Functional redundancy of mitochondrial enoyl-CoA isomerases in the oxidation of unsaturated fatty acids

Michel Van Weeghel, Heleen Te Brinke, Henk Van Lenthe, Wim Kulik, Paul E. Minkler, Maria S.K. Stoll, Jörn Oliver Sass, Uwe Janssen, Wilhelm Stoffel, K. Otfried Schwab, Ronald J.A. Wanders, Charles L. Hoppel, Sander M. Houten

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


Mitochondrial enoyl-CoA isomerase (ECI1) is an auxiliary enzyme involved in unsaturated fatty acid oxidation. In contrast to most of the other enzymes involved in fatty acid oxidation, a deficiency of ECI1 has yet to be identified in humans. We used wild-type (WT) and Eci1-deficient knockout (KO) mice to explore a potential presentation of human ECI1 deficiency. Upon food withdrawal, Eci1-deficient mice displayed normal blood β-hydroxybutyrate levels (WT 1.09 mM vs. KO 1.10 mM), a trend to lower blood glucose levels (WT 4.58 mM vs. KO 3.87 mM, P=0.09) and elevated blood levels of unsaturated acylcarnitines, in particular C12:1 acylcarnitine (WT 0.03 μM vs. KO 0.09 μM, P<0.01). Feeding an olive oil-rich diet induced an even greater increase in C12:1 acylcarnitine levels (WT 0.01 μM vs. KO 0.04 μM, P<0.01). Overall, the phenotypic presentation of Eci1-deficient mice is mild, possibly caused by the presence of a second enoyl-CoA isomerase (Eci2) in mitochondria. Knockdown of Eci2 in Eci1-deficient fibroblasts caused a more pronounced accumulation of C12:1 acylcarnitine on incubation with unsaturated fatty acids (12-fold, P<0.05). We conclude that Eci2 compensates for Eci1 deficiency explaining the mild phenotype of Eci1-deficient mice. Hypoglycemia and accumulation of C12:1 acylcarnitine might be diagnostic markers to identify ECI1 deficiency in humans.

Original languageEnglish
Pages (from-to)4316-4326
Number of pages11
JournalFASEB Journal
Issue number10
StatePublished - Oct 2012
Externally publishedYes


  • Inherited metabolic disease
  • Mouse models


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