What you carry at this position in your DNA and what research says about it.
DNA Repair Capacity: 6/10 evidence, 60 publications.
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Sample genotype (not yours): C/C
Efficient DNA Repair and Typical Cancer Risk
Presence of the reference C allele is associated with fully functional DNA repair mechanisms. This genotype represents the typical baseline risk for various cancers and standard responses to platinum-based chemotherapy.
What this genotype means: Optimal DNA repair capacity; Typical baseline risk for several cancers; Standard response to platinum-based chemotherapy.
Sample genotype (not yours): C/T
Typical DNA Repair and Intermediate Chemotherapy Response
Possession of one T allele results in a mixture of standard and slightly less active DNA repair enzymes. This genotype generally maintains typical baseline health risks but may influence responses to certain cancer therapies.
What this genotype means: Intermediate DNA repair capacity; Typical baseline cancer risk; Variable sensitivity to chemotherapy agents.
Sample genotype (not yours): T/T
Reduced DNA Repair and Altered Chemotherapy Sensitivity
Presence of two T alleles is linked to slightly reduced DNA repair efficiency. This genotype may modestly increase susceptibility to certain cancers and alter responses to platinum-based chemotherapy.
What this genotype means: Slightly reduced DNA repair efficiency; Modestly increased risk for certain cancers; Altered sensitivity and toxicity risk with chemotherapy.
Gene function and biological role
Gene Function: The ERCC2 gene, also known as XPD, encodes an essential enzyme involved in the nucleotide excision repair pathway [1]. This ATP-dependent DNA helicase is a core component of the transcription factor IIH complex, which helps unwind the DNA double helix to allow repair of damaged sections [1]. It plays a critical role in fixing DNA damage caused by ultraviolet radiation, chemical carcinogens, and environmental toxins [2]. Proper functioning of this pathway is vital for maintaining genomic stability and preventing the accumulation of mutations that can lead to cancer [2]. Severe mutations in this gene can cause rare genetic disorders like xeroderma pigmentosum, which is characterized by extreme sensitivity to sunlight [1].
Variant Impact: The rs1799793 variant is a missense mutation in exon 10 of the ERCC2 gene that changes the amino acid at position 312 from aspartate to asparagine [1]. This structural alteration, often referred to as Asp312Asn, can influence the helicase activity of the ERCC2 protein and affect overall DNA repair capacity [3]. While the variant does not cause severe genetic disorders like xeroderma pigmentosum on its own, it is widely studied for its subtle impact on cancer susceptibility and chemotherapy outcomes [1] [4]. The minor T allele is relatively common across global populations, particularly in European and Middle Eastern ancestries.
Key Insight: The same genetic variant that slightly reduces DNA repair efficiency and increases cancer risk can also make cancer cells more vulnerable to chemotherapy drugs like cisplatin.
Location: ERCC2. Chromosome 19 · 19q13.32 · 45.4 Mb
Estimated prevalence by population
Global 55.4%; European 42.1%; African 78.7%; East Asian 90.9%; South Asian 43.3%; Americas 59.4%; Ashkenazi 42.0%; Finnish 39.7%; Middle Eastern 40.0%; Amish 23.7%.
Estimated CC genotype frequency.
Global 36.3%; European 45.6%; African 20.0%; East Asian 8.9%; South Asian 45.0%; Americas 35.3%; Ashkenazi 45.6%; Finnish 46.6%; Middle Eastern 46.5%; Amish 50.0%.
Estimated CT genotype frequency.
Global 8.3%; European 12.3%; African 1.3%; East Asian 0.2%; South Asian 11.7%; Americas 5.2%; Ashkenazi 12.4%; Finnish 13.7%; Middle Eastern 13.5%; Amish 26.3%.
Estimated TT genotype frequency.
Showing effects for C/C genotype
Cancer & Oncology
General Cancer Risk
DNA Repair Capacity. Evidence: 3/10. Source: PMID 28707579. Efficient.
Urologic Cancers
Bladder Cancer. Evidence: 4/10. Source: PMID 19846926. Typical Risk.
Breast Cancer
Breast Cancer. Evidence: 4/10. Source: PMID 29544444. Typical Risk.
Pharmacogenomics
Chemotherapy Response
Chemotherapy Response. Evidence: 6/10. Source: PMID 21826087. Typical Response.
Showing effects for C/T genotype
DNA Repair Capacity. Evidence: 3/10. Source: PMID 28707579. Typical.
Chemotherapy Response. Evidence: 6/10. Source: PMID 21826087. Variable Response.
Showing effects for T/T genotype
DNA Repair Capacity. Evidence: 3/10. Source: PMID 28707579. Reduced.
Bladder Cancer. Evidence: 4/10. Source: PMID 19846926. Increased Risk.
Breast Cancer. Evidence: 4/10. Source: PMID 29544444. Increased Risk.
What this genotype means for the people who carry it
Sample genotype: CC (Homozygous)
Inheriting two copies of the C allele ensures the production of the standard aspartate amino acid at position 312 of the ERCC2 helicase [1]. This wild-type form of the enzyme maintains optimal nucleotide excision repair capacity, allowing the body to efficiently correct DNA damage from environmental toxins and UV light [1]. Consequently, this genotype is associated with a typical baseline risk for bladder, breast, and lung cancers [2] [3]. In the context of cancer treatment, clinical studies suggest that individuals with this genotype experience standard efficacy and toxicity profiles when treated with platinum-based chemotherapies like cisplatin [4]. It is the most common genotype globally, providing a stable foundation for genomic maintenance.
Optimal DNA repair capacity; Typical baseline risk for several cancers; Standard response to platinum-based chemotherapy.
Sample genotype: CT (Heterozygous)
Possessing one copy of each allele means the body produces both the standard aspartate and the variant asparagine forms of the ERCC2 enzyme [1]. This hybrid state typically provides sufficient DNA repair capacity to protect against everyday environmental DNA damage [1]. Most epidemiological studies show that this heterozygous genotype does not significantly elevate the risk of developing bladder or breast cancers compared to the general population [2] [3]. However, in the realm of pharmacogenomics, this genotype is associated with variable outcomes during chemotherapy [4]. Some studies indicate an increased likelihood of survival with cisplatin, while others note a higher risk of side effects like neutropenia or lung inflammation [4] [5]. Overall, this genotype represents a common, intermediate genetic profile with minimal impact on daily health.
Intermediate DNA repair capacity; Typical baseline cancer risk; Variable sensitivity to chemotherapy agents.
Sample genotype: TT (Homozygous)
Inheriting two copies of the T allele results in the exclusive production of the asparagine variant of the ERCC2 helicase [1]. This structural change is associated with a slightly reduced capacity to repair bulky DNA adducts and damage caused by environmental carcinogens [1]. Meta-analyses have linked this genotype to a modest increase in susceptibility to bladder, breast, and gastric cancers, particularly when combined with environmental exposures like smoking [2] [3] [4]. Conversely, this reduced repair capacity can make cancer cells more vulnerable to DNA-damaging chemotherapy drugs [5]. Clinical research shows that individuals with this genotype may experience altered survival rates but also a higher risk of toxicities, such as anemia, when treated with cisplatin or other platinum compounds [5] [6]. It is a relatively common genetic variant that highlights the delicate balance between environmental exposures and cellular repair.
Slightly reduced DNA repair efficiency; Modestly increased risk for certain cancers; Altered sensitivity and toxicity risk with chemotherapy.
Variants with shared genetic architecture
rs13181 · ERCC2 Gene · Chr 19 · Melanoma Risk
rs238406 · ERCC2 Gene · Chr 19 · Chemotherapy Toxicity Risk
rs11615 · ERCC1 Gene · Chr 19 · DNA Repair and Cancer Risk
The Involvement of ERCC2/XPD and ERCC6/CSB Wild Type Alleles in Protection Against Aging and Cancer.
Contribution of DNA Repair Xeroderma Pigmentosum Group D Genotype to Gastric Cancer Risk in Taiwan.
Content updated August 2026.
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