Mitochondrial disease

Abstract

Mitochondrial encephalomyopathies are caused by primary defects of the respiratory chain that lead to disturbed generation of adenosine triphosphate by aerobic metabolism. This characteristically impairs the function of high-demand tissues such as the brain, eye, cardiac, and skeletal muscle, as well as endocrine organs. The numerous proteins involved are encoded by genes in mitochondrial or nuclear DNA. Mutations in these genes can lead to clinical disorders. Disorders of intermediary metabolism (such as fatty acid β‎-oxidation or tricarboxylic acid cycle defects) involve mitochondrial enzymes, but the term ‘mitochondrial disease’ usually means a disease which is due to an abnormality of the final common pathway of energy metabolism—the mitochondrial respiratory chain, which is linked to the production of adenosine triphosphate by oxidative phosphorylation. The respiratory chain is essential for aerobic metabolism, and respiratory chain defects characteristically affect tissues and organs that are heavily dependent upon oxidative metabolism.