primary hyperoxaluria type 1

What is Primary Hyperoxaluria Type 1?

Primary hyperoxaluria type 1 (PH1) is an inherited disease in which the lack of a particular liver enzyme causes the body to accumulate excess amounts of a substance called oxalate. This oxalate leads to a buildup of insoluble calcium salts in the kidneys and other organs. If untreated, it results in life-threatening kidney failure.

People with PH1 are prone to recurrent kidney stones that can lead to kidney failure. Among people with PH1, 50% experience kidney failure by the age of 15, 80% by the age of 30.

In addition to the kidneys, PH1 also leaves insoluble calcium deposits in other body tissues. This can lead to bone pain; vision loss; tingling, numbness, or pain in the extremities; enlargement of the liver and spleen; and problems with the electrical system of the heart (heart block).

Symptoms typically begin between the ages of 1 and 25, with roughly 80% showing signs of the disease in late childhood or early adolescence. Another 10% of people with PH1 show symptoms in early infancy (before the age of 6 months) while the remaining 10% do not show symptoms until their 40s or 50s.

How common is Primary Hyperoxaluria Type 1?

PH1 is quite rare, with estimates placing its frequency worldwide between 1 in 100,000 and 1 in 1,000,000. In Europe, it affects an estimated 1 in 120,000 people. It is thought to be more common in Tunisia, Iran, and Israeli Arab and Druze populations.

How is Primary Hyperoxaluria Type 1 treated?

About half of people with PH1 respond to high doses of vitamin B6, which can reduce the amount of oxalate in the body. In some of these people, the oxalate level can be normalized, while in others it is merely reduced to a healthier level.

People with the condition should drink plenty of water. A physician may prescribe medication or other vitamins to help lower oxalate levels and inhibit the formation of kidney stones.

One important option in treating PH1 is organ transplantation of the liver and kidneys. Because a deficient liver enzyme leads to kidney failure, early liver transplantation may avoid the need to also transplant new kidneys. Kidney replacement alone is not a sufficient treatment as the liver could destroy the new kidneys as well.

People with PH1 should avoid extremely large doses of vitamin C as well as foods high in oxalate, including chocolate, rhubarb, and starfruit.

What is the prognosis for a person with Primary Hyperoxaluria Type 1?

The prognosis for a person with PH1 is variable and depends on how early the disease is detected and treated. Among people with PH1, 50% experience kidney failure by the age of 15, 80% by the age of 30. In more severe cases, children will develop kidney failure between the ages of 3 and 6 and will require organ transplants in order to survive. Early detection and treatment with vitamin B6 can help avoid kidney failure in some cases.

Following organ transplant, some people have lived normal or near-normal lifespans.

Women with PH1 have successfully given birth to healthy babies following a liver/kidney transplant.