Rita Horvath works in the Department of Clinical Neurosciences at the University of Cambridge, John van Geest Centre for Brain Repair, Cambridge, United Kingdom Michio Hirano is the Lucy G. Moses Professor, Director of the H. Houston Merritt Neuromuscular Research Center, and Chief of the Division of Neuromuscular Medicine in the Department of Neurology at the Columbia University Irving Medical Center, New York, NY, United States. Patrick Francis Chinnery works at the MRC Mitochondrial Biology Unit and Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom.

• Section I. Introduction to Mitochondrial Diseases 1. Mitochondrial disease in neurology – Past, present, and futureSection II. Most Common Neurological Manifestations of Mitochondrial Disease2. Progressive external ophthalmoplegia3. Mitochondrial optic neuropathies4. Leigh syndrome5. Stroke-like episodes in adult mitochondrial disease6. Ataxia and spastic paraplegia in mitochondrial disease7. Peripheral neuropathy in mitochondrial disease8. Complex neurological and multisystem presentations in mitochondrial diseaseSection III. Diagnosing Mitochondrial Disease9. Investigation of oxidative phosphorylation activity and composition in mitochondrial disease10. Genetics of mitochondrial diseases: Current approaches for the molecular diagnosis11. Laboratory and metabolic investigations12. Neuroimaging in mitochondrial diseaseSection IV. Therapy and Future Challenges13. Currently available therapies in mitochondrial disease14. Reproductive options in mitochondrial disease15. Clinical trials in mitochondrial disease16. Blood biomarkers of mitochondrial disease – One for all or all for one?17. Experimental therapy for mitochondrial diseases