Hyperoxaluria is an excessive urinary excretion of

oxalate Oxalate (systematic IUPAC name: ethanedioate) is an anion with the chemical formula . This dianion is colorless. It occurs naturally, including in some foods. It forms a variety of salts, for example sodium oxalate (), and several esters such as ...

. Individuals with hyperoxaluria often have

calcium oxalate Calcium oxalate (in archaic terminology, oxalate of lime) is a calcium salt of oxalic acid with the chemical formula or . It forms hydrates , where ''n'' varies from 1 to 3. Anhydrous and all hydrated forms are colorless or white. The monohydr ...

kidney stone Kidney stone disease (known as nephrolithiasis, renal calculus disease, or urolithiasis) is a crystallopathy and occurs when there are too many minerals in the urine and not enough liquid or hydration. This imbalance causes tiny pieces of cr ...

s. It is sometimes called Bird's disease, after Golding Bird, who first described the condition.

Presentation

Causes

Hyperoxaluria can be

primary Primary or primaries may refer to: Arts, entertainment, and media Music Groups and labels * Primary (band), from Australia * Primary (musician), hip hop musician and record producer from South Korea * Primary Music, Israeli record label Work ...

(as a result of a genetic defect) or secondary to another disease process. Type I primary hyperoxaluria (PH1) is associated mutations in the gene encoding AGXT, a key enzyme involved in

metabolism. PH1 is an example of a protein mistargeting disease, wherein AGXT shows a trafficking defect. Instead of being trafficked to

peroxisome A peroxisome () is a membrane-bound organelle, a type of microbody, found in the cytoplasm of virtually all eukaryotic cells. Peroxisomes are oxidative organelles. Frequently, molecular oxygen serves as a co-substrate, from which hydrogen perox ...

s, it is targeted to

mitochondria A mitochondrion () is an organelle found in the cells of most eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is us ...

, where it is metabolically deficient despite being catalytically active. Type II is associated with GRHPR. Secondary hyperoxaluria can occur as a complication of jejunoileal bypass, or in a patient who has lost much of the

ileum The ileum () is the final section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms posterior intestine or distal intestine may ...

with an intact colon. In these cases, hyperoxaluria is caused by excessive gastrointestinal oxalate absorption. Excessive intake of oxalate-containing food, such as rhubarb, may also be a cause in rare cases.

Diagnosis

Types

The types are the following: *

Primary hyperoxaluria Primary hyperoxaluria is a rare condition (autosomal recessive) resulting in increased excretion of oxalate (up to 600 mg a day from normal 50 mg a day), with oxalate stones being common. Signs and symptoms Primary hyperoxaluria is an a ...

* Enteric hyperoxaluria *

Idiopathic An idiopathic disease is any disease with an unknown cause or mechanism of apparent spontaneous origin. For some medical conditions, one or more causes are somewhat understood, but in a certain percentage of people with the condition, the cause ...

hyperoxaluria *

Oxalate Oxalate (systematic IUPAC name: ethanedioate) is an anion with the chemical formula . This dianion is colorless. It occurs naturally, including in some foods. It forms a variety of salts, for example sodium oxalate (), and several esters such as ...

poisoning

Treatment

The main therapeutic approach to primary hyperoxaluria is still restricted to symptomatic treatment, i.e. kidney transplantation once the disease has already reached mature or terminal stages. However, through genomics and proteomics approaches, efforts are currently being made to elucidate the kinetics of AGXT folding which has a direct bearing on its targeting to appropriate subcellular localization. A child with

primary hyperoxaluria Primary hyperoxaluria is a rare condition (autosomal recessive) resulting in increased excretion of oxalate (up to 600 mg a day from normal 50 mg a day), with oxalate stones being common. Signs and symptoms Primary hyperoxaluria is an a ...

was treated with a liver and kidney transplant. A favorable outcome is more likely if a kidney transplant is complemented by a liver transplant, given the disease originates in the liver. Secondary hyperoxaluria is much more common than primary hyperoxaluria, and should be treated by limiting dietary oxalate and providing calcium supplementation. LDHA inhibitors (such as CHK-336) have been evaluated in clinical trials for treatment of primary hyperoxaluria, though none have been approved as of 2025.

References

External links

GeneReviews/NIH/NCBI/UW entry on Primary Hyperoxaluria Type 1
{{DEFAULTSORT:Hyperoxaluria Abnormal clinical and laboratory findings for urine Inborn errors of carbohydrate metabolism