The Zellweger spectrum of peroxisome biogenesis disorders (PBD) are autosomal recessive disorders characterized by neurological defects (including demyelination, retinal dystrophy, hearing loss and seizures), craniofacial abnormalities, liver dysfunction and poor feeding and can be lethal at very young ages. These disorders were categorized clinically into a continuum of three phenotypes prior to their molecular characterization - Zellweger syndrome (the most severe form), neonatal adrenoleukodystrophy (NALD), and infantile Refsum disease (the least severe). Zellweger syndrome is indicated by the "A" in the OMIM subtype designation; the less severe forms are indicated with a "B" in the OMIM subtype designation.
Zellweger spectrum disorders are caused by mutations in one of 12 PEX genes. Mutations in PEX1 account for almost 70% of cases.
See the Peroxisome disorders page for non-Zellweger spectrum peroxisome disorders
General information links for the Zellweger spectrum of peroxisome biogenesis disorders: