DPYD rs11572103: Understanding This Rare Genetic Variant
The rs11572103 variant is a rare genetic change located within the DPYD gene, which is responsible for producing the enzyme that breaks down certain chemotherapy drugs. This specific variant is associated with reduced enzyme function, which may increase the risk of severe side effects when taking fluoropyrimidine medications.
What each genotype means
Normal enzyme activity
This genotype represents the most common form of the DPYD gene, which typically produces a functional dihydropyrimidine dehydrogenase enzyme. Individuals with this profile are generally expected to process pyrimidine-based medications like 5-fluorouracil and capecitabine at a standard rate. Always consult with your oncologist or pharmacist before starting any chemotherapy regimen to discuss appropriate dosing.
This is the most common genotype found in the vast majority of the global population.
Reduced enzyme activity
This genotype includes one copy of the rare DPYD*7 variant, which is associated with impaired breakdown of pyrimidines. Carriers may have a higher risk of experiencing severe side effects, such as neurotoxicity or low blood cell counts, when treated with fluoropyrimidine-based chemotherapy. It is essential to discuss this genetic finding with your healthcare provider, as they may need to adjust your medication dosage to ensure your safety.
This genotype is rare, occurring in less than 0.1% of individuals across worldwide populations.
Severely impaired enzyme activity
This genotype indicates the presence of two copies of the DPYD*7 variant, which significantly impairs the body's ability to break down pyrimidines. Individuals with this profile are at a substantially increased risk for life-threatening toxicity if exposed to fluoropyrimidine-based drugs. You must inform your medical team of this result immediately so they can consider alternative therapies or specialized dosing strategies.
This genotype is extremely rare, with a frequency significantly lower than 0.1% in all known populations.
What is the rs11572103 Variant?
The rs11572103 variant is a single nucleotide polymorphism (SNP) found in the DPYD gene. In genetics, a SNP represents a variation at a single position in the DNA sequence. This specific variant is also known as DPYD*7, which corresponds to a change in the protein structure where the amino acid leucine is replaced by phenylalanine at position 311 (p.Leu311Phe). Because this change occurs in the coding region of the gene, it can alter the structure and function of the resulting protein. Scientists track this variant because it is categorized as a non-functional or deleterious change, meaning it may prevent the body from processing certain substances as efficiently as it would with the standard, or wild-type, version of the gene.
The Role of the DPYD Gene
The DPYD gene provides instructions for making an enzyme called dihydropyrimidine dehydrogenase (DPD). This enzyme is essential for the normal breakdown of pyrimidines, which are building blocks of DNA and RNA. More importantly in a clinical context, DPD is the rate-limiting enzyme responsible for metabolizing fluoropyrimidines, a class of chemotherapy drugs that includes 5-fluorouracil (5-FU) and capecitabine. When the DPYD gene functions correctly, the body clears these drugs from the system at a predictable rate. However, if a person carries variants that impair DPD activity, these drugs can accumulate in the body to toxic levels. This accumulation is what leads to the severe adverse reactions, such as neurotoxicity and low blood cell counts (cytopenias), that researchers associate with DPD deficiency.
Research and Clinical Evidence
The evidence linking rs11572103 to clinical outcomes is currently considered limited. While major DPYD variants like *2A or D949V have well-established clinical guidelines for dose adjustment, rs11572103 is less frequently studied in large-scale prospective trials. Research indicates that it is a non-functional variant, and its presence is hypothesized to contribute to the overall risk profile of a patient receiving fluoropyrimidine therapy. Because it is rare, gathering enough data to definitively quantify the risk of toxicity for this specific variant remains a challenge for the scientific community. Clinicians and researchers continue to study such variants to better understand how they contribute to the spectrum of DPD deficiency, but it is not yet as widely utilized in standardized clinical screening protocols as the more common, high-impact variants.
Population Frequency
The rs11572103 variant is classified as rare, occurring in less than 0.1% of the global population. Because of its low frequency, it is not commonly encountered in the general population, and its distribution can vary significantly across different ancestral groups. Genetic databases like gnomAD provide insights into these frequencies, confirming that the variant is not a common feature of the human genome. Due to this rarity, most individuals will not carry this specific variant, and its impact is primarily relevant in the context of specialized pharmacogenetic testing for patients preparing for specific chemotherapy regimens.
Managing Your Genetic Information
If you have received information about your DPYD genotype, it is important to understand that genetic variants are only one piece of a complex health puzzle. Having a variant like rs11572103 does not mean you will automatically experience side effects, nor does the absence of it guarantee a reaction-free treatment. This information is intended for educational purposes and should never be used to make personal medical decisions or to alter prescribed treatments. If you are concerned about how your genetics might influence your response to medication, the most important step is to discuss these results with your oncologist or a clinical pharmacist. They can interpret your specific genetic profile in the context of your overall health and current treatment plan to ensure your care is as safe and effective as possible.
How common is this variant?
The rs11572103 variant is rare, with a frequency of less than 0.1% across worldwide populations.
Frequently asked questions
What is DPD deficiency?
DPD deficiency is a condition where the body lacks enough of the DPD enzyme to properly break down pyrimidines and certain chemotherapy drugs. This can lead to the accumulation of toxic drug levels in the body, causing severe side effects.
Should I get tested for DPYD variants?
Genetic testing for DPYD is typically recommended by oncologists for patients who are about to start treatment with fluoropyrimidine chemotherapy. You should discuss the necessity and clinical relevance of such testing with your healthcare provider.
Does having a DPYD variant mean I cannot have chemotherapy?
Not necessarily. If a patient is found to have a DPYD variant, doctors often use this information to adjust the dosage of the medication to a safer level. This is known as genotype-guided dosing.
Is rs11572103 the same as DPYD*2A?
No, they are different variants. DPYD*2A is a well-known, high-impact variant, while rs11572103 (DPYD*7) is a distinct, rarer variant with different clinical evidence levels.
Sources & further reading
Educational information only, last refreshed 9/29/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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This intronic variant is a marker for reduced DPYD enzyme activity, increasing the risk of severe toxicity from fluoropyrimidine-based chemotherapies.
This variant is linked to decreased dihydropyrimidine dehydrogenase activity, increasing the risk of severe toxicity during fluoropyrimidine chemotherapy.
Constitutes the DPYD*13 variant (p.Ile560Thr), associated with significantly reduced DPYD enzyme activity and increased risk of severe fluoropyrimidine toxicity.
Also designated as DPYD c.557A>G (p.Tyr186Cys), this variant significantly decreases dihydropyrimidine dehydrogenase activity and predisposes patients to severe fluoropyrimidine toxicity.
Causes the c.2846A>T (p.Asp949Val) missense change in DPYD, associated with reduced enzyme activity and increased risk of fluoropyrimidine-associated toxicity.
A synonymous variant in exon 11 (c.1236G>A) that is in high linkage disequilibrium with the causal intronic variant c.1129-5923C>G (rs75017182), which defines the HapB3 haplotype associated with reduced DPYD activity and fluoropyrimidine toxicity.