ANALYSIS OF FATTY-ACID OXIDATION INTERMEDIATES IN CULTURED FIBROBLASTS TO DETECT MITOCHONDRIAL OXIDATION DISORDERS

We describe a method for the diagnosis of mitochondrial fatty acid oxi dation disorders that is based on the analysis of acylcarnitine and ac yl-coenzyme A (acyl-CoA) esters generated during fatty acid oxidation by permeabilized skin fibroblasts. This method requires only small-amo unts of cultured fibroblasts with minimal preparation, and no isolatio n of mitochondrial fractions is necessary. During oxidation of [U-C-14 ]hexadecanoate, normal human fibroblasts produce a characteristic patt ern of acylcarnitine and acyl-CoA ester intermediates. Incubations of fibroblasts from patients with fatty acid oxidation defects show a com pletely different pattern of intermediates, and in each case the obser ved profile reflects the site of the defect. The diagnosis and likely site of a mitochondrial fatty acid oxidation defect can be made readil y from two 80-cm(2) culture flasks of fibroblasts with this technique.