Primary hyperoxalurias are rare recessive inherited inborn errors of
glyoxylate metabolism. They are responsible for progressive renal involvement, which further lead to systemic
oxalate deposition, which can even occur in infants.
Primary hyperoxaluria type 1 is the most common form in Europe and is due to
alanine-
glyoxylate aminostransferase deficiency, a hepatic peroxisomal
pyridoxin-dependent
enzyme. Therefore
primary hyperoxaluria type 1 is responsible for
hyperoxaluria leading to aggressive stone formation and
nephrocalcinosis. As glomerular filtration rate decreases, systemic
oxalate storage occurs throughout all the body, and mainly in the skeleton. The diagnosis is first based on urine
oxalate measurement, then on genotyping, which may also allow prenatal diagnosis to be proposed. Conservative measures - including hydration, crystallization inhibitors and pyridoxine - are safe and may allow long lasting renal survival, provided it is given as soon as the diagnosis has been even suspected. No dialysis procedure can remove enough
oxalate to compensate
oxalate overproduction from the sick liver, therefore a combined liver and
kidney transplantation should be planned before advanced renal disease has occurred, in order to limit/avoid systemic
oxalate deposition. In the future,
primary hyperoxaluria type 1 may benefit from hepatocyte
transplantation, chaperone molecules, etc.