OSBOND ACID (all-cis-4,7,10,13,16-DPA) is an isomer of docosapentaenoic acid (DPA). DPA is a 22-carbon fatty acid found in fish oils. It is a minor constituent of the total serum unsaturated fatty acids in humans, ranging from 0.1 to 1%, and is used as a dietary supplement. OSBOND ACID is an ω-6 fatty acid formed by the elongation and desaturation of arachidonic acid. It is considered a marker of the functional DHA status. Levels of this fatty acid may be diminished during fatty acid desaturase syndrome and this possibly affects development. One study found that high levels of maternal OSBOND ACID (22:5n−6) were associated with higher verbal IQ in their children. Upregulation of OSBOND ACID also correlates with tumor burden in nonalcoholic steatohepatitis (a common preneoplastic condition of hepatocellular carcinoma).