Primary hyperoxaluria (PH) is not just one disease but rather a group of three rare genetic disorders: PH1, PH2 and PH3. They are linked to different genes, and each one causes you to make too much oxalate, a waste product produced by your body.
About 8,700 people in the United States have PH, but most do not know it. Among people who are diagnosed:
- 8 in 10 have PH1
- 1 in 10 have PH2
- 1 in 10 have PH3
All types of PH can lead to painful kidney stones, which often require visits to emergency departments and sometimes surgeries, but PH1 is the most damaging to your kidneys.
If someone has PH, their parents either had the disease or were carriers of one of the gene variants. PH can be seen in any racial or ethnic population, but each PH type occurs more often in certain groups. PH1 is highest among those of East Asian descent, PH2 among those of South Asian descent and PH3 among those of Ashkenazi Jewish descent.
Signs and symptoms of primary hyperoxaluria
The signs and symptoms of PH include:
- Frequent kidney stones
- Blood in the urine, called hematuria
- Pain when urinating
- Frequent urinary tract infections
- Sharp pain in the back, side, or abdomen
- Progressive kidney dysfunction, leading to kidney failure
In addition, oxalate can build up in other parts of the body. This is called systemic oxalosis. It could cause bone pain, fractures, heart problems like irregular heart beat (arrhythmias) and problems with your heart working properly, anemia, skin ulcers, changes in vision, dental problems and muscle pains, and other issues.
PH1 is the most severe type and it can begin as early as childhood. Most people with PH1 develop severe kidney disease, called end-stage kidney disease (ESKD), and systemic oxalosis is more common. PH2 is less aggressive and although people with PH2 can develop ESKD, it’s not as frequent. Finally, PH3 is the mildest form and ESKD is rare with this type.
PH symptoms change throughout life because they vary depending on how the disease is progressing and worsening as the oxalate causes more damage. It is important to report any changes in your health to your healthcare provider (HCP) so you can find out if the symptoms are related to PH or something else.
Getting a primary hyperoxaluria diagnosis
Since it is unusual for children to have kidney stones, they should be screened for PH if they have one. Other reasons to screen for PH include having:
- Close relatives who have PH
- Frequent kidney stones
- A family history of stone disease
The earlier PH is diagnosed, the better the chance of slowing it down. To diagnose PH, your doctor will take a family history and your detailed medical history. Tests could include:
- Genetic testing
- Blood test for oxalate and estimated glomerular filtration rate (eGFR), which tells your HCP how well your kidney is working
- Imaging tests of your kidneys, like ultrasounds or computed tomography (CT) scans
- 24-hour urine collection — you deposit all your urine passed over 24 hours
- Stone testing, if you can provide a stone you have passed
- Kidney or liver biopsy (although not commonly used for diagnosis)
Treating primary hyperoxaluria
The treatment goal for people with PH is to stop oxalate from building up and reducing damage to your kidneys and other parts of your body. Unless you have a condition (like kidney damage) that limits how much water you can consume, drinking large amounts of water and other liquids is one of the most important actions you can take. This dilutes oxalate in your urine, lessening the chances of kidney stones. Spreading this intake out throughout the day helps your kidneys produce a steady flow of urine.
Outside of high water intake, some people with PH1 take vitamin B6, which may help lower oxalate levels. Two prescription injectable medications, lumasiran (Oxlumo) and nedosiran (Rivloza), can lower oxalate in people with PH1. Citrate medications can help prevent kidney stones from forming for all types of PH.
People with PH are advised to avoid high levels of vitamin C, so don’t take supplements that contain it. You also should avoid eating foods that are high in oxalate, like nuts, chocolate, spinach, and tofu. Speaking with a dietitian can help you learn what foods are best to eat and which ones to stay away from.
If the disease progresses, especially PH1, and you have ESKD, you will need dialysis or ultimately a liver and kidney transplant. Primary hyperoxaluria is a rare disease, but to those who have it, it is life-changing. Knowing how to recognize and manage the condition can make a big difference in how quickly the disease progresses and what to expect when it does.
Resources
This educational resource was created with support from Alnylam.
- My Son Won the Basketball Championship, then Passed 15 Kidney Stones ›
- Living with Primary Hyperoxaluria ›
- Treatment and Management of Primary Hyperoxaluria ›
