DPYD rs1057516894: What Your Genotype Means
The rs1057516894 variant is located within the DPYD gene, which provides instructions for the dihydropyrimidine dehydrogenase enzyme. This enzyme is essential for breaking down fluoropyrimidine chemotherapy drugs, and variations in this gene may influence how an individual processes these medications.
What each genotype means
Normal enzyme activity
This genotype is considered the wild-type or normal state for this position in the DPYD gene. Individuals with this profile are expected to have standard dihydropyrimidine dehydrogenase (DPD) enzyme activity, which is responsible for breaking down fluoropyrimidine chemotherapy drugs. You should discuss your treatment plan and any concerns about medication side effects with your oncologist or pharmacist.
This is the most common genotype observed across all major global populations.
Reduced enzyme activity
This genotype indicates you carry one copy of the variant allele, which is associated with partial DPD enzyme deficiency. Because your body may process fluoropyrimidine chemotherapy drugs more slowly than average, you may be at an increased risk for severe treatment-related toxicity. It is essential to discuss this result with your clinician or pharmacist, as they may consider dose adjustments to ensure your safety during treatment.
This genotype is relatively uncommon, typically found in a small percentage of the population depending on ancestral background.
Significantly reduced enzyme activity
This genotype indicates you carry two copies of the variant allele, which is associated with a significant reduction or potential absence of DPD enzyme activity. This may lead to a high risk of severe or life-threatening toxicity when receiving standard doses of fluoropyrimidine chemotherapy. You must consult with your healthcare provider or a clinical pharmacist before starting any treatment involving these medications to discuss necessary dose modifications or alternative therapies.
This genotype is rare in most populations.
Understanding the DPYD Gene
The DPYD gene is responsible for producing the enzyme dihydropyrimidine dehydrogenase (DPD). This enzyme plays a critical role in the body by catalyzing the rate-limiting step in the breakdown of uracil and thymine, which are natural building blocks of DNA and RNA. Beyond its role in normal metabolism, DPD is the primary enzyme responsible for metabolizing fluoropyrimidine drugs, such as 5-fluorouracil and capecitabine, which are commonly used in cancer chemotherapy. When the DPYD gene functions normally, the body can efficiently clear these drugs. However, if the gene contains variants that reduce or eliminate enzyme activity, these medications can accumulate in the bloodstream to toxic levels. This accumulation is a significant concern in clinical oncology, as it can lead to severe, potentially life-threatening side effects, including bone marrow suppression, gastrointestinal toxicity, and neurotoxicity.
What is the rs1057516894 Variant?
The rs1057516894 variant is a specific genetic change located within the DPYD gene. In the context of pharmacogenomics, researchers study such variants to determine if they correlate with altered drug metabolism. While some DPYD variants, such as *2A and *13, are well-established as markers for DPD deficiency, rs1057516894 is a variant cataloged in databases like ClinVar. Genetic variants are essentially 'spelling differences' in the DNA sequence. When these differences occur in a gene as important as DPYD, they may change the structure or expression of the resulting enzyme. Scientists monitor these variants to see if they predict how a patient will respond to specific chemotherapy regimens. Because the DPYD gene is large and complex, researchers continue to investigate whether this specific variant contributes to the variability in drug response observed among different patients.
Evidence and Clinical Significance
The evidence regarding the clinical impact of rs1057516894 is currently considered moderate. In the field of pharmacogenomics, the Clinical Pharmacogenetics Implementation Consortium (CPIC) provides guidelines for clinicians on how to adjust drug dosages based on a patient's DPYD genotype. While major variants like *2A have clear, evidence-based dosing recommendations, newer or less-studied variants like rs1057516894 are often the subject of ongoing research to determine their exact functional impact. It is important to note that not all genetic variants in DPYD result in clinical toxicity. Some variants may have no effect, while others may only slightly alter enzyme activity. Because of this, clinicians often look at a panel of variants rather than a single one to assess a patient's risk profile. If you are undergoing chemotherapy, it is essential to discuss any genetic testing results with your oncologist or a clinical pharmacist who can interpret these findings in the context of your specific treatment plan.
Population Frequency and Interpretation
Genetic variants in DPYD are found across all human populations, though their frequencies can vary significantly by ancestry. Some variants are more common in European populations, while others may be more prevalent in Asian or African populations. The rs1057516894 variant is noted as being common in ClinVar, which indicates that it has been frequently identified and submitted by laboratories. However, 'common' in a database does not necessarily mean the variant causes disease or severe drug reactions. It simply means it is a frequently observed genetic difference. Because the prevalence of DPD deficiency and the associated genetic markers can differ by ethnicity, researchers emphasize the need for population-specific studies to ensure that pharmacogenetic screening is accurate for everyone. Understanding your own genetic background is a powerful tool, but it should always be used in conjunction with professional medical guidance to make informed decisions about your health.
How common is this variant?
The rs1057516894 variant is documented as common in ClinVar, though specific allele frequencies can vary significantly across different global ancestral populations.
Frequently asked questions
Does having a DPYD variant mean I will have a bad reaction to chemotherapy?
Not necessarily. While certain DPYD variants are associated with an increased risk of toxicity, many factors influence how your body processes medication, including your overall health, other medications you take, and the specific chemotherapy drug used. Always consult your oncologist regarding your specific risk profile.
Should I get tested for DPYD variants before starting cancer treatment?
Pharmacogenetic testing for DPYD is increasingly used in clinical practice to help guide dosing for fluoropyrimidine drugs. You should discuss the potential benefits and limitations of this testing with your healthcare provider to see if it is appropriate for your treatment plan.
What should I do if I find out I have a DPYD variant?
If you have a known DPYD variant, it is important to share this information with your medical team immediately. They can use this information to adjust your dosage or select an alternative treatment to minimize the risk of side effects.
Is rs1057516894 the same as DPYD*2A?
No, rs1057516894 and DPYD*2A are different genetic markers. DPYD*2A is a well-studied variant with established clinical guidelines, whereas rs1057516894 is a distinct variant that may have different implications for enzyme function.
Sources & further reading
Educational information only, last refreshed 10/10/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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This intronic variant is a well-established marker for reduced DPYD enzyme activity, significantly increasing the risk of severe toxicity when patients are treated with fluoropyrimidine-based chemotherapies like 5-fluorouracil.
This variant is linked to decreased dihydropyrimidine dehydrogenase activity, increasing the risk of severe toxicity during fluoropyrimidine chemotherapy.
A rare but high-risk variant for severe adverse reactions to chemotherapy.
Dramatically increases risk of life-threatening toxicity from 5-FU chemotherapy.
Associated with significantly reduced metabolism of fluoropyrimidine drugs.
Defines the non-functional DPYD*7 variant (p.Leu311Phe) that severely impairs pyrimidine degradation, predisposing carriers to fluoropyrimidine neurotoxicity and cytopenias.