What Is Infantile Refsum Disease (IRD)?
Infantile Refsum Disease (IRD) is one of the mildest disorders within the Zellweger spectrum of peroxisome biogenesis disorders (PBDs), a group of inherited disorders that damage the white matter of the brain and impact motor movements. It is caused by a mutation in the gene responsible for the metabolism of phytanic acid (a type of fatty acid). As a result, phytanic acid accumulates in blood plasma and tissues.
What Are the Symptoms?
IRD largely targets vision and motor movements, but it can also impact other areas of the body as well. Symptoms can include:
- Progressive loss of vision
- Poor muscle coordination
- Rapid, jerky eye movements
- Floppy muscle tone
- Enlarged liver
- Mental disabilities
- Abnormal facial features
- Loss of peripheral vision
- Bone and skin changes, specifically dry and itchy skin
How Do You Get Infantile Refsum Disease?
IRD is inherited through an autosomal recessive pattern. This means that both parents must be carriers of the genetic mutation that results in IRD, and that they must both pass it on to their child.
How Is Infantile Refsum Disease Diagnosed?
IRD can be diagnosed in a few ways. The presence of phytanic acid can be tested through a blood or urine sample. One can also determine the presence of the genetic mutation that causes IRD through genetic testing.
Is There a Treatment?
Unfortunately, while IRD is the mildest disorder of the Zellweger spectrum, it is still a fatal disease and currently uncurable. Symptoms, however, can be alleviated by avoiding foods containing phytanic acid, including dairy products, beef, lamb, and fatty fish.
Genetic and Rare Diseases Information Center
National Institute of Neurological Disorders and Stroke