Peroxisome biogenesis disorder (PBD) is a group of lethal disorders caused by mutation of peroxisomal biogenesis factor (PEX) genes. PBDs fall into 4 main phenotypic classes; Zellweger syndrome (ZS), neonatal adrenoleukodystrophy (NALD), Infantile Refsum disease (IRD), and rhizomelic chondrodysplasia punctata (RCDP1). Zellweger syndrome is the most severe form and results in neurological dysfunction, craniofacial abnormalities, eye abnormalities, hepatomegaly, and chondrodysplasia punctata. The patients of NALD and IRD have similar symptoms, but they survive considerably longer than ZS. NALD is the intermediate form and IRD is the mildest form.
