What Your Test Results Mean:

Carriers typically show no symptoms of primary hyperoxaluria type 2; however, carriers are at an increased risk of having a child with primary hyperoxaluria type 2. Risk for the current or future pregnancies is dependent on your partner’s carrier status. Carrier testing of your partner is recommended in addition to consultation with a genetic counselor for more detailed risk assessment.

Disease Explained:

Primary hyperoxaluria type 2 is an inherited condition that affects the body’s metabolism of oxalate. Accumulation of oxalate causes the oxalate ion to combine with calcium and crystallize in body tissues as calcium oxalate. This chemical is the main component of kidney stones, and deposits of calcium oxalate can lead to kidney damage, kidney failure, and injury to other organs. Primary hyperoxaluria has no cure, but the condition can be managed through diet and medication. Individuals with primary hyperoxaluria should drink lots of water and avoid foods high in oxalate, such as rhubarb and chocolate. Some patients also respond well to treatment with potassium citrate or pyrophosphate, which reduce the amount of calcium oxalate in the urine. Kidney and/or liver transplants may be recommended based on the severity of the disorder, which can be variable.

How the Genetics Works:

Primary hyperoxaluria type 2 is an autosomal recessive disorder caused by pathogenic variants in the GRHPR gene. In general, individuals have two copies of the GRHPR gene. Carriers of primary hyperoxaluria type 2 have a single variant in one copy of the GRHPR gene while individuals with primary hyperoxaluria type 2 have variants in both copies of their genes, one inherited from each parent. Risk for two carriers to have a child with the disorder is 25%.