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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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Tests & Diagnosis

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How is dihydropyrimidine dehydrogenase (DPD) deficiency diagnosed?

DPD deficiency may be diagnosed in various ways. In individuals with complete or profound DPD deficiency, laboratory testing can detect elevated levels of uracil and/or thymine in plasma or urine. Partial DPD deficiency is more difficult to detect, which has led to the development of a radioenzymatic test for the DPD enzyme. This test has remained the gold standard for diagnosing DPD deficiency even after the development of genetic testing for the condition, because of the complexity of the DPYD gene and the presence of multiple DNA sequence variations present in most affected individuals. Various types of cells and tissues can be examined this way.[1] More recently, a rapid, noninvasive, and cost-effective breath test was developed. This test permits the evaluation of DPD activity (normal activity and partial or profound deficiency) before the administration of fluoropyrmidine drugs such as 5-FU.[1]
Last updated: 8/20/2012

  1. Ezzeldin H, Diasio R. Dihydropyrimidine dehydrogenase deficiency, a pharmacogenetic syndrome associated with potentially life-threatening toxicity following 5-fluorouracil administration. Clin Colorectal Cancer. September 2004; 4(3):181-189.


  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.