A Defect in the Transport of Long-Chain Fatty Acids Associated with Acute Liver Failure

Abstract

Fatty-acid oxidation has a major role in en- ergy production during periods of fasting. When body glucose is depleted, fatty acids are mobilized from adipose tissue, taken up by the liver, and converted to ketone bodies, a major alternative source of energy for peripheral tissues. 1 At the cellu- lar level, after being transported through the cell membrane and then into the mitochondria by means of a carnitine-dependent system, long-chain fatty ac- ids are predominantly oxidized in mitochondria. 2,3 Common clinical features of disorders of fatty-acid oxidation are metabolic decompensation during fast- ing, hypoketotic hypoglycemia, and acute dysfunc- tion of fatty-acid–dependent tissues (skeletal muscle, heart, and liver), often leading to sudden death in early life. 4-6 Although understanding of the biochem- ical and molecular bases of these disorders has im- proved dramatically in recent years, affected patients are often given a diagnosis of an unspecified disorder of fatty-acid oxidation. 7 The study of such patients has provided valuable insights into the oxidative proc- ess. 8-10 We describe two young boys who presented with acute liver failure and were found to have a de- fect in the transport of long-chain fatty acids.