Description | 3D,7D,11D-Phytanic acid is an isomer of Phytanic acid, an unusual 20-carbon branched-chain fatty acid; Phytanic acid accumulates in blood and tissues of patients with Refsum disease (RD, an inborn error of lipid metabolism inherited as an autosomal recessive trait (OMIM 266500)), and is a reliable identifier of RD from a large number of other neurological disorders. Phytanic acid also accumulates in a number of other disorders with a very different clinical course: disorders of peroxisome biogenesis (Zellweger syndrome (OMIM 214100), neonatal adrenoleukodystrophy (OMIM 202370), infantile Refsum disease (OMIM 266510)) and rhizomelic chondrodysplasia punctata, type 1 (OMIM 215100). Phytanic acid is a 3-methyl fatty acid that cannot be beta-oxidized directly, and first undergoes an alpha-oxidation a reaction catalyzed by the enzyme phytanoyl-CoA hydroxylase, which is deficient in RD, the only true disorder of phytanic acid alpha-oxidation. (The Metabolic and Molecular Bases of Inherited Disease) |