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Genetic and Rare Diseases Information Center (GARD)

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Dihydropyrimidine dehydrogenase deficiency

Other Names for this Disease
  • DPD deficiency
  • Familial pyrimidinemia
  • Hereditary thymine-uraciluria
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Your Question

My doctor has prescribed Fluorouracil to treat pre-cancerous spots on my hands. To my knowledge, I don't have any family history of dihydropyrimidine dehydrogenase (DPD) deficiency, but I have read that up to 8% of the population has some form of this, which can be problematic when Fluorouracil is used. Should I be tested prior to use and is there an alternative course of treatment? 

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

Why can't people who have dihydropyrimidine dehydrogenase (DPD) deficiency use certain types of chemotherapy?

People with dihydropyrimidine dehydrogenase (DPD) deficiency, including people who do not have signs and symptoms, are at risk for severe, toxic reactions to specific drugs called fluoropyrimidines, which are used in some chemotherapy regimes to treat cancer. Examples include 5-fluorouracil (5-FU) and capecitabine. People with DPD deficiency cannot effectively break down and eliminate these drugs from the body, so they can build up to toxic levels.[1]

Individuals with a partial DPD deficiency (about 3% to 5% of the population) due to sequence variations in DPYD gene, as well as people with one mutated copy of the DPYD gene (carriers), also may have limited ability to fully metabolize the drug.[1][2] It has been suggested that individuals with known DPD deficiency and/or a family history of known mutations in the DPYD gene avoid therapy with these drugs. These individuals may consider treatment regimens that do not contain 5-FU or other fluoropyrimidines (if available). In some cases, modified doses of these drugs may still be recommended.[2] 
Last updated: 11/28/2012

Are there alternative chemotherapy agents which can be safely used by people with dihydropyrimidine dehydrogenase (DPD) deficiency?

Fluoropyrimidines are only one of various types of chemotherapy drugs that may be used to treat an individual with cancer. Several factors influence which drugs may be used and may include the type of cancer; the stage of the cancer (how far it has spread); the patient’s age; the patient’s general state of health; other serious health problems; and/or types of cancer treatments given in the past.[3] We strongly encourage you to discuss your treatment options with your healthcare provider.

Information about different types of chemotherapy drugs is available on the American Cancer Society's Web site and can be viewed by clicking here.

Last updated: 11/28/2012

How can I find out if I have a mutation which puts me at risk for dihydropyrimidine dehydrogenase (DPD) deficiency?

GeneTests lists laboratories offering clinical genetic testing for this condition. Clinical genetic tests are ordered to help diagnose a person or family and to aid in decisions regarding medical care or reproductive issues. We encourage you to consult with your health care provider or a genetic professional to learn more about your testing options.
Last updated: 11/28/2012

How can I find a genetics professional in my area?

Genetics clinics are a source of information for individuals and families regarding genetic conditions, treatment, inheritance, and genetic risks to other family members. More information about genetic consultations is available from Genetics Home Reference. To find a genetics clinic, we recommend that you contact your primary healthcare provider for a referral.

The following online resources can help you find a genetics professional in your community:

Last updated: 11/28/2012