Manifestations of the mitochondrial A3243G mutation.

The tRNA(Leu) A3243G mutation is one of the most frequently observed mutations of mitochondrial DNA genes. Eighty percent of the patients with mitochondrial myopathy, encephalopathy and stroke-like episodes (MELAS) syndrome carry the mutation. Nevertheless, MELAS is genetically heterogeneous and presents with a wide range of phenotypic features. One of the organs most frequently affected is the heart. Cardiac abnormalities manifest as impulse generation or conduction abnormalities or abnormalities of the left ventricular myocardium. To recognize cardiac disease in MELAS thorough and comprehensive investigations are a prerequisite. Early detection of cardiac involvement is essential to punctually treat cardiac disease in MELAS and to prevent sudden cardiac death. Additionally, drugs toxic to the respiratory chain or oxidative phosphorylation need to be avoided. Cardiac affection in MELAS requires special attention since patients may survive malignant rhythm abnormalities or hard failure if detected and treated early.