Studies on the use of skin fibroblasts for the measurement of cystathionine synthase activity with respect to homocystinuria.

The levels of cystathionine synthase have been examined in cultured skin fibroblasts obtained from a patient suffering from pyridoxine-non-responsive homocystinuria and compared with the normal and heterozygous states. Levels of synthase activity were found to vary with time in culture and composition of culture media. The physical properties of normal and abnormal synthase activities were markedly different. It has been concluded that caution has to be exercised when using cell culture methods for the purpose of defining normal, heterozygous and homozygous states with reference to homocystinuria.