Table 1.

Candidate genes potentially involved in the control of mtDNA mutation rate and ageing.

gene	protein product	function/process	involvement in mtDNA mutation and ageing
POLG	mtDNA polymerase	mtDNA replication and maintenance	protein defects leads to accumulation of mtDNA mutations
POLG2	Pol γ accessory subunit	mtDNA replication and maintenance	protein defects lead to accumulation of mtDNA mutations
TFAM	transcription factor A	mtDNA replication and maintenance	protein defects increase exposure of mtDNA to ROS
TWINKLE (PEO1)	mitochondrial helicase	mtDNA replication and maintenance	protein defects lead to multiple DNA deletions
ANT1 (SLC25A4)	ADP/ATP translocase 1	ROS production	under-expression stalls electron transport chain and increases ROS production
UCPs	mitochondrial uncoupling proteins UCP1,UCP2, UCP3	ROS production	protein defects may increase ROS production
SOD2	superoxide dismutases [Mn]	protection against oxidative damage	protein defects increase oxidative stress
MPV17I	peroxisomal membrane protein family	protection against oxidative damage	downregulation leads to increased ROS damage
HTRA2	serine protease HTRA2	protection against oxidative damage	downregulation leads to increased ROS damage and apoptosis
FOXO3A	forkhead box protein O3	protection against oxidative damage	protein defects increase ROS and trigger apoptosis upon cellular stress
PINK1	serine/threonine-protein kinase	protection against oxidative damage	protein defects triggers mitochondrial dysfunction and apoptosis