MSI_000053442

Phytanic acid (or 3,7,11,15-tetramethylhexadecanoic acid) is a 20-carbon branched-chain fatty acid that humans can obtain through the consumption of dairy products, ruminant animal fats, and certain fish. It is primarily formed by bacterial degradation of chlorophyll in the intestinal tract of ruminants. Unlike most fatty acids, phytanic acid cannot be metabolized by beta-oxidation (because of a methyl group in the beta position). Instead, it undergoes alpha-oxidation in the peroxisome, where it is converted into pristanic acid by the removal of one carbon. Pristanic acid can undergo several rounds of beta-oxidation in the peroxisome to form medium-chain fatty acids that can be converted into carbon dioxide and water in mitochondria. Refsum disease, an autosomal recessive neurological disorder caused by mutations in the PHYH gene, is characterized by having impaired alpha-oxidation activity. Individuals with Refsum disease accumulate large stores of phytanic acid in their blood and tissues. This frequently leads to peripheral polyneuropathy, cerebellar ataxia, retinitis pigmentosa, anosmia, and hearing loss. Therefore, chronically high levels of phytanic acid can be neurotoxic. Phytanic acids neurotoxicity appears to lie in its ability to initiate astrocyte/neural cell death by activating the mitochondrial route of apoptosis. In particular, phytanic acid can induce the substantial generation of reactive oxygen species in isolated mitochondria as well as in intact cells. It also induces the release of cytochrome c from mitochondria. A 20-carbon branched chain fatty acid, Phytanic acid is present in animal (primarily herbivores or omnivores) tissues where it may be derived from the chlorophyll in consumed plant material. Phytanic acid derives from the corresponding alcohol, phytol, and is ultimately oxidized into pristanic acid. In phytanic acid storage disease (Refsum disease) this lipid may comprise as much as 30\\% of the total fatty acids in plasma. These high levels in Refsum disease (a neurological disorder) are due to a phytanic acid alpha-hydroxylase deficiency.; A 20-carbon branched chain fatty acid. In phytanic acid storage disease (Refsum disease) this lipid may comprise as much as 30\\% of the total fatty acids of the plasma. This is due to a phytanic acid alpha-hydroxylase deficiency. [HMDB]