Zellweger Syndrome Disease: Causes, Symptoms, Diagnosis, Treatment

Overview

Zellweger syndrome (ZS) is a genetic disorder passed down from parents to children. The nerves and the metabolism is severely affected in the newborn. Newborns may have brain, liver, and kidney issues and difficulty feeding or moving.

In this blog, we cover all you wanted to know about Zellweger syndrome. 

What is Zellweger syndrome?

Zellweger syndrome is a genetic disorder found in newborns. Zellweger syndrome is the most serious and rare of the four types in the spectrum. It causes severe issues with nerves and metabolism (helps convert food into energy) soon after birth. 

It affects the brain, liver, and kidneys. It also harms principal functions throughout the body. Another term used for Zellweger syndrome is a cerebrohepatorenal syndrome. The condition is usually fatal.

What are the disorders in the Zellweger spectrum (ZSDs)?

These diseases affect peroxisomes and are also called peroxisomal biogenesis disorders. Peroxisomes are parts of cells that are crucial for ensuring many body functions work in harmony.

The other disorders in the Zellweger spectrum include:

• Infantile Refsum disease causes muscle movement issues and delays a baby’s growth.
• Heimler syndrome: Patients with Heimler syndrome suffer from tooth problems and hearing loss in late infancy or early childhood.
• Neonatal adrenoleukodystrophy causes hearing and vision loss and issues with the infant’s brain, muscles, and spine.  

The disorders share many symptoms, although not all individuals will have all the same symptoms or side effects depending on where they are on the spectrum.

 What are the symptoms?

Zellweger syndrome is quite rare. Both males and females can be born with this disorder. It affects several parts of body, including:

• Brain and Nervous System: Abnormal brain growth leading to seizures, diminished or absent reflexes, vision and hearing disability, severe mental retardation, and developmental delay
• Muscles and bones: Deficient muscle tone (called hypotonia), bone defects in the legs, hands, and feet
• Liver damage: Enlarged liver with impaired function, jaundice
• Kidney issues: Renal cysts, hydronephrosis

Facial abnormalities common in ZS include:

• Flattened face
• High forehead
• Broad nose bridge
• Wide-set eyes
• Epicanthal folds (skin folds at inner corners of eyes)
• Underdeveloped eyebrow ridges

Other symptoms include enlarged spleen, hearing and vision issues, bleeding in the digestive tract, seizures, underdeveloped muscles, movement issues, and problems in feeding.

Who Gets Zellweger Syndrome?

ZS is the outcome of mutations or changes in specific genes. It is an autosomal recessive disorder. A child can only inherit this disorder if both parents pass on a copy of the mutated gene.

And 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 disorder. The children also have a 25% chance of developing the disease.

How common is Zellweger syndrome?

As mentioned, Zellweger syndrome is quite rare. Along with the other diseases in the spectrum, they affect about 1 in 50,000 to 1 in 75,000 newborns.

How is Zellweger syndrome diagnosed?

A healthcare expert usually notices the facial features of the syndrome soon after birth. The following tests confirm the diagnosis:

• Imaging tests: An ultrasound helps check the size and function of the liver, kidneys, and other organs. A brain MRI (Magnetic Resonance Imaging) is also conducted during the diagnostic process.
• Blood and urine tests: Elevated levels of certain substances in the blood or urine, such as fat molecules, indicate the syndrome.
• Genetic tests: A blood test can help confirm the presence of the mutated PEX genes.

What are the causes of Zellweger syndrome?

It is caused due to the mutation in any of the 12 PEX genes. However, most cases of this syndrome are also due to the mutation in the PEX1 gene. They are responsible for controlling peroxisomes .

What are the complications of the syndrome?

Newborn babies with Zellweger syndrome may experience difficulty in hearing, seeing, or eating. If the babies have underdeveloped muscles, they may be unable to move. Infants often experience breathing problems and may develop liver failure or digestive tract bleeding.

What is the treatment?

Despite the progress science has made in understanding Zellweger syndrome, no cure exists yet, and infants born with this disorder usually die within the first year of their life. Health care and medical research focus on treating the symptoms present, such as liver dysfunction and seizures. 

Additionally, physical, occupational, and speech therapy can assist with feeding and speech issues.

Frequently Asked Questions

Can the syndrome be diagnosed before birth?

An unborn child is at risk if both parents carry the mutated genes. In such cases, doctors may conduct blood or imaging tests to diagnose to see if the unborn baby may develop the disorder.

How can Zellweger disease be prevented?

The disorder is not preventable as it is passed from parents to the children. A genetic counsellor may help evaluate the risks of passing the disease to the children or grandchildren.