[Mitochondrial encephalopathies: where are we going?].

In few areas of medicine has progress been more spectacular than in the field of mitochondrial diseases, especially those related to mtDNA mutations. Much remains to be done, however, and this brief review discusses the following areas of research where progress has been more limited or data are still controversial: 1. The pathophysiology of mtDNA related disorders; 2. The molecular base of nDNA mutations; 3. The coenzyme Q10 deficiency; 4. Defects of translocases; 5. Defects of mitochondrial protein importation, and 6. Defects of intergemonic signalling.