Determination of medium chain acyl-CoA dehydrogenase activity in cultured skin fibroblasts using mass spectrometry

Medium chain acyl-CoA dehydrogenase deficiency, a defect of mitochondrial beta-oxidation, is one of the most frequently occurring among inborn errors of metabolism. We describe a rapid and sensitive gas chromatographic/mass spectrometric method allowing reliable assessment of medium chain acyl-CoA dehydrogenase activity in cultured skin fibroblasts. We investigated MCAD activity in three presumed medium chain acyl-CoA dehydrogenase deficient (MCADD) patients and 10 control subjects. The medium chain acyl-CoA dehydrogenase activity determined in three patients was 1.0 +/- 0.4 nmol . min-1 . mg-1 protein (mean +/- SD; range: 0.6-1.4) and in controls it was 2.8 +/- 1.0 nmol . min-1 . mg-1 protein (mean +/- SD; range: 1.6-4.4)