Primary hyperoxaluria is a rare genetic disease. It can cause recurrent kidney and bladder stones due to an overproduction of oxalate in your urine.
Oxalate is a natural substance found in the human body. It can also be found in certain types of food, such as:
People with primary hyperoxaluria may not have enough enzymes to prevent a buildup of oxalate.
The substance can then bond with calcium and create kidney and bladder stones. The disease can progress into end stage renal disease.
Read on to learn about the types of primary hyperoxaluria, as well as the symptoms and treatments for the disease.
Primary hyperoxaluria affects about 1 in every 58,000 people around the world.
There are three main types of primary hyperoxaluria, which vary in severity. They’re broken down into primary hyperoxaluria type I, II, and III.
Primary hyperoxaluria type I
Primary hyperoxaluria type I is the most common variation of this disorder, accounting for about 8 in 10 cases.
It’s caused by mutations in the AGXT gene, which results in a deficiency of alanine-glyoxylate aminotransferase (AGT), a liver enzyme.
The disease can appear in people as young as infants, making it difficult for them to grow or gain weight. Primary hyperoxaluria type I can also develop during childhood or adolescence.
Babies and children with the disease may have kidney and urinary stones that can lead to more severe complications, such as repeated urinary tract infections and abdominal pain. It can result in progressive kidney damage and early end stage renal failure.
Primary hyperoxaluria type I is usually less severe if it develops in adulthood.
Advanced kidney disease or end stage renal disease affects between 20 and 50 percent of people who are diagnosed with primary hyperoxaluria type I in adulthood.
However, some people with the disease may only experience occasional kidney stones. The disease may affect other areas of the body as kidney function declines.
Primary hyperoxaluria type II
Primary hyperoxaluria type II is categorized by a deficiency of the enzyme glyoxylate reductase–hydroxypyruvate reductase (GRHPR). It’s less severe than primary hyperoxaluria type I and usually diagnosed in childhood. Around 10 percent of people with primary hyperoxaluria have this type.
Primary hyperoxaluria type II causes similar symptoms to those of type I, but it usually results in less frequent kidney and urinary stones. It also progresses to end stage renal disease more slowly than type I.
A buildup of oxalate from primary hyperoxaluria type II can go on to affect other areas of the body, including your:
- blood vessels
- central nervous system
Primary hyperoxaluria type III
Mutations in the HOGA1 gene cause a deficiency of the enzyme 4-hydroxy-2-oxoglutarate aldolase (HOGA), which results in primary hyperoxaluria type III.
Limited cases of primary hyperoxaluria type III have made it difficult for researchers to determine the definitive progression of the disease. Still, it’s considered mildest of the three types.
Some people with the disease may get kidney stones or have no symptoms whatsoever. It’s rare for primary hyperoxaluria type III to cause chronic kidney disease.
Symptoms of primary hyperoxaluria can vary from person to person. Kidney stones and urinary tract stones are typically the first signs of the disease.
Other symptoms of primary hyperoxaluria may include:
- severe or sudden back pain
- painful urination (dysuria)
- chronic pain below the ribs on the back
- hematuria (blood in urine)
- high levels of calcium in the kidneys (except with primary hyperoxaluria type III)
- childhood bedwetting or trouble controlling urine
- frequent urge to urinate
- repeated urinary tract infections
Because it’s a rare disease, primary hyperoxaluria can go unrecognized for several years after you begin experiencing symptoms.
If your doctor suspects you have this disease, they’ll:
- give you a thorough physical exam
- evaluate your diet
- look at your medical history
Your doctor may also:
- analyze the levels of oxalates and metabolites in your urine
- test oxalate levels in your blood
- conduct an analysis of your kidney stones
- use imaging to check for deposits of calcium oxalate or kidney stones
- conduct DNA testing to check for gene variations related to primary hyperoxaluria
Your doctor may order additional testing, such as a kidney biopsy, eye exam, or echocardiogram, to see if primary hyperoxaluria is affecting the rest of your body.
Treatment for primary hyperoxaluria can vary based on:
- the type of the disease you have
- its severity
- your symptoms
- your age and health
Treatment may involve a team of specialists that includes urologists and nephrologists (doctors who specialize in kidney problems). Some common treatments for primary hyperoxaluria include:
Gastrostomy is mostly used for infants and children. This treatment is involves placing a thin tube into the stomach through the abdomen to provide adequate fluid, which can help prevent kidney stones.
Your doctor may recommend taking potassium citrate, thiazides, or orthophosphates to prevent oxalate and calcium from crystalizing.
Prescription doses of vitamin B-6 are often recommended for people with primary hyperoxaluria type I. This can help reduce the oxalate levels in your body.
Lithotripsy uses shock waves to break up kidney and urinary tract stones.
High fluid intake
Drinking a lot of water can help prevent kidney stones by flushing out the kidneys and preventing a buildup of oxalate.
Doctors may recommend avoiding high oxalate foods, like:
Dietary changes are generally used as a precautionary measure, though, and may not make a major difference in the progression of primary hyperoxaluria.
Dialysis or kidney and liver transplants
If primary hyperoxaluria develops into advanced kidney disease or end stage renal disease, you may need more aggressive treatment, which may include:
- kidney transplant
- liver transplant
- combined liver-kidney transplant
Organ transplant can be a cure for primary hyperoxaluria.
Researchers are studying whether gene therapy may be a treatment or potential cure for primary hyperoxaluria. More research is required before gene therapy becomes a mainstream treatment for primary hyperoxaluria.
Primary hyperoxaluria types I and II can eventually progress into end stage renal disease, especially if the condition is left untreated. The speed at which the disease progresses varies from person to person.
As kidney function declines, you may experience other complications of primary hyperoxaluria, including:
- bone pain
- osteosclerosis (a hardening and increased density of the bones)
- multiple fractures
- optic atrophy
- dental problems like tooth mobility, pain, and root resorption
- nerve damage
- heart problems, like arrhythmias and myocarditis
- narrowing blood vessels
- arthropathy (joint disease)
- enlarged spleen or liver
- skin problems, including livedo reticularis, rash, necrosis, and gangrene of the hands and feet
Primary hyperoxaluria is a rare genetic disorder that can cause an accumulation of oxalate and frequent urinary and kidney stones.
You may experience symptoms for several years before getting a diagnosis. Doctors have a variety of diagnostic tools, including genetic testing, that can determine if you have this disease.
Early diagnosis and treatment are critical to preserving kidney function and slowing the progression of primary hyperoxaluria.
Without treatment, types I and II of the disease can develop into end stage renal failure.
Work with your doctor to determine the right course of treatment for your condition.