CYP2C9 rs2307243: Understanding This Genetic Variant
The rs2307243 variant is a rare genetic change located within the CYP2C9 gene. This gene is responsible for producing an enzyme that helps the body metabolize various medications, and variations in this gene may influence how individuals respond to certain drug therapies.
What each genotype means
Typical metabolic profile
This genotype represents the most common genetic sequence observed at this position. Research on this specific variant is limited, and it is currently classified as a rare variant in population databases. Please discuss any concerns regarding medication metabolism with your healthcare provider or pharmacist.
This is the most frequently observed genotype across global populations.
Rare variant carrier
You carry one copy of a rare genetic variant at this location. Because this variant is rare and evidence regarding its functional impact on drug metabolism is limited, its clinical significance remains uncertain. Always consult with your clinician before making changes to your medication regimen.
This genotype is rare and observed at very low frequencies in global population databases.
Rare variant carrier
You carry one copy of a rare genetic variant at this location. Current scientific literature provides limited evidence on how this specific change affects enzyme function or drug response. Please consult your pharmacist or doctor to discuss how your genetic profile may relate to your clinical care.
This genotype is rare and observed at very low frequencies in global population databases.
Rare variant homozygous
You carry two copies of a rare genetic variant at this location. The functional consequences of this genotype are not well-characterized in current research, and its clinical impact is currently unknown. Please discuss this finding with your healthcare provider to determine if it is relevant to your health.
This genotype is extremely rare in the general population.
Rare variant homozygous
You carry two copies of a rare genetic variant at this location. There is currently insufficient evidence to determine if this genotype influences drug metabolism or other biological processes. Please consult with a medical professional to interpret this result in the context of your overall health.
This genotype is extremely rare in the general population.
Rare variant compound heterozygote
You carry two different rare alleles at this location. The combined effect of these specific variants on your health or medication response is not established in current scientific literature. Please share this information with your doctor or pharmacist for professional guidance.
This genotype is extremely rare in the general population.
What is the rs2307243 Variant?
The rs2307243 variant is a specific single nucleotide polymorphism (SNP) found within the sequence of the CYP2C9 gene. In genetics, a SNP represents a variation at a single position in the DNA building blocks. The CYP2C9 gene is located on chromosome 10 and provides the blueprint for the cytochrome P450 2C9 enzyme. This enzyme is part of a large family of proteins that act as biological catalysts, primarily responsible for breaking down substances in the liver. Because rs2307243 is categorized as a rare variant, it is not as frequently studied or as common in the general population as other well-known CYP2C9 variants like *2 or *3. Researchers track these specific locations in the genome to understand how minor differences in DNA sequence might lead to differences in enzyme structure or function, which in turn can affect how the body processes foreign compounds, including therapeutic drugs.
The Role of the CYP2C9 Gene
The CYP2C9 gene is essential for the metabolism of a wide range of clinical drugs, including nonsteroidal anti-inflammatory drugs (NSAIDs), certain blood thinners like warfarin, and some antihypertensive medications. The enzyme produced by this gene functions in the endoplasmic reticulum of liver cells, where it performs chemical reactions to modify these drugs, often making them easier for the body to eliminate. When the CYP2C9 gene carries certain variants, the resulting enzyme may have reduced or altered activity. This can lead to changes in how quickly a drug is cleared from the bloodstream. If an enzyme is less efficient, a standard dose of a medication might remain in the system longer than intended, potentially increasing the risk of side effects. Conversely, if the enzyme is highly active, a drug might be cleared too quickly to be effective. Understanding these genetic differences is a core focus of pharmacogenomics, the study of how genes influence drug response.
Research and Evidence Strength
The current evidence regarding the clinical impact of the rs2307243 variant is considered limited. While many variants in the CYP2C9 gene have been extensively characterized—such as those defining the *2 and *3 star alleles—rs2307243 does not have the same depth of clinical data supporting its influence on drug metabolism. Scientific research often focuses on variants that are common enough to have a measurable impact on large populations. Because rs2307243 is rare, it is more difficult for researchers to gather enough data to definitively state how it affects drug response or clinical outcomes. While some studies investigate rare variants to build a more complete map of human genetic diversity, it is important to distinguish between a variant that has been identified and one that has been clinically validated as a predictor of drug response. Always consult with a healthcare provider or pharmacist regarding your specific genetic information and how it may relate to any medications you are prescribed.
Population Frequency and Interpretation
The rs2307243 variant is classified as rare, meaning it appears at a very low frequency across most human populations. Genetic frequency can vary significantly depending on ancestral background, and some variants that are rare globally may be more common in specific ethnic groups. Because this variant is not widespread, most individuals will carry the common, or 'wild-type,' version of the gene at this position. It is important to remember that having a rare variant does not automatically mean an individual will experience a clinical issue. Genetic testing provides information about your DNA, but it is only one piece of the puzzle. Factors such as age, liver function, diet, and other medications being taken simultaneously also play major roles in how the body processes drugs. This information should be used for educational purposes and discussed with a medical professional who can interpret your results in the context of your overall health and treatment plan.
How common is this variant?
The rs2307243 variant is documented as a rare variant in the CYP2C9 gene, appearing at low frequencies across global populations.
Frequently asked questions
What does it mean if I have a rare CYP2C9 variant?
Having a rare variant means your DNA sequence at that specific location differs from the most common version found in the population. It does not necessarily mean you will have a health problem, but it may be relevant to how your body processes certain medications.
Should I change my medication based on this result?
No. You should never change your medication or dosage based on genetic test results without consulting your doctor or pharmacist. They are the only ones who can safely evaluate your genetic data alongside your clinical history.
Is CYP2C9 testing standard for everyone?
Genetic testing for CYP2C9 is not standard for the general population. It is typically ordered by clinicians in specific scenarios, such as when a patient is starting a medication known to be metabolized by this enzyme and the doctor wants to optimize the dosage.
Where can I find more information about my specific genotype?
You can discuss your results with a genetic counselor or your primary care physician. They can help you understand the clinical significance of your findings and whether any further action is needed.
Sources & further reading
Educational information only, last refreshed 9/25/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Get my report — $29Related variants in CYP2C9
Defining the CYP2C9*3 (p.Ile359Leu) allele, this variant markedly decreases enzymatic activity, requiring reduced dosages for warfarin and phenytoin to prevent toxicity.
The CYP2C9*3 allele significantly reduces enzyme activity, necessitating dose adjustments for drugs like warfarin and phenytoin to avoid toxicity.
The CYP2C9*2 variant results in reduced enzymatic activity, which is a critical factor in determining appropriate dosing for warfarin and other substrates.
Defines the CYP2C9*4 missense variant (p.Ile359Thr) which leads to reduced clearance of warfarin and phenytoin.
Defines the CYP2C9*6 null allele resulting from an 818delA frameshift that completely abolishes catalytic activity.
Defines the CYP2C9*5 missense variant (p.Asp360Glu) leading to markedly decreased metabolic activity toward warfarin and nonsteroidal anti-inflammatory drugs.