phytanic acid
Definition: Phytanic acid is a branched fatty acid.
Phytanic acid (or 3,7,11,15-tetramethyl hexadecanoic acid) is present in human diet or in animal tissues where it may be derived from chlorophyll in plant extracts. Phytanic acid derives from the corresponding alcohol, phytol, and is oxidized into pristanic acid.
Pathology
Phytanic acid accumulates in Refsum syndrome.
This inherited neurological disorder is characterized by an accumulation of a normal metabolite of phytol (phytanic acid) in blood and tissues, and the disorder was later found to be related to deficiency in the alpha-oxidation pathway in the liver.
Refsum disease primarily affects the nervous system with a series of debilitating symptoms. Some symptoms include: degenerative nerve disease (peripheral neuropathy); vision loss (retinitis pigmentosa); loss of muscle control/coordination (ataxia); and possibly scaly, dry skin and scalp (ichthyosis).
Refsum disease is thought to be caused by the accumulation of phytanic acid due to some malfunction in metabolism, probably a deficiency in phytanoyl CoA hydroxylase .
This is thought to be caused by a faulty gene that codes for this enzyme that metabolizes phytanic acid. There is no current pharmacological cure for the syndrome, but a diet low in phytanic acid can be of benefit to patients with Refsum syndrome.
Plasma filtering to remove some of the dissolved phytanic acid from the blood is another common treatment.
See also
branched fatty acids