Zellweger syndrome (ZS) is a genetic disorder found in newborn babies. ZS is the most severe of the four disorders in the Zellweger spectrum. It causes serious problems with nerves and metabolism (changing food into energy) soon after birth. ZS affects the brain, liver and kidneys. It also harms important functions throughout the body. Another term for Zellweger syndrome is cerebrohepatorenal syndrome. The condition is usually fatal.
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| Zellweger syndrome |
What are Zellweger spectrum disorders (ZSDs)?
Also called peroxisomal biogenesis disorders, these diseases affect peroxisomes. Peroxisomes are parts of cells that are essential for many body functions.
The other Zellweger spectrum disorders include:
- Heimler syndrome, which causes hearing loss and tooth problems in late infancy or early childhood.
- Infantile Refsum disease, which causes muscle movement problems and delays in a baby’s development.
- Neonatal adrenoleukodystrophy, which causes hearing and vision loss, as well as problems with the infant’s brain, spine and muscles.
Who gets Zellweger syndrome?
ZS is the result of mutations (changes) to certain genes. It’s an autosomal recessive disorder. This means a child can only inherit the disorder if both parents pass on a copy of the mutated gene.
If both parents have the mutated gene, their children have a 50% chance of being carriers. A carrier inherits the mutated genes without developing the disease. The children have a 25% chance of developing the disease.
How common is Zellweger syndrome?
ZS is rare. Along with the other diseases in the Zellweger spectrum, they affect about 1 in 50,000 to 1 in 75,000 newborns.
What causes Zellweger syndrome?
ZS is the result of a mutation in any of the 12 PEX genes. Most cases of ZS are due to a mutation in the PEX1 gene. These genes control peroxisomes, which are needed for normal cell function. Peroxisomes break down toxins and fats. They play an important role in the development of the:
- Bones.
- Brain.
- Eyes.
- Heart.
- Kidneys.
- Liver.
- Nerves.
What are the symptoms of Zellweger syndrome?
Symptoms of ZS usually appear soon after birth. Facial abnormalities common in ZS include:
- Broad nose bridge.
- Epicanthal folds (skin folds at the inner corners of the eyes).
- Flattened face.
- High forehead.
- Underdeveloped eyebrow ridges.
- Wide-set eyes.
Other symptoms include:
- Difficulty feeding.
- Enlarged liver and/or spleen.
- Gastrointestinal (digestive tract) bleeding.
- Hearing and vision problems.
- Jaundice (yellow skin and eyes due to liver dysfunction).
- Seizures.
- Underdeveloped muscles and movement problems.
How is Zellweger syndrome diagnosed?
A healthcare provider usually notices the facial features of ZS right after birth. The following tests confirm the diagnosis:
- Blood and urine tests: High levels of certain substances in the blood or urine, such as fat molecules, indicate ZS.
- Imaging tests: An ultrasound checks the size and function of the liver, kidneys and other organs. A brain MRI is also done during the diagnostic process.
- Genetic tests: A blood test can confirm the presence of the mutated PEX genes.
Can Zellweger syndrome be diagnosed before birth?
A fetus (unborn baby) is at risk for ZS if both parents are known carriers of mutated PEX genes. In these cases, a healthcare provider may do blood or imaging tests for ZS while the baby is still in the womb.
What are the complications of Zellweger syndrome?
Infants with Zellweger syndrome may not be able to hear, see or eat. Those with very underdeveloped muscles may not be able to move. Babies often develop breathing problems, liver failure or digestive tract bleeding.
How is Zellweger syndrome treated?
There is no cure for Zellweger syndrome. Some therapies may ease symptoms, but there aren’t any treatments that address the cause of ZS. For example, a baby with difficulty eating may benefit from a feeding tube. But the baby won’t be able to eat normally on his or her own in the future.
How can I prevent Zellweger syndrome?
There’s no way to prevent ZS. People with a family history of ZS may consider genetic counseling. A genetic counselor can help you evaluate your risk of passing the disease to your children or grandchildren.
What is the outlook for infants with Zellweger syndrome?
Babies with ZS usually don’t live past the first 12 months of life. Other diseases in the Zellweger spectrum tend to have better outlooks. Children with Refsum or Heimler syndromes may live into adulthood.
What should I do if I have the Zellweger syndrome gene mutation?
If you’re a carrier of the genes associated with ZS, genetic counseling can help you weigh the risks of having children.
If you have a child born with ZS, a team of neonatologists (healthcare providers who specialize in newborns) can help you choose the right care plan for your child.
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