FunctionConverts phytanoyl-CoA to 2-hydroxyphytanoyl-CoA.
Tissue specificityExpressed in liver, kidney, and T-cells, but not in spleen, brain, heart, lung and skeletal muscle.
PathwayLipid metabolism; fatty acid metabolism.
Involvement in diseaseDefects in PHYH are a cause of Refsum disease (RD) [MIM:266500]. RD is an autosomal recessive disorder characterized clinically by a tetrad of abnormalities: retinitis pigmentosa, peripheral neuropathy, cerebellar ataxia, and elevated protein levels in the cerebrospinal fluid (CSF). Patients exhibit accumulation of the branched-chain fatty acid, phytanic acid, in blood and tissues. Less constant features are nerve deafness, anosmia, skeletal abnormalities, ichthyosis, cataracts and cardiac impairment. Manifestations of the disease appear in the second or third decade of life.