Mitochondrial diseases.

Mitochondrial diseases collectively describe a diverse group of heritable disorders that invariably affect mitochondrial respiratory chain function and cellular energy production. Together they represent the most common cause of inherited metabolic disease, may present at any age, have a wide spectrum of clinical manifestations, may be insidious in onset, and potentially have high morbidity and mortality. Due to the presence of mitochondria in all nucleated cells, mitochondrial disease can affect many different tissues, with single or multiple systems being involved. This leads to highly variable presentations, making the diagnosis of mitochondrial diseases challenging. Recent advances in biomarker and genetic testing, coupled with emerging treatments and reproductive options, hold great promise for improving the clinical identification and management of this highly mutable disease group.