Ornithine transcarbamylase (OTC) deficiency, like other UCD subtypes, results in elevated ammonia levels, putting patients at risk of neurological complications and hyperammonemic crisis.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
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
Connect your patient with a provider experienced in diagnosing and treating UCDs
Access resources for your practice to help in the diagnosis of UCDs
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.