POLG

Chr 15ARAD

DNA polymerase gamma, catalytic subunit

Also known as: MIRAS, MTDPS4A, MTDPS4B, PEO, POLG1, POLGA, PolG-alpha, SANDO

The encoded protein is the catalytic subunit of mitochondrial DNA polymerase, which replicates mitochondrial DNA. Mutations cause a spectrum of mitochondrial disorders including Alpers-Huttenlocher syndrome, progressive external ophthalmoplegia, sensory ataxic neuropathy with dysarthria and ophthalmoparesis (SANDO), and mitochondrial DNA depletion syndromes, inherited in both autosomal recessive and autosomal dominant patterns. The pathogenic mechanism involves defective mitochondrial DNA replication leading to mitochondrial DNA depletion or deletions.

OMIMResearchSummary from RefSeq, OMIM, UniProt
LOFmechanismAR/ADLOEUF 0.565 OMIM phenotypes
VCEP Guidelines: Mitochondrial DiseaseReleased
View SpecificationsClinGen Panel
Clinical SummaryPOLG
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Gene-Disease Validity (ClinGen)
Leigh syndrome · ARLimited

Limited evidence — not for standalone diagnostic reporting

Population Constraint (gnomAD)
Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.
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Clinical Trials
2 active or recruiting trials — potential therapeutic options may be available

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Moderate LoF intolerance
LoF Constraint
0.56LOEUF
pLI 0.000
Z-score 4.54
OE 0.40 (0.290.56)
Moderately constrained

More LoF-intolerant than ~75% of genes

Missense Constraint
-0.74Z-score
OE missense 1.08 (1.011.14)
770 obs / 714.2 exp
Tolerant

Tolerant to missense variation

Observed / Expected Ratios
LoF OE0.40 (0.290.56)
00.351.4
Missense OE1.08 (1.011.14)
00.61.4
Synonymous OE1.13
01.21.6
LoF obs/exp: 27 / 67.1Missense obs/exp: 770 / 714.2Syn Z: -1.77
Curated Mechanism (G2P)Gene2Phenotype (DDG2P) ↗
definitivePOLG-related progressive external ophthalmoplegiaOTHERAD
definitivePOLG-related mitochondrial ataxia syndromeLOFAR
definitivePOLG-related mitochondrial DNA depletion syndrome, Alpers typeOTHERAR
DN
0.5378th %ile
GOF
0.4678th %ile
LOF
0.3259th %ile

The highest-scoring mechanism for this gene is dominant-negative.

DN1 literature citation

Literature Evidence

DNThe WT/G451E p55 heterodimer impairs polg function in vitro, demonstrating that the POLG2 c.1352G>A/p.G451E mutation encodes a dominant negative protein.PMID:26123486

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

POLG · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

3D Protein StructureAlphaFold
Clinical Literature
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