Primary Hyperoxaluria Type 1 (PH1)

PH1 can present at any age and symptoms can vary depending on the patient’s age. Kidney stones are the most common symptom in patients with PH1. There are, however, patients with PH1 who are not stone formers and may present with other symptoms.

Symptoms of a kidney stone include:

• Flank pain
• Urinary tract infections
• Painful urination
• Blood in the urine

PH1 in Infancy:

• Insufficient weight gain
• Failure to thrive
• Formation of kidney stones
• Early end-stage renal failure

PH1 in Childhood to Adulthood:

• Recurrent kidney stones
• Progressive kidney disease (including kidney failure)
• Multi-organ dysfunction

Due to the similarities in presentation to other disease states, PH1 often goes underdiagnosed or patients get misdiagnosed. If PH1 is suspected, there are a few approaches to help towards the path of diagnosis.

• 24-hour Urine Test: Due to the nature of the disease, a urine test can be utilized in order to identify elevated oxalate levels. This test is useful in patient who have not reached end stage renal disease. While a urine test is not confirmatory for PH1, it can help guide further investigation to diagnosis.
• Genetic Testing: To confirm a diagnosis of PH1, a genetic test is conducted in order to identify mutations. If there is a family history of PH1, prenatal genetic testing can be performed to establish a diagnosis.

A liver transplant is the only measure to cure patients with PH1. However, there are supportive measures that can be taken in order to try and slow progression of the disease. One way to help prevent stone formation is a method known as hyperhydration. This method recommends that patients should drink 2-3 L/m2 of fluid daily, however it’s important to speak with your physician about a personalized plan for your treatment. For children, this may be more difficult, and a placement of a G-tube may be necessary. Another option is the use of vitamin B6 (pyridoxine). About 10-30% of patients have been shown to respond to vitamin B6 treatment. In order to be labeled a responder with B6 treatment, there needs to be a decrease in urinary oxalate levels of more than 30% from the start of B6 and treatment should be managed by your physician. Various forms of dialysis can be used and typically serve as a bridge to transplant. Most recently, a new RNAi therapeutic, Lumasiran, is available as a subcutaneous injection that targets a specific enzyme involved in PH1 to help reduce oxalate levels in the body.

In combination with treatment, patients with PH1 should be aware to avoid certain substances and circumstances to prevent further complications. Patients should avoid dehydration due to the negative impact it can have on the kidneys. Excessive vitamin C and vitamin D, loop diuretics, high doses of NSAIDs, or other medications that may compromise kidney function should also be avoided or discussed with your provider before use.