Genetic aspects of the polymodally distributed sulphoxidation of S-carboxymethyl-L-cysteine in man.

Interindividual variation in the sulphoxidation of S-carboxymethyl-L-cysteine (750 mg p.o.) was investigated in 200 healthy volunteers. Nearly a 100-fold difference was observed between individuals with respect to the amount of sulphoxide metabolites detected in their 0-8 h urine (0.6 to 59.1% recovery). Such a difference was shown to be reproducible over several months in 40 subjects who spanned the entire range of capacities. Cumulative plots and maximum likelihood analysis of the distribution indicated that a bimodal model was most probable. Analysis of pedigree data obtained from 12 families suggested a genetic effect with overlying environmental influences.