I was recently reviewing evidence for epigenetic control in mitochondrial DNA and came across a nice review by Iacobazzi et al (Mol Gen Metab 2013, 110(2) 25-34). In this review, the authors describe evidence for methylation and other mechanisms for epigenetic control of mtDNA, and methodology for exploration of this. They also discuss evidence for this mechanism in human disease.
In my opinion, this is a significantly under-discussed area in inborn errors of metabolism (IEM); particularly in how downstream effects of some well-known IEMs may affect expression of mtDNA genes, and a rich area for further study.
Hilary Vernon, MD PhD