GENE REFERENCE / HGNC:9179

POLG

DNA polymerase gamma, catalytic subunit

protein-coding gene15q26.1Gene information

What does this gene do?

The POLG gene provides instructions for making the active piece, called the alpha subunit, of a protein called polymerase gamma (pol γ). To be most effective, the alpha subunit attaches to two copies of another protein called the beta subunit to form pol γ. Pol γ is a DNA polymerase, which is a type of enzyme that "reads" sequences of DNA and uses them as templates to produce new DNA. These enzymes are important for copying (replicating) cells' genetic material. DNA polymerases also play critical roles in DNA repair.

Pol γ functions in mitochondria. Mitochondria are structures within cells in which a process called oxidative phosphorylation converts the energy from food into a form that cells can use. Mitochondria each contain a small amount of DNA, known as mitochondrial DNA (mtDNA), which is essential for the normal function of these structures. Pol γ is the only DNA polymerase that is active in mitochondria and that can replicate mtDNA.

Source: MedlinePlus, National Library of Medicine. Source publication: 2023-09-20. Source review: 2023-09.

ClinGen reviews

ClinGen reviews the evidence linking a particular gene to a condition. Each rating below describes the strength of that link. It does not classify a variant in your DNA file.

Condition	Inheritance	Evidence
Leigh syndromeMONDO:0009723 · Evaluated 2021-06-30	Autosomal recessive	LimitedMitochondrial Diseases Gene Curation Expert Panel

ClinVar records

These numbers show what has been submitted to ClinVar. They cannot tell you how likely you are to have a condition.

Submitted alleles: 3,532
Submissions for variants in or overlapping this gene: 7,665
Submissions explicitly reporting this gene: 7,487
Alleles reported pathogenic / likely pathogenic: 486
VariationIDs with uncertain significance: 1,532
VariationIDs with conflicting classifications: 297

The rows count different things: alleles, submissions or VariationIDs. Their categories can overlap, so do not add them together. Pathogenic/likely pathogenic counts exclude structural variants that merely overlap a gene. A dash in the source means “not reported,” not zero.

NCBI produces the gene-summary file each week using counts recorded at the start of the month. The numbers may differ from those on the live ClinVar website. Read the field definitions ↗

View this gene in ClinVar ↗

YOUR DNA FILE

Can your DNA file tell you about POLG?

From a DNA test kit (such as 23andMe, AncestryDNA or MyHeritage). These kits check a fixed list of about 600,000 to 700,000 positions across your whole genome. ClinVar lists 486 alleles in POLG reported as pathogenic or likely pathogenic. A kit checks only some of these positions, and often none of them.

From whole genome sequencing (a VCF file). Sequencing reads most of your genome. Your file lists the places where your DNA differs from the reference genome. Some regions are hard to sequence, including parts of some genes that have near-identical copies elsewhere, and a VCF file does not record which positions were read well.

If a variant is not in your file, that does not mean you don’t have it.

What BioDecode checks

BioDecode compares every variant in your file with ClinVar, on your own computer. For each match, it shows the ClinVar classification, the review status and the condition it was reported for. Your file is not uploaded.

A ClinVar classification applies to one particular variant and the condition it was reported for. It does not tell you about other variants in POLG.

BioDecode cannot fill gaps in your test, diagnose a condition or replace clinical testing.

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