PH type 1 (PH1, MIM 259900) is caused by loss-of-function mutations of the alanine–glyoxylate aminotransferase (AGXT) gene; PH type 2 (PH2, MIM 260000) in the glyoxylate reductase/hydroxypyruvate reductase (GRHPR) gene; and PH type 3 (PH3, MIM 613616) in the 4-hydroxy-2-oxoglutarate aldolase 1 (HOGA1) gene [2]. This evidence concerns the gene HOGA1 and primary hyperoxaluria type 1.