What do you need to know about your child’s Zellweger spectrum disorder (ZSD)?
It is 1 disease, but it has a spectrum of severity
Until recently, ZSDs were viewed as 3 separate diseases, but we now know they are a set of disorders that form a spectrum, or continuum, of 1 disease. This spectrum can range from mild (infantile Refsum disease, or IRD), to moderate (neonatal adrenoleukodystrophy, or NALD), to severe (Zellweger syndrome, or ZS).
ZSDs are also known as peroxisome biogenesis disorders (PBDs). These disorders are caused by a loss of function in important parts of your cells called “peroxisomes,” which can affect many parts of the body--from the eyes to the liver. Learn more about how it works here.
As a spectrum, ZSDs will affect each patient differently. How the disorders affect patients depends on their age when ZSD symptoms first start to appear.
No matter where someone is on the Zellweger spectrum, the impact is serious and lifelong, and it needs to be monitored consistently.
You are your child’s Champion—know how their ZSD is affecting them
What to watch out for when your child has a ZSD
How and when ZSDs affect different parts of the body can vary widely
ZSDs affect each person differently. Monitor your child for any changes to his/her symptoms, so you and your child’s healthcare team can provide timely care.
Not all changes to your child’s health can be easily noticed, so going to routine checkups with different specialists is very important
You may notice jaundice, but routine monitoring with liver function tests (LFTs)—which are done with a blood sample at the doctor’s office—and bile acid analysis are the best ways to know the condition of your child’s liver.
In ZSDs, a genetic defect causes a reduction or absence of an important component of many cells called “peroxisomes.”
A large number of peroxisomes can be found in the liver, helping with the production of bile acids, which are important for health.
When the liver lacks peroxisomes and cannot produce normal essential bile acids, abnormal toxic substances are produced in their place that cannot flow properly from the liver.
These toxic substances build up in the liver, which can lead to scarring of the liver and liver failure.
Unmanaged, progressive liver disease may increase the chance of having poorer disease outcomes.
LFTs help monitor liver health by checking the blood for liver enzymes.
Unusual spots on the ends of bones (ie, ankles, fingers)
Low bone density
X-rays may show abnormal spots around the growth plates (the growing tissue near the ends of long bones in children and adolescents) in severe cases. Your doctor may call this condition “chondrodysplasia punctata.”
Decreased bone density has been linked to worsening of disease.
Fractures can occur at random. A dual-energy x-ray absorptiometry scan is a bone density scan that can assess bone strength and risk of a fracture.