CYP2D6 rs72549352: Understanding Your Genetic Variant
The rs72549352 variant is a specific genetic change located within the CYP2D6 gene. It is a defining component of the CYP2D6*29 star allele, which is associated with altered enzyme activity and the metabolism of various clinical drugs.
What each genotype means
Normal enzyme activity
This genotype represents the absence of the specific genetic change associated with the CYP2D6*29 star allele. Individuals with this profile typically exhibit normal CYP2D6 enzyme function, though clinical drug response can still be influenced by other genetic and non-genetic factors. Please discuss any medication dosing concerns with your clinician or pharmacist.
This is the most common genotype globally, though frequencies vary significantly by ancestry.
Reduced enzyme activity
This genotype indicates you carry one copy of the variant associated with the CYP2D6*29 star allele, which is known to result in decreased enzyme activity. This may affect how your body processes certain medications, such as specific antidepressants or opioids, potentially leading to altered drug levels. Please consult your healthcare provider or pharmacist to determine if this impacts your current or future medication management.
This genotype is most frequently observed in individuals of African ancestry and is less common in other populations.
Significantly reduced enzyme activity
This genotype indicates you carry two copies of the variant associated with the CYP2D6*29 star allele, which is categorized as a reduced-function allele. Research suggests this may lead to a more pronounced decrease in the metabolism of CYP2D6-dependent drugs compared to those with one copy. Because this can influence the efficacy or safety of certain treatments, please discuss your specific genotype with your clinician or pharmacist before starting or adjusting medications.
This genotype is rare overall but is found primarily in populations of African ancestry.
What is rs72549352 and Where is it Located?
The rs72549352 variant is a single nucleotide polymorphism (SNP) situated within the CYP2D6 gene on chromosome 22. In the context of pharmacogenomics, this variant is recognized as a core marker for the CYP2D6*29 star allele. The CYP2D6 gene is highly polymorphic, meaning it contains many variations that can change how the body processes substances. Because this gene is located in a complex region of the genome that includes pseudogenes—non-functional segments of DNA that resemble the active gene—identifying specific variants like rs72549352 requires precise laboratory techniques. This SNP serves as a diagnostic anchor for researchers and clinicians to identify the presence of the *29 haplotype, which is one of many distinct genetic signatures that define how an individual's CYP2D6 enzyme might function compared to the standard or 'normal' version of the gene.
The Role of the CYP2D6 Gene
The CYP2D6 gene provides instructions for making an enzyme called cytochrome P450 2D6. This enzyme is primarily produced in the liver and is responsible for the metabolism, or breakdown, of approximately 25% of all clinically prescribed medications. This includes a wide range of drugs such as antidepressants, antipsychotics, beta-blockers, and certain opioids. Because the enzyme is so versatile, the efficiency with which it processes these drugs can vary significantly from person to person based on their inherited genetic makeup. Some individuals possess versions of the gene that produce highly active enzymes, while others have versions that result in reduced or absent enzyme activity. Understanding these variations is the foundation of pharmacogenomics, a field that aims to tailor medical treatments to an individual's genetic profile to improve efficacy and reduce the risk of adverse drug reactions.
Research Associations and Evidence Strength
Research associates the CYP2D6*29 allele, which contains the rs72549352 variant, with decreased enzymatic function. This means that individuals carrying this allele may metabolize certain drugs more slowly than those with normal-function alleles. The evidence strength for this association is considered moderate, as the clinical impact can depend on the specific drug being administered and the presence of other genetic variants on the second copy of the CYP2D6 gene. Because the CYP2D6 gene is so complex, the overall phenotype—the actual metabolic rate—is determined by the combination of both inherited alleles. While the *29 allele is well-documented in scientific literature as a reduced-function variant, it is important to note that clinical outcomes are not determined by this single SNP alone. Researchers continue to study how these specific genetic signatures correlate with real-world drug responses in diverse patient populations.
Population Frequency
The frequency of the CYP2D6*29 allele, and by extension the rs72549352 variant, varies significantly across different ancestral groups. It is most notably observed in populations of African descent, including Sub-Saharan African and African American groups, where it is more prevalent compared to European or East Asian populations. In many of these groups, the *29 allele is recognized as a common contributor to the overall landscape of reduced-function CYP2D6 activity. Because genetic diversity is high, the prevalence of this variant can also differ within specific regional or admixed populations. Understanding these frequency patterns is essential for researchers to ensure that pharmacogenetic studies and subsequent clinical guidelines are representative of the global population, helping to address health disparities in drug response and personalized medicine.
What You Can and Cannot Do With This Information
If you have information about your rs72549352 status, it is important to understand that this is not a medical diagnosis. Genetic data provides a piece of the puzzle regarding how your body might process certain medications, but it does not predict your exact response to any specific drug. You cannot use this information to self-prescribe, change your dosage, or discontinue any medication. If you are concerned about how a medication is affecting you, or if you are interested in how your genetics might influence your treatment plan, you should discuss this with your healthcare provider or a clinical pharmacist. They are trained to interpret pharmacogenetic results in the context of your full medical history, current medications, and other health factors. Always consult a professional before making any changes to your prescribed medical regimen.
How common is this variant?
The rs72549352 variant is found at low frequencies globally, though it is more commonly observed in populations of African ancestry as part of the CYP2D6*29 allele.
Frequently asked questions
Does having the rs72549352 variant mean I will have a bad reaction to drugs?
Not necessarily. While this variant is associated with reduced enzyme function, many factors influence drug response, including your overall genetic profile, diet, and other medications you may be taking.
Should I get a genetic test for CYP2D6?
Genetic testing for CYP2D6 is typically ordered by a physician when there is a specific clinical need, such as when a patient is not responding to a standard dose of a medication. You should discuss the necessity of such testing with your doctor.
Can I change my CYP2D6 genotype?
No, your genetic makeup is inherited and remains constant throughout your life. However, your doctor can adjust your medication or dosage based on your genetic profile to optimize your treatment.
Where can I find more information about my specific star allele?
The Pharmacogene Variation (PharmVar) Consortium is a primary resource for information on star alleles. You can also consult the Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines for clinical recommendations.
Sources & further reading
Educational information only, last refreshed 10/7/2026. Not medical advice — these associations describe population statistics, not individual predictions.
Curious what your genotype is for rs72549352?
Upload a raw DNA file from 23andMe, AncestryDNA, MyHeritage, or FamilyTreeDNA and see this variant — plus thousands more — interpreted in your full report.
Get my report — $29Related variants in CYP2D6
This variant is associated with altered metabolism of various medications, including antidepressants and antipsychotics.
This SNP is a well-established marker for reduced enzyme activity, impacting drug clearance rates.
This variant is associated with altered metabolism of various medications, including antidepressants and antipsychotics.
This variant is part of the complex CYP2D6 locus affecting the metabolism of numerous common medications.
Common variant in many populations causing poor drug metabolism.
A "null" variant causing a total lack of CYP2D6 enzyme activity.