CYP2C19 rs4986893: What Your Genotype Means
The rs4986893 variant is a specific genetic change within the CYP2C19 gene that results in a non-functional protein. This variant is associated with the 'poor metabolizer' phenotype, which can affect how an individual processes certain medications, including clopidogrel and proton pump inhibitors.
What each genotype means
Normal enzyme activity
This genotype represents the typical genetic sequence for this position in the CYP2C19 gene. Individuals with this result are generally expected to have normal enzyme function, though other genetic factors may still influence drug metabolism. Please discuss your medication management and any concerns about drug response with your clinician or pharmacist.
This is the most common genotype in most global populations, though the frequency of the alternative A allele varies significantly by ancestry.
Reduced enzyme activity
This genotype indicates you carry one copy of the CYP2C19*3 allele, which is associated with reduced or absent enzyme function. Research suggests this may lead to slower metabolism of certain medications, such as clopidogrel or specific antidepressants, potentially affecting their efficacy. You should consult your healthcare provider or pharmacist to determine if this result is relevant to your current or future medication regimen.
This genotype is more frequently observed in East Asian populations compared to European populations, where it is quite rare.
Poor metabolizer profile
This genotype indicates you carry two copies of the CYP2C19*3 allele, which results in a non-functional enzyme. This status is clinically recognized as a 'poor metabolizer' phenotype, which may significantly impact how your body processes drugs like clopidogrel, proton pump inhibitors, and certain antidepressants. It is important to share this information with your doctor or pharmacist, as they may need to adjust your medication selection or dosing.
This genotype is rare globally but is found at higher frequencies in East Asian populations compared to other ancestral groups.
Understanding the rs4986893 Variant
The rs4986893 variant, commonly referred to in scientific literature as the CYP2C19*3 allele, is a single nucleotide polymorphism (SNP) located on chromosome 10. Specifically, this variant involves a point mutation where a guanine (G) is replaced by an adenine (A) at a specific position in the gene. This change introduces a premature stop codon during the process of protein synthesis. Because the cell receives a signal to stop building the protein too early, the resulting CYP2C19 enzyme is truncated and non-functional. This loss of function is significant because the CYP2C19 enzyme is a critical component of the cytochrome P450 system, which is responsible for metabolizing a wide array of drugs in the liver. When this enzyme is absent or inactive, the body may not process these medications as expected, potentially leading to differences in drug efficacy or safety.
The Role of the CYP2C19 Gene
The CYP2C19 gene provides instructions for making an enzyme that plays a major role in the metabolism of many clinically important drugs. These include antiplatelet agents like clopidogrel, which requires activation by the enzyme to be effective, as well as various antidepressants, benzodiazepines, and proton pump inhibitors (PPIs) used for acid reflux. In a person with fully functional CYP2C19 enzymes, these drugs are processed at a standard rate. However, because rs4986893 creates a non-functional enzyme, individuals carrying this variant may be classified as intermediate or poor metabolizers depending on their other inherited alleles. For prodrugs like clopidogrel, which must be converted into an active form to work, a lack of functional enzyme can mean the medication is less effective. Conversely, for drugs that are deactivated by the enzyme, a lack of function might lead to higher levels of the drug remaining in the system, potentially increasing the risk of side effects.
Research and Clinical Evidence
Research into rs4986893 has primarily focused on its impact on pharmacogenomics—the study of how genes affect a person's response to drugs. Clinical studies have consistently identified this variant as a 'loss-of-function' allele. While the evidence linking this variant to altered drug metabolism is well-established in laboratory and clinical settings, the clinical impact can vary based on the specific medication and the individual's overall genetic profile. For example, studies have examined how this variant influences outcomes in patients taking clopidogrel for cardiovascular conditions. It is important to note that while genetic testing can provide insights into potential drug responses, it is only one factor among many, including age, diet, and other medications. The evidence strength for this variant is considered limited in some contexts because clinical outcomes are multifactorial. Always consult with your healthcare provider or pharmacist to discuss how your genetic information might relate to your specific treatment plan.
What You Can Do With This Information
If you have received results indicating you carry the rs4986893 variant, it is natural to have questions about what this means for your health. First and foremost, do not make any changes to your prescribed medications based on genetic test results alone. Genetic markers are tools that help clinicians understand potential variability in drug response, but they do not replace professional medical judgment. If you are concerned about how a medication is working for you, or if you are experiencing side effects, schedule an appointment with your doctor or pharmacist. They can interpret your results in the context of your full medical history and current prescriptions. They may consider alternative therapies or dosage adjustments if appropriate. Remember that this information is for educational purposes and is not a substitute for professional medical advice, diagnosis, or treatment.
How common is this variant?
The rs4986893 variant is significantly more common in East Asian populations, with allele frequencies ranging from approximately 5% to 9%, while it is rare in European populations, typically appearing at frequencies of less than 1%.
Frequently asked questions
What does it mean to be a 'poor metabolizer'?
A poor metabolizer has reduced or absent activity of a specific enzyme, in this case, CYP2C19. This means the body processes certain drugs much slower than average, which can affect how well the drug works or increase the risk of side effects.
Does having the rs4986893 variant mean my medication won't work?
Not necessarily. While this variant can affect how some drugs are processed, it does not mean a medication will be completely ineffective. Many factors influence drug response, and your doctor will consider your entire clinical picture.
Should I get tested for CYP2C19 variants?
Genetic testing for drug metabolism is typically ordered by a physician when there is a specific clinical need, such as when a patient is starting a medication known to be affected by these variants. Discuss the necessity of such testing with your healthcare provider.
Is rs4986893 the same as CYP2C19*3?
Yes, rs4986893 is the specific SNP identifier used in databases to represent the genetic change that defines the CYP2C19*3 allele. They refer to the same functional loss in the enzyme.
Sources & further reading
Educational information only, last refreshed 9/28/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Defines the CYP2C19*17 increased function allele, conferring rapid or ultrarapid metabolism for CPIC-actionable drugs including clopidogrel, PPIs, and SSRIs.
The CYP2C19*2 loss-of-function splicing defect results in impaired biotransformation of prodrugs including clopidogrel and altered clearance of proton pump inhibitors and select antidepressants.
Variant in the CYP2C19 locus associated with altered metabolism of clopidogrel and proton-pump inhibitors.
Defines the CYP2C19*8 loss-of-function variant (c.358T>C, p.Trp120Arg) which results in no enzymatic activity and impaired metabolism of CYP2C19 substrates.
Defines the CYP2C19*4 allele caused by an ATG start codon alteration that abolishes translation, resulting in reduced or absent drug metabolism capacity.
Known as CYP2C19*3, this premature stop codon (c.636G>A, p.Trp212Ter) results in a complete loss-of-function phenotype for clopidogrel and antidepressant metabolism.