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Mitochondrial structure, function, and genetics

Rami Massie, MD
Section Editors
Jeremy M Shefner, MD, PhD
Sihoun Hahn, MD, PhD
Deputy Editor
John F Dashe, MD, PhD


Mitochondrial diseases are a group of disorders caused by pathologic dysfunction of the mitochondrial respiratory chain. They present with a wide range of clinical expression [1]. Although neurologic impairment is a common manifestation (eg, in the mitochondrial encephalomyopathies), mitochondrial disorders can also affect other organ systems, either exclusively or in combination.

In this topic, we will review the mitochondrial structure and its unique genetic attributes. Clinical aspects of mitochondrial disorders are discussed separately. (See "Mitochondrial myopathies: Clinical features and diagnosis" and "Renal involvement in the mitochondrial cytopathies".)


Mitochondria are intracellular organelles found in almost all human cells. They are responsible for aerobic metabolism through oxidative phosphorylation, which leads to energy production in the form of adenosine triphosphate (ATP).

Mitochondria are thought to be derived from aerobic bacteria that invaded the proto eukaryotic cell more than a billion years ago and lived in a symbiotic relationship with it, exchanging energy in the form of ATP for residence. However, this "endosymbiotic hypothesis" is not universally accepted and has been challenged [2].

Each human cell contains on average hundreds to thousands of mitochondria. The exception is mature red blood cells, which rely exclusively on anaerobic metabolism and contain no mitochondria.


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Literature review current through: Mar 2017. | This topic last updated: Oct 01, 2014.
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