Table 1.

Nuclear genes associated with instability of mitochondrial DNA in patients.

Gene	Clinical Disorder*	Consequence of mtDNA	Chromosome locus	Function
POLG (POLG1)	Ar Alpers or ataxia ArPEO/adPEO	Depletion Deletions	15q25	Mitochondrial DNA polymerase
POLG2	AdPEO	Deletions	17q23-24	Pol γ accessory subunit
DNA helicase (C10orf2)	AdPEO Ar ataxia/encephalopathy	Deletions Depletion	10q24	Mitochondrial DNA helicase, Twinkle
TP (TYMP)	Ar MNGIE	Depletion Deletions	22q13.32	Thymidine phosphorylase
DGUOK	Ar encephalohepatopathy	Depletion	2p13	Mitochondrial deoxyguanosine kinase
TK2	Ar congenital myopathy	Depletion	16q22	Mitochondrial thymidine kinase
RRM2B	Ar encephalomyopathy Ad PEO	Depletion	8q23.1	p53-inducible small subunit of ribonucleotide reductase
ANT1 (SLC25A4)	AdPEO	Deletions	4q34-35	Adenine nucleotide translocator
MPV17	Ar neurohepatopathy	Depletion	2p21-23	Mitochondrial inner membrane protein
SUCLA2	Ar encephalomyopathy	Depletion	13q12.2-q13.3	β-subunit, Succinate-CoA ligase
SUCLG1	Ar encephalomyopathy	Depletion	2p11.1	α-subunit, Succinate-CoA ligase
OPA1	Ad optic atrophy	Deletions	3q28-q29	Dynamin related GTPase

^*Ad, autosomal dominant; Ar, autosomal recessive