Primary hyperoxaluria is caused by defective metabolism of:

In nonketotic hyperglycinemia, a rare inborn error of glycine degradation presently known only in Finland, glycine accumulates in all body tissues including the central nervous system. The defect in primary hyperoxaluria is the failure to catabolize glyoxylate formed by the deamination of glycine. Subsequent oxidation of glyoxylate to oxalate results in urolithiasis, nephrocalcinosis, and early moality from renal failure or hypeension. Glycinuria results from a defect in renal tubular reabsorption. Ref: Harper 28th edition, chapter 29.