Frequently Asked Questions about Peroxisomal Disorders

You have been told that your child has or may have a peroxisomal disorder. This is a scary and difficult time for you and your family.

All parents have questions about the diagnosis and what it means for their child and their family. We wish we could tell you it will all go away. Unfortunately, it won’t. You may have some really difficult days ahead of you. But please remember, there are many of us who have been there, done that. Please do not hesitate to come to us for advice and support. Here are some questions and responses from other parents whose families have been impacted by Peroxisomal Disorders. Keep in mind these are responses of parents, not doctors. They are not a replacement for your doctor’s advice.

1. What is a Peroxisomal Disorder? Are there different types?

You may have been told that you or your child has Zellweger Syndrome (ZS), Neonatal Adrenoleukodystrophy (NALD), Infantile Refsum Disease (IRD), or Heimler syndrome. As the understanding of peroxisomal disorders has grown, there has been a movement away from the use of how these were historically described. It is now recommended to replace these names with the overall classification of this spectrum by using the terminology, Peroxisome Biogenesis Disorder-Zellweger Spectrum Disorder (PBD-ZSD). You may also see us simply use peroxisomal disorders to be inclusive of all phenotypes the GFPD supports, including, D-Bifunctional Protein Deficiency (DBPD), and Acyl-CoA Oxidase Deficiency (ACOX). These are all rare, genetic, metabolic, terminal conditions affecting all major systems of the body. To watch a video that expands please visit:

2. Why do they think my child has a Peroxisomal Disorder?

Global developmental delay is a hallmark characteristic of peroxisomal disorders. This is often accompanied by severe craniofacial abnormalities, including a high forehead, a flat occiput (the bone-forming the rear and rear bottom of the skull), a large fontanelle (the child’s “soft spot”), a broad nasal bridge, shallow orbital ridges (the ridge beneath the eyebrow), and a high arched palate. Another typical feature of the Zellweger Spectrum involves abnormalities of the eye, such as Brushfield spots (speckled iris, although this can occur in normal children), cataracts, and glaucoma. Hepatomegaly (enlargement of the liver), renal cysts, impaired adrenocortical function, and hypotonia (poor muscle tone, or “floppiness”) are also common features. Many children, but not all, also fail their newborn hearing screening.

Biochemical assays can determine definitively whether an individual has a peroxisomal disorder. The measurement of plasma very-long-chain fatty acid (VLCFA) concentrations is the most commonly used and most informative initial screen. Elevation of the plasma concentrations of C26:0 and C26:1 and the ratios of C24/C22 and C26/C22 is consistent with a defect in peroxisomal fatty acid metabolism. The degree of VLCFA plasma concentration elevation may vary, with a small percentage of individuals demonstrating only modest elevations. For more information visit the GENE Review for Peroxisomal biogenesis disorders at

3. How does a child become affected by a Peroxisomal Disorder? Will it happen again?

Peroxisomal Disorders are inherited in an autosomal recessive manner, meaning each parent is an unaffected (asymptomatic) carrier. Any additional children conceived by parents who are both asymptomatic carriers have a 25% chance of being affected, a 50% chance of being an asymptomatic carrier, and a 25% chance of being unaffected and not a carrier. (GENE Reviews – )

4. What type of pediatric medical specialists should my child see?

In addition to a primary care physician/pediatrician your child may need the following pediatric specialists: Audiologist, Endocrinologist, Gastroenterologist (GI), Geneticist, Neurologist, Ophthalmologist, Orthopedic, Otolaryngologist (ENT) and Pulmonologist.

5. What treatments exist for Peroxisomal Disorders?

While there is currently no cure for peroxisomal disorders, treatment is symptomatic. It is recommended that all children diagnosed with peroxisomal disorder take a multivitamin supplement which includes higher levels of vitamins A, D, E, and K (ex. Source CF and AquADEKs). Some children experience Coagulopathy (impaired blood clotting) and therefore require additional supplementation of vitamin K (ex. Mephyton). Many children also take a DHA supplement. Children with adrenal insufficiency will require daily steroid treatments as prescribed by their endocrinologist. Children experiencing seizures will require anti-seizure medicine as prescribed by their neurologist. Children also may experience spontaneous bone fractures as well as osteopenia. A pediatric orthopedic specialist can advise families on the best treatment for osteopenia. Reminder: This information is not to take the place of your child’s primary care physician and medical team.

6. What does my child’s future look like?

We often say that an individual affected by a peroxisomal disorder “writes their own story,” as each one is unique. Even individuals with the same mutations are often impacted differently. Children at the severe end of the spectrum typically do not survive their first year. Children on the moderate or mild end of the spectrum may live into childhood, teen years or beyond, although most children do not live past age ten. Hallmark symptoms of peroxisomal disorders include sensorineural hearing loss, vision loss, hypotonia, seizures, developmental delays, liver and kidney issues, problems with bone formation, feeding issues, and adrenal insufficiency. 

Children who are at the most severe end of the spectrum typically meet very few developmental milestones. Children at the mild end of the spectrum often learn to walk, talk, read, and develop varying degrees of independence. Some children have suffered a regression resulting in the loss of skills previously gained. Therefore, it is difficult to determine where an individual may ultimately fall along the spectrum. Early intervention and ongoing therapy services such as physical therapy, occupational therapy, speech, feeding therapy/nutrition, hearing and vision services are often necessary and prescribed for a child with a peroxisomal disorder throughout his/her lifetime.

7. How does a Peroxisomal Disorder affect my child’s physical and cognitive abilities?

Peroxisomal disorders affect each child differently, however nearly all children experience global delays along with combined hearing and vision impairments. Children who are at the most severe end of the spectrum typically meet very few developmental milestones. Children at the mildest end of the spectrum often learn to walk, talk, and a few can even read. Some children have suffered a regression resulting in the loss of skills previously gained. Therefore, it is difficult to determine where your child may ultimately fall along the spectrum.

8. How can I find out more about Peroxisomal Disorders and connect with other parents?

The Global Foundation for Peroxisomal Disorders, a 501(c)(3) public charity,  currently connects more than 500 families from over 40 countries with the following types of Peroxisomal Disorders: Zellweger Spectrum Disorder (ZSD), D-Bifunctional Protein Deficiency (DBPD), and Acyl-CoA Oxidase Deficiency (ACOX). These patients and families have an array of diverse experiences creating an invaluable source of support. You may have some difficult days ahead of you, but please remember that there are many of us who are walking this journey with you. The Global
Foundation for Peroxisomal Disorders (GFPD) can help; you do not have to face this diagnosis alone.

The GFPD Supports these families through connections to medical & scientific professionals. Additionally, The GFPD supports it’s families through family support and informational conferences, connecting families through online support groups, and provides an equipment exchange program. The GPFD also shares objective and credible information to families, caregivers of patients, and adult patient self-advocates, with Peroxisomal Disorders, and is a voice in the public arena for children affected by the disorders