Please ensure JavaScript is enabled for purposes of website accessibility Navigating the Types of Urea Cycle Disorders | A Guide for HCPs

UCD Subtypes Eight Subtypes of Urea Cycle Disorders

There are 8 subtypes of urea cycle disorders (UCDs) identified based on the affected enzyme or transporter.1-3

You Are Leaving UCDinMind.com

You are about to go to an external website operated by an independent third party. Your activities at the external website will be managed by their policies and practices. By clicking “Continue,” you will go to the external website.

Continue

Process of Protein Degradation

A urea cycle disorder (UCD) affects the process of protein degradation in the body.1,2 When protein is broken down into amino acids, any excess nitrogen is converted into ammonia, which is then converted by the urea cycle into urea for safe removal from the body.2,3

Eight Subtypes of Urea Cycle Disorders

  1. Ornithine transcarbamylase (OTC) deficiency
  2. Carbamoyl phosphate synthetase 1 (CPS1) deficiency
  3. Argininosuccinate synthetase (ASS) deficiency or citrullinemia type 1 (CTLN1)
  4. Argininosuccinate lyase (ASL) deficiency
  5. Arginase-1 (ARG) deficiency
  6. N-acetylglutamate synthase (NAGS) deficiency
  7. Hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome or ornithine deficiency
  8. Citrulline deficiency or citrullinemia type II (CTLN2)

All UCD deficiencies except OTC are inherited in an autosomal recessive manner. OTC deficiency is inherited in an X-linked manner.3

learn-about-otd

Learn About OTC Deficiency

Review the most common UCD subtype

Explore OTC Deficiency
Info-icon

Resources for Your Practice

Access resources for your practice to help in the diagnosis of UCDs

View Provider Resources
  • References

    1. Matsumoto S, Häberle J, Kido J, Mitsubuchi H, Endo F, Nakamura K. Urea cycle disorders-update. J Hum Genet. 2019;64(9):833-847. 2. National Organization for Rare Disorders (NORD). The Physician’s Guide to Urea Cycle Disorders. Accessed March 23, 2020. https://rarediseases.org/physician-guide/urea-cycle-disorders 3. Ah Mew N, Simpson KL, Gropman AL, Lanpher BC, Chapman KA, Summar ML. Urea Cycle Disorders Overview. In: Adam MP, Mirzaa GM, Pagon RA, et al., eds. GeneReviews®. Seattle (WA): University of Washington, Seattle; April 29, 2003.