Please ensure JavaScript is enabled for purposes of website accessibility Understanding Ornithine Transcarbamylase Deficiency | For HCPs

OTC Deficiency OTC Deficiency, The Most Common Urea Cycle Disorder Subtype

Ornithine transcarbamylase (OTC) deficiency, like other UCD subtypes, results in elevated ammonia levels, putting patients at risk of neurological complications and hyperammonemic crisis.1

late-onset-urea-cycle-disorder-prevalence-chart
late-onset-urea-cycle-disorder-prevalence-chart

Ornithine transcarbamylase (OTC) deficiency, or OTCD, is the most common subtype of urea cycle disorder (UCD).1

OTC deficiency may be life-threatening at any age. Triggers such as protein consumption, exercise, puberty, menstruation, pregnancy/postpartum, menopause, and stress may lead to toxic levels of ammonia or hyperammonemic crises.4-8 Prognosis for UCDs can vary. A study found that the 11-year survival rate for urea cycle defects was reported as 35% for early-onset hyperammonemia and 87% for late-onset hyperammonemia.9

OTC-Deficiency-in-females-desk
OTC-Deficiency-in-females-desk-mobile

High ammonia levels could be a UCD symptom in adults.8

Although OTC deficiency is an X-linked disorder, heterozygous females may also experience late-onset UCD signs such as elevated ammonia levels. Heterozygous OTC deficiency may also present outside of childhood with nonspecific symptoms including lethargy, headaches and protein aversion.8

Metabolic-Specialist-icon

Find a Metabolic Specialist in Your Area

Connect your patient with a provider experienced in diagnosing and treating UCDs

Info-icon

Resources for Your Practice

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

  • References

    1. Lichter-Konecki U, Caldovic L, Morizono H, Simpson K. Ornithine transcarbamylase deficiency. In: Adam MP, Ardinger HH, et al, eds. GeneReviews®. Seattle, WA: University of Washington, Seattle; 1993-2019. 2. Summar ML, Koelker S, Freedenberg D, et al. The incidence of urea cycle disorders. Mol Genet Metab. 2013;110(1-2):179-180. 3. Stone WL, Basit H, Jaishankar GB. Urea Cycle Disorders. StatPearls Publishing; 2022. 4. Anstey JR, Haydon TP, Ghanpur RB, de Jong G. Initial presentation of a urea cycle disorder in adulthood: an under-recognised cause of severe neurological dysfunction. Med J Aust. 2015;203(11):445-447. 5. Machado MC, Pinheiro da Silva F. Hyperammonemia due to urea cycle disorders: a potentially fatal condition in the intensive care setting. J Intensive Care. 2014;2(1):22. 6. Fassier T, Guffon N, Acquaviva C, D’Amato T, Durand DV, Domenech P. Misdiagnosed postpartum psychosis revealing a late-onset urea cycle disorder. Am J Psychiatry. 2011;168(6):576-580. 7. Childress K, Robart S, Mofidi S, Regard M, Kronn D, Focseneanu M. Urea cycle disorders in the pubertal female and the role of hormone therapy. J Pediatr Adolesc Gynecol. 2014;27(2):e46-e47. 8. Häberle J, Boddaert N, Burlina A, et al. Suggested guidelines for the diagnosis and management of urea cycle disorders. Orphanet J Rare Dis. 2012;7:32. 9. Summar ML, Dobbelaere D, Brusilow S, Lee B. Diagnosis, symptoms, frequency and mortality of 260 patients with urea cycle disorders from a 21-year, multicentre study of acute hyperammonaemic episodes. Acta Paediatr. 2008;97(10):1420-1425.