DISEASE

Urea cycle disorders (UCDs)

,

What is it?

Urea cycle disorders (UCDs) are a group of genetic conditions that affect the function of proteins and enzymes involved in the urea cycle, which is responsible for removing ammonia from the bloodstream. These disorders result from inherited deficiencies in one of the six enzymes or two transporter molecules of the urea cycle pathway. Normally, ammonia is converted to urea and excreted by the kidneys. However, in UCDs, the impaired urea cycle leads to the accumulation of ammonia in the blood, which can cause hyperammonemia and damage various organs, particularly the brain.

What are its symptoms?

Urea cycle disorders (UCDs) are a group of genetic conditions that affect the function of proteins and enzymes involved in the urea cycle, which is responsible for removing ammonia from the bloodstream. These disorders result from inherited deficiencies in one of the six enzymes or two transporter molecules of the urea cycle pathway. Normally, ammonia is converted to urea and excreted by the kidneys. However, in UCDs, the impaired urea cycle leads to the accumulation of ammonia in the blood, which can cause hyperammonemia and damage various organs, particularly the brain.

What do I need to consider?

Urea cycle disorders require lifelong management and treatment to prevent hyperammonemic episodes and minimize the risk of complications. Treatment approaches include dietary modifications, such as protein restriction and supplementation of essential amino acids, as well as medications that help reduce ammonia levels and support urea production. In severe cases, emergency interventions like hemodialysis or hemofiltration may be necessary to rapidly remove excess ammonia from the blood. Early diagnosis and intervention are crucial to prevent long-term neurological damage and improve outcomes.

Downloads

No file for download

References

  • Mew NA. Urea Cycle Disorders. StatPearls. 2017. Available at: [https://www.ncbi.nlm.nih.gov/books/NBK482363](https://www.ncbi.nlm.nih.gov/books/NBK482363)
  • Häberle J. Urea cycle disorders: diagnosis, pathophysiology, and therapy. Adv Exp Med Biol. 2017;959:1-9.
  • Häberle J, et al. Suggested guidelines for the diagnosis and management of urea cycle disorders. Orphanet J Rare Dis. 2012;7:32.
  • Summar ML, et al. The diagnosis, symptoms, and management of urea cycle disorders. Pediatrics. 2001;108(4):E76.
  • Ah Mew N, et al. Urea Cycle Disorders Overview. In: Adam MP, et al., editors. GeneReviews®. University of Washington, Seattle; 2021.
  • Batshaw ML, et al. Amino Acid Metabolism Disorders. In: Kliegman RM, et al., editors. Nelson Textbook of Pediatrics. 21st ed. Elsevier; 2020. p. 2797-2798.