Enzymological diagnosis of primary hyperoxaluria type 1 by measurement of hepatic alanine: glyoxylate aminotransferase activity.

A deficiency of activity of the peroxisomal enzyme alanine:glyoxylate aminotransferase (AGT,EC 2.6.1.44)has been found in the livers of six patients with primary hyperoxaluria type 1 (PH), including three in whom the tissue was obtained by percutaneous needle biopsy. AGT activity, assayed in unfractionated liver tissue, ranged from 11 to 47% of the mean control value, and appeared to be related to the clinical severity of PH and to several biochemical variables which indicate the degree of pathophysiological derangement. There was no difference between patients and controls in the activities of glutamate: glyoxylate aminotransferase (GGT, EC 2.6.1.4) or catalase (EC 1.11.1.6). In the five most severe cases residual AGT activity could be largely accounted for by the crossover from another enzyme, presumably GGT. PH can be diagnosed using percutaneous hepatic needle biopsy and assay of AGT, whose activity may be useful in determining the prognosis and likely severity of the disease.