Three types of primary hyperoxaluria (PH) are currently known, all based on enzymatic defects of glyoxylate metabolism in the liver (Alanine:glyoxylate aminotransferase, AGT, in PH I, glycolate reductase:hydroxypyruvate reductase, GRHPR, in PH II and Hydroxy-oxo-glutarate aldolase type 1, HOGA-1, in PH III) [1–3]. This evidence concerns the gene GRHPR and primary hyperoxaluria type 3.