The Biochemistry and Physiology of Mitochondrial Fatty Acid beta-Oxidation and Its Genetic Disorders

Mitochondrial fatty acid beta-oxidation (FAO) is the major pathway for the degradation of fatty acids and is essential for maintaining energy homeostasis in the human body. Fatty acids are a crucial energy source in the postabsorptive and fasted states when glucose supply is limiting. But even when glucose is abundantly available, FAO is a main energy source for the heart, skeletal muscle, and kidney. A series of enzymes, transporters, and other facilitating proteins are involved in FAO. Recessively inherited defects are known for most of the genes encoding these proteins. The clinical presentation of these disorders may include hypoketotic hypoglycemia, (cardio) myopathy, arrhythmia, and rhabdomyolysis and illustrates the importance of FAO during fasting and in hepatic and (cardio) muscular function. In this review, we present the current state of knowledge on the biochemistry and physiological functions of FAO and discuss the pathophysiological processes associated with FAO disorders.