The metabolic basis of the Refsum syndrome.

Studies in patients with the Refsum syndrome show that accumulation of phytanic acid stems from a metabolic error in the pathway for its oxidative degradation. The major degradative pathway involves an initial alpha oxidation followed by successive beta oxidation steps. The enzyme defect in patients with phytanic acid storage appears to be at the very first step, alphahydroxylation of phytanic acid. Heterozygous carriers have a partial fibroblasts in cell culture. On diets low in phytanic acid content, plasma phytanic acid levels fall and objective studies in patients suggest therapeutic benefit.