Patterns of Refsum's disease. Phytanic acid oxidase deficiency.

Four children each exhibiting a profound deficiency of phytanic acid oxidase activity in cultured skin fibroblasts but with very different phenotypes, are described. A consistently raised plasma phytanic acid value, generally considered to be pathognomonic for Refsum's disease (phytanic acid oxidase deficiency), was observed in three of these children but not in the fourth, who also showed no evidence of accumulation of phytanic acid in liver or fat biopsies. Our data suggest that the clinical diagnosis of Refsum's disease in children is more difficult because the full spectrum of clinical features usually observed in adults with the disorder is not always present. Moreover, a failure to detect a raised plasma phytanic acid value may not necessarily indicate normal fibroblast phytanic acid oxidase activity.