Excessive urinary glycine excretion was found in four members of a family and was
associated in three members with nephrolithiasis. The glycinuria was due to a renal
mechanism. Failure to reabsorb glycine was not associated with defective reabsorption of
other amino acids or of phosphate or glucose. A kidney stone obtained from one of these
patients was composed mainly of calcium oxalate and contained a small amount of glycine
present in non-protein, non-peptide form.