Up to the present time, three distinct hereditary enzymatic deficiencies have been linked to PH, to be precise, PH type 1 (PH1) which results from mutations in peroxisomal enzyme alanine: glyoxylate aminotransferase (AGT; the AGXT gene product) [2, 12, 13], type 2 (PH2) which results from mutations in glyoxylate reductase (GR; the GRHPR gene product), and type 3 (PH3) which results from inactivating mutations in 4-hydroxy-2-oxoglutarate aldolase (HOGA; the HOGA1 gene product) [7]. This evidence concerns the gene AGXT and primary hyperoxaluria type 1.