What you carry at this position in your DNA and what research says about it.
DNA Repair and Cancer Risk: 4/10 evidence, 50 publications.
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Sample genotype (not yours): C/C
Optimal DNA Repair and Typical Cancer Risk
Two copies of the reference C allele ensure fully functional OGG1 enzyme activity. This genotype maintains robust repair of oxidative DNA damage and typical baseline cancer risks.
What this genotype means: Optimal DNA repair capacity; Typical baseline cancer risk.
Sample genotype (not yours): C/G
Typical DNA Repair and Slightly Altered Cancer Risk
Carrying one copy of the G allele generally maintains normal DNA repair capacity. Most baseline cancer risks remain typical, though a slight increase in gallbladder cancer risk has been observed.
What this genotype means: Maintained DNA repair capacity; Slightly elevated gallbladder cancer risk.
Sample genotype (not yours): G/G
Reduced DNA Repair and Elevated Cancer Risk
Two copies of the G allele result in an OGG1 enzyme that is highly sensitive to oxidative inactivation. This leads to reduced DNA repair capacity and an increased risk of certain cancers, particularly bladder and gallbladder cancers.
What this genotype means: Reduced DNA repair capacity; Increased risk of bladder and gallbladder cancers.
Gene function and biological role
Gene Function: The OGG1 gene encodes 8-oxoguanine DNA glycosylase, a key enzyme in the base excision repair pathway [1]. This enzyme is responsible for recognizing and removing 8-oxoguanine, one of the most common mutagenic DNA lesions caused by reactive oxygen species [2]. By initiating the repair of oxidative DNA damage, OGG1 plays a critical role in maintaining genomic stability and preventing mutations that can lead to cancer [3]. Without functional OGG1, cells accumulate oxidative damage, particularly under environmental stress [4].
Variant Impact: The rs1052133 variant is a missense mutation in the OGG1 gene that changes the amino acid serine to cysteine at position 326 (p.Ser326Cys) [1]. This structural change alters the enzyme's physical properties, making it more sensitive to inactivation under oxidizing conditions [2]. Consequently, the cysteine-encoding G allele is associated with a reduced capacity to repair oxidative DNA damage [3]. This reduction in repair efficiency can lead to a higher accumulation of mutagenic DNA lesions over time [4].
Key Insight: The OGG1 enzyme becomes significantly less active under oxidative stress, meaning environmental factors like smoking can compound the genetic effect of this variant.
Location: OGG1. Chromosome 3 · 3p25.3 · 9.8 Mb
Estimated prevalence by population
Global 61.2%; European 60.6%; African 69.8%; East Asian 18.3%; South Asian 44.9%; Americas 57.2%; Ashkenazi 64.4%; Finnish 65.2%; Middle Eastern 44.9%; Amish 68.4%.
Estimated CC genotype frequency.
Global 33.3%; European 34.5%; African 27.5%; East Asian 49.0%; South Asian 44.2%; Americas 36.9%; Ashkenazi 31.7%; Finnish 31.1%; Middle Eastern 44.2%; Amish 28.6%.
Estimated CG genotype frequency.
Global 5.5%; European 4.9%; African 2.7%; East Asian 32.7%; South Asian 10.9%; Americas 5.9%; Ashkenazi 3.9%; Finnish 3.7%; Middle Eastern 10.9%; Amish 3.0%.
Estimated GG genotype frequency.
Showing effects for C/C genotype
Cancer & Oncology
Gastrointestinal Cancers
Gallbladder Cancer. Evidence: 4/10. Source: PMID 21708280. Typical Risk.
Urologic Cancers
Bladder Cancer. Evidence: 4/10. Source: PMID 23079842. Typical Risk.
General Cancer Risk
DNA Repair Capacity. Evidence: 3/10. Source: PMID 31891019. Optimal Capacity.
Lung Cancer
Lung Cancer. Evidence: 4/10. Source: PMID 22540013. Typical Risk.
Showing effects for C/G genotype
Gallbladder Cancer. Evidence: 4/10. Source: PMID 21708280. ~1.9x Increased Risk.
DNA Repair Capacity. Evidence: 3/10. Source: PMID 31891019. Typical Capacity.
Showing effects for G/G genotype
Gallbladder Cancer. Evidence: 4/10. Source: PMID 21708280. ~4.5x Increased Risk.
Bladder Cancer. Evidence: 4/10. Source: PMID 23079842. ~2x Increased Risk.
DNA Repair Capacity. Evidence: 3/10. Source: PMID 31891019. Reduced Capacity.
Lung Cancer. Evidence: 4/10. Source: PMID 22540013. ~2x Increased Risk.
What this genotype means for the people who carry it
Sample genotype: CC (Homozygous)
Having the C/C genotype means both copies of the OGG1 gene encode the fully active serine form of the enzyme [1]. This form efficiently repairs 8-oxoguanine lesions, preventing the accumulation of mutagenic DNA damage [2]. Studies show that individuals with this genotype have typical baseline risks for bladder, lung, and gallbladder cancers [3]. The enzyme maintains its stability and repair capacity even under oxidative stress, such as exposure to tobacco smoke or environmental toxins [4]. Consequently, cellular defense mechanisms against oxidative damage remain highly effective [1].
Optimal DNA repair capacity; Typical baseline cancer risk.
Sample genotype: CG (Heterozygous)
This heterozygous genotype means one copy of the OGG1 gene encodes the active serine form, while the other encodes the less stable cysteine form [1]. In most tissues, having one functional copy is sufficient to maintain normal overall DNA repair activity [2]. Consequently, risks for bladder and lung cancers remain at typical baseline levels [3]. However, some studies have noted a slightly elevated risk for gallbladder cancer in carriers of this genotype [4]. Overall, cellular health and DNA maintenance remain well-supported under normal conditions [1].
Maintained DNA repair capacity; Slightly elevated gallbladder cancer risk.
Sample genotype: GG (Homozygous)
Having the G/G genotype means both copies of the OGG1 gene encode the cysteine variant of the enzyme, which has reduced repair capacity under oxidative stress [1]. This impairment allows mutagenic oxidative lesions to accumulate more readily in cellular DNA [2]. Research associates this genotype with an approximately 2-fold increase in bladder cancer risk and a 4.5-fold increase in gallbladder cancer risk [3]. Some studies also suggest a moderate increase in lung cancer susceptibility, especially when combined with environmental exposures like smoking [4]. Maintaining a lifestyle low in oxidative stressors can help mitigate these risks [1].
Reduced DNA repair capacity; Increased risk of bladder and gallbladder cancers.
Variants with shared genetic architecture
rs267607954 · MSH2 Gene · Chr 2 · Lynch Syndrome Risk
rs397507581 · BRCA2 Gene · Chr 13 · Breast Cancer Risk
rs397507727 · BRCA2 Gene · Chr 13 · Hereditary Cancer Risk
Content updated August 2026.
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