Refsum disease is one of a family of genetic disorders known as the leukodystrophies in which, as a consequence of the disruption of lipid metabolism, the myelin sheath that insulates and protects the nerves of the brain fails to grow. It is inherited as an autosomal recessive trait. It is characterized by progressive loss of vision (retinitis pigmentosa); degenerative nerve disease (peripheral neuropathy); failure of muscle coordination (ataxia); and dry, rough, scaly skin (ichthyosis).
The disorder is caused by the accumulation of a particular fatty acid (phytanic acid) in blood plasma and tissues. This occurs because of a malfunction of the gene that makes the enzyme that breaks down (metabolizes) this acid. The essential enzyme is absent.
Treatment with a diet low in foods that contain phytanic acid can be beneficial. Our bodies cannot make phytanic acid. Instead, it is introduced to the body in certain foods, including dairy products, beef, lamb and some seafood.