic fluid taken at 16 weeks' gestation. The enzyme activity was very low in the mother, within the normal range in the father, and at an intermediate level consistent with heterozygosity in the infant. The activity present in the amnion fibroblasts was similar to that found in the cell line cultured from the infant's skin biopsy.