Primary hyperoxaluria is a rare condition where people get kidney and bladder stones over and over again. This can lead to a serious problem called end stage renal disease (ESRD), which is when the kidneys can’t clean the body’s fluids and waste properly.
The main issue in primary hyperoxaluria is that the body makes too much of something called oxalate. This oxalate goes through the kidneys and comes out in urine, making the urine have too much oxalate (hyperoxaluria). When oxalate combines with calcium, it forms a hard thing called calcium oxalate, which makes up most kidney and bladder stones. These stones can hurt the kidneys and other organs, causing blood in the pee, infections, kidney damage, ESRD, and harm to other organs. As time passes, the kidneys can’t get rid of as much oxalate as they should. So, oxalate levels go up in the blood and the substance gets stuck in tissues all over the body (systemic oxalosis), especially in bones and blood vessels, which can lead to bone fractures.
There are three types of primary hyperoxaluria, and they’re different in how severe they are and what causes them. In type 1, kidney stones usually start anytime from childhood to early adulthood, and ESRD can happen at any age. Type 2 is like type 1, but ESRD comes later in life. In type 3, people often get kidney stones in early childhood, but there aren’t many cases described, so we’re not sure about the other signs and symptoms of this type.
Primary hyperoxaluria is caused by pathogenic (disease-causing) variants in the AGXT (type 1), GRHPR (type 2), or HOGA1 (type 3) genes and exhibits autosomal recessive inheritance. This means that both parents must be carriers to have a 25% chance to have a child with the condition. The risk of being a carrier is based on a person’s ancestry or ethnic background.
Other names for this condition are congenital oxaluria, D-glycerate dehydrogenase deficiency, glyceric aciduria, glycolic aciduria, hepatic AGT deficiency, oxalosis, and peroxisomal alanine:glyoxylate aminotransferase deficiency.