Simple urinary acylcarnitine profiling by gas chromatography mass spectrometry

Abstract

In many cases of sudden infant death, victims have been shown to be deficient in medium-chain acyl-CoA dehydrogenase (MCAD), a key enzyme for (3-oxidation of fatty acids. This disease, and several other inborn errors of metabolism leading to organic aciduria, are characterized by concentrations of certain acylcarnitines 1 in urine of the order of 1 pmol ml -1 . Normal levels of acylcarnitines are of the order of 1 nmol ml -1 . An affordable, routine analytical procedure for traces of urinary acylcarnitines would facilitate diagnosis of acidurias and acidemias. Acylcarnitines are essential to P-oxidation because they carry the fatty acyl units (RCO-) across the mitochondrial membrane. Carnitine detoxifies mitochondria of excesses of acyl groups by carrying them, as acylcarnitines, into urine. Thus profiling of urinary acylcarnitines would also allow the biochemistry of some currently ill-defined diseases, and the metabolic routes of acidic drugs, to be elucidated.