Infantile Refsum's disease: a peroxisomal storage disorder?

An 18-month-old infant presented with a history of arrest of neurological development from the age of eight months, with progressive ataxia, deafness, retinitis pigmentosa and hepatomegaly. Biochemical investigations revealed an elevated plasma phytanic acid level and deficiency of phytanic acid oxidase in skin fibroblasts. Histopathological findings in a liver biopsy were similar to those reported in infantile phytanic acid storage disease. Unexpected findings were the presence of elevated levels of plasma pipecolic acid, and elevated plasma long-chain fatty acid ratios, biochemical findings previously considered to be diagnostic of Zellweger's hepato-cerebro-renal syndrome, and of adrenoleucodystrophy, respectively. Recent biochemical evidence suggests that this patient, and other similar cases that have recently come to our attention, may have a fundamental defect in the peroxisomal enzyme system.