CYP2D6 rs34097093: Understanding This Genetic Variant
The rs34097093 variant is a genetic marker located within the CYP2D6 gene region, which is responsible for producing enzymes that metabolize many common medications. While initially cataloged as a stop-gain variant, current scientific literature suggests this specific variant may be a false positive resulting from genomic sequencing artifacts.
What each genotype means
Normal enzyme activity
This genotype represents the most common form of the gene, where both copies are expected to produce functional CYP2D6 enzyme. Individuals with this profile are typically classified as normal metabolizers for drugs processed by this pathway. Please discuss any medication dosing or concerns with your clinician or pharmacist.
This is the most common genotype found in the vast majority of the global population.
Reduced enzyme activity
This genotype indicates that one copy of the gene carries the R378X stop-gain variant, which results in a non-functional enzyme, while the other copy is functional. This may lead to altered metabolism of certain antidepressants and antipsychotics. Please consult your healthcare provider or pharmacist to determine if this impacts your specific medication regimen.
This genotype is rare, occurring in less than 0.2% of the population based on the variant's overall frequency.
Inactive enzyme activity
This genotype indicates that both copies of the gene carry the R378X stop-gain variant, which prevents the production of a functional CYP2D6 enzyme. This status is associated with a poor metabolizer phenotype, which can significantly affect how your body processes specific psychiatric medications. You should discuss this result with your clinician or pharmacist to ensure your treatment plan is appropriate for your metabolism.
This genotype is extremely rare, occurring in significantly less than 0.1% of the population.
What is rs34097093 and Where is it Located?
The rs34097093 variant is a single-nucleotide polymorphism (SNP) historically associated with the CYP2D6 gene. This gene is located on chromosome 22 and encodes the cytochrome P450 2D6 enzyme, a critical protein involved in the breakdown of approximately 20% of clinically used drugs. In genetic databases, rs34097093 has been studied for its potential to alter protein function. However, the genomic region surrounding CYP2D6 is notoriously complex, containing highly similar pseudogenes like CYP2D7. Because of this structural similarity, researchers have identified that some variants reported in this region may not be true biological mutations but rather technical errors caused by the misaligning of DNA sequences during the sequencing process. Consequently, rs34097093 is frequently flagged in scientific literature as a suspected false positive.
The Role of CYP2D6 in Drug Metabolism
The CYP2D6 enzyme is a cornerstone of pharmacogenomics, the study of how genes influence an individual's response to medications. It is responsible for metabolizing a wide array of drugs, including antidepressants, antipsychotics, beta-blockers, and certain pain medications. Individuals are often categorized into metabolizer phenotypes—such as poor, intermediate, extensive, or ultrarapid—based on the functional capacity of their CYP2D6 enzymes. These phenotypes are determined by the presence of various star (*) alleles, which represent different functional versions of the gene. When an individual carries alleles that result in absent or reduced enzyme function, they may experience altered drug concentrations in their bloodstream, potentially leading to either reduced therapeutic efficacy or an increased risk of adverse drug reactions. Understanding one's specific CYP2D6 profile is a key component of personalized medicine.
Evidence and Scientific Consensus
The evidence supporting the clinical significance of rs34097093 is limited and controversial. While some early cataloging efforts identified it as a stop-gain variant (R378X) that could theoretically lead to an inactive enzyme, subsequent research has cast significant doubt on its validity. Specifically, studies have noted that the presence of paralogous sequences—DNA segments that are nearly identical to the target gene—can lead to artifacts in genomic data. Because of these technical challenges, rs34097093 is not widely recognized by major clinical pharmacogenomics consortia as a reliable marker for predicting drug response. Unlike well-established variants such as CYP2D6*4 or *41, which have robust clinical evidence, rs34097093 lacks the validation required to be used in clinical decision-making. Researchers emphasize that caution is necessary when interpreting data for this specific SNP.
What You Can and Cannot Do With This Information
If you have received a report mentioning rs34097093, it is important to understand that this information is not a substitute for professional medical advice. Because the scientific community suspects this variant may be a sequencing artifact, it should not be used to make decisions about your medication or dosage. You cannot use this SNP to diagnose a condition or predict how you will respond to a specific antidepressant or antipsychotic. If you are concerned about how your body processes medication, or if you are experiencing side effects, you should consult your physician or a pharmacist. They can provide guidance based on established clinical guidelines and, if necessary, order validated pharmacogenetic testing that looks for confirmed, clinically relevant variants rather than suspected artifacts.
How common is this variant?
The frequency of this variant is reported as less than 0.1% in most populations. Its rarity, combined with the technical challenges of sequencing the CYP2D6 region, contributes to the difficulty in verifying its true prevalence.
Frequently asked questions
Is rs34097093 a reliable marker for drug metabolism?
No, current scientific consensus suggests that rs34097093 may be a false positive caused by technical artifacts in genomic sequencing. It is not considered a reliable marker for clinical pharmacogenomics.
Should I change my medication based on this SNP?
Absolutely not. You should never change your medication or dosage based on genetic information without consulting your doctor. Always discuss your concerns with a healthcare professional.
Why is the CYP2D6 gene so difficult to study?
The CYP2D6 gene is located in a complex genomic region that includes highly similar pseudogenes. This structural similarity makes it difficult for sequencing technologies to accurately distinguish between the functional gene and non-functional copies.
What are the established CYP2D6 variants?
Established variants are categorized into star (*) alleles, such as *3, *4, *5, and *41. These have been extensively studied and are recognized by clinical guidelines for their impact on enzyme function.
Sources & further reading
Educational information only, last refreshed 9/18/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Core variant defining the nonfunctional CYP2D6*7 allele causing loss of cytochrome P450 2D6 catalytic activity and poor drug clearance.
This CYP2D6 intronic marker in the CYP2D cluster influences metabolic conversion rate of tamoxifen and codeine in clinical cohorts.
Defining nucleotide substitution of CYP2D6*8 leading to a premature stop codon and complete loss of drug metabolic capacity.
Defining single nucleotide variant of CYP2D6*6 (c.1707delT) causing a frameshift that results in a completely nonfunctional cytochrome P450 2D6 enzyme.
Part of the defining core haplotype of the CYP2D6*2 and CYP2D6*10 alleles, modulating basal enzymatic expression and activity.
Defines the non-functional CYP2D6*6 allele caused by a single nucleotide deletion (c.1707delT) leading to a frameshift and impaired metabolism of substrates like codeine and tamoxifen.