Clinical presentation of inherited mitochondrial fatty acid oxidation disorders: an update

Fourteen hereditary disorders of fatty acid oxidation have been recognized within the last two decades. They can cause clinical symptoms ranging from antenatal manifestations such as malformations to neonatal acidotic coma, hypoglycemia, Reye syndrome-like episodes, sudden infant death, myopathy, cardiomyopathy, heartbeat disorders, myoglobinuria, retinitis pigmentosa, peripheral neuropathy, and renal manifestations. These inborn errors deserve prompt recognition since they can often be treated. Their overlapping clinical spectrum results in part from the accumulation of related toxic compounds, proximal to the metabolic block, and in part from the deficiency in energy production from fatty adds, ensuing distally from the defect in liver, myocardium, and skeletal muscle. This article reviews the pathophysiology and clinical presentation of known inborn errors of fatty acid catabolism. A summary of our experience with 84 patients, together with proposals for the diagnosis and therapeutic approach to these disorders, is presented.