Cerebro-hepato-renal syndrome, sometimes called Zellweger syndrome, is a rare genetically determined disorder identified as one of the leukodystrophies in which the area affected is the growth of the myelin sheath, which is the fatty covering that acts and as insulation on nerve fibers in the brain. It is characterized by the absence or reduction of cell structures that rid the body of toxic substances called peroxisomes. It has a prenatal onset and may be identified by physical characteristics such as unusual craniofacial features, enlarged liver, and a lack of muscle tone. There may also be developmental delays, jaundice, gastrointestinal bleeding, seizures, and an inability to suck.