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Genetic and Rare Diseases Information Center (GARD)

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Ornithine transcarbamylase deficiency

Other Names for this Disease
  • Ornithine carbamoyltransferase deficiency
  • OTC deficiency
  • OTCD
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What causes ornithine transcarbamylase (OTC) deficiency?

Ornithine transcarbamylase (OTC) deficiency is caused by mutations in the OTC gene. OTC deficiency belongs to a class of genetic diseases called urea cycle disorders. The urea cycle is a sequence of reactions that occurs in liver cells. It processes excess nitrogen, generated when protein is used by the body, to make a compound called urea that is excreted by the kidneys. In OTC deficiency, the enzyme that starts a specific reaction within the urea cycle is damaged or missing. The urea cycle cannot proceed normally, and nitrogen accumulates in the bloodstream in the form of ammonia. Ammonia is especially damaging to the nervous system, so OTC deficiency causes neurological problems as well as eventual damage to the liver.[1]
Last updated: 3/4/2011

  1. Ornithine transcarbamylase deficiency. Genetics Home Reference (GHR). 2006; Accessed 3/4/2011.