CYP2A6 rs1801272: Understanding Your Genetic Variant
The rs1801272 variant is a specific genetic change in the CYP2A6 gene that results in a non-functional enzyme. It is primarily studied for its association with reduced nicotine metabolism, which can influence how the body processes nicotine.
What each genotype means
Typical enzyme activity
You carry two reference copies at this site and do not have the non-functional CYP2A6*2 allele. Research indicates that this genotype is typically associated with expected, normal rates of CYP2A6-mediated nicotine and medication breakdown. If you are taking prescription medications metabolized by CYP2A6, discuss dosing with your clinician or pharmacist.
Carried by roughly 94% to 98% of people of European descent and over 99% of individuals of East Asian and African ancestries.
Intermediate metabolizer
You carry one non-functional CYP2A6*2 allele and one reference allele. Studies link this intermediate state to moderately slower nicotine metabolism and clearance compared to individuals with two functional alleles. If you take medications cleared by the CYP2A6 pathway or are using smoking cessation therapies, discuss dosing and monitoring with your clinician or pharmacist.
Carried by approximately 2% to 6% of people of European ancestry, but it is rare (<1%) in African and East Asian populations.
Poor metabolizer
You carry two copies of the non-functional CYP2A6*2 allele. Research indicates this genotype confers absent or severely decreased CYP2A6 catalytic activity, leading to substantially slower nicotine metabolism. Because altered CYP2A6 function may influence drug exposure, discuss any relevant medication dosing or smoking cessation strategies with your clinician or pharmacist.
Extremely rare across all global populations, occurring in fewer than 1 in 1,000 individuals worldwide.
What is the rs1801272 Variant?
The rs1801272 variant is a single nucleotide polymorphism (SNP) located within the CYP2A6 gene. In scientific literature, this specific change is often referred to as the CYP2A6*2 allele. At the molecular level, this variant causes a substitution of the amino acid leucine with histidine at position 160 (p.Leu160His). This structural change significantly impairs the enzyme's ability to function correctly. Because the CYP2A6 enzyme is responsible for breaking down various substances, including nicotine, this genetic alteration leads to a loss of catalytic activity. Individuals who carry this variant may produce an enzyme that is either less efficient or completely inactive compared to the standard, fully functional version of the protein. This makes rs1801272 a key focus in pharmacogenomics, the study of how genes affect a person's response to drugs and other compounds.
The Role of the CYP2A6 Gene
The CYP2A6 gene provides instructions for making an enzyme that belongs to the cytochrome P450 family. These enzymes are primarily found in the liver and are essential for metabolizing, or breaking down, a wide range of substances, including medications and environmental toxins. CYP2A6 is specifically recognized as the primary enzyme responsible for the metabolic inactivation of nicotine in humans. By converting nicotine into cotinine, the enzyme helps the body clear nicotine from the bloodstream. When the CYP2A6 gene contains variants like rs1801272, the resulting enzyme may have reduced or absent activity. This can lead to slower nicotine metabolism, meaning nicotine stays in the system for a longer duration. While this gene is most famous for its role in nicotine processing, it also plays a part in the metabolism of other substrates, such as certain medications, though the clinical significance for those drugs is still being researched.
Research and Clinical Associations
Research into rs1801272 has consistently linked the variant to a 'slow metabolizer' phenotype. Studies have shown that individuals who are homozygous for this variant—meaning they carry two copies of the non-functional allele—exhibit significantly reduced nicotine metabolism. This has been a subject of interest in smoking cessation research, as the rate at which a person metabolizes nicotine can influence their smoking behavior and their response to cessation therapies. However, it is important to note that the evidence regarding the clinical impact of this variant on specific health outcomes remains limited. While the biochemical effect on the enzyme is well-documented, the real-world implications for individual health or treatment success are complex and influenced by many other genetic and environmental factors. Current research continues to explore how this variant interacts with other genetic markers to influence overall metabolic profiles.
Population Frequency
The frequency of the rs1801272 variant varies significantly across different ancestral groups. In European populations, the minor allele frequency is typically observed between 1% and 3%. Conversely, the variant is considered very rare in African and East Asian populations. Because of these differences, the prevalence of the slow metabolizer phenotype associated with this variant is not uniform globally. Researchers use these frequency data to better understand the distribution of metabolic traits across diverse human populations. It is worth noting that even within populations where the variant is more common, the majority of individuals still carry the fully functional version of the gene. Understanding these frequency patterns is a fundamental part of population genetics and helps scientists contextualize the impact of specific variants on a broader scale.
What This Information Means for You
Knowing your genotype for rs1801272 provides insight into your potential metabolic capacity for nicotine, but it does not serve as a medical diagnosis. Genetic information is only one piece of a much larger puzzle that includes your lifestyle, environment, and other genetic factors. If you are interested in how your genetics might influence your response to medications or your health, it is essential to consult with a qualified healthcare provider or a pharmacist. They can interpret your results in the context of your overall health history and provide guidance that is specific to your needs. Never make changes to your medication or health regimen based solely on genetic test results without professional medical advice. Your clinician can help you understand the limitations of current research and determine if any further testing or clinical action is appropriate for your situation.
How common is this variant?
The minor allele frequency for rs1801272 is approximately 0.01-0.03 in European ancestries and is very rare in African and East Asian populations.
Frequently asked questions
Does having the rs1801272 variant mean I cannot quit smoking?
No, having this variant does not mean you cannot quit smoking. While it may influence how your body processes nicotine, many factors contribute to smoking cessation success, and there are various evidence-based strategies available to help you.
Should I get tested for CYP2A6 variants?
Routine genetic testing for CYP2A6 is not currently standard medical practice for the general population. If you have concerns about how your body processes specific medications, discuss the potential benefits and limitations of pharmacogenetic testing with your doctor.
Can this variant affect how I process other medications?
CYP2A6 is involved in the metabolism of several substances, but the clinical significance of rs1801272 for most medications is still being studied. Always inform your healthcare provider about all medications you are taking so they can monitor for potential interactions.
Is rs1801272 the only variant that affects nicotine metabolism?
No, nicotine metabolism is a complex process influenced by multiple genetic variants in the CYP2A6 gene and other genes. The rs1801272 variant is just one of several known markers that can impact enzyme activity.
Sources & further reading
Educational information only, last refreshed 10/17/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Functional splice-site variant defining CYP2A6*20 associated with significantly reduced enzyme activity and slower nicotine and coumarin clearance.
Defining functional variant for the CYP2A6*2 allele (L160H) causing defective nicotine C-oxidation and slower metabolic nicotine clearance.
Functional variant in CYP2A6 defining the *9 allele with decreased transcriptional activity and reduced rate of nicotine metabolism.
Associated with the CYP2A6 locus and variation in rate of nicotine metabolism and cigarette consumption.
Functional polymorphism defining the CYP2A6*9 reduced-function promoter variant causing slower nicotine and cotinine metabolism.
Defining coding polymorphism for CYP2A6*8 (p.Arg365Gln), resulting in significantly decreased catalytic activity towards substrate medications including tegafur.