Fig. 1

Mitochondrial genome and pathogenic mtDNA mutations. Human mitochondrial genome is shown as circular, double-stranded DNA molecule with annotations. The ribosomal RNA genes are shown in purple, while tRNA genes are shown in white and annotated with single letter abbreviations. The subunits of complex I (cyan), cytochrome b (green) of complex III, subunits of complex IV (yellow) and complex V (red) are denoted by the position along the mtDNA sequence, with the outer circle as the heavy chain, and inner circle as the light chain. The positions of pathogenic mtDNA mutations are marked by black arrows. KSS Kearns–Sayre syndrome, LHON Leber’s hereditary optic neuropathy, MELAS Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like episodes, MERRF Myoclonic Epilepsy and Ragged Red Muscle Fibers