A heterogeneous group of inherited metabolic disorders marked by absent or dysfunctional peroxisomes. Peroxisomal enzymatic abnormalities may be single or multiple. Biosynthetic peroxisomal pathways are compromised, including the ability to synthesise ether lipids and to oxidise long-chain fatty acid precursors. Diseases in this category include Zellweger syndrome; infantile Refsum disease; rhizomelic chondrodysplasia (rhizomelic chondrodysplasia punctata); hyperpipecolic acidemia; neonatal adrenoleukodystrophy; and adrenoleukodystrophy (X-linked). Neurologic dysfunction is a prominent feature of most peroxisomal disorders.