Ultramicro assays of enzymes for rapid and inexpensive diagnosis of inherited disorders of metabolism

This article summarizes simple ultramicro assays for enzyme activities in cultured human fibroblasts and their application to rapid diagnosis of inherited disorders of metabolism. This technique reduces the time and cost of culturing sufficient fibroblasts, and biochemical reagents. The methods are simple, requiring little equipment other than a lyophilizer, a constant temperature and humidity room, a fluorimeter and liquid scintillation counter. More than 35 disorders have been so diagnosed. The techniques are particularly valuable for rapid prenatal diagnosis with cultured amniotic fluid cells.