Tissue distribution of mutant mitochondrial DNA in mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS).

We analysed the distribution of mutant mitochondrial DNA (mtDNA) with A-to-G substitution mutation of tRNA(Leu)(UUR) in various autopsied tissues from a patient with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS). There was no significant difference in the proportion (76-86%) of mutant mtDNA in many tissues, except in the lung and spleen. Unequal partitioning of mtDNA in somatic cells appears less prominent than that in germ cells.