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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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How is dihydropyrimidine dehydrogenase deficiency inherited?

Dihydropyrimidine dehydrogenase (DPD) deficiency is inherited in an autosomal recessive manner. This means that in affected individuals, both copies of the DPYD gene in each cell (one inherited from each parent) have mutations. The mutations that cause DPD deficiency vary widely in severity; therefore, some people with 2 mutated copies of the gene may have signs and symptoms of the condition, while others may be asymptomatic. However, all individuals with 2 mutations are at risk for toxic reactions to fluoropyrimidine drugs.[1]

Individuals who carry one mutated copy of the disease-causing gene (including most parents of affected individuals) are referred to as carriers. Carriers typically do not have signs and symptoms of the condition. However, people with one mutated copy of the DPYD gene may still experience toxic reactions to fluoropyrimidine drugs.[1]

When 2 carriers for the same autosomal recessive condition have children, each child has a 25% (1 in 4) risk to have the condition, a 50% (1 in 2) risk to be a carrier like each parent, and a 25% risk to not have the condition and not be a carrier. A child of one carrier parent has a 50% risk to also be a carrier.
Last updated: 8/20/2012

  1. Dihydropyrimidine dehydrogenase deficiency. Genetics Home Reference. November 2011; Accessed 11/28/2012.