Fig. 1.

Metabolic pathway for 4-hydroxyproline showing the enzymatic block in primary hyperoxaluria type 3 and the proposed metabolic re-routing mechanism. Enzymes are as follows: 1 aspartate aminotransferase, 2 4-hydroxy-2-oxo-glutarate aldolase, 3 unidentified aldolase, 4 lactate dehydrogenase. Principal PH3 urine metabolites that exit the cell are underlined