Aubrey, diagnosed with PH1

PH1 At-A-Glance

Roughly 70% to 80% of all people with primary hyperoxaluria have PH1—the most common and severe type.

Approximately 1 to 3 of every million people in Europe and North America have PH1 and there is an even higher prevalence of the disease in the Middle East and North Africa regions.

It’s estimated that about 50% of all people with PH1 may be undiagnosed.

The earliest sign of PH1 is often kidney stones that form due to oxalate overproduction in the liver. However, not all patients with PH1 will experience kidney stones.

PH1 Inside The Body

PH1 is caused by defects in the AGXT gene, which impairs the function of the liver-specific enzyme glyoxylate.

In a patient with PH1, the AGT gene doesn’t process the glyoxylate normally, and instead, converts it into oxalate, which can’t be metabolized.

This excess oxalate then accumulates in the kidneys causing irreparable damage, ultimately leading to kidney failure.

Since oxalate can no longer be excreted through the kidneys, it deposits in multiple vital organs including the eyes, bones, skin and heart.

What Are The Symptoms of PH1?

For many patients, PH1 is not diagnosed immediately, and adult patients often spend many years undiagnosed until they present with severe kidney disease or until after their kidneys have failed and they require dialysis to help filter waste products from the blood.

As PH1 progresses, it often results in kidney failure, a life-threatening condition that prevents the kidneys from filtering fluids and waste from the body effectively. As a result, the build-up of oxalate can lead to the accumulation of oxalate crystals in the eyes, bones, skin, heart and central nervous system, causing diminished vision, bone fractures, ulcers, heart failure and other serious complications.*

*Not every person with PH1 will experience all symptoms listed here. Talk to your doctor if you think you are experiencing symptoms of PH1.

Oxalate Crystals
Flank Pain

PH1 Backgrounder

Download this fact sheet to learn more about PH1

PH1 Manifestations Can Vary By Stage of Life

Patients can be diagnosed with PH1 at any age, but most individuals experience their first symptoms in early childhood. Below are some examples of possible symptoms, but are not limited to such.

  • Insufficient weight gain
  • Formation of kidney stones
  • Early kidney failure

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

PH1 Perspectives


It was a huge shock to our family and her road ahead indeed proved very challenging.

– The Skinner Family, living with PH1


Additional Information

Take On PH1™

Take on PH1™ is dedicated to helping patients and their caregivers learn about primary hyperoxaluria type 1 (PH1).


Alnylam Act®

Alnylam Act® provides no-charge independent genetic testing and counseling to individuals in the U.S. and Canada who may have primary hyperoxaluria type 1 (PH1).


Take on PH1, Alnylam Act, and their associated logos are trademarks of Alnylam Pharmaceuticals, Inc. © 2023 Alnylam Pharmaceuticals, Inc. All rights reserved.

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