Phytanic acid storage disease (Refsum's disease): clinical characteristics, pathophysiology and the role of therapeutic apheresis in its management.

Phytanic acid storage disease (known also as Refsum's Disease) is caused by inherited defects in the metabolic pathway for phytanic acid, a dietary branched-chain fatty acid. Poorly metabolized phytanic acid accumulates in fatty tissues, including myelin sheaths, and in organs including the liver and kidneys. Over time, affected individuals may develop classical diagnostic features of retinitis pigmentosa, cerebellar ataxia, peripheral polyneuropathy and an elevated protein content in the cerebrospinal fluid. Liver, kidney, and heart disease may also develop. Dietary restriction of phytanic acid is useful in preventing acute attacks and arresting the progression of organ impairment, especially in the peripheral nervous system. Therapeutic plasma exchange has been shown to be particularly useful for rapidly lowering plasma phytanic acid levels during acute attacks and may play a significant role as maintenance therapy as well. Copyright 1999 Wiley-Liss, Inc.