RT Journal Article SR Electronic T1 Variability of acid hydrolase activities in cultured skin fibroblasts and amniotic fluid cells. JF Journal of Medical Genetics JO J Med Genet FD BMJ Publishing Group Ltd SP 224 OP 229 DO 10.1136/jmg.12.3.224 VO 12 IS 3 A1 Young, E A1 Willcox, P A1 Whitfield, A E A1 Patrick, A D YR 1975 UL http://jmg.bmj.com/content/12/3/224.abstract AB The specific activities of lysosomal hydrolases in cultured skin fibroblasts and amniotic fluid cells showed wide and unpredictable variations between cultures, which may lead to difficulty in differentiating normal, heterozygous, and homozygous cells. However, the variability for a given culture was similar for all enzymes assayed, so that a clearer differentiation of a relative deficiency of a given enzyme could be obtained by expressing its activity in ratio to that of another enzyme. Activity ratios were particularly useful in the evaluation of enzyme levels in cultured amniotic fluid cells. Results of their application to tests of pregnancies at risk for metachromatic leucodystrophy, Krabbe's leucodystrophy, GM1-gangliosidosis, and GM2-gangliosidosis (Sandhoff variant) are presented.