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Learn More - Primary Hyperoxaluria (PH)

What is Primary Hyperoxaluria?

Primary Hyperoxaluria is a rare, inherited disorder characterized by high levels of oxalate in the urine and calcium oxalate kidney stones which can result in reduced kidney function or can cause kidney failure. Among patients with primary hyperoxaluria, about 50 percent will have kidney failure by age 15, and about 80 percent will have kidney failure by age 30. For that reason, it is critical that primary hyperoxaluria be diagnosed and treated as early as possible. Patients most often develop the first symptoms, typically kidney stones, anywhere from birth to the mid-20s. But hyperoxaluria may go unrecognized until age 30 to 40. In some patients the first symptom is kidney failure.

Who gets Primary Hyperoxaluria?

Symptoms due to hyperoxaluria may appear anytime from birth to adulthood and presentation can vary from mild to severe. In its many forms, it may be found among all ages, from infants to people in their 70s. Among patients with primary hyperoxaluria, about 50 percent will have kidney failure by age 15, and about 80 percent will have kidney failure by age 30. For that reason, it is critical that primary hyperoxaluria be diagnosed and treated as early as possible. Patients most often develop the first symptoms, typically kidney stones, anywhere from birth to the mid-20s. But hyperoxaluria may go unrecognized until age 30 to 40. In some patients the first symptom is kidney failure.

What causes Primary Hyperoxaluria?

The cause of the Primary Hyperoxaluria is not always known, but may result from changes in the way kidneys handle normal amounts of body oxalate. The highest amounts of oxalate in the urine are seen in diseases in which the liver produces too much oxalate. This occurs in primary hyperoxaluria. Type I and Type II. Primary hyperoxaluria (PH) is a rare genetic, or inherited, disorder that is present at birth. In a person with Type 1 primary hyperoxaluria, the liver creates too little of an enzyme called alanine:glyoxylate aminotransferase, or AGT. In Type II, the liver is missing a different enzyme, called glyoxylate reductase (GR) or hydroxpyruvate reductase. Very large amounts of oxalate are produced when there are not enough of these enzymes in the liver. Over time, oxalate in the urine can cause kidney stones. When very large amounts of oxalate are present in the urine, such as in primary hyperoxaluria, the kidneys can be damaged to the point that they quit working (renal failure).

How is Primary Hyperoxaluria diagnosed?

Patients that have hyperoxaluria or suspected of having PH will need a comprehensive physical exam, including a medical history, family history, and diet and medication history. Depending on their symptoms, patients may have one or more of the following tests to measure the presence and level of oxalate in the body: blood and urine testing, kidney x-ray or CT scan, liver or kidney biopsy, echocardiogram, eye exam, bone marrow biopsy or family screening.

What is/is there treatment for Primary Hyperoxaluria?

The treatment for PH patients needs to be individualized and take into account each patient’s needs, the type and severity of disease, kidney function and how well the patient responds to treatment. Patients need to be closely monitored by their medical team to measure their responses to the following treatments: high fluid intake, medications, diet modifications, kidney stone management, and treatment for kidney failure, dialysis, kidney or combined liver-kidney transplant.


Frequently Asked Questions about Primary Hyperoxaluria

What is the difference between Primary Hyperoxaluria Type I and Type II?

Primary Hyperoxaluria (PH) Type I and Type II both cause increased production of oxalate. In a person with Type 1 primary hyperoxaluria, the liver creates too little of an enzyme called alanine:glyoxylate aminotransferase, or AGT. In Type II, the liver is missing a different enzyme, called glyoxylate reductase (GR) or hydroxpyruvate reductase. Very large amounts of oxalate are produced when there is not enough of either of these enzymes in the liver.

Why is the kidney affected if the liver enzymes are abnormal in PH patients?

In patients with PH there is an overproduction of oxalate that occurs due to the abnormalities of specific enzymes in the liver. Though it is the liver that is defective, the oxalate can only be eliminated from the body by the kidney and excreted in the urine and therefore the organ that suffers the most is the kidney.

What age are most PH patients diagnosed?

Patients most often develop the first symptoms, typically kidney stones, anywhere from birth to the mid-20s. But hyperoxaluria may go unrecognized until age 30 to 40. In some patients the first symptom is kidney failure.

What is the treatment for PH?

The goal for patients with PH is to prevent kidney stones, damage to the kidneys and the accumulation of calcium oxalate in the kidneys to other body tissues. It is important for patients to seek qualified medical care that will take into account the patients’ needs, the type and severity of the disease and how well the patient responds to various treatments. Patients should be closely monitored by their physicians during treatment, which may include: medications to reduce oxalate or stone formation, high fluid intake and dietary modifications and possibly kidney and/or liver transplantation.