This odd numbered omega-hydroxy heneicosanoic acid is ideal as an internal standard for studies involving long-chain omega-hydroxy fatty acids.1 omega-Hydroxy C21:0 fatty acid and other omega-hydroxy fatty acids can be lactonized by certain enzymes into mono- and oligolactones.2 omega-Oxidation is a minor fatty acid pathway used for fatty acid metabolism and usually occurs in the smooth endoplasmic reticulum. Stimulation of omega-hydroxylation has been proposed as a method for treating X-linked adrenoleukodystrophy, a disease that is characterized by elevated levels of very long chain fatty acids.3 omega-Hydroxy fatty acids have an important role while acylated to various lipids. omega-Hydroxylated very long chain fatty acid (VLCFA) ceramides are vital to skin barrier functions and a deficiency of these lipids can cause death from water loss through the skin. In atopic dermatitis, a common skin disease, there are considerable deficiencies of omegahydroxy long chain fatty acids acylated to ceramides and this may contribute to the severely damaged permeability barrier found in this disease.4
