3-Methyladipic acid is a catabolite of the branched-chain fatty acid phytanic acid , which is ingested via the diet.1 It is formed from phytanic acid via ω- and then β-oxidation in patients with adult Refsum disease, a disorder characterized by high levels of phytanic acid in the blood and tissues due to a deficiency in phytanoyl-CoA hydroxylase, the enzyme that converts phytanoyl-CoA to 2-hydroxyphytanoyl-CoA during peroxisomal β-oxidation.1,2,3 Urinary levels of 3-methyladipic acid have been used as a biomarker for the ω-oxidation of phytanic acid in patients with adult Refsum disease.1
1.Wierzbicki, A.S., Mayne, P.D., Lloyd, M.D., et al.Metabolism of phytanic acid and 3-methyl-adipic acid excretion in patients with adult Refsum diseaseJ. Lipid Res.44(8)1481-1488(2003) 2.Verhoeven, N.M., Wanders, R.J., Poll-The, B.T., et al.The metabolism of phytanic acid and pristanic acid in man: A reviewJ. Inherit. Metab. Dis.21(7)697-728(1998) 3.Van Veldhoven, P.P.Biochemistry and genetics of inherited disorders of peroxisomal fatty acid metabolismJ. Lipid Res.51(10)2863-2895(2010)