|A service of the U.S. National Library of Medicine®|
On this page:
Reviewed January 2008
What is primary hyperoxaluria?
Primary hyperoxaluria is a rare condition characterized by the overproduction of a substance called oxalate (also called oxalic acid). In the kidneys, the excess oxalate combines with calcium to form calcium oxalate, a hard compound that is the main component of kidney stones. Deposits of calcium oxalate can lead to kidney damage, kidney failure, and injury to other organs.
Primary hyperoxaluria is caused by the shortage (deficiency) of an enzyme that normally prevents the buildup of oxalate. There are two types of primary hyperoxaluria, distinguished by the enzyme that is deficient. People with type 1 primary hyperoxaluria have a shortage of a liver enzyme called alanine-glyoxylate aminotransferase (AGXT). Type 2 primary hyperoxaluria is characterized by a shortage of an enzyme called glyoxylate reductase/hydroxypyruvate reductase (GRHPR).
How common is primary hyperoxaluria?
Type 1 primary hyperoxaluria is estimated to occur in 1 to 3 per million people; it is more common in some Mediterranean countries, such as Tunisia. Although the incidence of type 2 primary hyperoxaluria is unknown, it is less common than type 1.
What genes are related to primary hyperoxaluria?
Mutations in the AGXT and GRHPR genes cause primary hyperoxaluria.
The breakdown and processing of certain sugars and protein building blocks (amino acids) produces a substance called glyoxylate. Normally, glyoxylate is converted to the amino acid glycine or to a compound called glycolate through the action of two enzymes, alanine-glyoxylate aminotransferase and glyoxylate reductase/hydroxypyruvate reductase, respectively. Mutations in the AGXT or GRHPR gene cause a shortage of these enzymes, which prevents the conversion of glyoxylate to glycine or glycolate. As levels of glyoxylate build up, it is converted to oxalate. Oxalate combines with calcium to form calcium oxalate deposits, which can damage the kidneys and other organs.
How do people inherit primary hyperoxaluria?
This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
Where can I find information about diagnosis or management of primary hyperoxaluria?
These resources address the diagnosis or management of primary hyperoxaluria and may include treatment providers.
General information about the diagnosis and management of genetic conditions is available in the Handbook. Read more about genetic testing, particularly the difference between clinical tests and research tests.
To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.
Where can I find additional information about primary hyperoxaluria?
You may find the following resources about primary hyperoxaluria helpful. These materials are written for the general public.
You may also be interested in these resources, which are designed for healthcare professionals and researchers.
What other names do people use for primary hyperoxaluria?
What if I still have specific questions about primary hyperoxaluria?
Where can I find general information about genetic conditions?
The Handbook provides basic information about genetics in clear language.
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding primary hyperoxaluria?
acids ; aciduria ; alanine ; amino acid ; autosomal ; autosomal recessive ; breakdown ; calcium ; cell ; compound ; deficiency ; dehydrogenase ; enzyme ; gene ; glycine ; hepatic ; incidence ; inherited ; injury ; kidney ; kidney stones ; protein ; recessive
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (6 links)
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.