PH1 is caused by loss-of-function mutations in the AGXT gene (Danpure and Jennings 1986), encoding the PLP-dependent enzyme alanine:glycine aminotransferase (AGXT, EC 2.6.1.44) that catalyzes the transamination of glyoxylate and alanine to glycine and pyruvate in the hepatocyte peroxisome. Here, AGXT is linked to primary hyperoxaluria type 1.