Oxalose

Oxalosis is the systemic deposition of calcium oxalate crystals, caused by primary hyperoxaluria type 1 (PH1), the most frequent variety of primary hyperoxaluria. PH1 is an autosomal recessive disease due to an hepatic enzymatic defect of alanine : glyoxylate aminotransferase (AGT), resulting in oxalate overproduction. Because of the poor solubility of calcium oxalate in urine, the first symptom is usually a recurrent lithiasis, beginning in childhood. Associated nephrocalcinosis results almost always in terminal renal failure before the adult age, and oxalate crystals accumulate in many tissues, particularly bones. Liver transplantation, or more often combined liver-kidney transplantation, is the only curative treatment ; at an early stage, permanent urine dilution by hyperhydration may prevent nephrocalcinosis. Primary hyperoxaluria type 2, a much rarer disease due to a defect of glyoxylate/hydroxypyruvate-reductase (gr/HPR), is associated with L-glyceric aciduria. Its main manifestation is also recurrent lithiasis ; however renal failure is a rare occurrence.