What you carry at this position in your DNA and what research says about it.
Carbamazepine Side Effects: 5/10 evidence, 28 publications.
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Sample genotype (not yours): G/G
Typical Carbamazepine Side Effect Risk
This genotype is associated with standard clearance of carbamazepine and a typical risk of neurological side effects. However, it may carry an increased risk of anemia during certain chemotherapy regimens.
What this genotype means: Typical carbamazepine clearance; Standard risk of neurological side effects; Potentially higher risk of chemotherapy-induced anemia.
Sample genotype (not yours): A/A
Higher Carbamazepine Side Effect Risk
Carrying two copies of the A allele is associated with an increased risk of neurological side effects from carbamazepine and slower metabolism of apixaban.
What this genotype means: Increased risk of carbamazepine side effects; Slower metabolism of apixaban; Lower risk of chemotherapy-induced anemia.
Sample genotype (not yours): G/A
Carrying one copy of the A allele is linked to a higher risk of neurological side effects when taking carbamazepine. It may also result in slower metabolism of certain medications like deferasirox and apixaban.
What this genotype means: Increased risk of carbamazepine side effects; Slower metabolism of deferasirox and apixaban; Lower risk of chemotherapy-induced anemia.
Gene function and biological role
Gene Function: The ABCC2 gene encodes multidrug resistance-associated protein 2, a critical cellular efflux transporter [1]. This protein is primarily expressed in the liver, kidneys, and blood-brain barrier, where it pumps metabolic waste products and foreign substances out of cells [1] [2]. By actively transporting compounds into bile or urine, it plays a vital role in detoxification and drug clearance [2]. Variations in this gene can significantly alter how the body processes and eliminates various medications [2].
Variant Impact: The rs2273697 variant is a missense mutation in the ABCC2 gene that changes the amino acid at position 417 from valine to isoleucine [3]. This specific structural alteration directly impacts the transport efficiency of the encoded protein [3]. Functional studies demonstrate that the change selectively reduces the transporter's ability to pump certain medications across cell membranes [3]. Consequently, drugs that are substrates for this transporter can accumulate in tissues, potentially altering their efficacy and increasing the risk of adverse reactions [3].
Key Insight: This variant alters the blood-brain barrier's ability to pump out certain medications, leading to localized drug accumulation in the brain and a higher risk of neurological side effects.
Location: ABCC2. Chromosome 10 · 10q24.2 · 99.8 Mb
Estimated prevalence by population
Global 66.4%; European 64.1%; African 66.9%; East Asian 81.8%; South Asian 53.5%; Americas 70.9%; Ashkenazi 63.1%; Finnish 70.8%; Middle Eastern 65.9%; Amish 77.1%.
Estimated GG genotype frequency.
Global 30.1%; European 31.9%; African 29.8%; East Asian 17.3%; South Asian 39.3%; Americas 26.6%; Ashkenazi 32.7%; Finnish 26.7%; Middle Eastern 30.6%; Amish 21.4%.
Estimated GA genotype frequency.
Global 3.5%; European 4.0%; African 3.3%; East Asian 0.9%; South Asian 7.2%; Americas 2.5%; Ashkenazi 4.2%; Finnish 2.5%; Middle Eastern 3.5%; Amish 1.5%.
Estimated AA genotype frequency.
Showing effects for G/G genotype
Pharmacogenomics
Antiepileptic & Mood-Stabilizer Response
Carbamazepine Response. Evidence: 5/10. Source: PMID 20216337. Typical Risk.
Drug Metabolism Enzyme Activity
Deferasirox Metabolism. Evidence: 6/10. Source: PMID 25348619. Typical.
Chemotherapy Response
Chemotherapy Toxicity. Evidence: 5/10. Source: PMID 29507678. Increased Anemia Risk.
Anticoagulant & Blood Thinner Response
Apixaban Metabolism. Evidence: 5/10. Source: PMID 41187610. Typical.
Showing effects for A/A genotype
Carbamazepine Response. Evidence: 5/10. Source: PMID 20216337. Increased Risk.
Chemotherapy Toxicity. Evidence: 5/10. Source: PMID 29507678. Typical Risk.
Apixaban Metabolism. Evidence: 5/10. Source: PMID 41187610. Slower Metabolism.
Showing effects for G/A genotype
Deferasirox Metabolism. Evidence: 6/10. Source: PMID 25348619. Slower Metabolism.
What this genotype means for the people who carry it
Sample genotype: GG (Homozygous)
This genotype represents the standard genetic baseline for the ABCC2 transporter. Individuals with this genotype typically process and transport the anticonvulsant medication carbamazepine normally, avoiding the elevated risk of central nervous system side effects seen in carriers of the variant allele [1]. However, clinical research indicates that during breast cancer chemotherapy regimens containing fluorouracil, doxorubicin, and cyclophosphamide, this genotype is associated with a higher risk of developing anemia [2]. Additionally, some studies suggest that this genotype may correlate with decreased survival outcomes when treated with imatinib for gastrointestinal stromal tumors [3]. Overall, drug transport functions at a standard baseline level for most medications.
Typical carbamazepine clearance; Standard risk of neurological side effects; Potentially higher risk of chemotherapy-induced anemia.
Sample genotype: AA (Homozygous)
Carrying two copies of the variant A allele leads to a more pronounced reduction in the transport activity of the ABCC2 protein [1]. This functional impairment prevents the efficient efflux of carbamazepine across the blood-brain barrier, leading to localized drug accumulation and a higher incidence of neurological adverse reactions [1]. Research also indicates that this genotype is associated with slower clearance of the blood thinner apixaban, which could potentially influence its therapeutic levels [2]. Conversely, this genotype avoids the increased risk of chemotherapy-induced anemia associated with the G/G genotype during breast cancer treatment [3]. Understanding these transport differences can help clinicians personalize medication choices and monitoring strategies.
Increased risk of carbamazepine side effects; Slower metabolism of apixaban; Lower risk of chemotherapy-induced anemia.
Sample genotype: GA (Heterozygous)
Carrying one copy of the variant A allele alters the function of the ABCC2 transporter, reducing its ability to pump carbamazepine out of brain tissue [1]. Clinical studies have demonstrated that this reduction in transport efficiency significantly increases the risk of central nervous system side effects, such as dizziness and ataxia, in patients treated with carbamazepine [1]. Furthermore, this genotype has been associated with slower metabolism of the iron-chelating drug deferasirox and the anticoagulant apixaban [2] [3]. On the other hand, individuals with this genotype may have a lower risk of developing anemia when undergoing specific breast cancer chemotherapy regimens compared to those with the G/G genotype [4].
Increased risk of carbamazepine side effects; Slower metabolism of deferasirox and apixaban; Lower risk of chemotherapy-induced anemia.
Variants with shared genetic architecture
rs3740066 · ABCC2 Gene · Chr 10 · Pregnancy Liver Health
rs717620 · ABCC2 Gene · Chr 10 · Medication Response
rs8187710 · ABCC2 Gene · Chr 10 · Chemotherapy Heart Risk
Apixaban kinetics could be influenced by sex, cytochrome P450 enzymes and SLC6A2 transporter.
Influence of single-nucleotide polymorphisms on deferasirox C trough levels and effectiveness.
Content updated August 2026.
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