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PEX1 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

PEX1 gene

The PEX1 gene provides instructions for creating a protein essential for the formation and function of peroxisomes, which are critical for breaking down fatty acids and toxic substances.

Normal Function

The PEX1 gene provides instructions for making a protein called peroxisomal biogenesis factor 1 (Pex1p), which is part of a group of proteins called peroxins. Peroxins are essential for the formation and normal functioning of cell structures called peroxisomes. These sac-like compartments contain enzymes needed to break down many different substances, including fatty acids and certain toxic compounds. They are also important for the production of lipids used in digestion and in the nervous system. Peroxins assist in the formation (biogenesis) of peroxisomes by producing the membrane that separates the peroxisome from the rest of the cell and by importing enzymes into the peroxisome. Pex1p enables other peroxins to bring enzymes into the peroxisome.

Health Conditions Related to Genetic Changes

Zellweger spectrum disorder

At least 114 mutations in the PEX1 gene have been identified in people with Zellweger spectrum disorder, a group of conditions that affect many parts of the body. Mutations in this gene are the most common cause of the disorder, found in nearly 70 percent of affected individuals. Features of the condition vary in severity and can include:

  • Weak muscle tone (hypotonia)
  • Developmental delay
  • Vision problems
  • Hearing problems

Two common mutations include:

  • Gly843Asp (G843D): Replaces the amino acid glycine with aspartic acid at position 843. This leads to reduced protein levels, and individuals often experience signs and symptoms at the less-severe end of the spectrum.
  • 1700fs mutation: Leads to the production of an abnormally short, nonfunctional Pex1p. People with this mutation often have signs and symptoms at the severe end of the spectrum.

Mutations in the PEX1 gene reduce or eliminate the activity of the Pex1p protein. Without enough functional Pex1p, enzymes are not properly imported into peroxisomes, resulting in empty peroxisomes that cannot carry out their usual functions.

Genomic Location

The PEX1 gene is found on chromosome 7.

Frequently Asked Questions

Seek immediate medical care if your child develops sudden worsening of muscle tone (increased weakness or floppiness), unexplained seizures, severe vomiting or feeding intolerance, rapid decline in vision or hearing, or signs of respiratory distress. These can signal metabolic decompensation that requires urgent metabolic and supportive treatment.
Testing usually starts with a targeted DNA test that looks for the most common PEX1 mutations (e.g., G843D, 1700fs). If the result is negative but suspicion remains high, a full gene sequencing or a multigene panel for peroxisomal biogenesis disorders may be ordered. Results will report whether you carry two pathogenic variants (consistent with disease), one variant (carrier), or no pathogenic changes.
While diet cannot correct the underlying peroxisomal defect, limiting long‑chain fatty acids and avoiding foods high in phytanic acid (e.g., dairy, beef, lamb, certain fish) may reduce metabolic stress. Some clinicians also prescribe medium‑chain triglyceride (MCT) oil to provide an alternative energy source. Always coordinate dietary changes with a metabolic dietitian familiar with peroxisomal disorders.
Management is supportive and multidisciplinary: regular physiotherapy for hypotonia, vision and hearing aids, seizure control, and nutritional support. Liver‑protective agents (e.g., cholic acid) and antioxidant therapy are sometimes used, though evidence is limited. The G843D mutation is associated with a milder phenotype; many patients survive into childhood or early adulthood, but long‑term outcomes vary based on organ involvement and early intervention.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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