What is infantile Refsum disease?
Infantile Refsum disease (IRD) is a medical condition within the Zellweger spectrum of perixisome biogenesis disorders (PBDs), which are inherited genetic disorders that damage the white matter of the brain and affect motor movements. PBDs are part of a larger group of disorders called the leukodystrophies.
The Zellweger spectrum of PBDs include related, but not more severe, disorders referred to as Zellweger syndrome (ZS) and neonatal adrenoleukodystrophy. Collectively, these disorders are caused by inherited defects in any one of the 12 PEX genes that are required for the normal formation and function of peroxisomes.
Peroxisomes are cell structures required for the normal formation and function of the brain, eyes, liver, kidneys, and bones. They contain enzymes that break down toxic substances in the cells, including very long chain fatty acids and phytanic acid (a type of fat found in certain foods), and synthesize certain fatty materials (lipids) that are required for cell function.
When peroxisomes are not functioning, there is over-accumulation of long chain fatty acids and phytanic acid, and a lack of bile acids and plasmalogens, which are specialized lipids found in cell membranes and the myelin sheaths that encase and protect nerve fibers. IRD has some residual perixisome function, resulting in less severe disease than in Zellweger syndrome.
Symptoms of IRD begin in infancy with retinitis pigmentosa, a visual impairment that often leads to blindness, and hearing problems that usually progress to deafness by early childhood. Other symptoms may include:
- Rapid, jerky eye movements (nystagmus)
- Floppy muscle tone (hypotonia) and lack of muscle coordination (ataxia)
- Enlarged liver
- Mental and growth disabilities
- Abnormal facial features
- White matter abnormalities of brain myelin
At the mildest extreme of the disorder, intellect may be preserved. Although adult Refsum disease and IRD have similar names, they are separate disorders caused by different gene defects. IRD is a fatal disease, but some children will survive into their teens and twenties, and possibly even beyond.
How can I or my loved one help improve care for people with infantile Refsum disease?
Consider participating in a clinical trial so clinicians and scientists can learn more about IRD and related disorders. Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.
All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.
Where can I find more information about infantile Refsum disease?
Information may be available from the following resources: